Expert witness Simon Lay provides evidence on smoke control systems, focusing on the system installed at Grenfell Tower during refurbishment, design standards, and regulatory compliance.
00:00:26 good morning everyone welcome to today's hear ing uh today we're going to embark on module 7 in the course of which we shall hear evidence from a number of different
00:00:37 evidence from a number of different expert Witnesses relating to various aspects of the matters we've been investigating in previous modules yes M gr yes Mr chairman good morning um yes
00:00:48 gr yes Mr chairman good morning um yes um this morning we're going to start with the topic of smoke control and we're going to be hearing from two experts over the next two days Mr Simon lay today and Dr Barbara Lane tomorrow
00:00:59 lay today and Dr Barbara Lane tomorrow thank you so if I could call uh Mr Simon leay please thank you very
00:01:07 much please stand behind the chair good morning Mr Le morning I understand you're going to affirm correct yes and the words are on the screen would you read them out please I do solemnly
00:01:18 read them out please I do solemnly sincerely and truly declare and affirm that the evidence I shall give shall be the truth the whole truth and nothing but the truth thank you very much please sit down and make yourself comfortable
00:01:33 good thank you yes M Grinch yes thank you yes and thank you very much Mr lay for attending the inquiry today to assist us with our work it's very much appreciated um I'm going to be asking you the questions today if you don't
00:01:44 you the questions today if you don't understand any of my questions please just ask me to repeat the point uh or uh I'll put it in a different way and if you can also keep your voice up and nice and clear for the transcriber who's
00:01:55 and clear for the transcriber who's sitting to your right that's also much appreciated now um you prepared a report in August 2001 if we go to that report now it's at La
00:02:06 now it's at La y701 there we can see it's dated the 6th of August
00:02:11 of August 2021 and we can see that this report focuses on the smoke control system installed at gemfield Tower and if we go on within it to page 13 paragraph three
00:02:23 on within it to page 13 paragraph three we can see you say in the first lines there this report's been prepared as an independent expert review of The Smoke control system system installed as part of the refurbishment project at the
00:02:34 of the refurbishment project at the tower and you go on to tell us that your instructions came from sh Smith's LLP solicitors who act for PSB UK limited uh
00:02:45 solicitors who act for PSB UK limited uh and they are one of the core participants to the inquiry yes that's correct yeah and it's right isn't it that it was PSB who had an involvement in designing and commissioning the smoke control system orbe it they didn't
00:02:56 control system orbe it they didn't install it themselves that's my understanding yes yeah and uh following the provision of this report the inquiry has decided to call you to give oral evidence on this topic and we'll as I said earlier we'll be
00:03:08 and we'll as I said earlier we'll be hearing from you today and then from Dr Barbara Lane on the same topic uh tomorrow now in terms of the content of your report if we could go to the introduction at page
00:03:20 22 and we can see in paragraph two you say uh that this report considers the smoke control system uh during the refer M project which concluded in mid
00:03:32 M project which concluded in mid 2016 and it also looks at the operation of the system during the fire in the early hours of the 14th of June 2017 when the GRL Tower fire occurred is that correct that's correct yes and then at
00:03:44 correct that's correct yes and then at paragraph 17 on page 25 you just list briefly the the areas you've been asked to comment on and they are the legislation and guidance relating to the system the approach
00:03:56 relating to the system the approach taken in designing installing and commissioning the system with reference to what I would expect in a project of the type undertaken at grfl Tower and then assist in clarifying how compliance
00:04:07 then assist in clarifying how compliance with relevant legislation is evaluated for smoke control systems and comment on the system is in that regard was that the main work that you undertook in preparing this report yes it was and you
00:04:19 preparing this report yes it was and you tell us also at paragraph 18 that you were also asked to comment on the approach taken and the conclusions drawn by Dr Barbara Lane and Miss barl Menses in their respective reports which have
00:04:30 in their respective reports which have also considered the smoke control system or the building Control process in respect of it yes yes and then if I take you to the final section of the of your report on page
00:04:41 report on page 475 we can see there there's certain uh declarations uh and a statement of Truth which continues over the page and if we
00:04:52 which continues over the page and if we look at that uh is that your signature there it is my signature yes thank you and you've prepared two irata Corrections reports uh as well there's a
00:05:03 Corrections reports uh as well there's a a I'll just give the transcript references that's at La y72 and la y74 and you've also prepared a further
00:05:15 y74 and you've also prepared a further statement dated the 31st of May 2022 if we could just bring that up that's a la
00:05:23 y73 so this is a statement that uh you served on the inquiry last week is that correct correct yes and if we could go to the final page in this
00:05:34 statement there there again is that your signature it is yes and have you provided your report and your recent statement in the same way that you would have provided a
00:05:45 way that you would have provided a report or a statement to a court yes I have yes now any matters of law within your reports will ultimately ultimately be matters for the chairman and the panel to decide but can you confirm that
00:05:57 panel to decide but can you confirm that the factual matters set out in your report and in your statement are true to the best of your knowledge and belief yes and as your report and your statement do they represent your true and complete professional opinion on the
00:06:09 and complete professional opinion on the matters addressed within them yes they do thank you now just some questions about your uh qualifications and your background if we can go back to your main report and look at page 25
00:06:21 main report and look at page 25 [Music]
00:06:23 [Music] please this is section c of your report which starts in the middle of that page headed my experience and you provide us with a summary of your experience and qualifications and
00:06:34 your experience and qualifications and then a copy of your full CV appears later at the end of your report now in paragraph 21 you tell us that you're a chartered engineer specializing in fire
00:06:45 chartered engineer specializing in fire engineering um does that remain the case yes it is and your chartership is is through your registration is through the Institute of fire Engineers is that correct that's correct yes and you've
00:06:56 correct that's correct yes and you've held that since October 2009 as is that right uh yes I think so yeah yeah that's what you tell us in your CV and you also tell us in that paragraph that you are a professional member of the Society of
00:07:07 professional member of the Society of fire protection engineers and a fellow of the Council on tall buildings in urban habitat is that correct yes and that was an independent peer reviewed title for which you were nominated based
00:07:19 title for which you were nominated based on your contribution to the fire safety design of tall buildings is that right yes and you also tell us that you were appointed a fellow of the Royal Society of Arts in recognition of the contribution you've made to positive
00:07:31 contribution you've made to positive social change through your work in fire engineering is that correct now in terms of your qualifications at the end of paragraph 21 there that last sentence we can see
00:07:43 21 there that last sentence we can see on the page you tell it tell us that you hold uh a bachelor of Engineers Degree in Aeronautical Engineering is that correct that's correct yes and you tell
00:07:54 correct that's correct yes and you tell us in your CV that you obtained that from the University of Manchester between 1989 and 199 two yes is that correct yes and then if we go to page 453 of this report we can see your
00:08:07 453 of this report we can see your career history is summarized helpfully in this
00:08:11 in this table so we can see that after University you spent some time as a so it starts if we look um at the bottom of the table to begin with and go up so you
00:08:23 the table to begin with and go up so you you were a research assistant at the University of Manchester and then you worked as a so sometime as a commissioning engineer at size wellb is that correct that's
00:08:34 at size wellb is that correct that's correct yeah I was doing some um research work at the University and then I got a job as a commissioning engineer correct yeah yeah and that's a nuclear facility uh yes it is a nuclear power station in suffk yeah and then you spent
00:08:46 station in suffk yeah and then you spent some more time as a research assistant and then we can see that you became a um senior fire engineer for Warrington fire uh between uh 1995 and 1998
00:08:59 fire uh between uh 1995 and 1998 um so did you go straight into the position of senior fire engineer at Warrington fire or did you make your way up to that position uh yeah so that's the position I was at when I left Warrington fire so I think I joined I
00:09:12 Warrington fire so I think I joined I think it was a might have been a graduate position or it might have been fire engineer I can't remember the exact title of him onest I think it might have been graduate they called us yeah so is that where you began to obtain fire engineering skill and expertise um I
00:09:25 engineering skill and expertise um I actually started when I was at bnfl as a safety assessor um I was mainly doing safety cases for the decommissioning of Legacy nuclear facilities and the big hazard in those is is fire um so I
00:09:36 hazard in those is is fire um so I learned to use some of the tools um that a fire engineer uses before realizing actually that fire engineering even existed as a discipline right so yeah yeah and so and after you left
00:09:48 yeah and so and after you left Warrington fire we can see that you were then at Arup as an associate fire engineer between 99 and 2001 yes yes and then you spent quite a long time at wsp
00:09:59 then you spent quite a long time at wsp between January 2002 and December 2011 and uh that position of director of fire engineering and leader of specialist engineering was that the
00:10:10 specialist engineering was that the position you were in at the end of the time at wsp yes it was yes right so again did you work your way up uh as a a fire engineer at wsp I think I joined again I think the title when I joined
00:10:21 again I think the title when I joined was associate fire engineer um and then yeah there there was only a couple of people in the team and we we grew the team and then I ended up leading not just the fire Engineers but the whole Specialist Team and um having a director
00:10:32 Specialist Team and um having a director position and was there any particular speciality you had while you were at wsp um I think the area that we really focused on was tall buildings um wsp at the time and I think still is is the
00:10:44 the time and I think still is is the leading designer of tour buildings um certainly in this country with a lot of Global Experience so I was very fortunate to join them just as we were rediscovering tall buildings in this country we we had a bit of a Hiatus for
00:10:56 country we we had a bit of a Hiatus for about 30 years and then we came back to designing them and and wsp brought a lot of expertise through a company they bought in America it also worked in the far east as well so they had this
00:11:07 far east as well so they had this continuous work they'd done in tour building design um so I was very fortunate to learn from people who had um had been designing tour buildings for a very long time yeah and then we can see you went to Acom as director of fire
00:11:20 see you went to Acom as director of fire engineering January 2012 to January 2016 did you hold that position as director throughout that time yes I was yeah yeah and then in January 2016 we can see that you founded ofr Consultants do you
00:11:33 you founded ofr Consultants do you remain the director of ofr Consultants that's actually changed since this report was written um so I um dissolved all my shares um my ownership shares back into the business they've been
00:11:44 back into the business they've been redistributed to other senior people in the business um this part of our Legacy planning within the business and I'm no longer a director I don't sit on the board I I sorry I I sit as an advisor to
00:11:55 board I I sorry I I sit as an advisor to the board I've been invited to be an adviser to the board but I don't exercise any control all over the business right and have you moved on to a different uh business or a different post uh no I'm I'm still at ofr I'm just
00:12:06 post uh no I'm I'm still at ofr I'm just an employee I'm just my the title I decided to hold was just fire engineer that's yeah yeahh um and then um can you help us do you have any formal qualifications in fire
00:12:18 fire engineering um no formal qualifications no no uh what about in Smoke control do you have any formal qualifications in Smoke control um not really um although
00:12:29 Smoke control um not really um although I'm not really aware of any formal qualifications one might might get in that area um specifically but my degree um in aeronaut engineering is all about fluid dynamics
00:12:40 fluid dynamics thermodynamics um and it is highly relevant to smoke control yeah if we look back at page 26 of your report and and at paragraph 24 now you say that
00:12:52 and at paragraph 24 now you say that your the focus of your current role is the delivery of fire engineering advice to projects including a number of tall Residential Building schemes as part of my role I produce review and support
00:13:03 my role I produce review and support others in the development of fire safety strategies is that correct that is correct yes and then at paragraph 25 you go on and say within my role I carry out
00:13:14 go on and say within my role I carry out commission and review complex smoke control analyses support the development of smoke control system specifications review subcontractor proposals for designs Carry Out
00:13:26 proposals for designs Carry Out Inspections during work on site and during the witness ing commissioning and demonstrating of smoke Control Systems now just very briefly um those
00:13:37 Systems now just very briefly um those smoke control analyses are those written documents that you review um it varies um so there's um sometimes I carry out the analyses and it might be simple hand calculations or
00:13:48 calculations or spreadsheets sometimes um these days I I tend to um have other people who do the more complex analyses we have a big team that that specializes on those sorts of things um whereas the past I used to
00:13:59 things um whereas the past I used to actually do the Hands-On analyses for myself um but uh yeah it varies so yeah most of it is written documentation eventually but it's it's computational modeling and analyses yeah do you have
00:14:10 modeling and analyses yeah do you have any experience of actually designing such a system yourself as opposed to reviewing or or simply being involved in reviewing the process uh yeah very much so yeah absolutely then at page 460 just
00:14:24 so yeah absolutely then at page 460 just going back to that you've set out selected project experience for highrise residential buildings which you've worked on in The Last 5 Years now um in terms of smoke Control Systems um can
00:14:37 terms of smoke Control Systems um can you confirm that you do have experience in the design specifying reviewing and commissioning of smoke smoke control systems in high-rise residential buildings uh yes absolutely highrise buildings and what I call tall buildings
00:14:49 buildings and what I call tall buildings as well I think there's a a slight distinction between those two and many of those projects are Legacy um toour buildings as well yes and how much of that experience was in the context of
00:15:00 that experience was in the context of refurbishment projects or Legacy projects as opposed to new build um I would say I mean a huge amount of my work has involved tour buildings um probably around about sort of 50% of the
00:15:12 probably around about sort of 50% of the work I've done in my career has been tour residential buildings a smaller proportion of that is Legacy Buildings simply because um there's fewer of them um that that tend to get involved it's been more recently um actually
00:15:24 been more recently um actually interestingly enough there's been more interest in Legacy Buildings not just since grall but also just before grandall um so give us an idea in The Last 5 Years how many Legacy Buildings might you have looked at um so I've done
00:15:36 might you have looked at um so I've done some uh major Estate reviews for um developers who've had sort of 20 or 30 um type buildings um I think one of them had over 60 projects that we looked at
00:15:47 had over 60 projects that we looked at um and then I've been uh very involved in a number of projects that involve three or four Tower clusters so it's probably around about 100 um Legacy projects um in the last sort of you know
00:15:58 projects um in the last sort of you know six or seven news yeah now we're going to come on to the specifics of gremi tower in due course in in some detail but but just just help us with this at this stage in terms of your prior
00:16:09 this stage in terms of your prior experience have you ever come across a system which was designed and which operated in the same way as that installed at Grille Tower do you mean the existing system or do you mean the system that was put in at the system
00:16:21 system that was put in at the system that was put in at the refurbishment yeah yeah so um yes I have yes yeah you have you've come across systems that are are the same as that which was installed at greni Tower have you uh yes yeah yeah
00:16:33 at greni Tower have you uh yes yeah yeah the the system type um where you have a single shaft and you get your makeup air coming through the door um is is a common type right and have you come across a system with exactly the same
00:16:44 across a system with exactly the same parameters as set for the system at Grandfield Tower um what do you mean by the parameters so for example the 2 m/ second through the stair door Criterion that was set by PSB have you come across
00:16:56 that was set by PSB have you come across a system that was set with that kind of criteria in um well generally you set the criteria to to keep the stair relatively free of smoke um and then from that you derive what your parameters are going to be but trying to
00:17:08 parameters are going to be but trying to achieve a adequate extract rate and an adequate flow rate through the door because you need both of those things in these systems um yes I've come across very similar yeah okay now um before we
00:17:19 very similar yeah okay now um before we turn to the specifics of that system in more detail I want to First cover with you the principles that apply to installing a such a system in an existing building in your report you
00:17:31 existing building in your report you provided an appendix appendix B which sets out your view on how part two of the building regulations applied in the context of the new system at greml Tower um now if we go to that it starts
00:17:44 Tower um now if we go to that it starts at page 465 in this report there and if you look at section B at the foot of the page um and then over into page three of this Annex you take the view that the
00:17:56 this Annex you take the view that the works to the Smoke control system weren't a material change of use in respect of levels 4 to 23 because those levels remained residential dwellings
00:18:07 levels remained residential dwellings yes that's my interpretation and the way I've seen that sort of guide the regulations applied in the past yes yeah and then you go on to consider whether the works to the system were a material alteration within the meaning of
00:18:19 alteration within the meaning of Regulation three of the building regulations 2010 um and let's just have a look at that this is a CLG 30198 97 at page
00:18:33 97 at page six so there we've got uh section three and if we look at sub paragraph 2 at the bottom of that page it tells us an alteration is material for the purposes of these regulations if the work or any
00:18:45 of these regulations if the work or any part of it would at any stage result a in a building or controlled service or fitting not complying with a relevant requirement where previously it did OR b in a building or controlled service or
00:18:56 in a building or controlled service or fitting which before the work commence did not comply with a relevant requirement being more unsatisfactory in relation to such a requirement and if we go over the page we can see that
00:19:08 go over the page we can see that regulation 23 below makes clear that where it refers to relevant requirements it means the functional requirements of the building regulations is that correct that's what
00:19:20 regulations is that correct that's what it says yes thank you and then um regulation 43 is below this and if we look at the bottom of page
00:19:31 bottom of page seven little three it says here building work should be carried out so that after it has been completed any building which is extended or to which a material alteration is made or any building in or
00:19:44 alteration is made or any building in or in connection with which a controlled service or fitting is provided extended or materially altered or any controlled service or fitting complies with the applicable requirements of schedule one or where it did not comply with any such
00:19:57 or where it did not comply with any such requirement is no more unsatisfactory in relation to that requirement than before the work was carried out now um so that is regulation
00:20:09 carried out now um so that is regulation 43 and the requirements of schedule one are set out at page 34 of this uh copy of the building regulations there we have it and we can see fire safety
00:20:22 have it and we can see fire safety starts at the bottom and we've got B1 there the building should be designed and constructed so that there are appropriate Provisions for the early warning of fire and appropriate means of
00:20:33 warning of fire and appropriate means of Escape in case of fire from the building to a place of safety outside the building capable of being safely and effectively used at all times so that's the B1 requirement and if we go over to page 35 we can see other requirements
00:20:46 page 35 we can see other requirements including B3 internal fir spread B4 external fir spread I'm not going to read them all out in detail and then b51 is at the bottom of that page access and
00:20:59 is at the bottom of that page access and facilities for the fire service the building should be designed and constructed so that so as to provide reasonable facilities to assist firefighters in the protection of life now would you agree therefore that
