Evidence from Hugh Marney, smoke control system designer at PSB UK Ltd who worked on Grenfell Tower refurbishment. His testimony reveals he knew the existing system was non-compliant and believed no compliant system could be installed within the project constraints.
00:00:42 good morning everyone welcome to today's hearing today we're going to hear evidence from mr hugh marney who was the designer of the smoke uh ventilation system installed during
00:00:55 uh ventilation system installed during the refurbishment of grenfell tower now mr marley is going to be examined by miss grange but i'm afraid again miss grange isn't able to be with us in person so she's going to conduct the proceedings
00:01:07 going to conduct the proceedings remotely and mr mani also is not able to be with us in person so we're going to be taking his evidence remotely
00:01:16 remotely so the picture you get will be a little different from that which you would normally get when watching the proceedings of the inquiry but i hope that things will go well without any great difficulties
00:01:28 difficulties so the first thing i must do is to make sure that we have contact with miss grange ms grange are you there yes good morning mr chairman can you hear me good morning we can thank you and i take it you can see us and hear us
00:01:40 and i take it you can see us and hear us all right is that the case yes i can very clearly thank you very much the the next step then is to make contact with mr mani mr mani are you there yes i'm here thank
00:01:53 mr mani are you there yes i'm here thank you very much and i can hear you loud and clear oh good good morning it's very nice to see you um well as you know miss grange isn't with us in the room so you and she are both going to uh conduct this remotely
00:02:05 conduct this remotely um i hope that'll be fine you might need to take a little bit of care not to talk over each other because of the very slight time delay that can occur in these matters right now mr marnier i
00:02:16 matters right now mr marnier i understand that you're going to make the affirmation is that right that is correct and you should have the words of the affirmation on the screen coming up now could i ask you please to
00:02:27 coming up now could i ask you please to read them out i do solemnly sincerely and truly declare
00:02:33 declare and affirm that the evidence i shall give
00:02:36 give shall be the truth the whole truth and nothing but the truth good thank you very much now mr money um just to put you in the picture we you may know this but we have a break during
00:02:47 may know this but we have a break during the morning and the afternoon sessions roughly 11 15 and 3 15 whenever it turns out to be convenient but if you would like to have a break any other time would you just indicate that and we can accommodate you without
00:02:59 that and we can accommodate you without difficulty thank you for that right thank you very much uh well if you're ready to go i'll invite miss grange to uh put some questions to you yes we're strange
00:03:09 strange yes thank you yes can you please give the inquiry your your full name hugh malcolm manny thank you very much for coming to give evidence today and to assist the inquiry with its
00:03:20 assist the inquiry with its investigations it's very much appreciated i'm going to be asking you the questions today if you have any difficulty understanding anything i'm asking you please just ask me to repeat the question or put the point in a different
00:03:32 question or put the point in a different way
00:03:33 way and as the chairman's just said if you feel you need an additional break over the ones that we normally take please just let us know now you've made two witness statements to the inquiry can i take you to your first statement
00:03:45 can i take you to your first statement this is at psb
00:03:58 401329
00:04:02 so there is your first witness statement and if we go on to page 16
00:04:11 we can see that it's dated the 28th of september
00:04:15 september 2018 and is that your signature it is and have you read that statement recently i have and can you confirm that the contents are true to the best of your knowledge and belief yeah thank you and let's go to your
00:04:27 yeah thank you and let's go to your second witness statement this is
00:04:31 psb401373 there's the second statement and if we look at page 15 we can see it's dated the 26th of march
00:04:42 we can see it's dated the 26th of march 2021
00:04:44 2021 and is that your signature it is and have you read that statement recently i have and again can you confirm that the contents are true to the best of your knowledge and belief they are and have you discussed the
00:04:56 they are and have you discussed the evidence you're going to give with anyone before coming here today no now i'm going to start by asking you some questions about your background including your qualifications and experience
00:05:07 experience if we could look first at paragraph 10 of your first witness statement on page two of that
00:05:16 psb401329 so here you set out your qualifications and you tell us after leaving school i completed an indentured apprenticeship
00:05:27 i completed an indentured apprenticeship with a company that was originally called
00:05:29 called richard crittel and zd bury limited now known as crownhouse engineering this apprenticeship lasted five years and covered the design and operation of mechanical systems
00:05:40 mechanical systems and you tell us that you also completed a four year course at technical college and hold a 632 city and guilds qualification in heating and ventilation is that right that's correct in terms of that last
00:05:52 that's correct in terms of that last sentence
00:05:53 sentence are those separate courses you say there's a four year course at technical college and a city and guilds qualification are they the same thing or were they different causes same thing yeah when did you undertake that
00:06:05 yeah when did you undertake that training
00:06:07 training from 1960 on to 1969 for the next five years
00:06:13 years and did this training cover anything about the design of smoke control systems
00:06:18 systems no and have you undertaken any further professional qualifications or training other than what we see there in your statement no and are you a chartered engineer no
00:06:32 and are you a chartered engineer no now if we go to paragraph four of your first witness statement on page one
00:06:43 in this part of your statement you're setting out your experience prior to your work on the grenfell tower refurbishment project and you tell us that you have worked in the smoke control system
00:06:54 the smoke control system industry for over 35 years developing and designing smoke control systems is that right yes that's correct and in terms of your employment history is
00:07:06 in terms of your employment history is it right that your experience with smoke control systems began while working for noire limited a fan manufacturing company in about 1983
00:07:16 1983 that's correct new air is the pronunciation sorry yes new air and then at paragraph five of your second witness statement uh we i don't think we need to turn that up
00:07:27 we i don't think we need to turn that up you say
00:07:28 you say that new air limited had invented a smoke clearance fan that would work at certain temperatures which you were then involved in selling to the market is that correct that's correct yeah
00:07:40 is that correct that's correct yeah and then if we can go to paragraph 11 of your first witness statement on page two
00:07:54 you explain that you worked at new air
00:08:00 um
00:08:05 as a specialist smoke control that was especially stroke control business including as an in-house expert for eight years after 1992 is that correct yes and then at
00:08:16 is that correct yes and then at paragraph 12 below that you say that after working in a couple of interim positions you then set up and run your own business advanced smoke technology from 2003 to 2010 which you ran with a
00:08:29 from 2003 to 2010 which you ran with a business partner yes that is correct and you also explain that during that time you began working alongside psb on some projects and you got to know martin booth the managing director of
00:08:40 martin booth the managing director of psb
00:08:41 psb that's correct and then after briefly working for two dutch smoke control companies you joined psb in early 2013 is that correct
00:08:52 joined psb in early 2013 is that correct that's correct now thinking back to your time before joining psb so at new air and well running your own business at advanced smoke technology
00:09:03 smoke technology and indeed those dutch companies did any of those roles involve actually designing smoke control systems
00:09:10 systems yes all of them or some of them all of them yeah now roughly what proportion of the work that you did on smoke control
00:09:22 that you did on smoke control systems before you joined psb was in a residential context rather than in commercial buildings more residential than commercial right
00:09:33 more residential than commercial right and in terms of residential how common was it for you to be designing a system for a residential high-rise building less common and small rise because there were less high-rise buildings right so
00:09:46 high-rise buildings right so just approximately how many high-rise projects residential projects do you think you've been involved in before you joined psb um do you mean projects that were taken through to conclusion or
00:09:58 through to conclusion or just designing and tendering let's put designing
00:10:02 designing designing a lot um i couldn't put a number to it okay now while working at psb if we look at paragraph 13 of your first statement
00:10:13 at paragraph 13 of your first statement on page three just bring that up
00:10:22 you tell us that while working for psb that your
00:10:25 that your your job changed this is in the last two lines from commercial manager to technical sales manager during your time at psb that you tell us that this did not involve any change to your role or
00:10:37 involve any change to your role or responsibilities what products or systems does psb design and sell
00:10:47 and sell psb um don't sell directly a product other than the controls right so they they would buy in other products that would form
00:10:58 buy in other products that would form parts of the system so i'm not sure what you mean by your question i think in terms of design work um do psv only work on smoke control
00:11:09 do psv only work on smoke control systems or do they design other types of system only smoke control systems
00:11:14 systems yeah and as commercial manager and then technical sales manager at psp what were your roles and responsibilities um at that time i was effectively
00:11:27 um at that time i was effectively leading what we call the above ground technical people designing smoke control systems and also i was through my committee work
00:11:38 and also i was through my committee work able to inform the company of any changes that were going on within the industry i see so you were you were leading the above ground technical people on the design of smoke
00:11:49 technical people on the design of smoke control systems were you yourself actually responsible for designing smoke control systems in those roles i was still responsible yes it was a very small team so i was very active in design yes and that included
00:12:02 in design yes and that included residential high-rise projects did it predominantly residential yes yeah and and did you have dedicated designer roles within psb for people beneath you no
00:12:18 anyone designing um smoke control you say below me there there wasn't a hierarchy that no one answered to me i wasn't managing people i see you were just part of a team
00:12:30 i see you were just part of a team yes that designed smoke control systems that's correct i see and for those of you that were part of that team and were designing those systems did psb require you to carry out any
00:12:41 did psb require you to carry out any specific technical training no
00:12:47 and you also tell us in your statements that in february 2016 you left psb and you moved to colt
00:12:58 you left psb and you moved to colt smoke control part of colt international limited is that right that's correct and what was your role at colt techno sales consultant
00:13:11 at colt techno sales consultant and what did that role involve designing and selling of smoke control systems so you were both designing and selling them yes yes
00:13:22 them yes yes and is it correct that you then retired from work in december 2020 that's correct yeah and were you designing smoke control systems for residential
00:13:33 residential high-rise buildings from time to time while at colt yes yes
00:13:40 yes yes now you also tell us in your statement about your experience on various committees who issue standards and guidance can we just look at paragraph 14 of your first witness statement on page three
00:13:58 you tell us there i've always been interested in smoke control systems and the regulations surrounding them i have watched things develop and have also had the opportunity to contribute myself
00:14:08 myself as the industry has evolved over the last 40 or so years during that time i was for many years an independent member of british standards institute
00:14:17 institute fsh 25 committee for smoke control systems
00:14:21 systems and i also have a long history of involvement with the smoke control association and you tell us you held the post of chairman of the smoke control association from 1998 to 2000
00:14:32 association from 1998 to 2000 and had an active role in the association as a member of both the technical and plenary committees and then if we look at paragraph 18 um actually we don't need to go to it in
00:14:43 actually we don't need to go to it in paragraph 18 of your second witness statement
00:14:46 statement you explain that that british standard institute fa fsh 25 committee was responsible for reviewing any documents information etc which was or could be related to smoke
00:14:58 which was or could be related to smoke control systems is that right correct now can you just help us what do you mean what does it mean to be an independent member of that fsh-25
00:15:09 an independent member of that fsh-25 i was on the committee i was co-opted to the committee because of my background in stair pressure differential systems and i did not represent any other organization
00:15:20 organization at all so i was independent i see
00:15:28 did you have a specific role having been co-opted to that committee once you were co-opted onto it not initially no and and after a time did you develop a specific role i was
00:15:40 specific role i was no i was asked by the committee to take on the responsibility to represent the committee
00:15:45 committee at uh send working group 191 um subsection working group six which was for pressure differential systems yes great i'm just going to come to that in a moment
00:15:56 in a moment just in general can we take it from your experience and your involvement with the british standards institute that you were familiar with the british standards that applied to smoke control systems i was now if we go to paragraph 21 of
00:16:08 i was now if we go to paragraph 21 of your second witness statement at page four
00:16:18 here we deal with the point you were just mentioning you say you were then proposed and accepted by the members of the
00:16:25 the of the fsh 25 to be the committee's representative on this working group six and you explain that that was the working group you can go over it was the european
00:16:36 you can go over it was the european group responsible for drawing up british standard en 12106 part 6 2005 which was titled smoke and heat control systems specification for pressure differential
00:16:48 specification for pressure differential systems kits and you say at that time the uk did not have a principal expert on that working group
00:16:56 group and so i was asked by the bsi to take the position of principal expert for the uk on the working group so can we take it from that that you would be very familiar with that particular british standard 12101 part
00:17:08 british standard 12101 part 6. yes it was were you also familiar with the practical guidance set out in approved document b on fire safety insofar as that was relevant to smoke control
00:17:19 relevant to smoke control yes thank you now if we go to paragraph nine of this second witness statement this is on page two you tell us a little bit more about the
00:17:30 you tell us a little bit more about the smoke control association you tell us that the smoke control association was established in 1987 it's part of the federation of environmental trade associations
00:17:42 environmental trade associations it was originally called the smoke ventilation association and then you tell us that the sca has members from a range of organizations which are involved in the manufacture design supply and fitting of smoke
00:17:53 design supply and fitting of smoke control systems and equipment the organization is run by several committees each of which carries out a specific function and is it right that you were part of the sca from 1992 until you began your
00:18:07 the sca from 1992 until you began your employment with colt in march 2016. that's correct and as a trade association is it correct that the smoke control association is effectively a group
00:18:17 group run by the industry bringing together those with experience in smoke control systems
00:18:22 systems from the industry that's correct
00:18:27 and you also tell us that you were as we've seen that you were chairman of that smoke control association from 1998 to 2000 and you continued to have an active role after that
00:18:40 after that and to what extent did your work as as chairman of the smoke control association relate to the design of smoke control systems for residential high-rise buildings that came later so when did when did
00:18:53 that came later so when did when did that come
00:18:54 that come that that work with the smoke control association that probably i can't remember when it started it was probably 2009 somewhere around there right yeah now if we look at that smoke
00:19:07 yeah now if we look at that smoke control association guidance first if we look at the 2012 version
00:19:14 lfb3059241 we could pull that up
00:19:22 this is the first edition um june 2012 uh oh sorry revision one june 2012 and if we look on page 12 we can see that you are a contributor is
00:19:35 we can see that you are a contributor is that right that's correct marnie you're the first in the list for novenko limited yes and then if we go to the 2015 version
00:19:47 rbk402932
00:19:51 this is revision two dated october 2015 on guidance on smoke control to common escape routes in apartment buildings flats and maisonettes and if we go to page two again we can
00:20:03 and if we go to page two again we can see that you're acknowledged as a contributor to the guidance in fact um hugh marney is listed twice in this list once for psb limited four up from the
00:20:16 once for psb limited four up from the bottom
00:20:18 bottom and once for fan systems group kind of towards the middle of that list nine lines down are these both you are they're not two mr hugh marnies
00:20:29 you are they're not two mr hugh marnies oh they're both me i see i must say as well at this stage that this document does not relate in any way to grenfell tower because it's uh post states it
00:20:41 well um it doesn't post date uh the commissioning of the system does it it is not an applicable document to grenfell tower the documents that are applicable are
00:20:52 the documents that are applicable are those that are set at the date of the planning approval for the project and this post states that i see so are you saying that you didn't pay any attention to
00:21:03 any attention to i'm not saying i'm just saying this document pool states it it's not relevant to grantor i see but just to answer my question are you saying you didn't pay any attention to this 2015.