00:21:11 life now would you agree therefore that in simple terms if one's making a changes to a building which have to comply with the regulations the changes must either achieve compliance with the functional requirements of schedule one
00:21:22 functional requirements of schedule one or resulting in the building being no more unsatisfactory in relation to those functional requirements than it was before the
00:21:31 changes I think how it's applied in in practice is complex but that is the principle yes yeah and that no more unsatisfactory approach is often referred to as the non-w worsening
00:21:43 referred to as the non-w worsening principle isn't it yes the language that's used to reflect it does change but um yeah it's the non- worsening the no less satisfactory and yeah yeah now if we just look at paragraph 23 of your
00:21:54 if we just look at paragraph 23 of your report page 470
00:22:01 there um you're talking about the existing system and you say this so you're talking about the existing smoke control system and you say if the existing system was nonfunctional then this would arguably
00:22:14 nonfunctional then this would arguably set the bar for testing the no more unsatisfactory condition very low it is unlikely that any work would make a smoke control system more unsatisfactory than a nonfunctional system therefore
00:22:26 than a nonfunctional system therefore the system would not be a material material alteration and hence not building work now so you say that arguably you compare um with a
00:22:37 arguably you compare um with a nonfunctioning system is that how you yourself interpret the regulations and how you apply them in your work well I mean it's a it's a statement from the
00:22:48 mean it's a it's a statement from the regulations that it uses the term before the works are carried out as The Benchmark for the no less satisfactory condition um so if you have a building that has a non-functional system but somebody has determined that that system
00:23:00 somebody has determined that that system is not um necessary from a life safety perspective it might be a legacy condition that people no longer consider to be necessary um then it may well be that you no longer take it into account so it can arise and I've seen it arise
00:23:12 so it can arise and I've seen it arise in in certain circumstances um but in this particular case I don't think it was particularly relevant or or pertinent um I also feel that there is other legislation that's supposed to
00:23:24 other legislation that's supposed to stop buildings um falling into a state where they're unsafe because the system is non-functional so this situation shouldn't arise if if a system is needed for fire safety purposes um it should be
00:23:35 for fire safety purposes um it should be kept functioning through the legislation such as the fire safety order that governs the operation of buildings um so there's an underlying background there to this as well which I think I go want to say in my report I see I just want to
00:23:47 to say in my report I see I just want to be absolutely clear about what your approach to the non-w worsening uh principle is um are you saying that in a position like we were in with granfield Tower you you could say well the
00:23:59 Tower you you could say well the existing system is nonfunctioning so anything we do is better is that uh an approach that uh you think is it's not an approach that I would personally take
00:24:10 an approach that I would personally take um but it is an approach that somebody could take um now it's not approach that say I would personally want to see because I prefer buildings to to be safe but it is a benchmark that could be
00:24:21 but it is a benchmark that could be used oughtn't The Benchmark to be where you've got a non-functional system how that system would per form if it was functioning and whether it was compliant with the functional requirements or not
00:24:33 with the functional requirements or not in my um my preference is that it ought to be like that but that's not specifically what the regulations say but like I say there's also other legislation which means that system should not be in a a a dilapidated state
00:24:46 should not be in a a a dilapidated state so it shouldn't really arise in practice and I think it's wrong to look at the two completely separately I think there is an interrelationship between those the different pieces of legislation but it is theoretically possible
00:24:58 it is theoretically possible I
00:24:59 I see so can we leave it at this you're saying it's theoretically possible but not an approach that you would ever take not that I would personally endorse no not unless I could be absolutely sure
00:25:10 not unless I could be absolutely sure the system wasn't necessary for Life Safety purposes um yeah and I say I have seen situations not with smoke control systems but with other fire safety um Provisions um where they've become
00:25:22 Provisions um where they've become redundant but nobody considers it to be problematic and therefore um it can be could be left as it is right and do you consider that such an approach the approach you've put in here uh is open
00:25:34 approach you've put in here uh is open to a reasonably competent engineer to take well it's not really for the engineer necessary to decide it's for the um the approver to decide if they really want to accept that particular
00:25:45 really want to accept that particular perspective um I wouldn't expect someone acting in a um professional competent manner to Advocate that unless they were absolutely sure that the system did not or was not required for Life Safety
00:25:57 or was not required for Life Safety purposes right now if we go to page 471 of your report and paragraph
00:26:06 27 you tell us there that not withstanding the complexities as to how the material alteration test applied to gemville the system works were ultimately treated as building work for
00:26:17 ultimately treated as building work for the purposes of the building regulations yes that's what we saw in practice yes can we just go back slightly on this though um so the combination of regulations three and four um tell you
00:26:29 regulations three and four um tell you what is building work and and how building work is treated under regulations it's very easy to to slip up here because you have work so work is anything that happens in a building and you have the very specific term building
00:26:41 you have the very specific term building work which lots of other requirements apply to the test of whether something is building work as I think we've just looked at um in this context anyway is whether it results in a material
00:26:52 whether it results in a material alteration and judging whether something is a material alteration is quite a complex matter because you might have to work work out with the no less satisfactory condition has been reached now if you think about it on a complex
00:27:03 now if you think about it on a complex project you're quite a long way down the line of spending time and effort working out if something is material or not um so you can kind of take two approaches I think um you could either say we can
00:27:15 think um you could either say we can either work out before we consider what is building work or not whether it's no less satisfactory which is I think the sort of let to the letter of the regulations you work out if something is no less satisfactory and that determines
00:27:26 no less satisfactory and that determines whether it's building work or not alternatively and particularly on a more complex project you could say well everything's building work but when I come to judge those items which were existing I may play May apply a certain
00:27:38 existing I may play May apply a certain amount of latitude to that and apply a no less satisfactory test um because that's then putting it into the context of all the other works so it's a the regulations themselves are are are are
00:27:50 regulations themselves are are are are really quite simple I used to hate the regulations I used to think they were they were terribly worded and they were cumbersome but actually I've come to over time particularly doing expert witness work to realize that they're actually a very clever piece of Regulation that's designed to cover a
00:28:02 Regulation that's designed to cover a huge range of building projects and lots of variation within those projects whether you've got all new build whether you've got some existing restrictions and constraints and it's very difficult
00:28:13 and constraints and it's very difficult to apply a very rigid set of rules to that so there is a certain amount of flexibility and this is one of those areas that allows the approver to um apply their judgment to work out the
00:28:24 apply their judgment to work out the best way of approaching it okay um and I think that happened here sorry just to go back to the paragraph you you noted that they treated it all as building work because it's far more
00:28:35 as building work because it's far more pragmatic to treat everything as building work and then perhaps apply a different judgment to certain aspects of the work than it is to try and say right we're going to treat this bid as building work this bid is work and and split it up like that it's not a very
00:28:47 split it up like that it's not a very pragmatic approach yeah now can we agree that the relevant functional requirements when we're thinking about the smoke control system would have been B1 means of warning and Escape B5 access and facilities for the fire service yes
00:29:00 and facilities for the fire service yes yes MH but also B3 internal fire spread in terms of the systems vertical smoke shafts yes yeah thank you now if we look at page 473 of your report now at
00:29:14 at page 473 of your report now at section D you've got a a section where you consider schedule one that that's the setting out the functional requirements and also regulations 8 and 11 of the building regulations which I
00:29:26 11 of the building regulations which I don't think we've looked at much all yet in this
00:29:29 in this inquiry and um if we go to paragraph 40 um there you you say uh when considering what the functional requirements in schedule one may require
00:29:41 requirements in schedule one may require a BCB so that's a building control body is also bound to apply the reasonableness test created by regulation 8 do you see that there I do see that Y and you also highlight in the
00:29:54 see that Y and you also highlight in the next um paragraph that a building control body body you say further a building control body will be aware that it has the power to relax or dispense with regulations if it wants by virtue
00:30:06 with regulations if it wants by virtue of Regulation 11 yes that's correct yeah and then um looking at the next page page 43 you also say that the regulations don't require the building
00:30:18 regulations don't require the building control body to document whether the approach it has taken has been specifically informed by the provisions of Regulation 8 or 11 yes that's correct yeah mhm and you say that in practice
00:30:30 yeah mhm and you say that in practice this is the last sentence a relaxation may also simply be made by the building control body deciding or agreeing to adopt a lesser standard of provision when applying approving Works under the regulations do you see that I do it's
00:30:43 regulations do you see that I do it's it's it's one of those interesting things when from coming out of the inquiry and looking back over some of the older legislation particularly through one of um Luke bisby's recent reports if you look back at the regulations from the
00:30:54 regulations from the 1970s um they used to have a little form that was set out in the regulations that said if you were going to dispense or relax from regulation you had to fill that paperwork in um now Mr bis sorry
00:31:07 that paperwork in um now Mr bis sorry Professor Bisby makes the point that as more changes were coming up and people were worried about building Control Officers being sort of overburdened with workload it seems that form was was lost um when we got to the regulations in the
00:31:18 um when we got to the regulations in the 80s and then onto these regulations as well so the the process of documenting um that used to be set out in the regulations was was taken away right so in effect is this right you say that
00:31:29 in effect is this right you say that it's up to building control to decide if it would not be reasonable to meet the requirements of schedule one with no requirement to expressly document this is that your is that effectively what you're saying in those paragraphs
00:31:41 you're saying in those paragraphs ultimately I think that's the um uh the power that's created for building Control Officers under regulation 11 yes let's look at regulation 8 which is the first one you you referred to in that
00:31:52 first one you you referred to in that section this is at CLG 301 9897
00:31:58 301 9897 at page
00:31:59 at page nine it's the very bottom of the page this is regulation 8 it's called limitation on requirements and it says this Parts a to d so that would include part B on fire
00:32:10 d so that would include part B on fire safety F to K and P except for a number of paragraphs of schedule one shall not require anything to be done except for
00:32:21 require anything to be done except for the purpose of securing reasonable standards of health and safety for persons in or about buildings and any others who may be affected by buildings or matters connected with
00:32:32 buildings or matters connected with buildings do you see that yes I do and if we could look at what you say about this in another section of your report if we go to page 60 paragraph 1572 perhaps we could have the that on
00:32:44 1572 perhaps we could have the that on on the right hand page leaving this on the left hand page if that's possible
00:33:01 sorry no it was page 60 of his report don't worry if it's difficult to spit the pages let's just have page 60 of your report up La y 701 page 60 ah there we have it thank you so at
00:33:16 60 ah there we have it thank you so at 17.2 of your report you say this regulation 8 introduces the word reasonable into the limitation on requirements section what is reasonable
00:33:27 requirements section what is reasonable is a matter of interpretation unreasonable requirements will not just include impossible requirements but could also include requirements which are unly prohibitive with regards to the viability or functionality of a building
00:33:39 viability or functionality of a building in my experience this has had an important effect on the operation of the regulatory regime by introducing a reasonableness test into the process of considering what the functional
00:33:50 considering what the functional requirements in schedule One require in the circumstances of Any Given project do you see that I do see that can I just also make the point that there is also paragraph
00:34:01 paragraph 17.1 which makes it clear that regulation 8 um relates to um health and safety of persons in or about buildings um yes I've just read that in regulation 8 uh yeah sorry you didn't sorry you
00:34:12 8 uh yeah sorry you didn't sorry you went straight to paragraph 57.2 yes yes there's been a suggestion made that I didn't make a statement as at 57.1 and I just want it to be clearer that I did no no I'm not I'm not suggesting sorry it's been suggested
00:34:24 suggesting sorry it's been suggested elsewhere it's going to be better if you don't anticipate my question okay okay um so um looking at the language of Regulation 8 itself that we've got on
00:34:35 Regulation 8 itself that we've got on the left hand side can we agree that it's saying that specified parts of schedule one don't require anything to be done except when it comes to securing reasonable standards of health and safety do you see that I do yeah and I
00:34:48 safety do you see that I do yeah and I think also you have to be aware of the language of the functional requirements which also have the words adequate and reasonable within times as well yeah yes they do and I'm coming to that mhm now
00:34:59 they do and I'm coming to that mhm now um but just on this regulation 8 point and what what the thrust of Regulation 8 is about there's there's some discussion of this in the approved document B which I just wanted to take you to this is at
00:35:10 I just wanted to take you to this is at CLG
00:35:11 CLG 50224 at page
00:35:17 7even if we go to page seven within
00:35:25 this perhaps we could have that as the full page because this is quite small
00:35:36 text so there's a section here uh called limitation on requirements in approved document B do you see that I do yes in the left hand column and we can see in
00:35:47 the left hand column and we can see in the first paragraph of that section it effectively repeats the text of uh regulation 8 which we've already read and at the end sentence it says this is one of the categories of purpose for
00:35:59 one of the categories of purpose for which building regulations may be made and then it says paragraphs H2 and j7 are excluded from regulation 8 because they deal directly with prevention of the contamination of water Parts E and M
00:36:12 the contamination of water Parts E and M which deal respectively with resistance to the passage of sound and access to and use of buildings are excluded from regulation 8 because they address the welfare and convenience of building uses part L is excluded from regulation 8
00:36:24 part L is excluded from regulation 8 because it addresses the conservation of fuel and Power all these matters are amongst the purposes other than health and safety that may be addressed by the building regulations do you see that I
00:36:35 building regulations do you see that I do yes so isn't it the case that the the real thrust of Regulation 8 what it's really getting at is simply to tell you that certain parts of the functional requirements don't require anything to
00:36:46 requirements don't require anything to be done save for the purposes of securing reasonable standards of health and safety well that's one part of it yes but there is also it has the word reasonable in there for a reason I
00:36:57 reasonable in there for a reason I presume um and I've seen it applied in practice and that's how I've seen it interpreted but quite why it has the word reasonable in there is I guess a matter of law it's written into the regulations yes and and are you saying
00:37:09 regulations yes and and are you saying in practice there's a separate stage a separate test of reasonableness that's applied to the functional requirements themselves is that what you're saying I think they can be
00:37:21 think they can be yes but aren't those functional requirements themselves already addressed in a way which incorporates such reasonableness requirements we saw it before and you've just made the point B1 appropriate provision for means of
00:37:34 B1 appropriate provision for means of Escape uh B4 adequately resisting the spread of fire B5 reasonable facilities for the fire service in B5 I just want to be really clear what you're saying are you saying that
00:37:46 you're saying are you saying that there's some additional test or gloss that Aries over and above those functional requirements uh which you say applies an additional reasonableness test
00:37:58 additional reasonableness test um I don't know if I say it's a specific additional gloss over the top but it it's it's the wording that's in there it's a wording I've seen applied in practice and you have to take the fact that some of the functional requirements
00:38:09 that some of the functional requirements not all of them say reasonable I mean B5 says reasonable Provisions for firefighters um B1 doesn't say reasonable it says adequate um and it says at all material time so there's
00:38:20 says at all material time so there's there's lots of um uh complex wording in there so perhaps this is there just to remind people that it is only reasonable and I didn't write the regulations I talk about how it's applied um how I see
00:38:31 talk about how it's applied um how I see it applied so no I entirely appreciate that I just want to understand what your interpretation is and we'll come to how you say it applies at greml in a moment
00:38:42 you say it applies at greml in a moment um are you saying for example that there's a test of using reasonable Endeavors to comply with the functional requirements is that your
00:38:52 understanding um yeah I think so yeah MH and if it's unreasonable if there if if if complying with the requirement is unreasonable then the person reviewing
00:39:05 unreasonable then the person reviewing the word the building control body could then decide to um either relax or they could um just decide that they they're happy with it it's adequate yeah right
00:39:16 happy with it it's adequate yeah right if we look at regulation 11 now of the building regulations that's at CLG 30 1 9897 page 10 mhm
00:39:28 here we can see it's towards the bottom of the page above the part three and it's headed power to dispense with or relax requirements and it says subject to paragraph three the power under
00:39:39 to paragraph three the power under Section 81 of the ACT that's under the building act 1984 to dispense with or relax any requirement contained in these regulations shall be exercise exercisable by the local Authority so
00:39:51 exercisable by the local Authority so it's telling us that it's the local Authority that can relax or dispense with regulations yeah cuz the ACT provides for um Secretary of State to do it and the SEC and then this is passing on to the building control yes local
00:40:02 on to the building control yes local Authority building control yeah now Dr Lan has told us in her report for the transcript that's at paragraph 2.5.3 of her supplementary report uh BL RP 250 43
00:40:15 her supplementary report uh BL RP 250 43 at page 29 she said that in her experience it's extremely rare for a dispensation or relaxation of a functional requirement certainly B B1 to B5 to be s or granted is that your
00:40:29 B5 to be s or granted is that your experience as well no it's not um and it's often not done quite so explicitly as that I would say I mean I just discussed with you just just now about
00:40:40 discussed with you just just now about the possibility of treating building Works in a way where you treat them as no less satisfactory well the actual strict wording of the regulations is things either building works or they're not but you might treat something as
00:40:51 not but you might treat something as building works you then might apply a reasonable test because it's an existing building and that's using the powers of Regulation 11 technically I don't think building Control Officers necessarily
00:41:02 building Control Officers necessarily think of it in that way um they don't necess dissect it in that way but there is certainly a um a climate you might argue of um reasonableness and the such
00:41:14 argue of um reasonableness and the such like which is created by the combination of these
00:41:17 of these regulations right if a building control body did decide that applying for example the B1 functional requirement um that that was unreasonable in a particular case uh
00:41:28 unreasonable in a particular case uh wouldn't one expect to see that very clearly documented and communicated on a particular project given the importance of the functional requirements to Life Safety so as I said just now in Prior
00:41:42 Safety so as I said just now in Prior versions of the legislation that did happen um but these days it comes down to the professionalism of the the people applying it and it depends on the context as well um I mean you have to remember the regulations cover
00:41:53 remember the regulations cover everything from the extension on the back of your house up to a a massive multi-user high-rise super tall building um so in the has to be looked at in the context so I would expect them to
00:42:04 context so I would expect them to document it in the case of a more complex project but I can understand why in a simpler case um it might not get documented just tell me with this who would if um the building control officer
00:42:16 would if um the building control officer passes
00:42:17 passes something which you might consider was not fully
00:42:21 not fully compliant do you assume that he or she has applied his mind to it and decided to pass it or can you think he might have made a mistake how do you know all
00:42:34 have made a mistake how do you know all that I I totally agree that is a that is a significant problem with the way the regulations work um I've come across situations where I've seen um build Control Officers um or other approvers
00:42:46 Control Officers um or other approvers um approve things that that I don't think do meet the regulations um but they have passed them now whether they passed them because they consider it does meet the regulations um whether they passed them because they've not
00:42:58 they passed them because they've not understood something um or whether they've passed them um you deliberately falsely I don't know but it's it it does happen I think and it's it's a really complicated thing to one pick because
00:43:10 complicated thing to one pick because the only real test you have of budha regulations compliance in in practice is whether people have given completion certificates and and approved works but then you might have thought that perhaps
00:43:21 then you might have thought that perhaps sorry to interrupt me but one might have thought that if you're going to exercise a dispensing power one ought to to not only apply one's mind to the question but to make it clear that you have applied your mind and granted a
00:43:34 applied your mind and granted a dispensation is that not I I I agree it would be better if these things were properly documented and there's certain guidance out there so when you do things like hospitals you do specifically document where you vary from the
00:43:46 document where you vary from the guidance for hospitals but that isn't carried across into every building like I said it could be because the regulations apply across this AB well some would say absurdly but very wide group of buildings
00:43:57 group of buildings right thank you and just to be clear what you're saying about the relevance of this to gemfield Tower are you saying that rbkc building control did take this dispensation or relaxation route uh in
00:44:10 dispensation or relaxation route uh in relation to the Smoke control system at gemfield Tower is that what you're saying um it's difficult to say exactly how they determined it but um certainly through a combination of various factors whether it was treating existing works
00:44:24 whether it was treating existing works as building works and then applying um uh a different test or whether it was um through through a different pathway of these regulations I think they did consider the building within the context
00:44:35 consider the building within the context of existing nature um and therefore applied the test of reasonabl to the works that could be carried out there yes but I'm talking about regulation 11 now the power to dispense with or relax
00:44:47 now the power to dispense with or relax requirements are you saying that at gemfield Tower you think that rbkc building control did decide to relax or dispense with some of the requirements of the functional requirements well as I
00:44:59 of the functional requirements well as I said just now I don't think in practice it's often set out in that way that they particularly pick through the regulations and say right I'm going to apply regulation 11 I think what regulation 11 and regulation 8 create is
00:45:11 regulation 11 and regulation 8 create is a a climate within which building control feel that they can exercise um their own
00:45:17 their own considerations so I wouldn't necessarily believe that they particularly chose that particular route and and documented it because that's not necessar the way that building control work in practice in my experience are you saying that in
00:45:29 in my experience are you saying that in effect the building control body has a complete discretion to decide what they think is reasonable in the circumstances I think ultimately they do have that discretion yes
00:45:40 discretion yes right if we go to paragraph 169.50 of your report on page
00:45:48 63 so it's 1695 I want to look at where you and this is where you've been discussing regulation 11 and 8 before it and you say here by these means latitude
00:46:01 and you say here by these means latitude is provided to the building control body within the structure of the building regulations which enables the building control body to take into account particular building constraints yes yes is that another way of putting the point
00:46:13 is that another way of putting the point I just put to you that effectively you're saying building controller has a complete discretion to decide what they think is reasonable in the circumstances um I think it's probably a better way of putting um the explanation I gave a few
00:46:24 putting um the explanation I gave a few minutes ago about the fact that it creates a a climate of of of latitude right yeah and and and you don't think that that effectively renders parts of the building regulations uh oos if you read them like
00:46:36 regulations uh oos if you read them like that sorry what's that word mean sorry I'm not familiar uh irrelevant wouldn't that render the non-w worsening provision I wouldn't say irrelevant sorry I think irrelevant would be taking that far too far um they have to take it
00:46:47 that far too far um they have to take it they take these things into account but they decide what is reasonable so the test under the regulations is about whether or not you achieve um adequate safety but what is equate or not can change it changes with time it changes
00:47:00 change it changes with time it changes between buildings um so I I think that's that's the way it's used is to work out what they consider is adequate and reasonable right now um you we saw earlier that you
00:47:13 right now um you we saw earlier that you said there was no obligation on the building control body to document how compliance with the building regulations had been achieved yes as far as I'm aware that's what the regulations say
00:47:24 aware that's what the regulations say yeah yes but can we agree that regulation 14 of the building regulations which deals with full plans applications let's just look at that CLG 301
00:47:35 301 19897 page
00:47:40 13 regulation um 14 if we look at um sub paragraph two it makes it clear that full plans shall be deposited in duplicate of which the local Authority
00:47:51 duplicate of which the local Authority May retain one copy and where Part B of schedule one fire safety imposes a requirement in relation to proposed building Works an additional two copies of any such plans as demonstrate
00:48:03 of any such plans as demonstrate compliance with that requirement shall be deposited both of which may be retained by the local Authority and you can see that below that uh sub paragraph three little C it
00:48:17 that uh sub paragraph three little C it it tells you that full plans shall consist of and it has to consist of various things including at C any other plans which are necessary to show that the work would comply with these
00:48:28 the work would comply with these regulations now I appreciate you may be drawing a distinction between what building control has to document and what the person making the full plans application has to demonstrate but can
00:48:39 application has to demonstrate but can we agree that when it comes to the full plans application the person carrying out the work does have a duty to document how it's going to comply with the building regulations so they have a
00:48:50 the building regulations so they have a the
00:48:51 the person people who have responsibilities under the building regulations have a duty to um do doent how they are going to achieve compliance um exactly what level that they have to document that to
00:49:03 level that they have to document that to is is another question it's a separate question because you might just document compliance um I mean we're talking about the smoke control system but I don't want to to to jump your questions here
00:49:14 want to to to jump your questions here but um you wouldn't necessarily provide at a full plans application every nut and bolt detail um you might set out the principles that are going to be applied and then when it comes to the um
00:49:26 and then when it comes to the um completion certificate and the review of The Works on site further information is covered and again this is part of the regulations covering a very wide set of of of buildings if you build a kitchen extension you'd expect to put on the
00:49:38 extension you'd expect to put on the plans all the things you need to do to comply with the regulations and it's fairly simple when it comes to a massive complex project um there's a special provision so the the um the duty um and
00:49:50 provision so the the um the duty um and for the building control officer under the regulations actually of course comes from the building act section 16 and they are required to either um accept reject or offer a conditional approval
00:50:02 reject or offer a conditional approval and what tends to happen in practice on complex buildings because the level of detail you would need to go into to show that every aspect of regulations is is definitively um complied with uh you
00:50:14 definitively um complied with uh you tend to get what's called conditional approval um at which point the F detail sorry I'm going to stop you there brenel Tower uh wasn't a case where we had a conditional approval was
00:50:25 where we had a conditional approval was it there's no evidence that any conditional approval was issued by build and
00:50:31 and control um to some extent there was um well what we know from the fact is that in fact there was no response At All by building control to the full plans application that was made so this is not
00:50:42 application that was made so this is not a situation where there was a conditional approval there was take with with respect to the Smoke control system there was an approval of the technical submission at submission s1a subject to
00:50:55 submission at submission s1a subject to it um me meeting or being expected to meet the guidance in the Smoke Control Association so that's a form of conditional approval it may not have been written down as that but again exactly how you document approval comes
00:51:07 exactly how you document approval comes down to the individual Protocols of each build control office I understand that there may be um there may be a range of behavior reasonable behavior in terms of what you have to show what you have to
00:51:19 what you have to show what you have to document but can we agree that this full plans provision does require looking at little C again any other plans which are necessary to show that the work would comply with these regulations you can't
00:51:32 comply with these regulations you can't just have nothing can you you can't have nothing well I wouldn't expect somebody to accept nothing um but as I say there there is latitude within that thanks to things like additional approval and
00:51:43 things like additional approval and everything else yes if we could go to your report uh page 14 paragraph
00:51:51 8 you say um you say in the first lines of paragraph F first the reports of Dr Lane are critical of the absence of detailed analysis and documentation in
00:52:02 detailed analysis and documentation in relation to the system including the commissioning process Dr Lane's criticism is to some extent valid and my own preference is that designs and works are properly documented at the time
00:52:13 are properly documented at the time however neither the building act nor the building regulations 2010 impose a separate Duty on relevant persons to document how they achieve compliance now I would suggest to you
00:52:24 compliance now I would suggest to you that that's simply not right in in relation to what we've just read in regulation 14 where the full plans application has to contain enough information to show that the functional
00:52:35 information to show that the functional requirements have been met I would say what what I mean by that is it doesn't specify exactly how much detail is required and how much um uh the level of detail that's required to demonstrate compliance you have to demonstrate
00:52:47 compliance you have to demonstrate compliance but depending on um what the building control officer wants will vary what level of information is required to demonstrate that compliance yes but that's not the point you make here is it
00:52:58 that's not the point you make here is it you're not saying the building regulations uh don't tell you in what detail you have to document compliance you say here that they don't impose a separate Duty on relevant persons to
00:53:10 separate Duty on relevant persons to document how they achieve compliance I think that's what I mean um is what I've just said um and I mean it with the word how they achieve compliance so they want they need to show The Works would
00:53:21 they need to show The Works would achieve compliance exactly how they achieve compliance is the level of detail
00:53:26 detail I see I apologize if that's not clear but that's that's what I mean by no that's helpful thank you I want to ask you some questions now about the local government Association guide on fire
00:53:37 government Association guide on fire safety and purpose-built blocks of flats now that guidance is dated we'll look at it in a moment it's dated June 2011 um but can we um agree that the
00:53:48 2011 um but can we um agree that the primary purpose of that LGA guide was to provide guidance to housing providers and enforcing Authorities on compliance with the regulatory reform fire safety
00:53:59 with the regulatory reform fire safety order 2005 and the Housing Act 2004 rather than addressing the building regulations and the functional requirements in the building regulations so that's the purpose for
00:54:10 regulations so that's the purpose for which it was created but I wouldn't exclude it from having relevance elsewhere okay can we look at um ADB again if we go to CLG
00:54:23 50224 and I want to look at page 13
00:54:32 there's a section there headed alternative approaches in the right hand column MH and I just want to read those the three paragraphs underneath that so uh it says at
00:54:43 uh it says at 0.21 the fire safety requirements of the building regulations should be satisfied by following the relevant guidance given in this approved document however approved documents are intended to provide guidance for some of the more
00:54:54 provide guidance for some of the more common building situations and they may May well be alternative ways of achieving compliance with the requirements if other codes or guidance are adopted the relevant recommendations concerning fire safety in the particular
00:55:06 concerning fire safety in the particular publication should be followed rather than a mixture of the publication and Provisions in the relevant sections of this approved document however there may be circumstances where it's necessary to
00:55:18 be circumstances where it's necessary to use one publication to supplement another and then it goes on guidance documents intended specifically for assess ing fire safety in existing buildings will often include Provisions
00:55:30 buildings will often include Provisions which are less onerous than those set out on this approved document or other standards applicable to new buildings as such these documents are unlikely to be appropriate for use where building work
00:55:43 appropriate for use where building work controlled by the regulations is proposed do you see that so looking at the final paragraph do you agree or can we agree that approved document B is is quite clear that guidance documents
00:55:54 quite clear that guidance documents intended for fire safety in existing buildings are not likely to be appropriate when we're looking at building work controlled by the building regulations themselves um I think there's there's
00:56:06 themselves um I think there's there's two points to make there first of all everything in the approved document B is couched within the caveats at the start of the approved document B um which say that you do not have to apply the approved document B you can apply
00:56:17 approved document B you can apply anything else that you you consider to be appropriate um and secondly as I just explained um there's in practice two ways that um existing buildings or works
00:56:29 ways that um existing buildings or works or existing works are treated under the regulations um the strict way as I understand it of following um regulations three and four is you determine whether something is building
00:56:40 determine whether something is building work or Not by the no less satisfactory condition so if it was no less so if it wasn't any less satisfactory sorry this that's what the language keeps getting changed on that particular point it can
00:56:51 changed on that particular point it can be quite confusing if it's no less satisfactory it wouldn't be building work in which case you would argue that that paragraph doesn't apply however if you as apply as building work and then
00:57:02 you as apply as building work and then you apply a reasonable test to decide whether it's no less satisfactory um you might argue that that that paragraph applies um but that's I think because the pro document B is reflecting the
00:57:13 the pro document B is reflecting the strict version of interpreting the regulations saying that you shouldn't even consider it building work if it's already no less satisfactory I I think what I'm putting
00:57:24 satisfactory I I think what I'm putting to you is the specific point that's made in that third paragraph which is that guidance documents other guidance documents like the LGA guide which are intended specifically for assessing fire safety and existing
00:57:35 safety and existing buildings it's warning that that that will often include a provision that's less onerous than what we see in the approved documents and they're unlikely to be appropriate when work is controlled by the building regulations
00:57:47 controlled by the building regulations that's the point I'm I'm putting to you yes I think that that's what it says yeah but okay yeah um I've explained I think it needs to be looked in in context yes and paragraph two is also
00:58:00 context yes and paragraph two is also warning about mixing guidance isn't it it's saying you that really if you're looking at fire safety you perhaps ought to follow a particular guidance publication in full rather than mixing
00:58:11 publication in full rather than mixing different sections of different documents it's it's warning about that yeah the the the term that's often used for that is cherry picking where people take the the least onerous provision from one place and the lease owner from somewhere else there are absolutely
00:58:23 somewhere else there are absolutely cases where you need to mix guidance or guidance might help inform you to make a decision particularly more complex scenarios so it does say that but there may be circumstances where it's
00:58:34 may be circumstances where it's necessary to use one publication to supplement another right now let's go to the LGA guide itself cg50
00:58:44 453 if we could just look at the first page just to start with just to orientate ourselves there it is fire safety and purpose built blocks of flats would be well familiar uh to a number of
00:58:56 would be well familiar uh to a number of people watching we've looked at it a number of times um if we could go um to page three the forward starts sorry the forward starts at page two and this is the end of the forward um so in page
00:59:09 the end of the forward um so in page three and I want to look at the beginning of the second paragraph there it says this guide is intended to meet the needs of housing providers and enforcing authorities for guidance
00:59:20 enforcing authorities for guidance tailored to purpose-built blocks of flats yes yes so um that's its purpose it doesn't say for example does it that it's there to assist specialist
00:59:31 it's there to assist specialist designers of smoke Control Systems well it doesn't say that but I'm not sure okay yeah it doesn't say that yeah and can we agree that that
00:59:42 say that yeah and can we agree that that there there's one section specific to smoke control in this document um it's at page 85 it starts at page 85 in this 192 page guide and it contains guidance
00:59:55 192 page guide and it contains guidance of the most General nature this specific bit on smoke control it's very general guidance here and over the page on smoke control
01:00:06 and over the page on smoke control there's nothing specific and detailed about it is there in here it's not detailed specific but it does make some very important points um about the shift in Smoke control Philosophy for example yes I'll come to that in a moment it was
01:00:18 yes I'll come to that in a moment it was on the page you just had up previously sorry that's why I mentioned it now
01:00:27 if sorry spoke control has mentioned obviously in more detail you're going to go into that I presume some DET yeah if we look back at your report for a moment um at page
01:00:44 167 and I want to look at the very bottom of 167 at paragraph 539 you say this is where you're talking about the existing system you say the the system focused on the protect the
01:00:56 the system focused on the protect the stair by extraction and creating a flow of air through the open stair door which would limit the potential for smoke to reach the stair sorry that's the new system that was the intention of the new
01:01:07 system that was the intention of the new system which was focused on protecting the stair by extraction and creating a flow of air through the open stair door which would limit the potential for smoke to reach the stair and you go on
01:01:18 smoke to reach the stair and you go on you say this would offer a degree of protection to the common Lobby by extracting smoke from that space and Cooling diluting smoke that was in the common
01:01:29 common Lobby and then if we look at paragraphs um 540 you say this was different to the existing system which had intended to create a flow of air through the common
01:01:41 create a flow of air through the common Lobby without a specific consideration of whether the stair would be protected that is to say the existing system sought to protect the lobby and by consequence to provide a degree of
01:01:52 consequence to provide a degree of protection to the stair whilst the system the new system start to protect the stair and by consequence to provide a degree of protection to the lobby yes
01:02:04 yes and if we look at paragraph um 542 below
01:02:10 below that you say opposing air flow through the stair door needed to protect the stair is only created when the stair door is opened until the door is open the flow of air through the lobby will be low and the smoke clearance available