00:21:14 to this 2015. i'm aware of its i participated in drawing it up right so i'm aware of it and did you take it into account in any way in the design work you did on the
00:21:25 in the design work you did on the grenfell project
00:21:28 and so much as it it affected the design
00:21:33 so that's a yes insofar as it affected the design yes yes thank you but also it must be noted that the design didn't go forward as a design it was a um system
00:21:45 it was a um system improvement that was given not a design the design didn't get carried forward i see okay well we'll come back to that um when we look in detail at the your involvement in the project um
00:21:59 the your involvement in the project um just thinking about those two versions of the sca guide we've seen that you're named as a contributor to both how did you contribute to these two versions let's take the 2012 version
00:22:10 versions let's take the 2012 version first
00:22:12 first well you're part of a review group and looking at the information that's flowing that's going to be forming that particular standard so you're reviewing everything you're part of a review group did you actually write any of the 2012 guide i
00:22:26 actually write any of the 2012 guide i honestly can't remember i know i wrote part of the original but i can't remember 2012. certainly involved in reviewing it yeah and 2015
00:22:35 and 2015 again was your involvement to review but not to write any of it that's correct yeah and who was fan systems group the owners of psp i see
00:22:48 the owners of psp i see as as it's a trade association the smoke control association members or automatic members if they're already trade associated members under different names so fan
00:23:00 members under different names so fan fan manufacturers would be able to sit on the smoke control association as with damper manufacturers they weren't signed up and paying members of smoke control association they were automatically able to sit on it
00:23:11 automatically able to sit on it by being part of the feta organization i see so does that mean that you effectively wore two hats on that body to represent fan systems group limited and to represent psv
00:23:23 limited and to represent psv no i see
00:23:26 no i see now um
00:23:30 based on what you tell us at paragraphs 12 and 13 of your second statement and i think we need to turn it up for the transcript that's page three is it right that you were an instigator of the guidance
00:23:42 of the guidance in the late 2000s and the coordinate of the work
00:23:45 the work coordinator of the working group that produced the original november 2010 version
00:23:51 version that's correct yeah
00:23:55 now if we go to paragraph 12 of your second
00:23:59 second statement we can read on page 3 of your second
00:24:12 you say that the idea of the smoke control association guidance was to provide individuals and companies with consolidated information about how to design effective smoke
00:24:24 about how to design effective smoke control systems is that right that's correct and you go on to tell us if we can move down the page to paragraph 14 just below that
00:24:34 you say this you say until the sca guide was published practical guidance in relation to the design of smoke control systems was sparse what little there was was spread across several publications
00:24:46 several publications the aim of the sca guide was to bring the guidance from industry professional and government organizations together in one place to assist individuals and companies involved in the design of smoke control systems
00:24:57 smoke control systems to be installed in apartment buildings the guide also provided details and gave recommendations not previously covered in other standards or code of codes of practice as we explained in the
00:25:09 codes of practice as we explained in the introduction to the sca guide whilst there were some prescriptive methods of providing smoke control these methods could not always be implemented and it had become necessary to develop performance-based solutions
00:25:22 to develop performance-based solutions to improve conditions within common escape routes so that's your explanation really as to what the rationale was behind the sca guide is that right that's correct thank you
00:25:35 that's correct thank you now i want to turn now to uh psb's initial involvement and your initial involvement uh in the grenfell tower project paragraph 16 of your first witness
00:25:47 paragraph 16 of your first witness statement
00:25:47 statement on page three you say that you first became involved
00:26:00 you say that you first became involved in the project in or around april 2014 that's in the first line now can you recall how did you become involved in the project who was it that contacted you i was
00:26:12 was it that contacted you i was contacted on the phone by matt smith of matt's missouri max fordham um who explained
00:26:19 explained uh in that conversation the system that he was working on or the building he was working
00:26:24 working on and that he had to either reinstate the existing system as it stood
00:26:31 it stood but his preference was to increase upon that because he wanted to include a system of environmental ventilation within the common lobbies that was the basis of that initial introduction plus
00:26:43 introduction plus what restrictions were in place through the employer's requirements for the project
00:26:46 project which were that we were to reuse the existing shafts and wall openings and there would be no further changes to the system yes i see and when you say that you were
00:26:57 yes i see and when you say that you were told that you were to reuse the existing shafts and wall openings is that something that mr smith of max fordham told you in that first conversation part of the employer's requirements for
00:27:08 part of the employer's requirements for the project yes yes and what what became your role on the grenfell project at that time we were just being asked for some free advice of what we've
00:27:20 for some free advice of what we've been doing and subsequently what what occurred
00:27:24 occurred were you appointed as the designers of the project of the smoke control system we weren't appointed until much later at that time we went back to matt with
00:27:35 at that time we went back to matt with advice and that was it was impossible to install any system at all
00:27:40 at all that complied with any current codes or practices regulation or guidance it was absolutely impossible because of the employer's guidance restrictions therefore we put forward suggestion of an
00:27:51 we put forward suggestion of an alternative design solution that met the spirit of the requirements because we could not meet the requirements and that was the second conversation sorry you say that was the second
00:28:02 sorry you say that was the second conversation you had with mr man when we effectively reported back on our findings i see yeah now is it right that your discussions about the new smoke control system began with mr cross smith of max
00:28:14 system began with mr cross smith of max fordham
00:28:15 fordham but then from late 2014 onwards you were reporting to j.s wright is that right no we were not involved in a project whatsoever
00:28:27 sorry when you say no we were not involved in the project whatsoever what do you mean by that well we were not contracted we weren't employed we weren't paid we weren't we were just being asked for advice
00:28:38 were just being asked for advice and that's what we gave are you saying this is just initially or are you saying later that's what occurred initially and later we didn't get involved in the project as in
00:28:50 involved in the project as in we were now involved too much later we were only being asked for advice i think now if we go to paragraph 35 of your first witness statement on page
00:29:14 you say this you say in the end however psb was only contracted to design the system
00:29:18 system supply a limited number of specific equipment parts and commission the system
00:29:23 system rather than entering into one overall subcontract jsri ended up placing a series of separate orders starting with the order to carry out the design work that was placed in may 2015.
00:29:37 design work that was placed in may 2015. psb was not contracted to install the system
00:29:40 system i understand that the installation was instead carried out by a company called rj electrics which is a subcontractor of jsright
00:29:48 jsright and we were not in the end asked to perform our works in phases so that's the explanation you give
00:29:56 give as to uh how you ended up being asked to carry out the design work yes yeah but that design work actually is the expansion of the design
00:30:08 actually is the expansion of the design written down in the performance specification to a working system not designed as in what you think it means
00:30:16 means well um i don't know whether you know what
00:30:19 what what's in my head mr mr marnie but what do you think i think it means the design work you're starting at the very beginning with a blank piece of paper and designing a system
00:30:29 system i see so you're you're saying you didn't do that
00:30:32 do that it is what you're saying that you took the design intent that was set out by max fordham in the employers requirements and developed that design i'll go back to a statement i made earlier the design that we have proposed
00:30:44 earlier the design that we have proposed was not carried forward what happened was that max fordham reviewed the information that we provided them with to say you couldn't install a compliant system it was impossible that therefore in order to find a
00:30:57 that therefore in order to find a solution which entered to the spirit of the guidances not compliant we put forward a suggestion of a system that was not taken up what they then did was to take the
00:31:08 what they then did was to take the volumetric flow rate that we had specified
00:31:10 specified and put it forward as an improvement to the existing system and that was how the project went forward it was on develop an improvement not a design
00:31:20 design and they did a document that they sent through to for approval by building control who approved the betterment right i see well look we're going to come to the specific documents that you
00:31:31 come to the specific documents that you prepared
00:31:31 prepared in due course but um i i think i understand your answer at this stage um just going back to what you said in that paragraph that i just read out about the fact that it was a company
00:31:43 about the fact that it was a company called rj electrics that would be installing the system in your experience was it typical that psb would be asked to design but not install a smoke control
00:31:55 design but not install a smoke control system
00:31:56 system not typical but not uncommon did you ever have any concerns about somebody else i rj electrics installing the system yes so i had put in a statement within
00:32:10 yes so i had put in a statement within our proposal which was accepted that we would send our controls experts to site once they'd installed the first couple of modules to benchmark it and to check that they
00:32:22 to benchmark it and to check that they were installing it correctly and it was being wired incorrectly so that they could then use that as a benchmark
00:32:27 benchmark for the continuation of the project so yes i did have consumed i see and is what you're saying that that wasn't taken up that proposal that proposed was taken up and we did send engineers to site
00:32:39 send engineers to site when the first few modules were installed to check they've been installed correctly i see now in his witness statement to the inquiry mr matt cross smith of max fordham
00:32:49 fordham says that he telephoned psb at the end of april 2014 to ask about the design of the smoke control system for the submission to building control now i think from what you've said
00:33:00 now i think from what you've said earlier that it was you that spoke to mr macross smith at that point at the end of april 2014 is that correct
00:33:09 and can you tell us what was discussed in that phone call uh yeah yes to repeat uh that we were told what the working brief was we were given a brief that they had to work in which was the
00:33:21 that they had to work in which was the employer's requirements for the project which was to refurbish the existing system and bring it back to an operational system or to offer some development to improvement
00:33:32 improvement and during that conversation we were also told they wanted to maximize the system to them to incorporate an environmental system
00:33:43 to incorporate an environmental system as well as smoke and i said at that stage let's look at the smoke side first let's see what we can do i do recall saying in that conversation the original push-pull you were talking about is not going to work
00:33:55 about is not going to work in the way we would need it to given the restrictions we've just been told and that we would look at the information he was then to provide because we asked for further information
00:34:06 because we asked for further information we would review that and get back to them with our proposals okay i'm going to come and ask you in a moment and come on to ask you about the the push pull proposal and your concerns about that so i'm just going to come to that in a moment
00:34:18 that in a moment before we do if we go to paragraph 16 of your first witness statement on page three
00:34:31 now you tell us in this statement um four lines down you tell us that fergus mcgregor
00:34:39 mcgregor who was a system designer who worked for psb
00:34:42 psb had already had a brief discussion with mr
00:34:46 mr matt smith about this potential job previously back in 2012 is that correct
00:34:55 now can you confirm that mr mcgregor was a he was a system designer for psp yes rather than a commercial manager yes yes
00:35:07 can you explain why was the project assigned to you rather than mr mcgregor from 2014 onwards
00:35:15 onwards on the day of the phone call mr mcgregor was not in the office and i took the phone call i see so simply because you'd taken the call in 2014 you then carried on with with the
00:35:26 you then carried on with with the dealings with it yes
00:35:33 were you provided with any update from mr mcgregor or max fordham about the previous discussions that they'd had about the project
00:35:45 about the project an update yes did you did you when you got off the phone to max fordham did you speak to mr mcgregor and say
00:35:53 say what what have you already been discussing with them when he was next in the office we got together and i went through uh asked him to go through with me what he'd been talking about
00:36:04 he'd been talking about and at that stage it was just a again another telephone conversation with information taken down over the phone and no real detail i see is it right to say that the previous discussions between mr mcgregor
00:36:16 previous discussions between mr mcgregor and max fordham had been more than just a brief discussion about a potential job and involved some preliminary design advice being provided by mr mcgregor not directly no it was a case of uh he
00:36:29 not directly no it was a case of uh he had a phone call he was told how many floors there were and he was asked what kind of system could
00:36:34 could we put forward he was told what was already there so we decided push pull was a better solution because of the trial extended travel distances within the lobby area and decided that was
00:36:46 the lobby area and decided that was the best system put forward but he was not given the employer's requirements at that stage which added the restrictions that meant you couldn't use that system i see well let's let's just look at an
00:36:58 i see well let's let's just look at an email from mr mcgregor um it's at max403366 and i want to look at page two
00:37:13 this is an email dated the 9th of november
00:37:16 november 2012 and it's from mr mcgregor to mr mcquatt andrew mcquatt at max fordham um
00:37:27 at max fordham um and you can see in the first line he says put it to your email below assuming the fans are okay and meet with the requirements i can see nothing wrong with the proposal
00:37:38 with the proposal and if we look at page three of this uh clip we can see from the previous email from mr mcquatt
00:37:49 from the previous email from mr mcquatt at the bottom of that page and we can see it in the first line that mr mcquatt had sent a sketch schematic of the proposed smoke ventilation control at grenfell tower to mr mcgregor
00:38:02 control at grenfell tower to mr mcgregor and i think you've already mentioned it but is it right that max ford's proposal was what you've called a push pull fully mechanical extract system that is
00:38:13 fully mechanical extract system that is correct
00:38:14 correct and by push pull is it right that what this meant is that fresh air is drawn from the outside via the south shaft vents and then air is extracted from the
00:38:26 and then air is extracted from the lobbies through the north shaft to the outside with the use of fans is that correct that is correct you push air in on the one side with a fan and pull it out on the other with another so you're pushing air through the south
00:38:38 so you're pushing air through the south shaft and then you're pulling air out of the north shaft that's correct push pull
00:38:46 push pull so were you told about this early advice that had been given by mr mcgregor when you became involved in the project yes you were now
00:38:58 yes you were now just some questions on the existing system that was already there in grenfell tower in your first statement at paragraph 17 i don't think we need to go to it you tell us
00:39:07 tell us that to understand how the pre-existing smoke control system worked you visited grenfell tower and you considered some information from max fordham now can you help us when was your first
00:39:19 now can you help us when was your first visit to grenfell tower gosh i have no idea i can't remember and approximately how many times do you think you visited the tower between 2014 and 2016.