01:02:23 be low and the smoke clearance available will be limited as a result of this relying on air flow via the stair is not appropriate where there is a need to focus on protecting the lobby such as where the travel distances in a building
01:02:35 where the travel distances in a building are excessive yes yes so you're saying there that if you've got excessive travel distances in your lobby then focusing so on the primarily on
01:02:46 focusing so on the primarily on protection of the stair may not be appropriate because you may need to protect the lobby with those extended travel distances yes yes you would need to both protect the stair and and the lobby because there could be a buildup
01:02:58 lobby because there could be a buildup of smoke in the lobby before the residents make it to the stair correct yes in fact there almost certainly will be a buildup of smoke in the lobby that's the the way that most of the other guidance puts it now I want to
01:03:11 other guidance puts it now I want to focus on what's an excessive travel distance travel distance in this context if we look at paragraph 548 on page
01:03:21 170 you note that um under picking up in the second line Second sentence under current guidance where sprinklers are not provided the
01:03:32 where sprinklers are not provided the maximum travel distance occupants are expected to walk in an unventilated portion of Escape Route is 7.5 M as shown for example in ADB figure 2.7 left
01:03:44 shown for example in ADB figure 2.7 left and Bs 91 figure 2.7 right and you've then helpfully set out those diagrams below that if we could just blow those up so it's not terribly clear um what
01:03:57 up so it's not terribly clear um what I'm going to do is let's look at ADB itself CLG 50 224 at page 28 we see diagram
01:04:04 diagram 7 there it is and it's much clearer there yeah better and we can see looking uh focusing on Lobby access dwellings in the bottom diagram that we've got a
01:04:15 the bottom diagram that we've got a 7.5 meter maximum travel distance set by ADB is that right um so I mean I focus on the single stair condition here um just because because I think it was just
01:04:26 just because because I think it was just it was clearer in my report to use this but it it recommends a maximum 7.5 M yes well say it's a requirement could we not use the word requirement please because it's not a requirement it's a recommendation I fully appreciate that I
01:04:39 recommendation I fully appreciate that I I'm well aware of what the status of the approved document is and I apologize if I said requirement but if you following this guidance it's telling you that the maximum travel distance is 7.5 M yes yes
01:04:50 maximum travel distance is 7.5 M yes yes and that's the approved document yes and we see something similar in bs9 one don't we we don't need to go to that in your report so those two pieces of guidance are saying 7.5 M you can
01:05:03 of guidance are saying 7.5 M you can also see here that the protection is to the space that is attached to the staircase so you have 7.5 m in an unventilated space so there's no provision of any ventilation to that
01:05:15 provision of any ventilation to that space at all and in diagram 7B you have protection um with a ventilated space yes and just in summary your view is
01:05:26 yes and just in summary your view is that these excessive travel distances uh that were experienced at gemfield Tower were acceptable based on the LGA guide which indicates that travel distances up to 10 MERS would not be considered
01:05:38 to 10 MERS would not be considered excessive that that's that's in summary your view yes sorry just say that question again in your report you say that the travel distances experienced at Grenville Tower which were more than 7.5
01:05:51 Grenville Tower which were more than 7.5 M um were acceptable based on the LGA guide which indicates that travel distances up to 10 m would not be considered excessive I think that's one way of looking at them um in my report
01:06:03 way of looking at them um in my report I've tried to provide a number of different ways of looking at the travel distances at gremel Tower in the existing levels one way of looking at it could be to use the LGA guide but there's other ways of looking at it as
01:06:14 there's other ways of looking at it as well I've just trying to provide Clarity on how someone might reach a conclusion that they were not excessive yes let's look at those travel distance measurements um if we could go to Dr Lane's report bla RP
01:06:28 Lane's report bla RP 25043 at page 271 this is in her supplemental report if we go to page
01:06:39 271 and if we could blow up these diagrams what we can see here is um Dr Lane's measured travel distance is on the left hand side and we can see that
01:06:51 the left hand side and we can see that she is saying from the flat four she has measured with the lines there 10.3 M do you see that yes I see that yeah yeah that's her calculation in her report
01:07:03 that's her calculation in her report then we've got your travel distance and you've measured with with more direct lines more direct diagonal lines than she has and we can see that
01:07:15 lines than she has and we can see that you come to 9.5 m is that correct I do make it 9.5 M yeah and she notes on the right that when the when exova did their existing fire safety strategy
01:07:27 existing fire safety strategy report on the right hand side of this page um
01:07:33 page um exov said in their existing fire safety strategy that the furthest distance from Flat for was 9.3 mters yes um I think that's the BR not xover who said that
01:07:44 that's the BR not xover who said that they measured it on site at 9.3 oh I beg your pardon sorry you're absolutely right that's the BR measurement in their um forensic fire report you're right sorry so we've got 9. three 9.5 and
01:07:57 sorry so we've got 9. three 9.5 and 10.5 um can we agree that there isn't any piece of guidance which gives any detailed description of how you measure travel
01:08:06 travel distance well there is there there's detailed guidance for some circumstances um certain things you have to take count of like obstructions and the such like but um when you're walking
01:08:17 the such like but um when you're walking across a space it's the direct distance it's the actual distance someone would walk yes which is why I've included so there's the little yellow circles provide space for someone to walk past a corner for example so you couldn't take
01:08:29 corner for example so you couldn't take it cut right across the corner right because someone couldn't walk that close to a wall yes so that's the actual distance that someone would have to walk and that's the I think BS 91 uses that yeah so in BS 91 the closest we get to
01:08:41 yeah so in BS 91 the closest we get to something it says it's got to be the actual distance to be traveled by a person along an Escape Route yes for the transcript that's BSI 50621 at page 21 yeah and within within all the guidance
01:08:53 yeah and within within all the guidance documents there's plenty of cases of people walking in diagonal lines and and taking angles of more or less than 45 degrees they all have examples of that within them yes now let's go to the LGA
01:09:04 within them yes now let's go to the LGA guide again because this is one of the pieces of guidance you rely on yes uh in relation to travel distance well I reference it but as as I say it's I don't think it's the only piece of guidance I'm trying to use it to explain
01:09:16 guidance I'm trying to use it to explain how a competent person as I believe Mr Hansen said in the inquiry that you know he didn't consider it to be an unreasonable travel distance and meny said the same thing so I'm trying to
01:09:27 said the same thing so I'm trying to provide um the inquiry with with my interpretation of of how they might have reached such a conclusion yes I understand you say that um and and we have the evidence of Mr
01:09:38 um and and we have the evidence of Mr Hansen and Miss men's that's understood but I'm I'm seeking to to put to you um can I put this before we go to the LGA guide is there any other piece of
01:09:49 guide is there any other piece of guidance you can point to that suggests that um something over 7 .5 m is not excessive well I think you have to be very careful to treat 7.5 M as a hard
01:10:00 very careful to treat 7.5 M as a hard and fast maximum the approved document itself says you can have extended distances in some cases um so and I wouldn't even treat 10 m as a as a hard and fast requirement I think it's it's
01:10:12 and fast requirement I think it's it's wrong to think of these things that at 10.1 M it becomes unacceptable and at 9.8 M or or 10 m it is acceptable it's all about the context of the space I mean this this was quite a simple space
01:10:24 mean this this was quite a simple space you had a short um dead end region but then you had a a large open Lobby space it's a space people are familiar with and all of these things feed into whether something is excessive or not if it had been a much more complex La
01:10:36 it had been a much more complex La labyrinthine type Arrangement you might take a different view so I think it's it's it's wrong to this I I always think of numbers like 7.5 MERS I mean it has no specific scientific basis to it um
01:10:50 no specific scientific basis to it um it's just a number that's been shown to be acceptable over the years and has come about so I would look at that as something to say well should we think about this if it's more than 7 1/2 M well have we got any ventilation because
01:11:02 well have we got any ventilation because the ADB says 7 a half met is okay without ventilation so maybe we need some ventilation and that's actually quite reflective of what the LGA guide says so there's a a commonality of thought across the industry on that
01:11:13 thought across the industry on that point so I wouldn't treat them as hard and fast let's go back to the LGA guide cst3 14237 and look at page 87
01:11:31 CST 30 14237 page 87 now
01:11:40 87 now um we can see that it indicates what the current Benchmark gu design guidance is it's it's under the heading Benchmark guidance at 58.2 three and it says the
01:11:51 guidance at 58.2 three and it says the following reflects the current Benchmark design guidance for both single and multiple stairway blocks of flats with Corridor or Lobby access and we can see that it says at the second bullet point
01:12:03 that it says at the second bullet point the distance of travel between the flat entrance door and the door to a Lobby or stairway should be limited to 7.5 M and if you look at the following page figure eight they've essentially got the
01:12:14 figure eight they've essentially got the same diagram as in uh approved document B yes yes it appears in here and then if you go to page 94 of this guide
01:12:27 and if we look at
01:12:30 62.1 it says this although the above benchmarks reflect current design guidance many existing blocks of flats designed to earlier standards or in which alterations have taken place will
01:12:41 which alterations have taken place will not comply with these benchmarks for example existing blocks of flats may have increased travel distances and there may be no Corridor or Lobby protection to the stairways
01:12:52 or Lobby protection to the stairways smoke control Arrangements may be non-existent or differ from is acceptable today and this section of the LGI then goes on below at 62.2 to say that it says in these circumstances
01:13:03 that it says in these circumstances upgrading to current standards although ideal may not be possible due to the physical constraints in the building or justifiable on the basis of risk therefore there will need to there will
01:13:14 therefore there will need to there will need be a need to consider the overall risk now does this suggest that even if you are using this guidance and even if you accept that it could be relevant to
01:13:26 you accept that it could be relevant to building work under the building regulations that there ought to at least be some assessment of the overall risk which is presented by increased travel
01:13:37 which is presented by increased travel distances I think there should be some assessment but the extent of that assessment will depend upon the distances involved and as I said the complexity of the space okay and the such like I think it's also worth
01:13:49 such like I think it's also worth remembering that all of this exists under guidance for means of Escape but it it's not entir clear that those distances relate only to means of Escape now the LGA guide then refers to
01:14:02 Escape now the LGA guide then refers to potential compensatory measures in 62.3 it says in some blocks restoring the block back to the standard of the day might be all that's needed in others compensatory measures might be needed to
01:14:13 compensatory measures might be needed to be considered in exceptional circumstances automatic fire detection and alarm systems and automatic fire suppression systems might also need to be considered yes yes now there was no
01:14:24 be considered yes yes now there was no such comp atory measures put in place at greni Tower in respect of the travel distances was there um not that I'm aware of No and then at 62.4 it says the
01:14:35 aware of No and then at 62.4 it says the acceptance of standards in existing blocks of flats where they differ significantly differ from current benchmarks should be subject to careful scrutiny this may
01:14:47 require
01:14:50 assessment sorry it's just gone off my page this may require assessment by a suitable specialist however the following General guidance May assist when considering the available options
01:15:01 when considering the available options for means of Escape now again doesn't this suggest that if you are effectively deciding not to follow current benchmarks then this should be assessed by a suitable specialist yes if they
01:15:13 by a suitable specialist yes if they significantly differ there may be circumstances where you need to use a suitable specialist but that will come down to the individual circumstances and who would be a
01:15:24 circumstances and who would be a suitable specialist in the context of a smoke control system well I would expect it to be a fire engineer right and then if we look at 62.6 over the page and you rely in particular on on
01:15:37 page and you rely in particular on on this section in your report it basically says that accepting uh travel distances may be considered um sorry accepting increased travel distances may be considered appropriate
01:15:48 distances may be considered appropriate in individual circumstances and will be particularly relevant in older types of property where there's little scope for alternatives sorry which bit was that I can't sorry I've lost track of where you were on the
01:15:59 I've lost track of where you were on the page sorry that's a summary of 62.6 the travel distances specified earlier have been found to achieve the requisite level of safety but were never intended to be hard and fast and different limits have applied in the
01:16:10 different limits have applied in the past yes and it talks in the last sentence this will be particularly relevant in older types of property where there will be little scope to reduce the existing travel distances or provide alternative means of Escape yes
01:16:22 provide alternative means of Escape yes and then looking at the table below 62.7 s this provides some benchmarks for existing blocks of flats and we can see in the third bullet point it says inv ventilated lobbies and corridors
01:16:33 ventilated lobbies and corridors increases from 7.5 M up to 10 m may be acceptable sorry are likely to be acceptable in most situations with no additional measures do you see that I do
01:16:44 additional measures do you see that I do see that
01:16:46 see that yes so in this respect the LGA guide is different to both approved document B and Bs 91 2011 in its definition of extended travel distances isn't it um
01:17:00 extended travel distances isn't it um yes it is but I think again it's worth thinking about a little bit of context to what those distances mean so why might a 10 meter travel distance be acceptable so I mentioned just now that
01:17:12 acceptable so I mentioned just now that that this is all about means of escape and that's a section that appears under but we have to be careful and be aware of the fact that in residential buildings the firefighting Provisions refer back to the means of Escape
01:17:23 refer back to the means of Escape Provisions as well so we have some weird situations occurring in residential buildings like two staircase buildings that have massively extended travel distances with no ventilation to the corridor um I think the current guidance
01:17:34 corridor um I think the current guidance allows you to have up to 30 m effectively in an unventilated Corridor now whether you've got two staircases it for the person who's escaping from a flat it doesn't matter how many staircases you've got they're still in a
01:17:45 staircases you've got they're still in a corridor full of smoke but those distances actually relate more to firefighting um so in a firefighting condition when you've got in this instance perhaps different ventilation conditions you might accept longer
01:17:56 conditions you might accept longer distances as well so there's it's slightly more subtle than that um I think and you need to be alive to the fact that these impact on lots of measures within the building okay but isn't it important to recognize that
01:18:08 isn't it important to recognize that this guidance is focused on compliance with the rro 2005 so although this is suggesting that when you're doing a fire risk assessment one can generally leave distances between 7.5 and 10 m
01:18:21 distances between 7.5 and 10 m unmitigated in an a ventilated Lobby is isn't that different to the position where one is carrying out new building work which is caught by the building regulations so the the test under the
01:18:32 regulations so the the test under the fire safety order um is that you achieve an adequate level of safety um so I would say in an existing building if you're carrying out work part of your test about whether you're no less
01:18:43 test about whether you're no less satisfactory will be whether you're you're tested against the level of adequate safety that's achieved under the fire safety order so I think it would it would carry across and you know
01:18:54 would it would carry across and you know this this might be written or might have come about to assist people with carrying out fire risk assessments and other matters it does say to support approval authorities um in existing buildings doesn't then it goes on to
01:19:06 buildings doesn't then it goes on to talk about the fire safety order in the opening paragraphs um I would exclude it as being something that someone might take into consideration or that it might represent um a collective industry view
01:19:18 represent um a collective industry view on what might typically be the sort of distance you could extend to without worrying about it right Mr chairman just one more question before we break yes um in this instance it's not just a like for like replacement of the smoke
01:19:30 for like replacement of the smoke control system but a newly designed system being put in so wouldn't you expect to see at the very least a detailed analysis carried out if the view was that the travel distances would
01:19:42 view was that the travel distances would remain in excess of 7.5 M I would expect to see that if they were significantly excessive if they were excessive but I wouldn't necessarily expect to see that because for example the guidance in the
01:19:54 because for example the guidance in the LGA guide says that if you go up to 10 meters you don't do anything and then it goes say up to 15 MERS um you can as long as you put automatic ventilation in and you have upgraded fd3s doors so I I
01:20:07 and you have upgraded fd3s doors so I I don't think you would expect to see a lot of calculation in there sorry just just one more question when you say I would expect to see that if they were significantly excessive so yes or no are
01:20:20 significantly excessive so yes or no are you saying that they weren't significantly excessive here so you wouldn't expect to see any analysis of the travel distance no I wouldn't no I think I think a reasonable person um could reach a conclusion that um the
01:20:33 could reach a conclusion that um the existing travel distances were not unduly excessive and therefore didn't need a specific consideration thank you Mr chairman I think that's a good moment for our break there are more questions
01:20:44 for our break there are more questions on this subtopic but I think we should break now right thank you very much well as you probably know Mr lay we have a break during the morning and this is the time to have it so we'll stop there we'll resume please at uh 25 to 12 and
01:20:59 we'll resume please at uh 25 to 12 and um please while you're out of the room don't talk to anyone about your evidence or anything relating to it certainly all right thank you very much would you go with the aser
01:21:15 please thank you m gra 25 to 12
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01:37:02 would you ask Mr leay to come back here
01:37:14 please all right Mr Le ready to carry on yes thank you thank you very much yes yes thank you yes now you tell us in your report that the existing smoke control system at G Tower the one in
01:37:25 control system at G Tower the one in existence before the refurbishment between 2012 and 2016 was a corridor smoke dispersal system can you just explain to the panel very briefly what a
01:37:36 explain to the panel very briefly what a corridor smoke dispersal system was um so it's a throwback to the 1960s guidance of CP3 um so it's a a method of effectively diluting smoke um through um
01:37:50 effectively diluting smoke um through um sort of cross flow and and and air flowing through the space thank you now if we go to the LDA guide again CST 30
01:38:00 14237 and look at page 96 now and I want to look at 62.9 Under The Heading unsatisfactory smoke control and it says there although
01:38:11 smoke control and it says there although there have been changes in Smoke control design it is still appropriate when assessing an existing building smoke control arrangements to review these in the light of the standards that were in place at the time the block was built
01:38:22 place at the time the block was built start by ensuring that what is there continues to work as originally intended before considering the need to improve the arrangements however in relation to smoke dispersal previous Benchmark
01:38:33 smoke dispersal previous Benchmark design guidance is far removed from what is acceptable today and then we go on to the next paragraph the next page 62.1 smoke dispersal has proved to be very
01:38:45 smoke dispersal has proved to be very unreliable for a number of reasons and is no longer seen as an accepted method of smoke control in existing blocks of flats with smoke dispers veral action should be taken to review both the smoke
01:38:57 should be taken to review both the smoke control arrangements and the existing travel distance the advice of Specialists may need to be sought so can we agree that this would suggest if following this part of the LGA guide and
01:39:09 following this part of the LGA guide and certainly for compliance with the rro that um there needed to be specific consideration of the smoke control arrangements and the existing travel distance which may involve the advice of
01:39:21 distance which may involve the advice of Specialists um I would say need to be reviewed and considered yes yes and documented as part of that review and consideration I think that would depend
01:39:32 consideration I think that would depend on again as I've said it depends on the um uh the nature of the particular case and I don't think at Grell it was a case where you would expect a huge amount of documentation you might not expect a
01:39:43 documentation you might not expect a huge amount of documentation but correct me if I'm wrong there's no consideration in any of the documentation dealing with the smoke control system of the extended travel distance is there not I wouldn't I wouldn't
01:39:55 is there not I wouldn't I wouldn't expect it to be in with the smoke control system I'd expect it to be in the fire strategy so um are you saying it was ex over's responsibility as part of the fire safety strategy for the
01:40:07 of the fire safety strategy for the proposed refurbishment works that there should have been in consideration of extended travel distances in these lobbies I think I think there should have been and I think it was mentioned in their existing building um review document F strategy document that there
01:40:19 document F strategy document that there was a longer travel distance than you would have under current guidance and that some form ventilation was needed because of that yes Miss Cooney in her existing fire safety strategy not the one for the refurbishment noted longer
01:40:31 one for the refurbishment noted longer travel distances yeah but there was no detailed consideration in any of the exov documentation was there about extended travel distances in the lobbies and the effect that that might have in no I think I think it just said there
01:40:42 no I think I think it just said there was going to be some uh ventilation um included and yeah mhm you're saying that should have been in the fire strategy we know it wasn't in the fire strategy for the refurbishment
01:40:53 the refurbishment it's not there in those circumstances would you have expected the designer of the system PSB to at least have given it some consideration in their documentation I think by the time PSB
01:41:04 documentation I think by the time PSB were involved it was quite late on so again I I wouldn't necessarily expect the smoke control designer to to do that I think they would they would take the conditions as it's been sort of handed to them when they when they arve late in
01:41:15 to them when they when they arve late in the project I mean I would prefer if the person um involved in design remote control system was engaged much earlier so they were engaged in those discussions but um when they're not then I think it does you I would expect them
01:41:27 I think it does you I would expect them to necessar pick it up right so you would have expected the uh fire engineer to have put it in their fire safety strategy but in circumstances where it's not in there
01:41:38 circumstances where it's not in there you wouldn't have expected the designer of the system to have picked that up and documented it not not in this sort of case no because it because it wasn't an obviously significantly excessive
01:41:49 obviously significantly excessive extended travel distance um and to some extent xover did did mention it because they said they needed to be um an improvement to the Smoke control system and if you think back to I think it was the previous page of the documents on
01:42:00 the previous page of the documents on the screen it talks about um having some kind of smoke ventilation being included um is a compensating feature so I mean you could even argue um that exov did
01:42:13 you could even argue um that exov did cover it with n strategy but in the the absolute bare minimum way um but you know that's that's it's definitely in there but it's not really covered about how they going to achieve the the smoke
01:42:24 how they going to achieve the the smoke control no um and if we look at 6211 it says an approach to three commonly found situations in which there are unsatis unsatisfactory smoke control Provisions is as below and there's some suggestions
01:42:37 is as below and there's some suggestions in here and if we look at the third bullet point for example it states in a single stairway blocks with Corridor or Lobby approach requiring smoke ventilation and with travel distances of 7.5 to 10 m ovs that opening vents in
01:42:51 7.5 to 10 m ovs that opening vents in corridors or lobbies are acceptable up to six stories in height M so an OV is an openable vent so it's a manually operated V so that wouldn't have any bearing on um a means of Escape period
01:43:02 bearing on um a means of Escape period for example because you expect firefighters to open those um an aov is an automatic opening vent or ventilator it can can mean either and a PV would be a permanent vent so it's always open yes
01:43:13 a permanent vent so it's always open yes so if we look at the second sentence there it says if this travel distance exceeds 10 m or the number of stories exceeds
01:43:20 exceeds six so that's screenful all the ventilation is provided in the stairway and not the corridor or Lobby aovs or PVS are required do you see that yeah and I think that links back to what
01:43:32 yeah and I think that links back to what was included in kone's existing building strategy now if we go um back to your report La y701 page
01:43:44 172 at paragraph 555 and following you effectively say in summary that the lobby distances at Grille were ultimately not sufficiently problematic such that any specific Lobby protection
01:43:57 such that any specific Lobby protection expectations would be triggered is that right yes and if you look at paragraph 556 you say this you say the travel pathway at grel Tower was simple and
01:44:08 pathway at grel Tower was simple and familiar to Residents the extension of travel arose because of the extended Corridor leg off the main space and in line with the guidance in PD 7974 part six no recommendation for
01:44:21 7974 part six no recommendation for increased time due to root complex would be expected for this typee of arrangement also from that guidance assuming smoke at the limit of tenability one could add around 4
01:44:32 tenability one could add around 4 seconds to the travel time from an additional 2 meters of travel this would not suggest a need for dedicated smoke control in the lobby now um I want to put to you isn't
01:44:44 lobby now um I want to put to you isn't 4 seconds actually rather a long additional time in the context of toxic smoke exposure
01:44:54 no and I think it was about 4 seconds between your question and my answer so I don't think it is necessarily a particularly long time and it would depend on the level of exposure that you're seeing the level of exposure
01:45:06 you're seeing the level of exposure you'd expect while someone is escaping with the amount of smoke that's come out of a flat um I wouldn't expect 4 seconds to be a significant period of time and again I'm I'm including this calculation
01:45:17 again I'm I'm including this calculation just like I referenced the LGA guide to help understand the sort of thought process that a reasonably competent person might go through to ask themselves is this travel distance excessive or not I understand that the
01:45:28 excessive or not I understand that the difficulty we've got is we've got no documentation that suggests that anybody at Grenville went through that thought process have we well it was mentioned in the existing fire strategy um and then we only have as far as I can tell the
01:45:40 we only have as far as I can tell the the oral evidence from witnesses that say they did take it into account but didn't consider it to be I think they I think they felt it was so obvious that it wasn't a problem um and I I could absolutely see how that would come about
01:45:51 absolutely see how that would come about I mean that calculation tied up in that paragraph 556 I mentioned it within there but there's there's lots of things to unpick there you know the fact that if you are looking at extended travel distances you have to think about the
01:46:02 distances you have to think about the complexity of the route the familiarity with the route you have to think about whether you're at the limits or not of tenability and the such like so the the calculation has got lots of different charts and tables you can pick those numbers from um but really that reflects
01:46:16 numbers from um but really that reflects an industry view I would say um so it's it's it's putting a putting a number on something that actually people would probably do quality itively right you refer to the travel pathway as familiar you've just mentioned it again it might
01:46:28 you've just mentioned it again it might be familiar to Residents who' lived there a while but what if what if there are new residents in the tower or visit visitors or guests well does the travel distance calculations take that into
01:46:39 distance calculations take that into account so I would say um if even if you're a new Resident to the tower you've probably found your way from the lifts to your flat so you would be at least slightly familiar with it um and most guests are escorted in and out of
01:46:51 most guests are escorted in and out of the tower um or would be with somebody who is in the tower I wouldn't necessarily expect to have to take into account somebody who might come into the tower Uninvited or or with access without a resident there um you know
01:47:03 without a resident there um you know that's this this is that's the the fringes of of what people typically consider because you're trying to deal with the typical condition in the the vast majority of cases in a building
01:47:14 vast majority of cases in a building right you know and does this assume I mean we've we know and we'll come on to it that it's expected that there'd be some smoke in the lobby potentially quite early if there's a flat on fire um
01:47:25 quite early if there's a flat on fire um does this assume that the lobby is completely clear of smoke when you're doing these calculations you assume that there might be some impediment due to smoke so as I've said in the in the paragraph they're assuming smoke at the
01:47:36 paragraph they're assuming smoke at the Lim limit of tenability so that changes the walking speed of the person within the calculation so I've used the value um that assumes that there is smoke in the lobby okay can we look at BS 91 um
01:47:49 the lobby okay can we look at BS 91 um now BSI 50621
01:47:54 um this are sorry can ask are we going to come back to PD 7974 or no I'm not coming back to it it's just worth worth noting that the application of PD 7974 part 6 I've used
01:48:07 application of PD 7974 part 6 I've used there um if you go to the guidance document for 7974 it talks in there um in the frequently asked questions and the sections in there about people making qualitative assessments and not always making quantitative and
01:48:19 always making quantitative and documented decisions so it's not just me saying this is accepted within the industry um and within um the application of the building regulations that people might sometimes make
01:48:30 that people might sometimes make decisions that aren't fully
01:48:34 documented I understand that and I understand it may be industry practice is IT industry good practice not to document for example that there was an extended travel distance and have some
01:48:46 extended travel distance and have some consideration of what that might mean at Grenville and whether compensatory measures are realistic or possible so I would say um in a situation like grall it would be best practice if you
01:48:58 grall it would be best practice if you documented it um I don't think it was such a significant travel distance that even good practice would necessarily pick it up um and I think the extent to which it was picked up being mentioned in the existing fire strategy being
01:49:09 in the existing fire strategy being noted that there was going to be a repair to the Smoke control system in the fire strategy was probably about as far as I typically expect it to go so that would be yeah classes good practice so it's good practice simply to note
01:49:21 so it's good practice simply to note that there's going to be a refurbished smoke control system and that they extended travel distances and leave it at that that's good practice is it um I I think it probably would be in a case like gr for Tower yeah because of the
01:49:33 like gr for Tower yeah because of the distances were were relatively minor with no analysis even cursory analysis you've given your four seconds but we see none of that in the documentation do
01:49:44 see none of that in the documentation do we so if I was doing it I would I would provide a calculation or a reference back to something like the LGA guy to give some grounding to to my opinion um and often a building control officer
01:49:55 and often a building control officer might ask you to put that in but yeah if you're dealing with a very experienced building control officer who understands all the these things they might not ask you to and and some fire Engineers wouldn't do it so I I think there is a
01:50:06 wouldn't do it so I I think there is a huge amount of variation in this when you've got this sort of case if it was a much bigger distance it would be a completely different circumstance but it isn't and what do you mean by much bigger what would trigger the need to
01:50:17 bigger what would trigger the need to document in a clear way an analysis of an extended travel distance um I would say cly over 15 M right now if we go to Clause um 0.2.3 in this guide it's at
01:50:29 Clause um 0.2.3 in this guide it's at page
01:50:31 page 11 here it's called Smoke control in common parts and I want to read the second paragraph it says smoke can be controlled in the common areas through fitted ventilation systems which are
01:50:42 fitted ventilation systems which are either natural or mechanical these ventilation systems have two main purposes the first of which is to provide some protection to the stair core and the second of which is to Aid firefighters when tackling a fire
01:50:53 firefighters when tackling a fire ventilation systems can also be used to compensate for extended travel distances within the common Corridor leading to the stairs and thereby help occupants to escape safely where smoke control is
01:51:06 escape safely where smoke control is used to provide compensation for extended travel distances it is the responsibility of the designers to demonstrate that the ventilation system can provide tenable conditions see Annex
01:51:18 can provide tenable conditions see Annex e for the occupants using the route with extended travel distances so can we agree that this guidance was not followed at gremi Tower well not
01:51:29 not followed at gremi Tower well not really because it says where smoke control is used to provide compensation for extended travel distances I see so you're saying because they decided despite extended travel
01:51:40 they decided despite extended travel distances that they weren't compensating for it this wasn't triggered is that what you're saying I I think that would be a reasonable interpretation of it yeah okay so you don't interpret this guidance as saying where there are
01:51:51 guidance as saying where there are extended travel es which by defin by defin definition might need some compensation it's the responsibility of the designers to demonstrate that the
01:52:02 the designers to demonstrate that the system can provide tenable conditions in those circumstances then it becomes that that responsibility yes right but I think you have to also think about in the context of again this comes back to
01:52:13 the context of again this comes back to all the context we were talking about earlier of of no less satisfactory and such like and you might look at it and say well hang on a minute I do have a situation which is 2 and a half me it's a Well understood Lobby space Etc um am
01:52:26 a Well understood Lobby space Etc um am I likely to see a comparison of tenability compared to the the default condition of no ventilation versus a condition that has some ventilation in the space and a slightly longer distance
01:52:38 the space and a slightly longer distance and you might do it qualitatively which is provided for within the relevant
01:52:45 Frameworks I see uh let's look at the 2015 version of the smoke Control Association guidance that's at rbk 4's 2932 and I want to look at page six
01:52:56 4's 2932 and I want to look at page six Clause
01:53:02 2.1 so here in the second paragraph it says where the travel distances are no more than 7.5 m in distance from the door to the staircase or sterile Lobby
01:53:15 door to the staircase or sterile Lobby to the most remote apartment entrance Door the primary objective of smoke control in residential buildings is to protect the St staircase enclosure by ensuring that the stairways remain relatively free from smoke and heat in
01:53:27 relatively free from smoke and heat in the event of a fire within a dwelling and then if you go two paragraphs down from that there's a paragraph beginning how however the fourth paragraph however where corridors
01:53:38 fourth paragraph however where corridors are extended the primary objective of the smoke control system is to protect both the common Corridor and the staircase enclosure there are considered to be two forms of extended corridors and it talks about extended corridors
01:53:51 and it talks about extended corridors and it says these typic Al have no more than 15 M travel distance from the furthest apartment door to the staircase or sterile Lobby the primary objectives of the smoke control system are to protect the common Corridor for means of
01:54:03 protect the common Corridor for means of escape and the staircase enclosure for means of escape and firefighting now do you accept that this 2015 SCA guidance if it was being
01:54:14 2015 SCA guidance if it was being followed indicates that it wasn't permissible to treat protection of the stair as the primary objective and instead the primary objective should have been both the common Corridor in
01:54:25 have been both the common Corridor in this case the lobby and the staircase well I would say if you read it prescriptively yes you would get that from it but I wouldn't read it prescriptively do you agree with Mr Hansen's view in his oral evidence the
01:54:36 Hansen's view in his oral evidence the inquiry that given the travel distances at gremi Tower the design documentation for the system should have explained what approach was being taken to protecting both the stair and the lobby
01:54:47 protecting both the stair and the lobby I wouldn't necessarily expect the design documentation to pick that up but I like I say it should have been covered somewhere and I think it was covered perhaps in the fire strategy although not in a particularly explicit way or a way that I would like to see it
01:54:59 way that I would like to see it done have you seen any evidence that there was actually any discussion between the designers and approvers about these extend extended travel distances and whether there was a need to protect the lobby and all the stairs
01:55:12 to protect the lobby and all the stairs so there was discussion between designers and imprs about extended travel distances but I think it was primarily associated with the internals of Flats on level 0 to three um I don't
01:55:23 of Flats on level 0 to three um I don't recall seeing anything that said they specifically discussed that travel distance um on the existing levels no and would you have expected that to have been explicitly raised and
01:55:34 that to have been explicitly raised and considered I would certainly prefer it to be explicitly documented that it had been considered um but it could have been in a meeting or they might have just I don't know it's it's hard to know not every decision gets documented and I
01:55:46 not every decision gets documented and I wouldn't like to speculate on what those people
01:55:49 people discussed okay now I'm want to ask you about um documentation more generally now and and I want to look at the sca guide B the 2012 version of the sca
01:56:01 guide B the 2012 version of the sca guide at lfb 30
01:56:09 59241 this is the June 2012 smoke Control Association guidance and if we could go within it to page
01:56:20 five here we we have the introduction and if you look at the fifth paragraph down there's a paragraph beginning four it says for the design and approval process to be successful it
01:56:32 and approval process to be successful it is strongly recommended that except perhaps in the simplest cases the system objectives the scenarios to be calculated or modeled the modeling
01:56:43 calculated or modeled the modeling criteria the expected reporting and the success criteria are all agreed and documented prior to commencement of design do do you see that I do see that yeah and then if we go to page
01:56:56 yeah and then if we go to page 14 under Section uh five which is headed objectives and performance criteria and then then there's a heading documentation there 5.4 it says this results should be
01:57:09 5.4 it says this results should be presented in an appropriate form for each agreed Criterion sufficient information should be provided to allow relevant parties to assess the analysis undertaken in relation to checking and meeting the required performance criteria the results of the analysis
01:57:21 criteria the results of the analysis should be documented and may be provided in the form of a report together with any necessary supporting animations from Advanced modeling the documentation should include at least the following
01:57:34 should include at least the following information a description of the residential area and the proposed ventilation system the design criteria and performance objectives of the analysis the scenarios investigated details of the techniques used and
01:57:46 details of the techniques used and related
01:57:48 related information the results of the analysis are statement as to whether the design criteria and objectives have been met do you see that I do see that y so if you're adhering to this guide one would
01:58:00 you're adhering to this guide one would expect to see all of those various aspects of the system documented uh unless it was one of the I think in the simplest of cases I think it says at the start yes would you have said gremel Tower was one of the simplest of cases
01:58:12 Tower was one of the simplest of cases um I would say with regards to the issue of travel distance yes um I would absolutely agree that there should be more design documentation and calculation provided for smoke Control
01:58:24 calculation provided for smoke Control Systems um I spend a lot of my time criticizing other people for not doing precisely that and for insisting that we do do that in the business that I work within um but I have to accept that not
01:58:35 within um but I have to accept that not everybody does that and I think one of the things we've seen I think Dr Lane sort of touches upon this within her report she talks about the history of these systems is that systems of this type which is a mechanical shaft with an
01:58:47 type which is a mechanical shaft with an inp via the stair they've become to some extent um an industry Norm you have um companies that are producing um sort of standardized products which have a
01:58:58 standardized products which have a standardized um sort of pre-approval process for them and one of the problems you have with the building regulations is as Things become a norm people stop asking about the evidence to prove it um
01:59:10 asking about the evidence to prove it um sort of Regulation 7 and the guidance regulation 7 kind of reinforces that that as Things become except practice people stop questioning it and particularly when it ends up into sort of guidance documents and and