00:39:30 between 2014 and 2016. twice twice yes so you remember visiting twice yeah if we go to psb 50703
00:39:43 if we go to psb 50703 and look at the foot of page one
00:39:54 at the very bottom we can see an email from matt smith max fordham to hm psb is that you hm that's correct yes it's dated the 2nd
00:40:05 hm that's correct yes it's dated the 2nd of may 2014 and if we go over the page we can read he says morning hue thanks again for taking the time to discuss the refurbishment of the smoke extract
00:40:17 refurbishment of the smoke extract system i'm working on i'd like to clarify a few details from our conversation if that's all right i've attached a floor plan of a typical residential floor our previous smoke extract schematic a
00:40:29 our previous smoke extract schematic a rough and ready marked up schematic showing my understanding of our conversation with the addition of general ventilation provision and a few photos for reference the the building is
00:40:40 for reference the the building is grenfell tower in north kensington and then he he gives you some measurements in the next paragraph of the measurements of the supply shafts and extract shafts and the grills
00:40:53 and extract shafts and the grills and then he asks for clarification over a number of points arising from your discussion
00:41:01 now do we take it from this that you had spoken to mr croft smith by telephone on the 1st of may 2014 yes and can you remember what was discussed in that call
00:41:13 discussed in that call that's the one i've referred to where we were told what the employer's requirements were and that's confirmation of it and the size of the shafts and the wall openings etc um and the restrictions that would place
00:41:25 restrictions that would place on any proposals um and in that conversation as i say i mentioned to him the push pull is not going to work with that arrangement yes and again but i'm going to come on in a
00:41:36 and again but i'm going to come on in a moment um to look at your concerns which you've set out in your statement about why you didn't think push pull was going to work um no it's not just push pull the whole
00:41:48 um no it's not just push pull the whole there was no system type that you could install
00:41:51 install given those restrictions that complied with any current standards or guidance not any system type
00:41:59 type okay i i understand that's your evidence and again i'm going to take you to the sections of your statement and ask you where you about where you explain that so i am coming to that um now is this the information from max
00:42:13 um now is this the information from max fordham that you refer to in your statement
00:42:15 statement this information that you're being provided with at this time by max fordham
00:42:19 fordham yes yes were you provided with any other documents about the existing system
00:42:29 um there was a typical floor plan a typical floor plan i see and did that have measurements on it no
00:42:37 it no no um
00:42:41 you say in your statement that there was not much in the way of documentation was that a concern from your point of view
00:42:48 view yes i did i did during the course of the conversation i asked is there not a fire strategy for this particular project and i can't remember the precise wording group was something effective well there's not much in there um there was
00:43:00 there's not much in there um there was talk of
00:43:01 talk of i think 10 air changes 15 air changes and 30 air changes away as a way forward um conversation of that nature
00:43:09 nature we also discussed the reuse of the shafts were they suitable were they acceptable are they being inspected yes and he sent a photograph to show the construction method for the better term and
00:43:21 method for the better term and the grill type so that was the information we had the grill type the construction type through photograph and
00:43:28 and the size of the shafts and the all openings
00:43:31 openings and that typical floor plan that was what was
00:43:34 what was yeah i was concerned of the lack of information yes i see and you say he mentioned aspire strategy but he said um there's not much in there did you
00:43:45 um there's not much in there did you ever get to see that fire strategy no the only doctrines we had the ones i just referenced from that comes and did you ever asked to see that fire strategy even though you were told there was not much in there
00:43:56 was not much in there i did i did suggest that anything that was relevant be forwarded to us but did you ever ask to specifically see the fire strategy for the building in that statement yes anything relevant
00:44:09 in that statement yes anything relevant should be forwarded i see
00:44:13 was there anything particular in your view that was missing from the documentation that you were provided with
00:44:21 missing in what way that was all that was provided so there's nothing missing
00:44:26 now you tell us in paragraph 18 of your second statement if we go to that page
00:44:34 four
00:44:38 you tell us that the um
00:44:46 i think that must be a i think that must be a wrong reference you you tell us in your statements that the existing system was a natural ventilation system with a
00:44:59 natural ventilation system with a mechanical boost function yes that's correct yes now i'm just going to bring up a diagram from dr lane's phase one presentation i just want you to explain
00:45:10 presentation i just want you to explain how the existing system was meant to work
00:45:13 work this is a bla four zeros five four eight one and i want slide 173
00:45:29 so there we have a slide that dr lane prepared
00:45:32 prepared at phase one of our work in very basic term just explaining the operation of the original the existing smoke control system at grenfell tower that's not my understanding of the
00:45:43 that's not my understanding of the original system so um the original system has told to me didn't have a supply fan it only had an extract phone
00:45:54 extract phone i see so um is what you're saying that you didn't understand there to be where we've got at the very at the bottom left airflow and a red line to a fan at the south
00:46:05 and a red line to a fan at the south shaft level at the south shaft entry point you didn't understand there to be a fan there is that right that's correct that's not how the system is explained to us i think so did you understand that the airflow
00:46:17 so did you understand that the airflow would go in purely based on natural forces that's correct so it would go in it would enter naturally at that lower point rise up it would go through the the
00:46:30 rise up it would go through the the particular lobby where the smoke control system was activated yes yes because those those dampers would be open on that one level yes correct and then smoke would
00:46:42 yes correct and then smoke would be drawn up the shaft and is it right that the
00:46:45 that the the primary intention was that it would be drawn up naturally but that there was a fan that could be used by
00:46:52 used by the fire brigade as a boost to mechanically support that movement of smoke yes
00:47:00 smoke yes yes as we understood it it was a natural ventilation system with no fans operating when the detection went off
00:47:07 off when the fire brigade arrived at its point of intervention they had the facility to turn a manual switch that would bring a fan into operation if they deemed it necessary
00:47:17 necessary yes thank you that's helpful did you know how old the existing system was in the tower we were told it was an early 70s built building
00:47:29 building so you assumed that the system was also early 70s yes
00:47:35 yes because the actual were part of the construction of the building yes and was that system that existing system was it working when you first visited the tower
00:47:46 visited the tower no no so you weren't able to see it in operation in any way
00:47:55 did you ever consider whether the existing system was compliant with the standards in force at the time it was installed
00:48:04 no did you ever ask yourself what the original requirements might have been for that system yes and and what conclusion did you draw
00:48:15 yes and and what conclusion did you draw from well it was very difficult because um i've never seen anything that small that was compliant with any standard so to me it was some hybrid design that
00:48:28 to me it was some hybrid design that someone had carried out and there was no detail of it there was no information available on file anywhere as far as i can gather because we did ask the question that no one was able to trace the design
00:48:39 that no one was able to trace the design aspect of that particular system of what it was supposed to fulfill because in modern standards it wouldn't fulfill anything no were you aware that the existing system was not compliant with the standards in
00:48:51 was not compliant with the standards in force at the time it was originally installed
00:48:55 installed yes let's just look at something on that if we can go to dr lane's phase two smoke control report this is at blarp 2 5 0 35
00:49:08 2 5 0 35 page 44.
00:49:19 and i want to look at paragraphs 3.3.28 onwards it's in the second half of that page
00:49:28 page so this is compliance of the original system so dr lane tells us in the paragraph below that in natural ventilation mode the aggregate area of the smoke shafts on each side of the lobby was 0.48 meters squared
00:49:41 the lobby was 0.48 meters squared and the aggregate area of the dampers on each side was 0.28 meters squared these values are both significantly lower than the equivalent free area recommended by cp3 1971
00:49:54 area recommended by cp3 1971 right of 1.5 meters squared when automatically opening do you see that see that yes and she goes on
00:50:03 goes on and she looks at some other considerations as well and she says at 3.34 at the bottom therefore the system did not comply with the requirements of cp3 1971 due to the aggregate area of the dampers
00:50:15 the aggregate area of the dampers being lower than the equivalent free area recommended by that standard when automatically opening now is that a conclusion that you
00:50:24 you also came to at the time yes it was totally inadequate were you well did you specifically think about the cp3 1971 guidance and whether the
00:50:37 1971 guidance and whether the specifically i just knew that it should be 1.5 square meters
00:50:42 i see so i think what you're saying is you didn't consider the cp371 guidance specifically but you knew did you just instinctively you
00:50:53 you knew did you just instinctively you knew that
00:50:54 knew that that i knew it wrong regardless of what standard you were looking at yes because the smoke shafts were too small
00:51:02 small yes yes and the aggregate area of the dampers was too small yes correct yes
00:51:13 did you ever ask yourself what level of performance the existing system would have if it was working properly
00:51:20 properly i took a view on that yes
00:51:24 when you say you took a view on that what do you mean well the most efficient aspect would be with the fan operating pulling
00:51:32 pulling and it was obvious in the construction of the fan type because it was a bifurcated fan it would have limited volumetric flow rate
00:51:40 rate and given the diameter of that fan and given the size of the ducts you could evaluate fairly accurately the likely volume flow rate i see and did you ever produce any form of written analysis
00:51:52 of written analysis which set out your conclusions about what the existing system was capable of producing
00:51:57 producing if working no that wasn't in my brief
00:52:01 would the existing system have provided protection to the stair when working properly no why did you think that because there
00:52:12 why did you think that because there wouldn't be a sufficient ventilation rate to protect the stair would the existing system have provided protection within the lobby the lobby that it had activated on when working properly
00:52:23 working properly no so
00:52:27 no so you thought that the existing system wouldn't provide any protection to the stair
00:52:31 stair or the lobby is that correct i wouldn't say any it wouldn't it wouldn't provide satisfactory protection i see it and and which of those two was it intended to be protecting did you
00:52:42 it intended to be protecting did you think
00:52:43 think the stair or the lobby or indeed both i would say the lobby yeah now if we can go back to the email thread that we're
00:52:55 back to the email thread that we're looking at earlier psb 50703
00:53:05 and if we look at page one this email is an email from mr cross smith
00:53:12 smith to fergus mcgregor at psb and you are copied in to this email we can see that your cc'd it's dated the 2nd of may 2014 at 10 59 and he says
00:53:25 59 and he says um morning fergus i understand you're the person to speak to regarding the residential smoke extract system in hugh's absence i spoke to you yesterday about a refurbishment job in
00:53:36 yesterday about a refurbishment job in london which i believe a colleague of mine in our edinburgh office has previously discussed with jim shields we're looking to bring the existing non-compliant push-pull system up to scratch and after speaking with
00:53:47 up to scratch and after speaking with you it seems a pressure differential system would be the way to go i've recently been informed that a deficiency notice has been placed on the building
00:53:57 building due to the existing system being inoperative this expires on monday for this reason i'd like to have a chat with you to clarify a few points made by hugh and
00:54:08 to clarify a few points made by hugh and also to see if you may have any ideas for interim measures on the existing system
00:54:14 system so can we take it from this that fergus mcgregor was still working for psb in may 2014
00:54:20 may 2014 he was
00:54:23 and if we look at paragraph 20 of your first witness statement on page four
00:54:33 you say in the second line of paragraph 20
00:54:36 20 you say and there was even talk of a deficiency notice being placed on the building
00:54:41 building as a result that was as a result of the system being inoperative the existing system
00:54:46 system but would you accept that the email i just showed you um which you were copied into shows that psp
00:54:53 psp were aware in fact that a deficiency notice
00:54:57 notice had been placed on the building yes
00:55:02 was psb ever sent a copy of that deficiency notice no because we weren't involved in the project
00:55:12 did the fact of that deficiency notice affect
00:55:16 affect the advice that psg tsp gave about the design of the system in any way no were you also aware that there had
00:55:27 no were you also aware that there had been a fire at grenfell tower in april 2010 in which the existing smoke control automatic opening vents had failed to operate nope
00:55:38 so you were never aware that there was a fire where smoke had leaked from the system's extraction shafts into other floors of the tower nope
00:55:49 into other floors of the tower nope had you known that had you been told that would have would that have affected the design advice that you gave about uh improving the existing system i mean so much as to tell them they
00:56:00 i mean so much as to tell them they should be maintaining it making sure it operated correctly other than that no
00:56:06 now just stepping back and and just thinking about the the regulatory requirements which apply to the design of the refurbished smoke control system at grenfell tower can you just explain which of the
00:56:17 can you just explain which of the functional requirements in schedule one of the building regulations you considered when designing the system at grenfell tower
00:56:29 uh i don't think there's a straight answer to this is that because as i've already said you could not put forward
00:56:36 forward any system that would comply with any of the guidance it was impossible so there was no system type you could put in there so therefore we as designers
00:56:47 so therefore we as designers looked at it from a different direction and said well the spirit of the standard is to protect the stair can we come up with an alternative design that will protect the stare
00:56:58 will protect the stare that doesn't comply with anything and that was our starting point yes i see and when you say there you said to yourselves well the spirit of the standard is to protect the stare what standard
00:57:10 is to protect the stare what standard are you referring to there that protects the stair that's with the approved document b section 2.25 i see so you're saying that approved document b is talking about
00:57:22 approved document b is talking about protection of the stair as the first objective yes so that was the consideration you applied protect in the lobby as well as the stair that was part of the due process
00:57:33 stair that was part of the due process that we
00:57:34 that we adopted in the alternative proposal it wasn't
00:57:37 wasn't just firefighting which implies the stare
00:57:41 stare it also is to protect the lobby but do it in a way that met any of the standards
00:57:52 i see so just to be clear did you have requirement b1 on means of escape the building shall be designed so that there's appropriate means of escape in
00:58:03 there's appropriate means of escape in case of fire from the building to a place of safety that's functional requirement b1 did you have that in mind when you were giving your design advice yesterday
00:58:13 yesterday at 2.25 and b5 functional requirement b5 the building should be designed and constructed so as to provide reasonable facilities to assist firefighters in the protection of life
00:58:25 protection of life did you have that in mind when you were giving your design advice yes very much so because the building didn't comply therefore should have had a separate firefighting lobby which it didn't
00:58:34 didn't therefore yes that was very much in that mind because the building did not comply what about functional requirement b3 on internal fire spread including measures
00:58:45 internal fire spread including measures necessary to maintain complementation throughout the tower was that ever a consideration as part of your design work my memory says me well i might be wrong your b3 is not for flats
00:58:59 it's for buildings other than flats so you don't think functional requirement look i didn't say that i'm just saying what b3 is relevant to
00:59:10 b3 is relevant to so you think you thought that complementation and b3 was relevant to flats
00:59:15 flats and what not the whole building yes compartmentation is the primary um requirement to control the spread of fire and smoke in a residential building it is the pro
00:59:27 in a residential building it is the pro it's not the smoke control system it is the actual compartmentation is the primary
00:59:32 primary item that controls spread of fire and smoke
00:59:35 smoke the smoke control system is only required
00:59:38 required in residential buildings to deal with a small quantity of smoke that comes out when people are making their escape and then later on to protect the stair when the fire brigade are fighting the fire
00:59:50 brigade are fighting the fire but compartmentation is the primary requirement i see but just going back to my question did you think about functional requirement b3 at any stage
01:00:01 functional requirement b3 at any stage when you were designing the smoke control system in terms of the internal fire spread no
01:00:12 now i want to ask you some questions now about um the max ford and brief and an initial designs if we could go to paragraph 21 of your first witness statement on page
01:00:26 four
01:00:30 here you tell us you say max fordham's initial proposals for the smoke control system
01:00:36 system essentially involves stripping out the controls and equipment used in the pre-existing system and installing a new system which reused the ducts and shafts into the
01:00:47 reused the ducts and shafts into the existing
01:00:47 existing common lobbies and you say their proposal as set out in their employers requirements document they produced was to retain the broad principles of operation of the pre-existing system
01:01:00 operation of the pre-existing system but to turn it from a natural ventilation with mechanical boost system into a fully mechanized push-pull system
01:01:11 into a fully mechanized push-pull system and we've already discussed what what those two concepts meant a natural ventilation with mechanical boost and just to be clear what do you mean by a fully mechanized
01:01:22 what do you mean by a fully mechanized push-pull system when operated automatically
01:01:28 i see so you'd still be having inlet air through the south shaft and up into the lobby
01:01:35 lobby and extract coming out through the north but this time with mechanical assistance from the outset yes yes and will operate automatically on detection rather than manually by the
01:01:46 detection rather than manually by the fire brigade yes i understand now if we can go to paragraph 27 of your second witness statement on page five
01:02:04 you say this um you say the push-pull system
01:02:08 system proposed by max boredom is a type of smoke control system usually employed when the travel distance in the escape corridor leading to the stairwell is greater than that specified in the
01:02:19 is greater than that specified in the adb or bs
01:02:20 adb or bs triple nine one such systems are designed to provide smoke dilution on the escape route reducing the levels of smoke toxicity and visibility to acceptable levels
01:02:32 and visibility to acceptable levels this is achieved by introducing clean fresh air
01:02:36 fresh air through a mechanical inlet air shaft at low level
01:02:40 low level local to the stair door within the corridor an extract shaft is located at the furthest end of the corridor extracting diluted air smoke at a volumetric rate equivalent to the fresh air
01:02:51 fresh air inlet now if we just go back back to the start of that paragraph and just have that up on the page now at the time when you were working on
01:03:02 now at the time when you were working on the system design for grenfell tower were you aware what the travel distances were in the lobbies
01:03:09 lobbies between the flat doors and the stair door roughly yes by measuring off the drawing we were issued so you say roughly yes what did you understand those travel distances to be
01:03:22 understand those travel distances to be in a region of nine and a half meters at the worst point
01:03:28 and you say you understood that from measuring off the drawings you were issued with did you actually do that exercise of measuring those travel distances at the time yes were you aware that the maximum
01:03:41 yes were you aware that the maximum travel distance in the lobbies at grenfell tower exceeded the 7.5 meter threshold for an extended travel distance specified in approved document b
01:03:52 document b on fire safety by measuring 9.5 yes yes and we've we've seen this before with another witness but just for the transcript table 1 of approved document b makes clear that the maximum travel
01:04:04 b makes clear that the maximum travel distance
01:04:05 distance in common areas of blocks of flats is 7.5 meters and can we also agree that the maximum travel distance in bs triple nine one you mentioned that
01:04:16 bs triple nine one you mentioned that standard in your statement is also 7.5 meters and after that it's considered to be an extended travel distance correct
01:04:27 extended travel distance correct let's just briefly look at that it's bsi 50621
01:04:42 this is
01:04:47 ah that says eight four one four
01:04:50 sorry bsi five zero six two one yes this is bs triple nine one two thousand eleven fire safety and the design management and use of residential buildings code of
01:05:01 and use of residential buildings code of practice and if we look at figure six on page thirty six and in the bottom you can see the 7.5
01:05:12 and in the bottom you can see the 7.5 meters
01:05:12 meters is shown in that bottom diagram do you see that
01:05:16 see that yes and it makes clear for example at if we look on page 160
01:05:26 if we look right at the bottom of that page under extended corridors it says where the design of a block is such that the travel distances exceed those shown in figure six and
01:05:38 exceed those shown in figure six and figure seven a fire engineered mechanical smoke ventilation system msbs may be provided to compensate for the extended travel distance
01:05:49 the extended travel distance the primary objective for this type of system is to maintain terrible conditions within the extended corridor and and the associated staircase enclosure
01:06:00 associated staircase enclosure for means of escape purposes and then information about tenability criteria can be found and it gives the reference
01:06:10 so for the purposes of triple nine bs triple nine one anything above 7.5 meters is extended and that guidance we can see is provided
01:06:22 that guidance we can see is provided about
01:06:23 about needing to maintain tenable conditions in the corridor and the stairs
01:06:29 now if we look at dr lane's report at blas 5037 page 25
01:06:44 if we could zoom in on figure 15b there this is her measurement in her phase one report of the travel distances you can see the grenfell lobby in in the
01:06:56 you can see the grenfell lobby in in the middle
01:06:57 middle with all the flats around the outside and can you see that from flat 4 she's measured 10.3 meters do you see that yes now um just to be clear the bre in their
01:07:11 um just to be clear the bre in their report following their survey at the tower they measured the same distance at 9.3 so slightly less than that and you've said you thought it was
01:07:22 and you've said you thought it was around 9.5 in the worst part is that right
01:07:26 right correct but whether or not it's 9.3 9.5 or 10.3 that was an extended travel distance wasn't it compared with the 7.5 maximum
01:07:38 wasn't it compared with the 7.5 maximum in adb
01:07:39 in adb and bs triple nine one it was now just going back to the way you described the max fordham system going back to paragraph 27 of
01:07:51 system going back to paragraph 27 of your second statement page five
01:08:00 you say in that in the first part of paragraph 27 the push-pull system proposed is a type of smoke control system usually employed when the travel distance in the escape corridor leading
01:08:12 distance in the escape corridor leading to the stairwell is greater than that specified in those two pieces of guidance that's correct now do you agree that the way you've described that max forward and proposed system
01:08:23 and proposed system suggests that this extended travel distance wasn't the complication you were facing at grenfell tower no that complication was there the fact it's impossible to put the push-pull system in to
01:08:34 to put the push-pull system in to compensate for it it's impossible to put it in so the the dilemma was there the fact we could not design a system that complied with any of the guidance whatsoever
01:08:46 whatsoever was a problem i see so you're saying you were fully aware that there were extended travel distances at the time you were carrying out your design work yes that's correct
01:08:57 design work yes that's correct thank you now if we go to paragraph 23 of your first witness statement now page five
01:09:13 now in this paragraph and and some that follow
01:09:16 follow you are explaining your concerns about the max fordham proposal for a push-pull system
01:09:23 system and you say this you say when i looked at these proposals however i could see that they that could lead to problems with excessive pressure drop due to the high induct velocity within
01:09:35 due to the high induct velocity within the existing builders work shafts which could result in inadequate flow being achieved through the shafts and then you go on and say as a result i developed an alternative proposal which still reused the existing ducts
01:09:48 which still reused the existing ducts and shafts as per the employers requirements but which could achieve the functional objectives set out in the relevant guidance
01:09:54 guidance in place at the time now just taking that explanation in stages
01:10:01 stages firstly can you just explain to us why would air
01:10:05 would air entering the existing builders shafts potentially quickly result in an excessive drop in pressure
01:10:13 pressure not drop an increase i see can you explain
01:10:17 explain your your concern then you tried it a little bit like the old um quote into a point pot you're trying to push too much air through a small hole and it would lead to large pressure
01:10:28 and it would lead to large pressure drops within the system which are difficult to keep a balance of and in addition to that the wall openings into the lobby would have had velocity jets somewhere in a region at 20 to 25 meters a second
01:10:41 in a region at 20 to 25 meters a second which if there was a fire in an apartment in say the south end of the building
01:10:45 building then when the fire brigade were fighting the fire that jet would probably push smoke into the stairwell so we could not maintain this stable clear of smoke so the push-pull system was just impossible to put in to work in status because of the
01:10:58 to work in status because of the restrictions of size yes i see so so just to be absolutely clear
01:11:04 clear um you say first of all it's a bit like the old quartz into a pint pot you're trying to push too much air through a small hole and it would lead to large pressure
01:11:15 and it would lead to large pressure drops within the system which are difficult to keep a balance of can you just explain how that process occurs
01:11:22 occurs well as you as you're trying to force a large volume of air through a small duct it just increases the pressure drop within that shaft and uh the all performance
01:11:35 and uh the all performance characteristics for ventilation index is based upon laminar flow not turbulent flow
01:11:40 flow and it's on reasonable velocities not high velocities these would be high velocities that would lead to excess pressure differentials of what we pressure drops that we would normally
01:11:51 pressure drops that we would normally work to
01:11:51 work to we would normally work about eight meters a second in that maximum velocity and this was far in excess of that but it was also the velocity jetting through the wall opening was a problem
01:12:02 opening was a problem that would also create a big pressure yes i see
01:12:05 yes i see so you've got these large pressure drops within the system which you say are difficult to balance out and then you say in addition to that the wall openings into the lobby would have had velocity jets somewhere in the
01:12:16 have had velocity jets somewhere in the region of 20 to 25 meters a second which if there was a fire in an apartment
01:12:22 apartment um would mean that you couldn't maintain the stairwell clear a smoke again can you just explain slowly what the mechanism is for that to happen if you would bring up the sketch you just had from elaine's report
01:12:34 just had from elaine's report of the floor plan yes so that is um that's the one yeah if we look at flat three
01:12:45 three yeah if that was the flat that was on fire
01:12:48 fire and then you have the little duct in the middle alongside it which is the fresh air in input duct and then you have the stair door would be open when the fabric come to fight the fire they would then open flat three
01:13:00 the fire they would then open flat three door to fight the fire the smoke that comes out from that flat door
01:13:05 door will be picked up by the velocity jet from that low level grill potentially and pushed into the stair because it wasn't so that would then be a failure of the system
01:13:17 system and was that a particular feature of the layout of that lobby and the configuration of that that south event so
01:13:25 event so that cell phone isn't marked but i think for the panels it's a series of very small little lines between the 4.7 meters and the 2.8 meters that's where the south vents are
01:13:37 meters that's where the south vents are and then the north vents are up from that and you see some similar little dotted lines so so was it a particular feature of the configuration of this
01:13:49 configuration of this lobby that led to that problem no it's the size of the ducts i see it's the size of the is the velocity is a problem for that particular application in smoke
01:14:01 for that particular application in smoke vent terms we we generally work to a maximum inlet velocity of five meters a second again there are reasons for that but that's what we work to 20 to 25 is a lot more than five yes i see
01:14:15 is a lot more than five yes i see so you basically got kind of serious velocities going on across this lobby which potentially could be dangerous in terms of smoke being pushed towards the stair yes smoke
01:14:26 being pushed towards the stair yes smoke contamination of the diet yeah i understand now if we go back to your statement um and we look at paragraph 28 and 29 of your second witness statement on page
01:14:40 five
01:14:45 you sorry that's it since page six yes you tell us in 28 i knew from experience that there would be a number of problems with the proposed
01:14:56 a number of problems with the proposed use of a push-pull system in grenfell tower
01:14:59 tower and you say as well as the issues it raised in paragraph 23 of my first statement
01:15:04 statement i was also aware that the lobby layout at grenfell tower was not a typical corridor arrangement the two shafts were located on either side of the lobby but there were additional areas coming
01:15:15 but there were additional areas coming off the main lobby area which provided access to the flats in each corner of the tower one shaft had a grill at low level that's the south side and the other had a grill at high level
01:15:27 and the other had a grill at high level the north side the location of the door from the lobby to the stair was also an issue as it was not positioned at the end of a corridor i recognize that the specific orientation of the
01:15:39 that the specific orientation of the lobby
01:15:40 lobby and the position of the shafts and door to the stair in grenfell tower meant that it would not be possible to adequately mitigate the risk that smoke would enter the stair using a push-pull system
01:15:52 stair using a push-pull system given the size of the lobby and the position of the shafts there would also be dead spot areas in the lobby
01:15:58 the lobby where there would be no airflow and therefore no mixing of air and smoke to create dilution now if we just go back to that diagram
01:16:09 now if we just go back to that diagram from
01:16:10 from dr lane again while we're looking at this
01:16:15 this now is it is it right that one of your concerns was that given the unusual shape of the lobby i we can see this eye shape
01:16:23 shape where you've got kind of corridors going off to the corners top and bottom with the vents positioned in the middle of that eye yes it's one of your
01:16:35 of that eye yes it's one of your concerns
01:16:37 concerns that with a push-pull system where the smoke is going across that lobby that that might not mitigate the risk that smoke would enter the stair yes and you also
01:16:50 yes and you also expressed concern that there might be dead spots in the system at the branches of the lobby where there would be no airflow so is that say at the corners of say flat five and flat four
01:17:02 flat four flat six blacks one and then at the bottom left hand corner and the bottom right hand corner you've got these little corridors branching off you're concerned that there could be dead spots with no mixing of air in
01:17:14 dead spots with no mixing of air in those places is that correct that's correct yes the the principle of a push-pull system is usually air flowing through a straight tube or your corridor
01:17:23 corridor and it travels through that straight tube with a velocity and it mixes air with smoke as it travels and it reduces
01:17:31 reduces the level of toxicity and obscuration within that corridor because it's mixing and pulling out in that particular arrangement if we look at say flat four the doorway there smoke could stay
01:17:43 four the doorway there smoke could stay in that section of corridor and not be pulled in
01:17:46 pulled in to the system it would just stay there yes yes i understand and did you have any other concerns about any other aspect of max fordham's proposals
01:18:00 the main concern i had throughout any of the system types was the size of the shafts nuts but are you talking specifically about push pull
01:18:09 push pull um yes is it fair to say that those are the
01:18:13 the the main concerns they are the main concerns one we couldn't guarantee not contaminated in the state we could not guarantee that and we could not use a push-pull system in the normal
01:18:24 use a push-pull system in the normal sense i.e a straight corridor yes i understand mr chairman i think that's a good moment for our morning break
01:18:31 break yes strange thank you so do i i was going to suggest it anyway well mr mani i said we'd have a break during the course of the morning and this is a good time to have it so we'll stop now we'll resume please
01:18:43 we'll stop now we'll resume please at 25 to
01:18:47 at 25 to 12. and i must ask you please not to talk to anyone about your evidence or anything relating to it over the break all right thank you thank you we'll look forward to seeing you then in 15 minutes or a little more
01:19:00 you then in 15 minutes or a little more thank you very much thank you miss grange 25 to 12. thank you
01:36:14 right we're ready to carry on so i'm going to begin by ensuring that we have contact with ms grange
01:36:22 grange flemish grange we can see you can you see and hear us yes i can thank you thank you very much and then you better make contact with mr manny
01:36:30 manny mr marley are you there again yes sam thank you chairman good thank you very much and you're ready to go on i hope yes indeed thank you very much yes ms granger when you're ready
01:36:41 granger when you're ready yes thank you if we can just look back at paragraph 23 of your uh second statement i think it is
01:36:51 is no your first witness statement sorry page 5 paragraph 23
01:37:03 you say in that last sentence as a result i developed an alternative proposal
01:37:08 proposal which still reused the existing duct and shaft as per the employer's requirements but which could achieve the functional objectives set out in the relevant guidance
01:37:18 guidance in place at the time now i'm just concentrating on this grange i'm just going to interrupt you if that was the end of paragraph 25 i don't think mr marley could see it