01:59:22 of guidance documents and and published um uh uh uh presentations and reports and such like so I I would I'd be aware of that background to this that you know my criticism is that not enough
01:59:33 you know my criticism is that not enough people do analyses of these types of systems but I am very aware that a lot of people consider that these systems are well understood sufficiently so that they don't need to do enough analysis
01:59:44 they don't need to do enough analysis and they can effectively fall back on what have become industry Norms yes I appreciate many people might think that but is that um reasonably good practice is that reasonable practice to think that that
01:59:56 reasonable practice to think that that they're so well established these systems that one doesn't even have to think about documenting what we've just seen here um I certainly don't think it's best practice and I think in some certain building situations you could say it is good practice if it falls
02:00:08 say it is good practice if it falls entirely within the the boundaries of what's been modeled previously um it's certainly not what I like to see my preference is absolutely to do more than that just looking at that list and perhaps if we go back a page so we can
02:00:20 perhaps if we go back a page so we can see the list again at the bottom um at Grandfield Tower who do you say should have been responsible for ensuring that this documentation was prepared and available to use so I would normally
02:00:34 available to use so I would normally expect it to be um in the ideal situation uh a combination of two people I'd expect the fire engineer to do a version of it and then I'd expect the system designer to perhaps to complete that um again one of the criticisms I
02:00:46 that um again one of the criticisms I often make is that fire Engineers don't do enough of the analyses to settle this stuff out that it's P Downstream left to the system designer to do those analyses so I'm very aware that that varies from
02:00:57 so I'm very aware that that varies from Project to project in different cases so um so I can't really say there there's not even really a typical case I have a preference but I'm a fire engineer so I expect the fire engineer to do more work
02:01:09 expect the fire engineer to do more work um unusual in that regard some people expect fire Engineers to do less work but I think so here um are you saying primarily it should have been exov as the fire engineer who should have um
02:01:20 the fire engineer who should have um made sure that this documentation covered at least these CLE clearly key pieces of information according to this SCA guide I I would say that's my my my preference but I I say I'm very much
02:01:31 preference but I I say I'm very much aware that other people have a different View and so yeah other people have a reasonably different view that that it depends because there are there are um certainly
02:01:43 because there are there are um certainly competent people out there who design smoke control systems and that's all they do and they do do their own analyses and such like um and they're they're experts in their own and and involved some of them involved in writing guidance and such like um but
02:01:55 writing guidance and such like um but then you also have situations where you have people effectively putting together ad hoc systems with with no real experience so it it comes down to the individual competencies yes at Grenville we know this wasn't done by the fire
02:02:07 we know this wasn't done by the fire engineer so when PSB come into the project you haven't got all these descriptions you haven't got the scenarios investigated you've got none of this would that put the onus on the system designer to make sure that the
02:02:18 system designer to make sure that the documentation covered these Essential Elements I think it would put the onus that there was sufficient information yes what does that mean sorry sufficient information are we talking about this this in the first Parra suggests it's at
02:02:31 this in the first Parra suggests it's at least this list well sufficient information should be provided to allow relevant parties to assess the analysis undertaken um and if there was no analysis well I guess you would expect to see less documentation but I I would
02:02:42 to see less documentation but I I would expect it to be between the designers and the approvers to agree what is sufficient information and to include at least what we see in the list the bullet point list well I mean that list does kind of assume that you've carried out
02:02:54 kind of assume that you've carried out some form of detailed analyses so if you've not carried out detailed analyses um you wouldn't necessarily expect to see that information would you
02:03:04 you well this reads I would suggest that uh whether or not you've done a detailed analysis already there needs to be documentation that includes at least the following things in these bullet
02:03:16 following things in these bullet points is that your evidence that that is well not wholly because if you go back a couple of Pages there is an alternative pathway for setting out what the criteria for a system is and it talks about if you're using a
02:03:28 talks about if you're using a ventilation uh sorry velocity number I think um then you might just effectively just put that in so it's not necessarily the case that you would always do this level of detailed analyses again it's
02:03:39 level of detailed analyses again it's it's my preference but I accept that other people have a view on that right now just in terms of the design of the system let's think back for a moment to the design of the original smoke control
02:03:50 the design of the original smoke control system at Grille town when it was built in the 1970s Mr Man in his evidence uh described this this is at paragraph 18 of his second witness statement he said it was a natural ventilation system with
02:04:02 it was a natural ventilation system with a mechanical boost function would you agree with that description I think that's a description yeah let's look at um Dr Lane's phase one presentation now at bla
02:04:15 at bla 45481 page 173
02:04:23 and we just need to rotate it round so this is Dr Lane's um diagram of how the original smoke control system was meant to
02:04:32 to operate now and and is it right that effectively what we had was a a pushing in at the South low level of airf flow we can see there there's a a shaft that
02:04:45 we can see there there's a a shaft that you can see marked in blue a pushing in of air and there's some blue arrows into the lobby and then a pulling out of smoke up to high level and a fan at
02:04:56 of smoke up to high level and a fan at roof level is that how you understood the design intent of the original system to work so that's when the fire service have intervened and turned the fans on yes so before that it would be a natural
02:05:09 yes so before that it would be a natural system where air would naturally be drawn in at low level go up correct go through the lobby come out yes but yes you're right so it it's got this mechanical boost which means when the
02:05:21 mechanical boost which means when the fire service want to it can turn it into some form of mechanical operation by pushing in airf flow and pulling out airflow correct
02:05:32 airflow correct yes now if we look at what you say about the existing system in your report if we can go to page 114 of your report I want to look at paragraph 346 and
02:05:43 and following you say at the bottom of that page the existing system had been designed as a corridor smoke dispersal system it was intended to serve one floor at a to time and if we go on over
02:05:55 floor at a to time and if we go on over the
02:05:58 page 347 you say there were a pair of smoke exhaust shafts on the north side of the building and a pair of Inlet shafts on the south side of the building in each lift Lobby there were two pairs of
02:06:09 lift Lobby there were two pairs of dampers sometimes referred to as aov serving these shafts which were designed to open automatically when smoke was detected by sensors in a Lobby this allowed smoke to exhaust up the shafts on the north side of the building to the
02:06:20 on the north side of the building to the outside at roof level fresh makeup air could enter through the sh shafts and you say using the taxonomy I set out in part one the existing system was a hybrid system that used natural shafts
02:06:32 hybrid system that used natural shafts and had the option for a mechanical extract boost a natural shaft system could activate automatically prior to the fire Services arrival with natural exhaust shafts on the North side and a natural Inlet from shafts on the South
02:06:44 natural Inlet from shafts on the South Side fans were also provided for the fire service to achieve if they wanted these would extract via the north side at the top of the building and Supply via the South shaft at the walkway level hence it was a hybrid by being a natural
02:06:56 hence it was a hybrid by being a natural shaft type system during means of Escape but which could be a mechanical extract system after fire service arrival and can we also look at page 168 and what you say at paragraph 4
02:07:11 54.1 you say and we looked at it earlier but just to be clear that the existing system sought to protect their Lobby and by consequence to provide a degree of protection to the stair is that correct
02:07:25 protection to the stair is that correct yes so what would the performance objectives have been for the existing system if you'd been setting them down um I think the performance objective
02:07:36 objective was to some extent the same that they wanted to protect the staircase whether they wanted to protect the lobby is an interesting question um so you can so
02:07:47 interesting question um so you can so what I mean by that is sorry they they're protecting the lobby space and by that they're protecting the staircase whether they meant to protect the lobby as a result of an extended travel distance is an interesting question and
02:07:59 distance is an interesting question and one which is difficult to answer because we're not back at the end of the 1960s when they were doing the design for this building but CP3 allowed you to have um which is the old guidance allowed you to
02:08:10 which is the old guidance allowed you to have a travel distance of up to 15 M yes and they were much shorter than that so I don't think it wouldn't be right to infer that just because they were designing under that guidance that they
02:08:21 designing under that guidance that they were definitely designing to that performance objective um because they were also doing a very Innovative system I think I've mentioned in my report I don't know of an older building that has a
02:08:32 of an older building that has a centralized lobby with a ventilation system in this country okay um I think it's so I I I I would be careful about inferring what the performance
02:08:43 inferring what the performance expectations were from CP3 because they were clearly looking at this as a as a bespoke building I see um but can we agree that the existing
02:08:54 um but can we agree that the existing system does appear to be P primarily trying to protect the lobby by pushing fresh air in and extracting the smoke out it's certainly looking to achieve the protection to the building VI via
02:09:05 the protection to the building VI via the lobby space yeah yeahh now when Mr Man gave oral evidence in the inquiry he told us that he'd been told he didn't say who he'd been told by that the original system didn't have a supply fan
02:09:16 original system didn't have a supply fan at low level and only an extract fan in the north shaft at the top of the building are you able to shed any light on that in terms of the documentation you've read uh I'm I'm sorry I can't no
02:09:27 you've read uh I'm I'm sorry I can't no no um no yeah but um it sounds like you do agree with Dr Lane uh this much that the design guidance CP 371 which was in place at the time and
02:09:39 371 which was in place at the time and appears to have been the design guidance that inspired grenal Tower had as performance objectives first the protection of the common lobbies for means of Escape second the protection of the stair for means of Escape also the
02:09:52 the stair for means of Escape also the protection to Firefighters when using the common lobbies or corridors can we agree that that was those were the performance objectives of CP 371 yes yes yeah yeah now if we turn to
02:10:04 371 yes yes yeah yeah now if we turn to the system that was actually installed at gremel Tower if we go uh within Dr Lane's module 3 report blp
02:10:14 25035 page 260
02:10:22 here if we blow it up we can see an illustration of how the new smoke control system uh was
02:10:31 designed and what we can see is that rather than smoke being pushed in at South uh level to what's happening is smoke is being extracted at that level
02:10:44 smoke is being extracted at that level yes so you mean rather than fresh air being rejected for that level sorry rather than fresh air being pumped in at the South through the South shafts to push and then have a pull position
02:10:56 push and then have a pull position instead what we've got is smoke being exhausted at that South level yes yes and smoke also being exhausted so it's a pull pull rather than a push pull yes you could say that yeah yeah and if we
02:11:08 you could say that yeah yeah and if we go on to figure 7.6 and the next page at page
02:11:12 page 261 this shows the design intent on a floor
02:11:16 floor plan and it's right isn't it that the blue arrows indic at effectively that fresh air is intended to be provided through the
02:11:27 through the stairs
02:11:29 stairs um through the roof vent which is at the top of the stairs and through the door into the direction of the lobby yes uh yes those are the blue arrows and then
02:11:40 yes those are the blue arrows and then smoke is to be extracted uh through the the North and South shafts the pairs of southa North and South shafts that we can see in red with red arrows yes yes
02:11:52 with red arrows yes yes and is the system intended in your view to extract smoke from the lobby was that the primary performance objective or was the primary performance objective to achieve air flow across the door so the
02:12:04 achieve air flow across the door so the objective is to protect the staircase um and to do that this type of system um there there's three effects it induces there's extraction of smoke there is an induced flow through the doorway um and
02:12:17 induced flow through the doorway um and then there also as a result of that a dilution effect as well had you been designing or assisting with the design of this system would you have had any concerns about relying on the existing location of the South shaft
02:12:30 existing location of the South shaft dampers for extracting smoke given that they were low on the floor so we know we can look at a photo if we need to but that the South shaft had vents at low level and the north shaft had vents at
02:12:42 level and the north shaft had vents at much higher level now would you have had any concerns about the the idea of extracting smoke from the south through the South shafts but using very low um
02:12:55 the South shafts but using very low um vents so I think you'd have to think about it um and a lot of it comes down to to experience if this was a much sort of longer Corridor type design um you'd expect that to um potentially change the
02:13:07 expect that to um potentially change the Dynamics of the smoke because in a in a nice long Corridor you get a nice stratified layer of smoke and if you're pulling down at one end and pulling out higher high level at the other end you might distur disturb that but to be
02:13:19 might distur disturb that but to be perfectly honest in a in a smaller Lobby type situation you end up with so much turbulent air um that it doesn't make a huge amount of difference so you wouldn't be concerned that the smoke would rise in the lobby
02:13:30 that the smoke would rise in the lobby and therefore if you're trying to assist with smoke control in the lobby in the early stages of the fire it's not likely to be helpful to be taking it from very low level um I don't know how much of an
02:13:43 level um I don't know how much of an effect it would have on it but I don't think in a Lobby of this size it would necessarily have a significant effect on that like I say the the turbulence effects you like to see in that sort of space um are probably going to mean it
02:13:55 space um are probably going to mean it doesn't make a huge amount of difference what about extracting smoke downwards through the South shaft so previously air was being pushed up through the South shaft to go through the lobby now
02:14:07 South shaft to go through the lobby now this design involves pulling air through those extraction Vents and downwards down the building would you have had any concerns about that I wouldn't say a
02:14:19 concerns about that I wouldn't say a concern but I would say it's a more difficult thing to design because you've got um you're fighting against gravity you know smoke likes to Rise um so you're going to have to pull it down through a shaft then um you're going to
02:14:32 through a shaft then um you're going to have to take that into account where your found you might get a lower extract rate from that side than you would from the other side for example yes now um just in terms of your overall view just help me with this and I'm I'm going to
02:14:43 help me with this and I'm I'm going to try and summarize your view in your report you're critical of EX over's outline fire safety strategy which you say didn't set out the purpose of the smoke control system and what it was to
02:14:55 smoke control system and what it was to what what was to be achieved by it is that correct yeah I think as I said earlier it set the very bare minimum that that you might interpret and is it right there therefore that you agree with Dr Lane that you would have expected the fire
02:15:06 that you would have expected the fire engineer to take a lead role in setting the performance objectives and monitoring the delivery of those objectives on a system like this that is what I think a fire engineer should do
02:15:17 what I think a fire engineer should do yes and are you critical of xover for not doing that in this situation yes yeah yeah and you also appear to be critical of Max forom you say that they
02:15:28 critical of Max forom you say that they prepared uh smoke control proposals revision a and then revision B and you're critical of them for not setting out the functional performance of the system what it was intended to achieve or the basis for their proposed extract
02:15:40 or the basis for their proposed extract rate is that correct yes yeah because they were basically presuming they were just going to copy the existing system and you are therefore critical of work done before psv's involvement and
02:15:53 work done before psv's involvement and you say it hadn't adequately addressed and documented the areas to be protected yes yeah because if we think back to what the LGA guy said it talks about um you know um the existing systems you
02:16:05 you know um the existing systems you should be you should be wary of them you should try and improve upon them Etc and Max swon hadn't considered that option at all really they just said well we're just going to I mean they were going to make some improvements I think it's fair to say um but not substantially to the
02:16:17 to say um but not substantially to the mode of operation yeah and you're also critical of Studio stud e in your report this is at paragraph 404 page 133 for the transcript where you say studioe as Architects should have been very
02:16:29 Architects should have been very concerned that the smoke control provision was not properly resolved at the end of stage D is that correct yes yeah so you're critical of exov you're critical of Max forom and you're
02:16:40 critical of Max forom and you're critical of Studio e yes are you critical of PSB in terms of um the way in which uh they went about designing this system the planning of it I think I
02:16:51 this system the planning of it I think I have been critical about the level of documentation that was provided um of PSB in terms of design and the such like it's not the level that I would like to see they didn't set um did they set clear performance objectives um and um
02:17:04 clear performance objectives um and um scenarios to be investigated thinking back to the the LGA guide so sorry the sca guide no they didn't but wasn't that only if you have significantly extended travel distances or a non-s simple case
02:17:16 travel distances or a non-s simple case and I think they probably thought it was a simple
02:17:19 a simple case now in terms of this system is it right that your view is that this was a mechanical extract natural Inlet system where the inlet was via the stair is that right yes but isn't it right that
02:17:32 that right yes but isn't it right that this system didn't have a permanent natural Inlet Air Supply as would be expected for those types of systems well it's a a version so if if it's an inlet via the stair um which is the system
02:17:44 via the stair um which is the system type I described you wouldn't expect it to have a permanent Inlet the inlet would come via the staircase that's the purpose of that description wasn't this a system where natural leakage mainly
02:17:55 a system where natural leakage mainly around the stair door was relied upon for replacement air supply to the lobby um so during the means of Escape phase when the fans are running in a lower mode yes it would draw air in around for
02:18:07 mode yes it would draw air in around for example from the staircase um to to create some benefit in the lobby can we agree that the more accurate description of the system is a mechanical extract only system as
02:18:19 mechanical extract only system as described in the sca guide 2015 well I don't think it is um because the the point is it's quite important to make the point that the inlet is provided when you open the door because
02:18:30 provided when you open the door because you're trying to protect the staircase so that's the description I would use is the reason you're reluctant to categorize this system as a mechanical extract only system because the sca guide 2015 warns that such systems are
02:18:43 guide 2015 warns that such systems are unsuitable where extended travel distances
02:18:46 distances occur no that's not why I say that I've set out a whole aomy um of smoke control systems and I think describing where the inlet comes from is part of the description of the system because it
02:18:57 description of the system because it helps you understand the different mechanisms that are used to protect the staircase right now Dr Lane's evidence uh in her supplemental report is that
02:19:08 uh in her supplemental report is that typically a multidisciplinary team comprising mechanical engineering fire safety engineers and commissioning expertise would be required to design smoke ventilation systems in such a
02:19:20 smoke ventilation systems in such a build building as Grandfield Tower and she says that in her experience smoke ventilation systems require one of the largest arrays of professional of relevant professionals to ensure
02:19:31 relevant professionals to ensure adequate performance now now do you agree with that I would say it's certainly one of the most um complex things to design in buildings um arguably more so in in new buildings but