01:37:29 could see it 23 23. oh i'm sorry am i fallen so you're referring there to uh but which could achieve the functional objectives set out in the relevant
01:37:41 objectives set out in the relevant guidance in place at the time now can we just be clear what was that relevant guidance from which you were taking those functional objectives
01:37:52 were taking those functional objectives that we had to provide ventilation to the
01:37:56 the lobby to provide ventilation of any smoke that may reach that lobby when people were making an escape
01:38:04 escape and to provide an open door condition for the firefighters when they were fighting the fire so that was the b1 and b5 requirements i see so are you saying that the could
01:38:17 i see so are you saying that the could achieve the functional objectives set out in the relevant guidance are you saying those are the functional objectives of the building regulations as set out in for example approved document b is that what you're referring
01:38:28 document b is that what you're referring to there
01:38:29 to there yes so are you referring to any other pieces of relevant guidance in which there are functional objectives set out in that paragraph no
01:38:40 in that paragraph no so you're not referring to functional objectives that may have been set out for example in bsen12101 part 6 on pressure differential systems it was impossible to put such a system
01:38:52 impossible to put such a system in those systems anyone knows anything about smoke control we'll know it's impossible to put a pressure differential system in that's fully compliant in a block of flats so no it wouldn't be anything to do with that particular
01:39:03 anything to do with that particular standard because that is impossible to apply and just to be absolutely clear about what you thought those functional objectives were so in terms of the stare what were your
01:39:16 so in terms of the stare what were your functional objectives keep it relatively clear of smoke when you say relatively clear of smoke that's the wording from the standards
01:39:27 that's the wording from the standards which standards are you referring to there um
01:39:31 there um i think at in double 991 and adb
01:39:37 so you're keeping the stare relatively clear of smoke what about the lobby to put ventilation in there that will
01:39:44 will deal with some smoke which may enter the lobby
01:39:47 lobby when people are escaping from their flat from the fire apartment sorry and again where are you getting that requirement from some smoke which may enter the
01:39:59 from some smoke which may enter the lobby
01:39:59 lobby 2.25 of adb 2.25 of adb yes and did it include protection of the stair for firefighting operations
01:40:12 stair for firefighting operations yes i've already said that and protection of the lobby for firefighting operations yes
01:40:21 were those functional objectives so what you've just said that we're trying to keep the stair relatively clear of smoke etc were those functional objectives ever set out by you or anyone
01:40:33 objectives ever set out by you or anyone else at psb in a document no it wasn't necessary as i said before because the project didn't go ahead
01:40:40 go ahead based on the design it went forward on the betterment on a ventilation rate
01:40:46 so why was it not necessary to set out the functional requirements because the design was not accepted
01:40:54 accepted and when you say because the design was not accepted which design are you saying was not
01:40:58 was not accepted psp design we put forward a design proposal
01:41:04 to fulfill those functions max fordham and partners decided that they couldn't go with a system that didn't comply with them anything
01:41:13 anything that they could refer to so they went forward on a betterment they used the ventilation rate that we gave them to prove the betterment which it wasn't a design that went forward it was a
01:41:24 a design that went forward it was a betterment that went forward i see and when was that agreed with max fordham
01:41:30 when you say agreed with max ford and max fordham agreed it with building control
01:41:35 control i see and what you were just told that that's what happened yes when we tended the job a document was placed before us which said that's what was the case and that document was adopted and placed
01:41:46 and that document was adopted and placed in our technical submission right i see now if we go to paragraph 32 of your first statement page seven
01:42:05 in this part of your statement you've listed a number of um different types of smoke control system
01:42:13 system that can be installed in high-rise buildings and just to quickly run through them there's the natural ventilation system which we've discussed yes and is it right that the main problem with grenfell tower was the size
01:42:25 problem with grenfell tower was the size of the shafts which were not large enough to achieve a high enough airflow rate that's correct did you ever do a calculation to confirm that to confirm what the size to confirm
01:42:39 to confirm what the size to confirm were not large enough to achieve a high enough air flow rate with a natural ventilation system did you ever do a calculation it doesn't have a calculation it's based on a size a dimension cross sectional area 1.5 square meter
01:42:52 cross sectional area 1.5 square meter shaft it's not based on a calculation
01:42:57 on the day of commissioning for example you would measure the shaft you wouldn't do a calculation and then we have a natural ventilation with mechanical boost
01:43:08 mechanical boost again we've discussed that before um you say a paragraph 32 2 is on the page here
01:43:19 32 2 is on the page here that the big problem with this type of system
01:43:22 system you say in the last sentence however even with the addition of fans i did not think that the existing shafts were large enough to allow air and smoke to flow at an effective rate yes yes what do you mean there by
01:43:35 rate yes yes what do you mean there by an effective rate of airflow to meet the design requirements
01:43:45 where's that statement so it's the end of 32 it's in the middle of that page there's a sentence that says again however even with the addition of fans i didn't think that the existing shafts
01:43:57 i didn't think that the existing shafts were large enough to allow air and smoke to flow at an effective rate right they weren't large enough for natural ventilation to produce the desired requirement and even with
01:44:09 the desired requirement and even with the boost fan that was limited by the size of the fan not the duct i see so you concluded that simply because of the size of the fan
01:44:20 because of the size of the fan that wasn't a viable option yes it was certainly not a viable option no and then there's the push pull system which we've already discussed and you've explained what your concerns with about
01:44:31 explained what your concerns with about that
01:44:32 that yes and then going over the page you talk about a pressurization system which is another type of mechanical smoke control system yep and a pressurization system is this
01:44:44 yep and a pressurization system is this right would use fans to move air into the stairwell itself
01:44:48 itself creating a higher pressure in the stairwell and so preventing smoke moving into the stairwell is that right yes
01:44:59 and was the main problem with that in your view that that would require the stair
01:45:04 stair to be well sealed so that this positive pressure was maintained no um a pressure differential system to bsem 1206
01:45:13 bsem 1206 is very expressed in its requirements and its layout and it is impossible to install that compliance system within grenfell tower or for that matter any high-rise block of flats
01:45:25 any high-rise block of flats you just simply can't do it yes i understand that but it's right isn't it that that british standard refers to two types of pressure differential system and one of
01:45:36 pressure differential system and one of them
01:45:36 them is the pressurization of the stairs yes yes and no it's it's far more far more in detail than that you pressurize the stair you pressurize the
01:45:47 the stair you pressurize the firefighting lobby and you pressurize the firefighting lift and you must have an exhaust path within each dwelling
01:45:57 i see and was that considered and discounted for grenfell tower it's discounted on any block of flats never alone grandfather grenfell tower has just made it even more difficult because of the restriction of the employer's
01:46:09 restriction of the employer's requirements yes i see if we go to an email psb
01:46:15 6025
01:46:20 there's an email um from mr mcgregor to you
01:46:24 you on the 2nd of may 2014
01:46:37 he says in the first paragraph of this email
01:46:41 email hugh this is one i looked at some time ago and we discounted changing the system to pressurization system as it would be much too difficult getting the ducks in leakage paths would
01:46:52 getting the ducks in leakage paths would be a nightmare do you recall this email yes and can you just help us what what pressurization system had you discounted at that stage as being too difficult
01:47:05 being too difficult any just any pressurization system so when he says getting the ducks in leakage paths would be a nightmare what specifically is he referring to in terms of getting ducks in and leakage
01:47:17 terms of getting ducks in and leakage paths
01:47:18 paths right to to comply with the requirements of that standard you would have to put a large
01:47:23 large air delivery duct to serve the stair which no
01:47:27 which no slab openings are available for you'd have to put a very large duct in to deliver the air to the lobbies and there was no openings in the slabs
01:47:34 slabs to accommodate that you would also have to have a
01:47:37 to have a small much smaller deck but they dump nonetheless running through the height of the building for the firefighting lift and that didn't make the openness that didn't exist
01:47:45 exist and in every flat because you didn't have two opposing walls to put automatic opening window venting which i'm sure the tenants wouldn't have wanted anyway you've had to put a very large
01:47:56 you've had to put a very large 1.6 square meter minimum cross-sectional area duct
01:48:00 area duct in every flat running through the building
01:48:03 building so if they've got six flats per floor that's six very large ducks running through the height of the building so they just did not exist so therefore you couldn't put it in right now um mr mcgregor also continues
01:48:17 right now um mr mcgregor also continues in that in that same paragraph we're going to have the email back up on the screen
01:48:26 he carries on he says use exhibit in the third line down of that first paragraph use existing push-pull system uprating what they have got
01:48:35 got is the easiest solution by a long way do you see that yeah now do we take it that you didn't agree with that assessment i totally disagreed with that assessment
01:48:47 i totally disagreed with that assessment sorry can you say that again i totally disagreed with that assessment i see so did you and mr mcgregor disagree about whether the push-pull system was viable initially until we discussed it then he
01:48:58 initially until we discussed it then he agreed i see
01:49:05 now just moving on to um you're developing a design for a depressurization system can we look at paragraph
01:49:13 paragraph 24 of yours if you read my wording it's a smoke
01:49:18 a smoke sorry it's a mechanical extract ventilation system which would depressurize the lobby it's not a depressurization system per se well let's just look at paragraph 24
01:49:29 24 of your first witness statement on page five so i want to look at how you've described this system in your statements
01:49:37 you say in the first line the design i developed was for a depressurization system in other words a system which achieved smoke control using depressurization principles
01:49:49 depressurization principles achieved by mechanical extraction depressurization systems are one of the most common types of smoke control system used in buildings in the uk they are designed to deliver protection to the
01:50:01 designed to deliver protection to the protected space in this case the stairwell by extracting air
01:50:06 air and combustion products from the common lobby to create a pressure differential and opposing air flows between the stairwell and the common lobby
01:50:15 lobby so you were picking me up earlier on the fact that i described what you'd said as a designing a depressurization system can we agree that that is what you have said in the first
01:50:25 first line of this paragraph yes by using mechanical extraction any system in a lobby whether it's natural or mechanical depressurizes the lobby that's how it
01:50:36 depressurizes the lobby that's how it fulfills its function so whether it's got a fan or it's just natural it depressurizes the lobby yes i understand and just looking at that um
01:50:46 that um paragraph and and we'll come on to some more
01:50:49 more explanation that you give of this in a moment
01:50:52 moment you say in the middle four lines down that they are designed to deliver protection to the protected space in this case the stairwell now can we just be crystal
01:51:03 the stairwell now can we just be crystal clear
01:51:05 clear you are saying there that you designed it to give protection to the protected space either stairwell does that mean that it was only only the stairwell that was was the protected space in accordance
01:51:18 was the protected space in accordance with this system protection yes but it would also deal with any smoke that entered the lobby with the before the door closed again so just to be clear even though you're
01:51:29 so just to be clear even though you're saying here they're designed to deliver protection to the protected space in this case the stairwell
01:51:35 stairwell you're saying that your design also delivered protection to the lobby yes not full protection and no system does offer full protection if even if it's natural smoke will enter the lobby and
01:51:47 the lobby and will be diluted by whatever ventilation system is in there but it doesn't protect it so was it designed to deliver some protection to the lobby is that a fair
01:51:58 protection to the lobby is that a fair way of putting it all systems are designed that way whether it's natural or mechanical if you have a natural shaft that's how it fulfills function it does they're not smoke extract systems they're smoke control systems
01:52:10 they're smoke control systems they stop the smoke going where you don't want it to go we can't stop becoming a lobby that's a natural that's a as it says in the product would be that's a natural requirement or a
01:52:22 that's a natural requirement or a natural occurrence because people are evacuating a flat that's on fire and some smoke may come with them okay so that's why you ventilate the lobby because some smoke maker the smoke is already in the lobby what
01:52:33 the smoke is already in the lobby what we then have to do is stop it getting into the snare yes i understand now if we look at your second that was your first witness statement and how you describe the system there
01:52:44 system there if we look at your second witness statement at page seven starting at paragraph 34
01:52:57 you describe the system in in this second statement as a mechanical extract depressurization system
01:53:06 principally works by extracting air and smoke from the lobby so that when the door between the lobby and the stairwell is opened
01:53:12 is opened and airflow is created from the stair to the lobby which would limit smoked ingress into the stair that's correct
01:53:19 correct so is it right that the primary purpose of the system is not to extract the smoke from the lobby but it's to create an air flow between the stair and the lobby when the stair
01:53:31 the stair and the lobby when the stair door is opened is that correct i'll say it again it's not a smoke extract system it's a smoke control system
01:53:38 system thank you now there's a helpful illustration of this in dr lane's phase two report if we could go to blarp to 5035 at page 260.
01:54:06 so if we could blow up that diagram
01:54:11 here what dr lane has done in simple term is is tried to translate the design intent of the psb system into this diagrammatic
01:54:22 of the psb system into this diagrammatic form
01:54:23 form in simple terms yes this is a later design which design are we talking about originally everything was extracted from the top of the building the two
01:54:34 the top of the building the two shafts were joined together in the rooftop plant room with one extract phone set
01:54:39 phone set yes this is a much later development i see
01:54:42 see so um i think this is the design as it was uh finally intended to be is that correct
01:54:48 correct that's correct but it's not our design when you say it's not your design why do you say that
01:54:56 our design was to connect two shafts together this the south and north side in the rooftop plant room with a single fan set the design evolved through the course of
01:55:07 the design evolved through the course of the contract by other parties i see so are you saying it wasn't part of your design intent for the smoke to be extracted downwards as we can see on the bottom
01:55:19 as we can see on the bottom left hand side of that drawing initially now
01:55:23 now but did it become part of your design that it was extracting downwards we can see this
01:55:30 see this through the duct work at the lower levels and then out to the ex outside it became incorporated by the instruction of others
01:55:40 it sounds from what you're saying that you were not happy with that instruction by others is that the case well not that i'm not happy with it my preference would have been the original design
01:55:50 design it was a much cleaner simpler design than what then evolved during the course of the construction work on site but were you so unhappy with this
01:56:01 but were you so unhappy with this revised design that you actually spelt that out
01:56:04 that out to others other professionals on the project no it would still work but it's not as clean a design as i proposed i see so you didn't express any concerns about this final design
01:56:17 about this final design not overly known no so um this final design as we can see it's extracting down through the south shaft and through some
01:56:25 some new duct work at lower levels and out and at the same time it's extracting from the the north vents the north side lobby vents and then up and out at roof level is
01:56:37 and then up and out at roof level is that correct correct now we've got a diagram at showing on a floor plan how this was work
01:56:45 work was intended to work if we can go to
01:56:50 blarp25035 at 261 so again just in simple terms what dr lane has done here
01:57:01 lane has done here is give an indication of how and this is the final um design how the final design was intended to work
01:57:11 work so can you just explain for the panel what we can see here first of all we can see some red arrows extracting at south and north is that correct that's correct and so what was the
01:57:23 that's correct and so what was the intention of exhausting smoke at both sides this particular diagram shows the firefighting phase not the means of escape face
01:57:35 not the means of escape face and the the design proposal was that in extracting air from all four shafts uh we would create a velocity across