02:19:43 arguably more so in in new buildings but also in existing buildings as well um so yeah you do need array of professionals to do it yeah but then again you need that for pretty much anything as well but yeah you I think maybe I've got a
02:19:56 but yeah you I think maybe I've got a bias cuz I spend a lot of my time designing smoke control um but but yeah I think it is a complex and difficult thing to do yeah and paragraph um nine of your report if you could just look at your report on page
02:20:09 14 you say um picking it up in the second line you say I've used my own expert engineering experience to consider whether a reasonably competent person would in the circumstances have
02:20:21 person would in the circumstances have made the same substantive design decisions as those taken by the systems designers is that right that's correct yes and are you assessing the adequacy of the smoke control system design
02:20:33 of the smoke control system design against that which might reasonably be expected from what system designers or what you would expect from a reasonably competent fire engineer um I would say from the team as a whole um so so all
02:20:46 from the team as a whole um so so all those parties and and I'm again I I have to be careful here because I I I don't like to blow my own trumpet but I am considered to be an expert in this area so I'm expected to know a bit
02:20:57 this area so I'm expected to know a bit more than most fire Engineers would know and I might know a bit more than than some other people would know um but but I I've applied that experience in that particular case so I would expect the overall team to have come up with
02:21:09 overall team to have come up with um the same sort of design decisions yes in your opinion would it have been relevant to any non-w worsening approach that one would need to be comparing that
02:21:20 that one would need to be comparing that against the the performance criteria and the function of an of the existing system which may well have been there to protect the lobby not just the stair um I think that's one way of doing
02:21:33 stair um I think that's one way of doing it but in this particular case um I think you know there's General agreement that the system wasn't going to be very good at meeting the the um criteria that it was it was thought to be designed for
02:21:45 it was it was thought to be designed for that it may not have been particularly effective and in fact that that Effectiveness would have varied depending on which level you test the system on as well so it's it's not particularly good um it doesn't provide the same level of protection throughout
02:21:56 the same level of protection throughout the whole building and things like that so I think you you you might take it into account that's one way of doing it but at the same time if you didn't think it was going to be very effective um at dealing with for example ex standed
02:22:07 dealing with for example ex standed travel distances then it's it's setting a lower Benchmark isn't it for the no less satisfactory consideration right in terms of the basis for the PSB design do you agree with Dr Lane's
02:22:18 design do you agree with Dr Lane's conclusion that the design documentation doesn't provide any evidence that either CP3 1971 or any of the approved documents were considered as a means to
02:22:29 documents were considered as a means to derive design objectives nor were performance criteria set on that basis do you agree with that um I I agree with that yes yeah the documentation doesn't
02:22:40 that yes yeah the documentation doesn't set it out yeah and in terms of pb's design is it your view that PSB effectively took the design back to the beginning and was seeking to provide a new system which could achieve the
02:22:52 new system which could achieve the performance aligned to contemporary standards I think yeah compared to the max forom approach that is yes yeah yeah now miss meny has said that no
02:23:03 yeah now miss meny has said that no information was provided regarding the working of the existing system and as such it was not demonstrated that the various amended proposals would result in a no worse situation do you agree
02:23:14 in a no worse situation do you agree with that well there was some understanding regarding the um the for example the nature of the dampers the um operation of the control system or or lack thereof um there were some
02:23:26 lack thereof um there were some calculations done by Max forom of what the natural flow might be but I think the thing that was missing um I mean the fans were actually there I me when I visited gr Tower after the fire the fans from the original smoke control system
02:23:37 from the original smoke control system appeared to still be there but they weren't operable and they weren't running and they'd been moved and disconnected so at North and South level um well C certainly roof level whether they that may have also been the fans
02:23:48 they that may have also been the fans from lower level taking up there I don't know
02:23:50 know there was certainly ventilation equipment up there right because Mr man's evidence was that there might not have been a fan at low level but are you saying you saw that fan or not um I well I wouldn't have seen a fan at level two cuz it was completely remodeled um but
02:24:03 cuz it was completely remodeled um but certainly up at the the rooftop plant room there was still ventilation discarded ventilation plant up there um I think the the only evidence I know of I can recall right now um about there
02:24:15 I can recall right now um about there being fans at level two was I think some of the discussions about when the fans I think the original proposal from PSB um was simply the fans were going to be at roof level but that was probably before they'd been and visited the building
02:24:26 they'd been and visited the building then there was a discussion on site if I remember rightly and decision was taken and I think the comment that was made was to put them where the previous fans have been at level two and I think that's probably where my understanding
02:24:37 that's probably where my understanding of the fact that there were previous fans there comes from right thank you m gr do you mind if I just ask a question about we've referred once or twice the non- worsening principle and if I've understood it
02:24:48 principle and if I've understood it correctly the original system was a natural ventilation system until the fire brigade turned on the extract fan on the roof so from the point of view of people trying to leave
02:25:01 point of view of people trying to leave a flat on a fire floor there would be a degree of smoke clearance by a natural draft mechanism across the lobby and when they got to the stairs there might be some
02:25:13 got to the stairs there might be some inflow of air from the stairs but that wasn't the primary purpose so the stairs might or might not be fairly free so uh with the new
02:25:24 with the new system you actively seek to protect the stairs MH by extracting smoke uh from the lobby um but you're you're introducing a
02:25:37 lobby um but you're you're introducing a new factor which is the clearance of the stairs or at least the protection of the stairs how do you go about um determine non-w worsening when you've got two systems which are doing or designed to
02:25:49 systems which are doing or designed to do essentially different things it's it's complex isn't it yeah um I mean you could you could break it back down to um uh you could you could have for example you could have taken the existing system
02:26:01 you could have taken the existing system simply repaired the dampers um put in you could have run the fans got a calculation and put in exactly the same flow rates and said that's definitely no worse okay um as soon as you start
02:26:14 worse okay um as soon as you start changing the mode it does get more more complicated um and I think there's a number of ways of looking at that and I think the the way it was it seemed to be interpreted at grle Tower I'm taking this from looking at people like Mr
02:26:25 this from looking at people like Mr Hansen's evidence in context Etc and such like is that they kind of said look we know that dispersal systems and the old type of system isn't particularly well regarded these days be a little bit
02:26:37 well regarded these days be a little bit cautious about that because greni was quite an odd dispersal system as well but yeah we know that's not particularly well regarded we don't think the shafts are very big um it doesn't look like it's it's going to be doing much but let's look at trying to adopt something
02:26:49 let's look at trying to adopt something that's closer to current guide Ence where the staircas is the primary focus the travel distances don't look to be unduly excessive yeah that would be no less satisfactory so it's quite a qualitative judgment but I could
02:27:01 qualitative judgment but I could certainly see how they would they would come to that opinion so the advantage you think was the um priority given to keeping the stairs clear as smoke which the SEC which the new system
02:27:13 smoke which the SEC which the new system would provide yeah that was that was betterment if anything is it uh yes yeah careful of the word bman I know it has a a legal meaning and such like but yeah I think it was an improvement um because I
02:27:26 think it was an improvement um because I think the the previous presumption was that if we do a bit of smoke dilution or smoke um dispersal on the lobby that will protect the staircase and what we've discovered is that that doesn't necessarily work out very well um and in
02:27:38 necessarily work out very well um and in a building that does have you know not unduly excessive travel distances the staircase is what really matters um I mean if we'd had the existing system running um on on the night of the fire I think conditions would have been pretty
02:27:51 think conditions would have been pretty disastrous um much much earlier I mean it's difficult to do a a non- worling calculation if you don't know what the basis that you're from which you're starting it is it is tricky um like I say if you were taking the most simple
02:28:03 say if you were taking the most simple case of right we're going to replace like for like but we're going to put slightly better dampers in a slightly better control system in but we're going to use the same ventilation rate then you definitely hit non- worsing by by by
02:28:14 you definitely hit non- worsing by by by by by that regard and that kind of you might say sets a minimum standard but if what we're going to do do is going to apply a modern way of thinking um and do
02:28:25 apply a modern way of thinking um and do the best we can towards that but take into account the existing building constraints then you would also say that's non-w worsening thank you very much or no less satisfactory sorry I use apologies if I use both terms no I think we understand
02:28:37 use both terms no I think we understand each other yes thank you m okay thank you now I I want to look in a little bit more detail about um pb's design um in particular with reference to to leakage paths to start with um
02:28:50 paths to start with um can we look at the sca guide 2012 again
02:28:56 again um and sorry before we do it's right isn't it that the sca guide provides recommendations regarding the need to consider open doors when designing a
02:29:07 consider open doors when designing a mechanical smoke ventilation system because any such system needs to address the foreseeable scenarios which will occur when the system is operating yes and it's right isn't it
02:29:19 operating yes and it's right isn't it that both the 2012 and 2015 SCA guides provide indicative examples of design conditions including consideration of the stair and flat entrance doors opening at different times and different
02:29:32 opening at different times and different durations during both the Escape phase and the firefighting phase respectively yes there's a there's a timeline within the guide for that yeah let's have a look at that typical timeline for a if this is a Time dependent design it's lfb
02:29:45 this is a Time dependent design it's lfb 30
02:29:47 30 59241 and I want to look at page
02:29:54 13 this is table 5.3 at the bottom of the
02:29:58 the page headed typical timeline for time dependent design and you've got various stages I'm not going to go through all of them but let's look for example at the last few stages in that event we can
02:30:12 the last few stages in that event we can see in the last four lines you've got apartment Window breakes door to Stair opens fire service arrival and remains open that's because the fire service may be propping it open with their hoses yes
02:30:24 be propping it open with their hoses yes yep then door to the fire dwelling opens fire service inspection and door to the fire dwelling opens fire service arrival yes that's correct yeah MH so we can see
02:30:35 yes that's correct yeah MH so we can see that the effect there is that as the firefighting begins uh you've got different door opening conditions which a designer ought to be considering as part of a smoke control design yes um yeah I think
02:30:47 smoke control design yes um yeah I think they would although I just be careful this table is for use when you're actually doing a Time dependent design and doing the detailed analyses so there may be other ways of doing your
02:30:59 may be other ways of doing your calculations or or um evaluating your your system characteristics um which wouldn't necessarily follow analyses that looked at each of these particular points but you'd expect it still to
02:31:10 points but you'd expect it still to address those points yes so would you agree that the designers ought to at least be considering what the different scenarios are during both the Escape phase and the
02:31:22 are during both the Escape phase and the firefighting phase
02:31:26 phase yes and there's a a comparable table in the sca guide the 2015 SCA guide I don't think we need to go to it but again it's got stair door opening fire service arrival and door to the apartment fully
02:31:38 arrival and door to the apartment fully opens as some of the scenarios to work through yeah MH now having read therefore the sca guides which uh we certainly had the 2012 guide uh at the
02:31:51 certainly had the 2012 guide uh at the time that PSB was doing its design work um shouldn't PSB have made allowances for different door opening conditions as part of their design so I think the design would need
02:32:04 design so I think the design would need to take into account um providing protection when all the relevant doors are open yes um whether you would necessarily do a detailed design on that would depend upon the method you're
02:32:15 would depend upon the method you're using to justify the design I mean this is for a the the one on screen is for a Time dependent designer approach if you're doing a steady state approach um you might only compare a couple of extreme conditions so let's say for
02:32:27 extreme conditions so let's say for example you're comparing um what a a natural ventilation shaft might achieve compared to a mechanical shaft you might only do a steady state calculation for one of these conditions most likely the firefighting condition so you you do
02:32:39 firefighting condition so you you do take into account or or your system needs to be able to cope when the relevant doors are open yes yes now in her reports Dr laye concludes that she can't identify any time period in the the early stages of the Grandfield Tower
02:32:51 the early stages of the Grandfield Tower fire where only the stair door was open as per the systems design condition for example she points to the fact that the sole use of the stair for means of Escape ended by um one um just after 1
02:33:07 Escape ended by um one um just after 1 in the morning 1 minute past 1 in the morning when the first firefighters entered greml tower now doesn't that indicate that one single stair door being open with all the other doors
02:33:18 being open with all the other doors being closed on the relevant fire floor was an unrealistic design assumption to make so if you look at that timeline that's on the screen at the moment we assume that the person comes out the flat that's on fire the door closes
02:33:30 flat that's on fire the door closes behind them they go to the staircase they open that door and that's case the staircase is the only door that's open um there were situations I think during the early stages of the fire on level four for example when that may have
02:33:42 four for example when that may have happened um but then again we also have a situation at GRL Tower where a lot of the doors didn't close behind residents um but that wouldn't have been necessarily the designed for condition
02:33:53 necessarily the designed for condition and certainly wouldn't be anticipated in the sea guide which would presume that doors shut behind people in your report if we look at your report um at par uh page5 paragraph
02:34:08 496 you say this you're dealing with the type of system specified by PSB mhm and and you say so by contrast a mechanical extract system with a natural inlight via the stair can be defined by
02:34:20 via the stair can be defined by performance criteria of the 2 m/ second velocity through the open stair door that was the performance criteria set by PSB this is readily measurable and there only need be knowledge of the door area
02:34:32 only need be knowledge of the door area to enable the system to be appropriately specified and then you go on to say ideally leakage rates from the lobby would also be known but they can be accounted for by adding an allowance to
02:34:43 accounted for by adding an allowance to the volume flow rate for the fan do you see that yes now just helpers where you're referring to leakage rates from the lobby what exactly do you mean by leakage rates there so um there I'm
02:34:55 leakage rates there so um there I'm talking about the um air that might come through from um other doors and and around cracks and such like and and um lift shafts everything else yeah MH yeah so we've been talking about open doors
02:35:07 so we've been talking about open doors like open flat doors that's one area of leakage you you we know there's a a lift shaft at Grandfield Tower we know there are service Rises going through so there
02:35:18 are service Rises going through so there could be leakage from number of different Pathways in that Lobby can we yeah I would tend to think of leakage in terms of yeah smaller cracks non non-specific um leakage Pathways within
02:35:31 non-specific um leakage Pathways within the the building construction yeah and and just help us with this how do it's a simple question but just so we're all completely understood how do leakage rates potentially affect the performance of a system like the one which PSB
02:35:43 of a system like the one which PSB designed including its ability to protect the stair so if you didn't take that into account um um when you put your fan in um and you turn it on you'd be drawing some air from those other
02:35:54 be drawing some air from those other leakage Pathways and you would end up with a a lower velocity at the door so you'd have to increase your fan speed um to take into account those extra leakage rates yeah now if we look at paragraph
02:36:05 rates yeah now if we look at paragraph 572 on your report page
02:36:14 176 you you say there if inadequate extract is provided then more smoke can enter the stair and when this is coupled with inadequate makeup air this can result in increased smoke entering the corridor Lobby and migrating to the
02:36:26 corridor Lobby and migrating to the stair this type of effect can occur in an undersized mechanical extract system using Push Pull or undersized mechanical extract with natural shaft Inlet so the
02:36:38 extract with natural shaft Inlet so the latter being the type you say was installed at GRL Tower yes uh I'm not sure I think in this section here I'm discussing some of the differences between different system types right so I'm not entirely that that's being read
02:36:50 I'm not entirely that that's being read in context if if if I think what you're going to say is next but okay but you then go on and you say it is important therefore that systems such as these are fully calculated on a caseby casee basis
02:37:02 fully calculated on a caseby casee basis because they are more sensitive to the building physics yes y so what I'm referring to there is in particular where you have so where you have systems that use multiple shafts so that's absolutely my my my preferred design for
02:37:14 absolutely my my my preferred design for smoke control um particularly where you have extended corridors is you have more than one shaft um but to actually get those to work you have to be um aware of the fact that it's um uh it's got to
02:37:27 the fact that it's um uh it's got to draw it's got to protect the lobby and it's also got to create a flow through the staircase so it's much more sensitive to the building physics so that that's what I'm referring to there is is that type of system right but can
02:37:38 is is that type of system right but can we agree that it was important that a system like the one at greni Tower was fully calculated on a case- specific basis because it would also be sensitive to building physics well no because it
02:37:50 to building physics well no because it I'm talking about calculation here from a different perspective so it's important that the fan could achieve the necessary flow rate and you've got two ways of doing that you can either have a guess at what you think the extra leakage might be and stick a bit on your
02:38:02 leakage might be and stick a bit on your fan speed and you might argue that's a slightly less efficient way of doing it you might end up with a bigger fan than you needed or you might end up with still not a big enough fan and have to go and replace it or or or or tweak the fan you can you can tweak fans to
02:38:13 fan you can you can tweak fans to produce a bit more power what I'm talking about here is the actual um protection mechanism being much more complicated and needing to be calculated right I
02:38:25 see I think that's a second pfb they they took the former didn't they they basically had a guess at what the leakage might be and stuck on a bit for the fan yes is that fair I believe they
02:38:36 the fan yes is that fair I believe they applied their um experience or or engineering judgment to it yeah yeah MH I mean we don't see any um we don't have any documentation that
02:38:49 um we don't have any documentation that uh shows any kind of calculations about leakage or any analyses whether they be hand calculations or anything more sophisticated do we we don't have those that's right yeah yeah and and to be
02:39:00 that's right yeah yeah and and to be honest you wouldn't necessarily I mean even in the more detailed calculations you wouldn't necessarily try and work out every single leakage path you would always stick a bit on at the end um to make sure that the fan that's put in and
02:39:12 make sure that the fan that's put in and the shafts that you design are big enough to to accommodate it it's one of it's one of the biggest challenges I find in designing smoke Control Systems is is that um your leakage paths change throughout the design process they can
02:39:23 throughout the design process they can change in the lifetime of a building as well um so you have to be very careful about that and you you make allowances okay there's nothing worse than designing a building where your shafts aren't big enough and they started building it it's very difficult to undo
02:39:35 building it it's very difficult to undo and do you agree with Dr Lane that some mechanical calculations for pressure drop also ought to have been carried out when PSB was selecting its fan sizes for the new system so to specify a fan um
02:39:46 the new system so to specify a fan um you take into account the flow rate and the pressure drops you want to use and you do that using a fan curve which was included in the technical submissions so I presume I mean
02:39:57 submissions so I presume I mean typically when you're picking a fan and I think with the alter ones that they used at um at gfor Tower there's a calculator you you go online and you type in the various Dimensions that you need and it tells you which fan works
02:40:08 need and it tells you which fan works and it prints out a fan curve which tells you whether the fan can deliver required pressure drops right can we agree therefore that for the type of system designed by PSB the following important work ought to have been carried out out first the system should
02:40:21 carried out out first the system should have been fully calculated taking into account the foreseeable door opening conditions and any other leakage should a fire and a flat occur
02:40:31 occur um okay I I would certainly prefer it to be done like that but I can understand in in the industry why it's come about that isn't done because people have looked at um what's become the industry
02:40:43 looked at um what's become the industry Norms um or they've done their own modeling on previous projects and they've developed um they know what extract rate is needed to provide protection to the staircase um and
02:40:54 protection to the staircase um and therefore what they're really looking to do is provide an extract rate and then because it's hard to measure an extract rate on site they convert that back into a velocity that they achieve through the door in a commissioning state which
02:41:05 door in a commissioning state which would be just a single door open and I my understanding from um uh Mr Man is that that's what he did I see can we look um at paragraph 1429 of
02:41:16 see can we look um at paragraph 1429 of your report now on page 431
02:41:24 so at 1429 you say Dr Lan has also been critical in her Phase 2 smoke control report of the absence of calculations considering the potential impact on the system from doors to Flats on the fir floor including the far flat being open
02:41:37 floor including the far flat being open at the same time as the stair door such criticism is however not substantiated by an explanation or analysis of the competing resistance Pathways that would occur I have included in part two some
02:41:48 occur I have included in part two some basic flow pathway calculations which confirm that flow from the stair should remain the path of least resistance even when a flat front door is open a similar
02:42:01 when a flat front door is open a similar point was expressed by Mr Man in its all evidence now taking this in stages is it right that in your report the report from last August you've carried out some leakage calculations yourself to assess
02:42:13 leakage calculations yourself to assess the extent to which the air flow through the stair would be affected when for example a flat door was open with a pathway to air on the outside of of of the building um yeah I I included some
02:42:24 the building um yeah I I included some calculations to help explain that effect yes yeah no such calculations were carried out by PSB at the time this system was designed is that right not aware of yeah no should such calculations have been carried out by a
02:42:36 calculations have been carried out by a reasonably competent designer of one of these systems again that's my preference that they are calculated out on a case-by Case basis but I also understand that an engineer might take a value they've used on another project knowing
02:42:47 they've used on another project knowing that that's worked and applied that did it fall below the standards of a reasonably competent designer not to carry out those
02:42:58 calculations it's difficult to say because like I say I I have be very careful here not to put forward just what my preference is my preference is that it's done on a case-by casee basis and that's the way I think it should be
02:43:10 and that's the way I think it should be done um whether a it's it's okay to use previously calculated designs is difficult to argue it's difficult to argue against that because there are systems out there that use previously
02:43:22 systems out there that use previously calculated numbers um and put that forward as a standard design so I think there are people who certainly believe that in the industry so I think there's there's a range of views available on that I appreciate there might be a range
02:43:33 that I appreciate there might be a range of views in your opinion does it fall below the standards of a reasonably competent designer not to do those calculations I don't think I can say it definitely does I'd like to be able to say it does I'd like to be able to say
02:43:44 say it does I'd like to be able to say that that people should definitely do that but I can't really say it does because I think a lot of people particularly those in the Practical insallation end of smoke Control Systems feel that there's enough analysis done and that they can rely on the previous
02:43:56 and that they can rely on the previous studies that have been carried out okay now I'm going to go back um go looking back at paragraph 1429 it's still on the screen we can see that you say there that the on the basis of your
02:44:08 say there that the on the basis of your calculations you can confirm that the stair should remain the path of least resistance even when a flat front door is open and you use this phrase path of least resistance a number of times in
02:44:19 least resistance a number of times in your report and indeed Mr Man used it once in his evidence um what exactly do you mean when you say that the stair is the path of least resistance when the
02:44:31 the path of least resistance when the stair and the flat door are open so if you're extracting from a volume such as the lobby space and there are two primary Pathways we're considering of
02:44:42 primary Pathways we're considering of air getting to that Lobby either for example coming from outside through a flat through a kitchen window through a door way through a hallway into the lobby or coming through a staircase door from a vent at the top um I'm saying
02:44:55 from a vent at the top um I'm saying which one has the lower resistance to airflow and therefore that would determine which one has the majority of the air flow coming through it yes is path of lease resistance a technical term that we see defined in any of the
02:45:07 term that we see defined in any of the relevant standards or or guidance documents I don't think it is um I mean I use that term because um you'll assen the calculation I used in my report um people might be familiar with that from
02:45:19 people might be familiar with that from sort of high school physics when you calculate the resistance in a network for electrical reasons and and fluid flows and such like it's a standard calculation so I used that term because I thought it would be familiar and
02:45:30 I thought it would be familiar and accessible for people yes you see Dr Lan says in her report that um that's not a a a concept that she recognizes and that
02:45:41 a a concept that she recognizes and that what's
02:45:42 what's important is that you work out by how much does your flow through the stair reduce when you've got these leakage rates
02:45:49 rates forget which is still has more air going through it what you really need to know is whether your your flow rate through your stair door has been compromised and
02:46:00 your stair door has been compromised and by how much now do you agree with that well you do that by working out what the different resistance pathways are exactly and that's I mean that's a term I would use I mean I I I I started
02:46:12 term I would use I mean I I I I started off my career as an academic in um uh fluid dynamics um I've worked in research in fluid dynamics and I've used that term multiple times to to describe different complex networks and the such
02:46:24 different complex networks and the such like including research work I've done so I think it is a term that I think would is is is applicable to use but the process you've just described there Dr Lane saying the important thing is to
02:46:36 Lane saying the important thing is to work out whether or not you're getting enough flow through your Doorway to do that you do a resistance calculation yes can can I just ask you this um we we're postulating a situation in which a flat
02:46:47 postulating a situation in which a flat door is open mhm and there is a pathway to air from the flat yeah to what extent does the air flow through the flat front
02:46:58 does the air flow through the flat front door depend on the size of the uh opening to the outside um it is it is critically affected by it um so uh the the calculation realiz it's a it's a
02:47:11 the calculation realiz it's a it's a inverse Square relationship when you add them all up and such like if you put the calculation on screen I could talk you through it but but yeah if you so having a for example let's say you had two doorways let's say the the stair door
02:47:22 doorways let's say the the stair door and the flat door were both exactly the same size if your window the other side of a stair door was only one square meter but it was 2 square m um on the other side from the staircase you would
02:47:33 other side from the staircase you would have a much lower path of resistance from the staircase compared to the flat well that's how it struck me as a matter of common sense but I asked the question because the size of the opening to air
02:47:45 because the size of the opening to air on the outside of the flat will be inherently uncertain would it because they might have a broken window as a result of the fire or there might be large areas of Windows left open I mean
02:47:58 large areas of Windows left open I mean how this one account for that yeah yeah I mean window breakage is one of the most complicated areas of of fire engineering and it affects everything from smoke control through to to structural engineering design and the such like it's it's quite an interesting
02:48:11 such like it's it's quite an interesting area as well we we we've had a lot of concerns over the years as fire Engineers about people putting in more modern sort of double glazing Windows there was a big concern from America a few years back that it actually restricts ventilation that those windows
02:48:22 restricts ventilation that those windows don't break readly in a fire and you end up with um a hot um uh viated combustion condition that leads to what's called a backdraft when the fire service open the door um that doesn't seem to have been
02:48:34 door um that doesn't seem to have been the case at grf for Tower interestingly enough I think the the overall probably a lot of Plastics in the in the overall external construction meant that there was window failure but
02:48:45 meant that there was window failure but window failure also doesn't tend to happen with the whole window going you tend to get breakage fracturing it's a very very complicated area it's hard to work out I can I can understand the difficulties when not talking about the
02:48:56 difficulties when not talking about the design stage what's being suggested is one ought to do a calculation um to compare the inflow from the stairs and the inflow from the flat to to the lobby yeah and I was just
02:49:07 flat to to the lobby yeah and I was just wondering what you take as the uh postulated size of the opening to air on the other side of the flat front door which would seem to me to be inherently
02:49:18 which would seem to me to be inherently uncertain so yeah when when I do that sort of calculation within a model or or I work with my team to to do that sort of calculation you got to be quite careful as well because you might think that well a small opening um um makes
02:49:30 that well a small opening um um makes the the the is better or a big opening is better but your opening to outside is probably also where most of your ventilation for the fire is coming from so if you have a big opening you get
02:49:41 so if you have a big opening you get potentially a slightly bigger fire um and you get a lower resistance pathway but at the same time you will also see smoke flowing straight out of that window as well so we tend to model it for example with a very relatively small
02:49:54 for example with a very relatively small opening at low level so the smoke can't get out to put the system under more stress but that's the way we we we model them we're doing a fully calculated design but you're right there's a very complicated relationship between the
02:50:05 complicated relationship between the amount of ventilation the fire has so how big the fire is the amount of smoke that will actually eject straight out of that window which can be quite a substantial quantity um and also then um
02:50:17 substantial quantity um and also then um the amount of smoke that goes the other way it it is it is a you're right an inherently difficult and complicated relationship so it you tend to rely upon um well we tend to model it and and and
02:50:28 um well we tend to model it and and and do a number of different cases for example to to take that into account but a lot of people have modeled this stuff there's a lot of people who've done analyses for these types of systems and some people consider that enough analysis has been done I I don't I think
02:50:40 analysis has been done I I don't I think should do it each time but yeah right thank you very much thank you Mr yes um I want to go within um Dr Lane's supplemental report now to where she's um effectively responded to your
02:50:51 um effectively responded to your calculations and we've got a number of very helpful visual diagrams which help um look at your respective positions um can we start though if we look at um BL RP 250 43 at page
02:51:09 163 and at paragraph 7.4.1 where she's looking at the stair flow path um she says that you have overestimated in your calculations the
02:51:21 overestimated in your calculations the size of the door opening between the stair and the lobby at 7.4.4 we can see that she says that your calculations assume the stair was uh
02:51:32 calculations assume the stair was uh just over 2 m Square when in fact it was only 1.68 M Square now do you accept that um actually no I think there's I think there's probably a small typo in
02:51:44 think there's probably a small typo in my report which I need to have a look at but I have a recollection when I did that calculation um that I took into account the actual full size of the stairhead
02:51:52 stairhead vent um which is where you get a slightly different answer from as well I don't think I took into account a 2 squ meter doorway right um and she's tried to work backwards from your calculation to work out what uh size of stair door
02:52:05 to work out what uh size of stair door opening you were assuming well but she's also assumed that the vent at the top of the staircase was only one square meter um and I think it was actually slightly bigger than that so I think I think that's where the the difference is and it'd be wrong to back calculate like
02:52:16 it'd be wrong to back calculate like that just in terms of how you go about calculating this the methodology if we look back to page 160 can I just also just say as well I think the answer she came out with was 0.989 square meters
02:52:27 came out with was 0.989 square meters and I've and I quoted it as 0.9 square meters so I don't think it's not a huge difference it's a very very small difference that's fine no I I just I have to put these points to you um if we
02:52:38 have to put these points to you um if we go back to page 160 of of her report she explains that the relevant British standards when you're making these calculation refer to two types of leakage path there are parallel leakage
02:52:50 leakage path there are parallel leakage paths and there are series leakage paths and um if you look at the top of page
02:52:56 page one61 which is I think helpful at 7.3.6 she says to understand why leakage paths are treated in parallel or in series you can see the relevant bit of the British standard so a parallel path
02:53:09 the British standard so a parallel path occurs where all the doors opening out of a stair lead directly to an unpressurized space and then leakage paths in series occur where there's an intermediate space into which air from another pressurized space first flows
02:53:22 another pressurized space first flows before finally leaking out to the unpressurized space through other leakage paths and if you go to the diagram below as I understand it what she's saying is for the flat you have to do leakage paths in series because
02:53:35 do leakage paths in series because you've got a wind potentially a window opening going to the outside then you've maybe got a kitchen door and then you've got an open flat door so you look at those in series but then when you're
02:53:46 those in series but then when you're looking at the total effective leakage area to the lobby you look at those in parallel because you've got leakage coming through the stair and leakage from the flat does that makes sense yeah
02:53:57 from the flat does that makes sense yeah it's quite a nice diagram yeah yeah so um can I take it that there there's no disagreement between you about the methodology by which you can go about calculating these respective leakage paths um yeah that's that's just basic
02:54:11 paths um yeah that's that's just basic physics yes yeah and um at 7.37 yes we've got that uh methodology and then if we go to figure 7.4 at page
02:54:25 164 if we can blow this figure up what she has done is she has shown in visual form the scenarios that you've considered in your calculations and we can see that in
02:54:37 calculations and we can see that in yellow is is an opening to an area and in green is a partial door closure so to take your case one what we've got is at the bottom the
02:54:48 one what we've got is at the bottom the the space of the roof ventilator then we've got the stair door opening the flat entrance door opening the kitchen door opening and then we've got a little window opening there do you see that yes and then you've done three different
02:55:00 and then you've done three different case scenarios you've done a different case scenario where you've got a partially closed flat entrance door opening yes Y and then you've done another case scenario case three where
02:55:11 another case scenario case three where you've got a kitchen door opening that's partially closed and a flat door opening that's partially closed is that right yes and then if you go to figure 7.6 on page
02:55:25 169 and if we blow that diagram up what we've got is your on the right hand side are your uh case scenarios that we just looked at the three of them MH and then
02:55:37 looked at the three of them MH and then on the left hand side she has posited certain alternative scenarios which um she says are more realistic scenarios certainly when you get to firefighter
02:55:49 get to firefighter um that ought to have been considered are they all realistic though well I'll ask you about that in just a moment let's take this in stages um is it right that your
02:56:01 stages um is it right that your scenarios your leakage paths only ever assume a window opening of 0.25 M squared yeah I was basically making an estimate of what a window that being
02:56:12 estimate of what a window that being slightly a jar might might be you a window that was held open and what she's done is you can see in case one she's got a much bigger window opening in case two a smaller one
02:56:23 window opening in case two a smaller one I think case one is where the whole window unit is completely failed yeah Y and case two is her assessment of the window being partially open yes yeah now in in case three it might look on this
02:56:36 in in case three it might look on this diagram like it's the whole wall that's missing yes and you you say that in your I think in your your statement last week you make that point is that right well that's how how it appears to be drawn yes um but I think if if you read
02:56:49 yes um but I think if if you read there's some other sections of Dr Lane's report and we can clarify this with her tomorrow but if you look at page 168 and table 72 which show her calculations of her
02:57:02 72 which show her calculations of her three different scenarios in fact the window area she's got there is na not applicable and my understanding is the reason for that is that effectively once your window gets a certain
02:57:14 your window gets a certain size um it doesn't matter how much bigger it gets because it's the flat front door that is the governing parameter in terms of leakage well she's presumed that there is no resistance at
02:57:27 presumed that there is no resistance at all from the opening to outside that's what the calculation is assumed right well as far as I can tell anyway I I think she may disagree with that but I'll get her to clarify that um when she
02:57:38 I'll get her to clarify that um when she gives evidence tomorrow okay um if you look at
02:57:41 look at 7.5.2 on page
02:57:45 171 she says 7 5201 171 that her final scenario is assuming a flat door opening of 1.4 m a kitchen door opening of 1.5 and no restriction
02:57:57 door opening of 1.5 and no restriction by window opening which is what I just said yeah yeah yeah and and but my understanding is that's because it's the flat front door opening of 1.4 M squared which is the important
02:58:09 of 1.4 M squared which is the important uh figure there and it doesn't matter if your window is bigger than 1.4 M squ it's not going to make any difference does that make sense true but I'm not quite sure where she's derived that
02:58:20 quite sure where she's derived that window being that size from the way it's drawn it suggests it's the failure of the whole W no I appreciate that let's go back to figure 7.6 76 on page
02:58:36 169 even if we ignore case three for a moment in her cases doesn't this show that there are more realistic case scenarios certainly once firefighting
02:58:47 scenarios certainly once firefighting has begun which ought to have been calculated well I think there's lots of scenarios that you could calculate um I wasn't trying to do a detailed analysis of the system I wasn't trying to justify
02:58:58 of the system I wasn't trying to justify PSP system I was trying to explain the process by which different Pathways can emerge and how they interact so yeah there's lots of Pathways that
02:59:10 so yeah there's lots of Pathways that could emerge now if we go to figure 77 on page 173
02:59:18 here what could we have a could we have a look at the I think Dr Lan's got a diagram that shows the wall and how she's calculated the window areas um we may be able to go to that I tell you what let's do that after the lunch break
02:59:30 what let's do that after the lunch break and I can find the paragraph this might be a good point mightn't it um that sounds like it is a good moment Mr chairman I'll stop there I think it's time we all have a break um Mr Le we're
02:59:41 time we all have a break um Mr Le we're going to stop now so we can all have some lunch we'll resume please at 2:00 and as I said to you last time please don't talk to anyone about your evidence while you're out of the room all right thank you very much
03:00:02 2:00 thank you Miss Grange thank you 2 o00 please