01:57:46 uh we would create a velocity across that open door that would stop any smoke that was in the lobby
01:57:50 the lobby at that stage entering the stair and then once the fire door was actually open for the fire brigade to fight the fire it would still keep the stair reasonably clear smoke even with that fire door open and in
01:58:02 even with that fire door open and in fact a broken window in a fire flat yes so so let's just take this in stages assume wasn't the main design um intent for the design condition for
01:58:14 um intent for the design condition for the flat door to be shut that's not what's shown in that diagram well where where are you seeing the flat door open
01:58:22 door open it shows all the doors are open
01:58:27 okay well assume for the moment that all the doors around the lobby are closed yes right was the primary design of the system to ensure that if the stair door was opened there would be a
01:58:40 stair door was opened there would be a velocity across that stair door of two meters per second which would keep any smoke that had entered the lobby out of the stair is that correct that is correct yeah the main criteria
01:58:51 that is correct yeah the main criteria is extracting three cubic meters a second
01:58:56 when you say the main criteria is extracting three cubic meters per second if we go back to the original original design concept that we put forward we
01:59:07 design concept that we put forward we told max ford and we would want to extract from that lobby three cubic meters per second they asked where did you get that from so we can benchmark it in some way and we said right
01:59:17 right it's based on an open door velocity of two meters a second and that came from bsem went to another six but the key criteria was three cubic meters a second extraction rate
01:59:28 meters a second extraction rate is that three precisely where would you measure that extraction rate if this when the system's working at the vents in the
01:59:36 in the in the lobby you can measure that door because the velocity will give you the volume flow i see so what you're saying is the velocity of air across the door
01:59:47 velocity of air across the door will tell you what the volume flow is across that door across the stair door that is correct yeah so you're saying the volume just to be clear you're saying the volume rate at the door was three cubic
01:59:59 volume rate at the door was three cubic meters per second yes yes what about the extract rate at the vents
02:00:05 vents where the red arrows are they would total up to three cubic meters a second all four
02:00:13 and you said before that this diagram you said in your own words shows the fire fighting phase why do you say that
02:00:22 say that because it's showing the doors open in in the means of escape phase back to the adb it tells you that when someone escapes from the flap that's on fire
02:00:31 fire it is possible that some smoke may come with them
02:00:35 with them purely because they're escaping so take whichever door you want opens the people in that flat evacuate some smoke may come with them may not and then the door closes afterwards
02:00:46 and then the door closes afterwards because it should be a self-closing door and that level of smoke at that time is what the ventilation system should deal with with all the doors closed okay as in b1 so there will be a minus
02:00:58 okay as in b1 so there will be a minus 25
02:00:59 25 pa ventilation rate in that particular lobby
02:01:04 lobby so that gives you your b1 requirement once the fire brigade arrived they opened the stair door and the flat door and that time you got to go to b5 and the system would go to a much higher volumetric flow rate to give you the
02:01:16 volumetric flow rate to give you the three
02:01:17 three and not forgetting when the people first go to make that escape there is no ventilation whatsoever it's only a smoke enters and triggers the smoke detector in the lobby until that happens there's
02:01:28 in the lobby until that happens there's no ventilation yes and and just to be clear um can you just explain exactly what would happen when the stair doors would open was open but all other doors remain
02:01:39 but all other doors remain closed the fan system would ramp up to full duty because there's a pressure measuring device pressure differential measuring device between the stair and the lobby and it would show you can't maintain
02:01:50 would show you can't maintain the minus 25 pa tick over level and it would put the fans to a high speed yes so is this right that the fans would be at low speed yes that door was open and that pressure
02:02:03 yes that door was open and that pressure differential changed yes the fans would then move to high speed yes yes and there wasn't a system whereby the fans could then ramp up again was there if more doors
02:02:15 ramp up again was there if more doors were opened no there's no boost facility no no
02:02:23 now can you just explain in your own words why
02:02:26 words why this system this pressure differential system
02:02:30 system addressed the problem of the existing shafts being too small because we have four shafts that we're using
02:02:39 using uh as opposed to one or two we can use the four to get far more air through
02:02:46 through yes i see so instead of one one set of shafts
02:02:50 shafts putting in inlet air and the other one sucking out air what you're saying is under this system all four of those shafts are extracting air yes that's that's correct so the the
02:03:01 that's that's correct so the the velocity inductor velocity will be lower if it's a push-pull system for example you have 100 duty going in 100 duty going out with an extract system
02:03:11 system you have 50 across each side yes i understand is it common to have this kind of depressurization or pressure differential system like this
02:03:23 pressure differential system like this in a residential high-rise building like this no it's the employee's requirements it dictated this no if it was a new build it wouldn't go in that way there'd be a single duct
02:03:34 that way there'd be a single duct with a single extract realm are you aware of any other building that you've worked on
02:03:39 worked on which has a smoke control system sorry any other high-rise residential building
02:03:45 building that has a smoke control system like this one absolutely not as i said it was an alternative solution to try and reach the spirit of the standard
02:03:55 standard because we couldn't achieve it in a standard way it was impossible to put a standard system in because of the employer's requirements and what in your opinion would be the disadvantages of having this kind of
02:04:08 disadvantages of having this kind of system
02:04:10 system as long as the three cubic meters a second was achieved it would protect equally to a standard system and when you say as long as those three cubic meters were achieved it will
02:04:21 cubic meters were achieved it will protect equally to a standard system what do you mean when you talk about a standard system there standard shaft system
02:04:28 system whether it be mechanical or natural
02:04:33 so did you ask yourself the question at the time whether this system could provide equivalent performance to a standard mechanical or natural
02:04:44 to a standard mechanical or natural ventilation system yes and do we see evidence of that equivalency analysis set out anywhere in the documents you provided
02:04:56 provided no because it wasn't necessary because the design didn't go through
02:05:01 well you keep saying it wasn't necessary because the design didn't go forward i think you accept that this was the final design that we're looking at now yes
02:05:12 no what went forward was three cubic meters or so 3.5 cubic meters a second that's what went forward how you delivered it is a different thing the design is to get 3.5 cubic meters a second did you
02:05:25 to get 3.5 cubic meters a second did you ever ask yourself the question that with the system as it was designed and as it was intended to be delivered so extracting down the south shaft did you ever ask yourself the question whether that was providing
02:05:37 whether that was providing an equivalent performance to a standard natural or mechanical system yes and i'm satisfied if it was cfd modeled it would perform
02:05:49 cfd modeled it would perform so you're saying you're satisfied that had someone done a computational fluid dynamics
02:05:55 dynamics model of this it would have performed yes
02:05:59 yes yes but just to be clear no such cfd analysis was ever done yes no there was no no instruction ever issued to carry out the cfd model yes now
02:06:11 yes now let's look at a little bit more detail at the actual proposals that psb put forward
02:06:17 forward if we can go to the initial technical proposal this is psb four zeroes one two three three
02:06:30 four zeroes one two three three we can see it's smoke ventilation technical proposal it's issued for comment 22nd of april 2014
02:06:38 2014 and then it says approved hmm is that you
02:06:41 you that's me yeah and were you the author of this document yes and is it correct that this proposal was produced before psb had been formally engaged to do anything
02:06:53 had been formally engaged to do anything on the project yes and can you help us to your knowledge
02:06:57 knowledge was this document ever provided to building control no it wasn't if we look at section one the introduction on page two
02:07:10 i just want to read what what we see in the first two paragraphs it says having identified possible problems with the proposed push-pull system
02:07:19 system leading to excessive pressure drop due to the high induct velocity within the existing builders work shafts an alternative smoke control design solution is required
02:07:30 solution is required and then you say after discussions this report provides an alternative approach to designing a lobby smoke control system now just to be clear when you wrote this what did you mean by
02:07:40 mean by an alternative smoke control solution or an alternative approach well it was following the discussions with matt smith at max fordham where we pointed out it was impossible to put a appropriate
02:07:53 it was impossible to put a appropriate system in that met all the standards and could be said to be compliant therefore
02:07:58 therefore what we were proposing was to put forward a design that would protect the stair and ventilate the lobby but it didn't follow any of the guidance
02:08:09 but it didn't follow any of the guidance so it's an alternative approach
02:08:13 thank you and then if we look at what you said in the third and fourth paragraphs there you say these proposals will have to be firmed up and then submitted to the building control authority for discussion and agreement as an acceptable alternative
02:08:24 as an acceptable alternative to originally proposed the push pull system
02:08:27 system that's correct you go on the proposal is to design a depressurization system which will protect the stairwell by providing an airflow from the stairwell into the lobby when the
02:08:38 stairwell into the lobby when the stairwell lobby door is opened yes you see that now just to be clear it's only talking there about protecting the stairwell isn't it yes it doesn't talk about protecting the
02:08:49 yes it doesn't talk about protecting the lobby
02:08:50 lobby no
02:08:58 now in simple terms just pausing there can you just explain whether and how your system addressed the the problems of the layout of the lobby at grenfell tower the eye
02:09:10 of the lobby at grenfell tower the eye shaped lobby and uh dead spots which you were concerned about with the push-pull system proposal it doesn't have to deal with that no system has to deal with that
02:09:21 system has to deal with that because they're not smoke controls sorry smoke extract systems they're smoke control systems no system of compliant nature could deal with it either
02:09:32 with it either so it's not something you consider you can't do it so you've said that you were concerned about the push-pull system because of the way the lobby was was configured
02:09:43 configured its geometric configuration and its relationship with the stairs and the potential for dead spots along the corridors at the corners is what you're saying
02:09:54 at the corners is what you're saying that
02:09:55 that the system you proposed here would have the same problems as that push-pull system
02:10:00 system in that regard it would have a push-pull system is designed not to have that problem it's designed to reduce toxicity and obscuration levels that's what it's designed for
02:10:11 levels that's what it's designed for the system i'm putting forward isn't designed to do that and no system will remove those dead spots
02:10:19 spots [Music]
02:10:20 [Music] whether it be natural or mechanical because it's a dead spot if a push-pull system had a straight corridor as i suggested earlier you deal with it because it dead spot doesn't exist because it's a straight quota
02:10:33 so i think what you're saying is you didn't think that your design needed to concern itself with those dead spot dead spots it couldn't concern itself it's not that it didn't need to i think
02:10:44 need to i think and did you ever explain that in writing as part of the the design documentation you produced no we had we had discussions as that document stated
02:10:56 document stated did you ever explain to max fordham and others on the project that the system would have the same problem with dead spots and the same potential problems because of the geometrical shape of the
02:11:08 because of the geometrical shape of the lobbies
02:11:09 lobbies as the push pull system what stage are we talking about because as i said before we were not involved in the early stages of this project we were asked for advice and we gave advice so we weren't in contact with anybody other than max
02:11:21 in contact with anybody other than max williams initially at any stage did you explain to max fordham
02:11:27 fordham that those would be potential problems with the system that you were putting forward but they weren't potential problems i don't understand the premise of your question i see is is that because what you're
02:11:39 i see is is that because what you're saying is they weren't potential problems because although they would no no no no i'm not saying anything of the sort if it was a natural vent system that was compliant you would still have that dead spot if you put a mechanical system in
02:11:51 you put a mechanical system in that was compliant you would still have that dead spot i see so it was a feature of whatever you were going to install there
02:11:57 there you would have that that's right but if you had a push pull system you're not supposed to have that and did you ever consider whether the particular layout of the lobbies at grenfell tower including the travel distances
02:12:08 distances meant that actually those dead spots were something that needed to be grappled with as part of the design process they couldn't be as i keep saying if it's impossible to do something
02:12:20 it's impossible to do something it's impossible to do something you can't do the impossible so no i see now
02:12:27 i see now just going back uh to the proposal um if we can just look at the title page again
02:12:36 we can see it says smoke ventilation technical proposal stair
02:12:48 technical proposal stair depressurization systems yes let me just be absolutely clear i think you've already confirmed this but i just want to be crystal clear that unlike a simple mechanical extract system
02:12:59 system its primary purpose was not to extract smoke from the lobby but to prevent smoke entering the stair through the lobby door by maintaining an airflow across the door the stairwell door
02:13:11 door the stairwell door as a result of a pressure difference no it's by removing three cubic meters a second from the lobby that creates the pressure tip so that
02:13:22 that creates the pressure tip so that creates the velocity across the door so depressurizing the lobby creates that protection i see so are you saying that by
02:13:33 i see so are you saying that by what extracting three cubic meters a second from the lobby that was its primary purpose yes i see
02:13:45 i see when we asked mr hansen about this last week the building control officer he understood that it wasn't a depressurization system but was in what he called an extract system that's
02:13:56 what he called an extract system that's correct
02:13:57 correct and he says that when there was a meeting about it it was a meeting not about a pressurization system it was about an
02:14:02 about an extract system from the lobbies he said the reality of a pressurization system in the
02:14:07 in the existing building would be really quite difficult to do so it seems that it's almost not practical that was that wasn't the discussion at all it was an extract system that's correct
02:14:20 system that's correct so if it was an extract system why is it not described simply as an extract system in all of these documents we said mechanical extract is pressed to depressurize the lobby
02:14:31 depressurize the lobby that's what it does yes and that's right isn't it that as a consequence of extracting air from the lobby
02:14:39 the lobby you by definition create a pressure differential between the lobby and the stairs yes that's correct yes thank you now if we go back to the
02:14:50 thank you now if we go back to the proposal
02:14:51 proposal page two
02:15:01 if we look at the fifth paragraph down now
02:15:05 now it says this the velocity across the open stairwell to lobby door should be sufficient to meet the requirements for a class b system as outlined within bsen 12101
02:15:18 system as outlined within bsen 12101 part
02:15:18 part 6 smoke and heat control systems part six
02:15:22 six specification for pressure differential systems
02:15:25 systems kits you see that i see that now can you just explain to the panel briefly what what is a class b pressure differential system as
02:15:35 system as outlined in that british standard a class b
02:15:39 class b system would pressurize the stair would pressurize the lobby would pressurize the firefighting lift the stair would be 50 pa above ambient the stair sorry the lobby 45
02:15:52 the stair sorry the lobby 45 and this lift would be 50 pa and there would have to be a defined air leakage path out of the fire fight the fire flat so air would be pumped into the building in large quantities and then it would
02:16:04 in large quantities and then it would flow through the open door of the stair when the fire brigade were there through the door of a flat and out through a smoke shaft or whatever the uh egress pass was out to the flat
02:16:18 egress pass was out to the flat i understand and it's right isn't it that the class b system is for means of escape and firefighting yes that's correct yes for a residential building it's a class
02:16:30 for a residential building it's a class a
02:16:31 a and the difference is 0.75 meter a second across an open door for class b obviously class a doesn't do firefighting class b does both so it's got a 2 meter a second
02:16:42 does both so it's got a 2 meter a second open door velocity and that being greater than 0.75 is the dominant
02:16:46 dominant number that you would design to yes and we can see that if we just look briefly at that
02:16:51 at that in that british standard if we go to
02:16:55 rbk3045054 at page 17.
02:17:04 we get a helpful table here setting out the classes of systems and as as you've just confirmed a class b system
02:17:13 b system is for means of escape and firefighting that's correct a is for means of escape defending place yes
02:17:20 yes yep now can we take it that from from this that you chose the class b
02:17:28 class b requirement that's that velocity requirement because the system needed to provide protection for both means of escape and during firefighting no
02:17:42 during firefighting no it was to justify the three cubic meters a second extraction rate back to the discussion with max ferdinand partners when we said how the system would work they asked the question what is the ventilation rate we
02:17:53 question what is the ventilation rate we give them a ventilation rate and they said where does that come from so we give that as a benchmark of where it came from why did you choose that as your benchmark from that class b
02:18:04 benchmark from that class b system because that is the ventilation rate we would put in a standard smoke shaft system using mechanical means of exhaust i see so is it just a coincidence well
02:18:15 i see so is it just a coincidence well let's go back to your proposal it can't have been a coincidence that it's also in that british standard because you're specifically referring to that british standard
02:18:23 standard in the proposal yes yes when the industry developed these systems that was one of the things we looked at
02:18:31 looked at and that was a ventilation rate required to comply
02:18:34 to comply with both firefighting b5 and b1 and also in line with research that have been undertaken by the building research establishment and
02:18:45 the building research establishment and we
02:18:46 we most companies will work on a delivery of three cubic meter second extraction from the lobby as the ventilation rate required to protect the stair and but it came it came from that requirement of open door velocity we
02:18:58 requirement of open door velocity we knew that with that open door velocity we can protect the snow so that was where these systems developed from yeah and just going back to the proposal and the wording that we were just looking at so psb four
02:19:11 we were just looking at so psb four zeros yes
02:19:12 zeros yes the velocity across the open stairwell to lobby door should be sufficient to meet the requirements for a class b system as outlined in that standard
02:19:22 where you say should be sufficient to meet that
02:19:26 meet that did you mean that the velocity across the open stairwell door would meet that that requirement or was this just aspirational hence the use of the word should it would meet it with just that door
02:19:38 it would meet it with just that door open
02:19:39 open and the if there was a stairwell when the stairwell went open as in the case of grenville it was a permanent event i think what you're saying is if the stair
02:19:48 the stair door was open but all other doors on the lobby were closed it would meet that two meters per second yeah that's correct if all of the if other doors were then open as in the fire door it would still protect that stair by
02:20:00 it would still protect that stair by extracting three cubans a second from the lobby yes you don't ever say that second part of what you just said in any of the technical submissions do
02:20:11 in any of the technical submissions do you
02:20:12 you no because this was this is a follow-on from conversations that we'd had right we were just asked at this stage was to put some some notes together to
02:20:23 was to put some some notes together to help
02:20:24 help max fordham because we pointed out quite clearly this does not comply and because it doesn't comply you're gonna have to go through the building control and say is it okay to use this system because
02:20:35 is it okay to use this system because it's the only thing we can do and they say can you put some notes together don't go into any real detail at this stage because it may not be acceptable just give us some notes that we can discuss with them yes that's what this was
02:20:47 was and and just to be clear when you wrote these notes for the assistance of max fordham were you intending to convey here
02:20:53 here that only the velocity across the open stairwell door would meet the requirements of that british standard and that the system as a whole
02:21:01 a whole would not comply with that standard that was following from the conversation that we'd had yes yes so did you make it clear in conversations with max fordham that the system as a whole could not
02:21:14 that the system as a whole could not comply with the whole of that british standard
02:21:18 standard yes because we discussed how the system would operate and we were then asked to justify where we got our three cubic meters a second from and that's where this reference the class b come from so yes that was all discussed at the
02:21:31 so yes that was all discussed at the bottom of that page you say it's proposed to use all four of the builders works shaft as part of the smoke control system mechanical extract which will result in a much reduced average induct velocity
02:21:42 induct velocity of 5 meters per second yes let me just explain what you mean there by an average induct velocity well if you take the total volumetric flow rate and divided by the
02:21:53 flow rate and divided by the area of duct available it will give you the average index velocity
02:22:00 i see so that's the average velocity through each of the four different ducts is that right as an average yes it will not you can't balance those so it won't be it's not precise but yes yes and again
02:22:12 it's not precise but yes yes and again so you can see there we clearly state it's a mechanical extract i'm not liking that paragraph and then if we
02:22:19 if we go on through this document page three we see some calculations including your calculations of airway airflow through an open door
02:22:30 airflow through an open door yes
02:22:33 can you just explain in simple terms what this is what these calculations are showing
02:22:38 showing right if you if you have a volumetric folate it's cubic meters per second to find out what that number is you multiply area which is the area of the opening the door by the velocity that you require which
02:22:49 by the velocity that you require which is two meters a second so square meters times meters per second gives you cubic meters a second so multiply the air with the door by a velocity gives you 3.2.2
02:23:02 velocity gives you 3.2.2 and then you say you've added 50 for unforeseen losses yeah this will cover unidentified fabric losses so that's like leakage within the duct yeah or leakage within the shafts and dampers and dampers and why do you
02:23:15 and dampers and dampers and why do you add 50
02:23:16 add 50 for that it's just a notional number that's put in that british standard at this stage we hadn't gone into any detailed design work as it says on the other page it will need to be developed on
02:23:27 need to be developed on and detailed work we put into it so at this stage we're just saying it's not just 3.2 we need because to deliver that 3.2 we need a lot more air because we're going to lose it in the system
02:23:39 going to lose it in the system yes i see and then you've got a section underneath for fabric losses i think you're just explaining your 50 is that right there yes and then you've
02:23:51 is that right there yes and then you've got
02:23:52 got underneath that area for pressure relief at the bottom of that page again can you just explain in simple terms i think what you're saying here is that
02:24:02 that by extracting the air from the lobby you will by definition create um a force across the closed door to the stair which would be too great to open the door
02:24:14 great to open the door and so this is where your fan speed is important that you need to make sure that
02:24:19 that you've got pressure switches that are able to ensure that the fan is at low speed
02:24:25 speed until the doors are opened and then when the stair doors opened the fan goes up to high speed to keep that velocity is that right that's correct yes yeah
02:24:36 and then we can see on page four a list of components
02:24:41 we just go over the page
02:24:45 you've just outlined there a a a giraffe list of components and then there's brief mention of the environmental system yeah at the bottom of that page
02:24:56 yeah at the bottom of that page now if we can now go to the first version
02:25:00 version of the psb technical submission for the smoke control system this is at psb 50207
02:25:14 we can see from the revision history it's revision naught it's got you as the author hmm again and it's dated the 12th of november 2014 yes now again did you
02:25:28 yes now again did you did you write this technical submission i did
02:25:33 and is it right and i think you explained this in your first witness statement
02:25:37 statement at paragraph 36 that you produced all the subsequent revisions of the technical submission except for the final version revision 6 which was produced just after you left psb
02:25:49 you left psb that's correct now to what extent did any other staff at psb
02:25:55 at psb input into the design decisions that are shown in this technical submission none and what was the purpose of this technical submission can you help us
02:26:07 technical submission can you help us um this was put together to show what the components would be
02:26:12 when you say put together to show what the components would be
02:26:19 it's called a technical submission um does that mean that the entire purpose of this was simply to identify the components yes so
02:26:30 yes so it wasn't supposed to be acting as a full specification for the smoke control system
02:26:38 what do you mean by full specification well identifying um the design intent the objectives of it
02:26:46 it and then the facets of the system there's a brief introduction to the design intent which is to achieve the ventilation rate um i think
02:26:57 achieve the ventilation rate um i think there'll be then a reference i don't remember to the base documents that this was based upon i.e what influenced this document and then the components we would use to put a system together and is it
02:27:09 to put a system together and is it correct and we'll go to the text of it in a moment that this submission was prepared for js wright who were by this time receiving psb's proposals is that correct it may be i really
02:27:20 is that correct it may be i really remember and if we look at the very bottom of page three and on to page four
02:27:33 this document has two different phases of proposal that it's dealing with is it right in in general terms that phase one was a temporary
02:27:44 phase one was a temporary solution for the existing system and phase two was the permanent design of the refurbished system um going back to your previous question yes this was produced for js rights no
02:27:56 yes this was produced for js rights no i'm reading this i can see that was the case yeah yeah phase when we were asked to consider bringing the existing natural vent system
02:28:07 system to a working status because it was not working and to implement that as quickly as possible and then that would then be followed by converting it to a mechanical system
02:28:20 converting it to a mechanical system yes i understand and and if we go over the page i think we can see phase two is dealt with
02:28:31 yes phase two then is the mechanical smoke extract
02:28:38 at a predetermined day phase two will be to implement to convert the system into a fully mechanical extract system with a new smoke extract run etc now
02:28:48 etc now let's actually look now at the second version of this proposal jsw40
02:28:59 we can see this one's dated the 1st of december 2014 and again you were the author of this proposal yes yes and if we go to page three and look at
02:29:10 and if we go to page three and look at paragraph 1.1.2
02:29:15 we look at the bottom we see this about the design intent it says the final smoke control system has been designed
02:29:24 designed to provide the existing stairwell with protection from the ingress of smoke from a fire within a dwelling by means of a mechanical extract system the system has been designed to provide
02:29:35 the system has been designed to provide an average open door velocity across an open lobby stairwell door of two meters per second this velocity is in accordance with the recommendation for a class b pressure differential
02:29:46 for a class b pressure differential system as defined in that code of practice bsen 12101 part 6. that's correct and then in the next paragraph it says this i i think that should mean
02:29:57 this i i think that should mean it should be noted but as the system is designed to extract air from the lobby via the open stairwell door the system is not
02:30:07 is not designed to comply with all the requirements of the aforementioned code of practice now um just looking at that that
02:30:19 um just looking at that that paragraph i just read out and the first part of it what did you mean when you say that the system is designed to extract air from the lobby via the open stairwell door
02:30:33 stairwell door that we would be extracting from the lobby in the air would come in from the open stairwell door yes so the replacement air is coming from the open stairwell door is that correct
02:30:42 correct correct yes i see and then it's in this version of the proposal you've you've included the words then the system is not designed to comply with all the requirements of the
02:30:54 comply with all the requirements of the aforementioned code of practice why did you include that in this in this around that time there was a conversation with i think with david bradbury but i
02:31:05 with i think with david bradbury but i can't be
02:31:05 can't be definitive on that and there was reference to the sem 1201-6 and the comments were made and i said no no you're misunderstanding
02:31:16 you're misunderstanding it does not comply with that standard it is only the two meters a second that we've taken from that standard that is applicable the rest of the standard does not apply to this system other than the hundred
02:31:27 to this system other than the hundred newton's
02:31:27 newton's opening force to a door because that's a general guidance and that's given in other standards as well so i thought it was prudent to put that in there that that mistake made by one person would not be
02:31:38 mistake made by one person would not be made by another yes so you wanted to make it clear to everyone reading the proposal that it didn't comply with all of the requirements for a pressure differential system as set out in that code of practice yes
02:31:49 set out in that code of practice yes correct yes yeah and then if we go to page four
02:31:57 page four we can see some more details about how the system would be set up so it says at the top of that page if we look at the top half the plc control system what does plc
02:32:10 the plc control system what does plc stand for can you help a programmer logic yeah programmable logic control system will have links to the new fire alarm system to provide an initiating signal once a
02:32:23 to provide an initiating signal once a signal is received all the dampers extract and inlet air in the smoke affected lobby will open and all dampers on other floors are to remain closed and then you explain a human mechanical interface panel
02:32:34 interface panel hmi will be located within the entrance area to provide the fire and rescue service with a central override facility to close all dampers in a single operation
02:32:43 operation and then you go on each ventilated lobby will be provided with a key override and those are the little yellow key override switches that we will look at
02:32:53 at in due course a key override switch located within the stairwell at each story level providing the fire and rescue service with a local override facility to open the dampers on
02:33:04 override facility to open the dampers on any one floor once one switch has been activated to open the dampers on a given floor then all other floor switches will be locked out
02:33:12 out once the activated switch is returned to its original position another floor can be activated so that's explaining what the different components of the system would be in some of the controls
02:33:23 some of the controls and then if we could also go on to look at page 18.
02:33:34 at page 18. uh sorry actually i don't i think that must be a wrong reference i'm looking for section 3.3
02:33:42 where the section's mechanical function is explained yes thank you so here
02:33:53 uh is page 18 yes it says the mechanical fan set under 3.3 mechanical control system the mechanical fan set will be provided with a fan starter panel incorporating inverted speed drives to
02:34:04 incorporating inverted speed drives to control the speed of the fans between low speed and high speed so just to be clear low speed was all dork closed high speed was the door on the fire floor open yes and that's the stair
02:34:16 fire floor open yes and that's the stair door open
02:34:17 door open is that right yeah so there's just two speeder fans low and high the open closed door condition will be monitored by a pressure sensor which will measure the pressure differential between the lobby and the
02:34:29 differential between the lobby and the stairwell
02:34:30 stairwell the system is designed to maintain a 25 pascal in the lobby with all doors closed and will maintain the fans at low speed setting
02:34:41 at low speed setting once a door to the smoke affected lobby and only the smoke affected lobby i think it should mean opened the pressure differential will be lost and the fans will automatically ramp up to
02:34:52 the fans will automatically ramp up to full speed to extract air from the lobby at a rate which will provide an average phase velocity of two meters per second across the open lobby stairwell door
02:35:03 across the open lobby stairwell door that's explaining what we were just discussing about the fact that once the stair doors opened and there's a change in the pressure differential and some of that differential is lost
02:35:14 and some of that differential is lost the the fans have got to ramp up in order to get your velocity of two meters per second across that stairwell door yes
02:35:24 yes now is it correct that it was essentially this basic design the bits that we just read that did culminate in the final psb technical
02:35:36 culminate in the final psb technical submission revision six i would think so yes that's as we understand it so um
02:35:48 so um now can we go to max404665
02:36:05 max four zero is four five so this is an email from
02:36:14 matt cross smith of max fordham to claire williams at the tmo you're not a recipient or copied in here it's dated the 24th of november 2014 and
02:36:27 2014 and in essence what this email tells ms williams of the tmo is that psb and js wright had been part of a meeting earlier that day with building control ryden js wright
02:36:38 with building control ryden js wright and studio e all present and that building control had in principle accepted the proposed design we look at the first paragraph
02:36:47 paragraph it says we had a meeting this morning with building control regarding this proposed smoke extract system with ryden js wright studio e and the smoke extract system supplier psb
02:36:58 the smoke extract system supplier psb js wright have developed a slightly updated proposal with psb which would eliminate the need for the fresh air inlet which was previously at the top of the glazed foyer it would instead take the makeup air
02:37:09 it would instead take the makeup air from a vent at the head of the stair core
02:37:11 core we've yet to receive a technical submittal for this but in principle it appears to be a neat solution which also satisfies
02:37:18 satisfies building control now do you recall this meeting on the 20 um on the 24th of november 2014 i recall attending a meeting of that date i don't recall the detail of it
02:37:30 date i don't recall the detail of it though
02:37:32 though do you remember building control being part of that meeting yes i think it was at their offices now is it right that the proposal being
02:37:43 now is it right that the proposal being put forward was this pressure differential proposal that you had prepared for max fordham not in that we keep coming back to this particular point if you
02:37:54 particular point if you looked at my technical submission it's based document is the max forwarding justification exercise for betterment and that's what we discussed at that meeting but it was based upon the
02:38:05 meeting but it was based upon the principles that we set out yes but it's based on betterment not not a design solution so were those words used to building
02:38:17 so were those words used to building control that this was a betterment proposal not a i wasn't part of
02:38:22 of those meetings where that was agreed so i don't know
02:38:27 i see so is it your understanding that prior to this meeting it had already been determined that what you were looking at doing is simply bettering the existing system is that
02:38:39 bettering the existing system is that right
02:38:39 right prior to us tendering the project yes
02:38:44 and can you explain what what did you say to building control at this meeting about the proposal you were putting forward we were asked to describe its operational function how it would work
02:38:56 operational function how it would work and how did you describe that to building control
02:39:02 not sure what you mean how do we describe it we went through what would happen
02:39:05 happen if a fire occurred in an apartment and smoke got into a lobby we described the sequence of events i see so you described the extract process and and you described
02:39:16 described um the velocity across the door and the the door opening force and the fans changing
02:39:23 changing all of that was explained to building control was it yes and did you get the impression that building control understood the type of system that you were proposing at this meeting definitely
02:39:37 was it made clear to building control that this was a bespoke solution which didn't replicate any other
02:39:44 any other building that you'd ever worked on it wasn't a bespoke solution it was a betterment what do you mean by that it wasn't a bespoke solution it was a betterment
02:39:56 bespoke solution it was a betterment as long as you were able to show the system delivered three cubic meters a second
02:40:02 second then that was acceptable to building control
02:40:06 control a betterment exercise was carried out by max fordham in conjunction with building a drill
02:40:10 a drill they were asked to justify the amendments they were making to the system that's how the justification was made that what was going to be put in was better than what was already there so why wasn't that a bespoke
02:40:21 there so why wasn't that a bespoke system solution for the practical uh problems that you were presented with i
02:40:28 i sorry can you repeat that question wasn't that just a bespoke solution for the practical constraints you were presented with no as long as you achieved the three cubic meters a second
02:40:39 cubic meters a second it didn't matter how you achieved it well i think it would help me and perhaps others mr marley if you could just expand a little on what you mean
02:40:48 mean because you've used the expression several times as a distinction between a design solution and a betterment solution could you help me okay what the
02:40:59 could you help me okay what the employee's requirements for the project were
02:41:02 were that the original system as installed that was not operating should be refurbished and brought back to an operational standing that's all you had to do to
02:41:13 standing that's all you had to do to comply
02:41:13 comply with the employees requirements alternatively you could put forward a suggestion that would put a system in that would be better than what was already there therefore a
02:41:24 than what was already there therefore a betterment now what max fordham did was put forward a document that showed how the proposed 3.5 as they put in a document 3.5 cubic
02:41:35 as they put in a document 3.5 cubic meters a second was better than what a natural ventilation system would achieve they did a calculation and what the boost facility fan would give
02:41:45 give and i think that my memory shows me well it's something like one cubic meter a second for natural 1.2 cubic meters a second for the boost facility on the existing and the new system would deliver 3.5
02:41:58 and the new system would deliver 3.5 therefore 3.5 was better than 1.2 it was better so have i understood it correctly if i say that you weren't asked to design anything
02:42:11 asked to design anything what you were asked to do was to
02:42:16 enable max fordham or js wright to establish that the system that they were going to put in would result in an airflow
02:42:27 would result in an airflow at least as good and probably better than
02:42:31 than that which would have obtained under the original system that is correct however what i would like to qualify at that point to say is that it was always my intention that what was put in
02:42:43 what was put in would be a workable solution to the best of our ability given the constraints of the employer's requirements that made it impossible to put a compliance system in
02:42:54 in yes then you could not follow any of the standards
02:42:57 standards however i use these strange terms they're unique to me not to the trade and that is what was the spirit of the standards
02:43:05 standards what were they trying to achieve and i applied the spirit of the standards because i could not apply the standards i think that's very helpful thank you yes it's grange yes and did you ever
02:43:17 yes it's grange yes and did you ever look at the new system through the prism of the functional requirements in the building regulations we talked about b1 and b5 did you ever ask yourself whether the new system
02:43:28 new system was making b1 any worse or b5 any worse as as i said earlier my opinion is that if it was to be cfd modeled
02:43:40 it was to be cfd modeled it would show that to be the case that it is based on delivering for us ignoring a safe travel distance for a moment that's a different issue if you put a standard mechanical shaft
02:43:53 if you put a standard mechanical shaft system
02:43:53 system in that building if you're able to do that
02:43:57 that it would deliver the same answer volumetrically that i had put in but i achieved it a different way because i couldn't put a single shaft in with a single grille i had to adopt four
02:44:09 with a single grille i had to adopt four shafts
02:44:09 shafts with four grills but the delivery requirement of three cubic meters a second would be met but be met in a different way i see okay
02:44:20 i see okay thinking back to that meeting um was it your understanding that building control in principle accepted the type of system being put forward by psb
02:44:31 being put forward by psb and js right at this meeting they accepted it yes because when we talked through the principal operating factors and what would be delivered it was acceptable to them complied with
02:44:42 it was acceptable to them complied with the betterment that they'd given do you recall building control saying at that meeting that they needed to be provided with details about what the extract rate for the system was i the extract rate through the vents in
02:44:54 i the extract rate through the vents in the lobby do you recall that being said no i don't now if we move forward in terms of how the design developed you've explained paragraph 39 of your
02:45:07 you've explained paragraph 39 of your first statement if we could pull that up page nine what you do in this part of your statement is you explain
02:45:19 statement is you explain some of the changes that were made in subsequent revisions to the technical submission now is it correct that these included these included the smoke shafts were extended down
02:45:30 extended down to the ceiling of ground floor level with vents into each of the communal lobbies on the lowest four floors yes yes and is it right that the specification
02:45:42 and is it right that the specification was also
02:45:42 was also changed so that the specification and location of the smoke extract fan sets were incorporated into the design involving a change from having a single rooftop extract fan serving both north
02:45:54 rooftop extract fan serving both north and south shafts to having one smoke extract fan in the rooftop plant room and one at lower level at the walkway level
02:46:04 level is that correct that is correct yes yes and i think that's what you were explaining earlier that originally the fan sets were both going to be at at the top of the building and then there was a change to make one
02:46:15 and then there was a change to make one of the fan sets at low level and one at high level that's correct because the first meeting on site with max fordham was to establish how would we we would actually connect the south and north shafts
02:46:26 the south and north shafts together that was the purpose of that first meeting on site yes i understand now did this change in the arrangement of the fans for the system
02:46:35 system have any impact in your opinion on the system's likely performance
02:46:42 not in its likely performance no but anything you every time you overly complicate something you just have something else that could go wrong and what do you mean by that what was
02:46:54 and what do you mean by that what was the what was the complication here which might
02:46:57 might result in something else going wrong because we had to isolate a fan set from the environmental fan set so you're introducing more dampers than
02:47:08 so you're introducing more dampers than we would normally have had yes so i think what you're explaining is that at the lower levels and because of the way the environmental system worked that would have its own set of dampers
02:47:19 set of dampers and then when the systems changed over from environmental to smoke control mode those dampers would need to operate and different ducts would need to open up for the smoke control mode yes
02:47:31 for the smoke control mode yes effectively yes we we would normally have had one damper to isolate that fan set as it turned out we needed more than that because we had to isolate that fan set from the system and then the smoke extract from the
02:47:43 and then the smoke extract from the environmental system and that was working
02:47:44 working so we had additional dampers yes and i think what what you're the thrust of what you're saying is the more dampers you have the more potential there is for maybe one of those dampers to fail in the system not to operate correctly
02:47:56 in the system not to operate correctly indeed yeah now now that meant also um it's obvious that the design for the smoke was to be extracted in the south shaft
02:48:07 south shaft downwards through the south shaft for smoke to come down not to rise up yes in your view did that fact alone affect the likely performance of the system
02:48:18 system no it wouldn't and back back to a point i i know
02:48:21 i i know it's like i'm splitting hairs it's not a smoke extract system we're extracting air potentially only air or air and some smoke so extracting downwards is not a problem
02:48:33 so extracting downwards is not a problem it doesn't doesn't give you any additional issues to deal with
02:48:39 i see so you didn't think that it might be a problem that once there was smoke in that south shaft um that that smoke might rise up in the south shaft rather than
02:48:50 south shaft rather than get pulled downwards it wouldn't rise up if you had an extract fan running i see did you have any concerns about relying on the existing location
02:49:01 about relying on the existing location of the south shaft dampers in the lobby for extracting smoke we know that those south shaft dampers
02:49:08 dampers and the grills for them were at floor level low level whereas in the north side they were higher up on the wall did you ever consider that as part of the design process
02:49:19 the design process i did consider it but as they would assist in delivering the three meters a cubic meters a second stroke two meters second across the open door
02:49:28 door then that would be acceptable because they were not there to extract smoke they were there to extract from the lobby it's not a smoke control it's a smoke control system not a smoke ventilation system
02:49:40 ventilation system i think what you're saying is it wouldn't matter if there was smoke at higher level in the lobby as long as some air was being extracted at low level the design intent was satisfied that is correct yeah
02:49:51 correct yeah my preference i would prefer it at high level
02:49:54 level and if you look at the guidance it says it should be at high level that's my comment that i could not put a compliance system in yeah now if we go to revision two of the psv technical submission this is at psb
02:50:06 psv technical submission this is at psb four zeros one two three six at page three
02:50:19 this is dated the 14th of april 2015.
02:50:25 and if we look at paragraph 1.1.2 at the bottom of the page
02:50:31 we can see it still says in the second paragraph there it should be noted that the system is designed to extract air from the lobby etcetera and it's not designed to comply with all the requirements of the aforementioned code of practice
02:50:42 code of practice now if we go to an email now psb 50569. we go off this particular document could we go to the top of it please can i show you something yes that i think is relevant you mean
02:50:53 yes that i think is relevant you mean the top of this page particular page yes if we look at item 1.1 sub item 2 specification max ford and grenfell tower
02:51:04 grenfell tower ventilation analysis revision a dated 6th of may 2014 is the betterment document so my so my specification is based upon max fordham's betterment document i see
02:51:17 max fordham's betterment document i see okay
02:51:17 okay thank you that's helpful um so if we could go now to an email chain
02:51:30 psb50569 this is an email from um david bradbury within psb to you on the 11th of june 2015 and he says paul hanson from
02:51:43 2015 and he says paul hanson from building control has just called can we let him know asap if we mean the statement highlighted in yellow or can it be deleted and resubmitted he wants us to basically delete it as it
02:51:54 wants us to basically delete it as it doesn't tie in with what we've discussed with him
02:51:56 with him if we can respond quickly we can avoid him rejecting the technical submission and we can see that he's highlighted that paragraph that i just read to you about this what the system's designed to
02:52:08 about this what the system's designed to do and it's not designed to comply with all the requirements of the aforementioned um code of practice and revision three um for the transcript i don't think we
02:52:19 um for the transcript i don't think we need to go to it psb50209 that set that paragraph was then deleted in its entirety and doesn't appear thereafter do you recall that yes
02:52:32 now looking at this um email here can you help us why did that paragraph not tie in with what had previously been discussed with building
02:52:44 previously been discussed with building control did you understand why that's being said well reading it again it's very badly written what i meant to say was that we were
02:52:55 that we were extracting hair from the lobby and that make up air come via excuse me the stairwell door which it didn't quite see that does it but that's what was meant now uh the reason i put it in there as i
02:53:06 now uh the reason i put it in there as i said earlier was it was something that myself and dave bradley had a discussion and i was concerned he didn't understand what i was saying that's why i put it in there so we didn't have to come back to it again
02:53:17 didn't have to come back to it again i i know that when we went to the meeting with building control they understood what we were saying so taking it out wasn't an issue yes now i understand
02:53:28 an issue yes now i understand i understand why you're saying that that first part of that sentence was not as clear as it could have been um but what about the part which says the system is not designed to
02:53:40 which says the system is not designed to comply with all of the requirements of the aforementioned code of practice did you understand why there was a request for you to take that out
02:53:50 i think it's because the statement is wrong isn't it it implies i was extracting from the stair well i understand that about the first part but you're making two points in that uh sentence i was satisfied that
02:54:03 in that uh sentence i was satisfied that building control knew what we were saying when we had that meeting why were you happy for the part to be deleted which says the system is not designed to comply with all the requirements of the aforementioned code
02:54:14 requirements of the aforementioned code of practice because as i understand your evidence
02:54:16 evidence it wasn't designed to comply with all the requirements of that code of practice so why wasn't that a statement that needed to be in there because we discussed it with all the relevant parties and they were happy with it
02:54:27 with it they were they understood after my discussions so it is what you're saying that they understood through discussions that it didn't comply with all the requirements of that code of practice
02:54:39 requirements of that code of practice so you didn't need to say it in this written document that's correct but wasn't that something that the technical submission needed to make very clear for all future readers
02:54:50 make very clear for all future readers and users of the system that it didn't comply with all of the requirements of that code of practice but if you read the the document in line with
02:55:00 with all of the document it's clearly based upon the betterment it says at the very front of the document
02:55:09 the design principle is to achieve three cubic meters sorry 3.5 cubic meters a second are you saying that all readers of that document would have understood without that statement that
02:55:21 understood without that statement that it didn't comply with the requirements of that code of practice i can't say that the same as i can't say that anyone who knows anything about smoke control at all would know it's impossible to put a pressure differential system into that
02:55:33 a pressure differential system into that building
02:55:34 building but anyone who knows smoke control wouldn't know that can we look at what you said in your first witness statement for the inquiry at paragraphs 50 and 51 at this point this is on page 15.
02:55:54 you say here the psdb design was a for a depressurization system in other words a system which achieved smoke control using depressurization principles achieved by mechanical extraction
02:56:06 achieved by mechanical extraction bsen121 part 6 2005 is the relevant standard for designing pressure differential systems including depressurization systems it sets out functional objectives and
02:56:17 it sets out functional objectives and measures measurable performance criteria now do you still hold to what you said there that that standard that british standard is the relevant standard for designing
02:56:27 designing depressurization systems for that standard yes and if we go to paragraph 52 of your first statement below that you say this i drew upon the
02:56:41 below that you say this i drew upon the principles in this standard to develop a building appropriate solution and then you say this the psb design was in line
02:56:49 in line with the performance criteria of bs en 121 part 6 2005. now that's simply not correct is it no because the full stop shouldn't be there the primary performance criteria of the
02:57:00 the primary performance criteria of the design
02:57:01 design requiring a minimum of two meters a second that that dot there i believe is because it's come from the the title document but no it's nice no so when you told us in your first statement that the psb design was in
02:57:13 statement that the psb design was in line with the performance criteria of bsen12106 part 6 that was incorrect wasn't it that is incorrect
02:57:21 incorrect yeah and at paragraph 54 you told us achieving the functional objectives of that british standard indicates compliance with the functional requirements of the building regulations
02:57:33 requirements of the building regulations so you've said the design was in line with that british standard and achieving the functional objectives of that british standard shows compliance with the building regulations now my design proposal yes i beg your
02:57:47 now my design proposal yes i beg your pardon
02:57:47 pardon along with my design professor i drew upon the principles in this standard to develop a building appropriate solution it won't always understand it it was an appropriate solution
02:57:58 you couldn't put it in so it it it was we've developed an alternative design solution because nothing else would go in
02:58:06 in well if we can look at your second statement to the inquiry at page seven picking up a paragraph 36
02:58:17 in your second statement that we received this year you say mechanical extract systems which create a depressurized adjacent space in this case the lobby resulting in an induced airflow across the open door can
02:58:29 induced airflow across the open door can be referred to as depressurization systems
02:58:32 systems correct and then below that you say these types of systems should not however be confused with pressure differential systems which are designed to comply with all of the requirements of that standard correct and then at paragraph 39 and 40.
02:58:49 you could go over the page you say a decision had been made this is 39 before psb were instructed to make use of the existing shafts i was not possible to make the shafts
02:59:01 i was not possible to make the shafts any bigger or install new shafts i was there for us to design a system which reused the existing shafts etcetera and then you say at 40 it follows that i did not design a pressure differential system which are
02:59:12 a pressure differential system which are designed to comply with all the requirements of that standard
02:59:17 now can you just explain how you came to say in your first witness statement the design was in line with the performance criteria of that standard but then you've told us in your second
02:59:28 but then you've told us in your second statement that you did not design a system
02:59:31 system which complied with all the requirements of that standard they said that's not what i said that full full stop was in the wrong place it was the two meter a second i was referring to
02:59:39 to and i'd made the statement that we used it to develop a system type it wasn't following it it was designed we used it to come up with a different
02:59:50 we used it to come up with a different solution
02:59:51 solution can you explain why you didn't make that clear in your first statement to the inquiry that you hadn't adopted all the performance criteria of that standard and that you'd adopted at what you call a building appropriate solution
03:00:04 a building appropriate solution no i can't what was it that prompted you to serve that second statement on the inquiry some two and a half years after your first statement did you suddenly realize that the first statement could be read
03:00:16 statement could be read as suggesting you'd comply with that british standard when in fact you hadn't it could be read that way yes but there are other things that have occurred since then and now but was that one of the reasons why you
03:00:27 but was that one of the reasons why you chose to serve a further statement in order to clarify that point um i'm not sure that was my intent i see mr chairman i see it's one o'clock
03:00:39 i see mr chairman i see it's one o'clock i think that's an appropriate moment for a break i agree thank you very much well um mr manny we're going to have a break now so that we can all get some lunch
03:00:49 lunch we'll resume please at two o'clock and again i must ask you not to talk to anyone about your evidence or anything relating to it over the break all right
03:01:00 break all right and we're looking for we'll look forward to seeing you again at two o'clock look forward to it thank you very much good thank you two o'clock with miss grinch
03:01:08 grinch thank you