Grenfell Tower Inquiry - Expert Evidence - Smoke Control Systems - Tuesday 7th June 2022 (1/2)
00:00:27 Good morning everyone. Welcome to today's hearing. Uh today we're going to hear further expert evidence, this time from Dr. Barbara Lane. Yes, Miss Gr. Yes. Could we call Dr. Lane, please?
00:00:38 Yes. Could we call Dr. Lane, please? Thank you.
00:00:48 Good morning, Dr. Lane. Morning.
00:00:49 Morning. You're going to take the oath, I think. Is that right? Yes, ma'am. Yeah. There should be a testament on the uh table in front of you. Would you take it in your right hand and read the words on the screen, please? Yeah. I swear by Almighty God that the
00:01:00 Yeah. I swear by Almighty God that the evidence I shall give shall be the truth, the whole truth, and nothing but the truth. Thank you very much. Please sit down and make yourself comfortable.
00:01:21 Right. Yeah.
00:01:22 Yeah. Off we go. Yes, M. Yes. Thank you. Yes. Good morning, Dr. Lane. Thank you very much for returning to the inquiry to assist us with our work. It's very much appreciated. Um, I will be asking you questions today. If
00:01:33 will be asking you questions today. If you don't understand any of my questions, please just ask me to repeat them or I'll put the point in a different way. And if you can also try and keep your voice up so that the transcriber sitting to your right can take a clear note of your evidence.
00:01:45 take a clear note of your evidence. Yeah, that would also be good. Now um if we can go to um BLP25035.
00:01:55 This is the report that you produced for the inquiry during module 3 dated the 21st of May 2021 regarding the lobby smoke control system at Grenell Tower. We'll just wait for
00:02:07 at Grenell Tower. We'll just wait for that to come up. Yes.
00:02:09 Yes. So there we have that. And if we go to the introduction at page six,
00:02:16 we can see that you explain at paragraph 1.1.3
00:02:20 1.1.3 that that was a supplemental report to appendix J of your phase one report in which you presented your analysis of the requirements and provisions of the lobby smoke control system at Grimfield Tower.
00:02:32 smoke control system at Grimfield Tower. Yes. And then at paragraph 1.1.5, you say, "This module 3 report retains the results of my phase 1 investigations, but incorporates the findings I've made as a result of additional evidence available to me and
00:02:44 additional evidence available to me and my work in response to the investigations identified in my phase one report. Is that right?" Yes.
00:02:50 Yes. And then if we just look at the final section of this report, we find that at BLP25035
00:02:59 at 500 page 528 528.
00:03:05 528. There uh we can see a declaration and a statement of truth. Uh is that your signature? Yes, it is. Thank you. And you've also prepared a further supplemental report following um
00:03:17 further supplemental report following um receipt of Mr. delays report last summer [snorts] and if we could bring that up that's at BLP25043
00:03:33 there's the supplemental report. Yes, that's correct. Yeah. And we if we go on page six of this report to look at paragraph 1.14,
00:03:44 this report to look at paragraph 1.14, we can see you've listed there your earlier uh work in relation to smoke control.
00:03:50 control. Yes. [clears throat] And you tell us if we go over the page that this report concludes your analysis.
00:03:57 analysis. Yes.
00:03:58 Yes. Uh of smoke control. So uh there's the work that you've done on that. Yes. And if we go to section 11 of this supplemental report at page 266,
00:04:12 there we see an expert decoration and a statement of truth. And if we go over the page on 267 is that your signature? Yes, it is. And we can see that the report there is dated the 14th of April 2022. Yes.
00:04:25 dated the 14th of April 2022. Yes. Yes. [snorts] And uh you've also prepared an an arata and corrections sheet which uh for the transcript is at bl2 504.
00:04:37 504. Now have you provided your reports in the same way that you would provide a report to the court? Yes, I have. Um and can you confirm that the factual matters set out in your report are true to the best of your knowledge and
00:04:49 to the best of your knowledge and belief?
00:04:49 belief? Yes, I can. And do your reports represent your true and complete professional opinion on the matters addressed within them? Yes, they do.
00:04:56 do. Thank you. Now, I just want to start with some um updating questions about your qualifications of background. We first asked you about those in phase one uh in June and November 2018.
00:05:07 uh in June and November 2018. Yes.
00:05:08 Yes. Uh so I'll take this reasonably swiftly. If we could bring up your agenda and uh please BLP 250 44
00:05:20 44 and I want to look at page nine of this document.
00:05:26 Is it right that so what you've done here is just bring us up to date in terms of your professional memberships?
00:05:35 Well, actually they were set out in my CV when I was giving evidence for the RRO. So I'm just reminding everybody of those dates, right? Thank you. Yeah. Um so what we can see is that um looking at section
00:05:49 can see is that um looking at section 1.2.3
00:05:51 1.2.3 Yeah. Um
00:05:55 Yeah. Um there under professional registration on the next page. Yeah.
00:05:58 Yeah. Is that you were a chartered engineer via the institution of fire engineers between 2001 and 2020. Is that correct? Uh 2002 and 2020.
00:06:09 Uh 2002 and 2020. I beg you pardon. Thank you. And then in 2020 you left the IF and you became a member of Engineers Ireland in 2020 instead. Is that correct? Correct. Yeah. And you transferred your chartered
00:06:21 And you transferred your chartered engineer registration under a mutual recognition agreement because engineers in Ireland have a mutual recognition agreement with the engineering council. Is that correct? Yeah. And you've held chartered engineer
00:06:32 Yeah. And you've held chartered engineer registration via engineers Ireland since 2020. Is that correct? Yes.
00:06:36 Yes. And do you remain a director of ARP? Oh yes I do. Yes. Yeah. And what's your current role within ARP? Uh my current role of ARUP is I'm an officer to the group board and I'm responsible for what we call ARP
00:06:49 I'm responsible for what we call ARP University. So that's the collective knowledge learning um skills research and innovation programs for the global company. Um, and I'm responsible for
00:07:00 company. Um, and I'm responsible for things, for example, learning programs for 17,000 people to help improve and maintain our collective expertise because of the type of work we do and
00:07:12 because of the type of work we do and the complex problems that we're asked to solve. There's a whole array of duties there. I sit as an officer to the Arab Group board and therefore I'm considered to be part of the senior leadership team
00:07:24 to be part of the senior leadership team of of Arab Group, the global company. Great. Thank you. Now, we know from your previous appearances as an expert to this inquiry that your specialism is in fire safety engineering in the built
00:07:35 fire safety engineering in the built environment, including the design, construction, operational stages. And you have over 20 years experience on matters such as the consideration of regulatory compliant fire safety design
00:07:46 regulatory compliant fire safety design and construction solutions, the performance and testing for construction materials in fire and the handover process, including cause and effect testing of fire safety systems, management duties, and handover
00:07:57 management duties, and handover documentation. Is that is that right? Yeah, that's correct. And that's something that I and others call total fire safety. And because I'm being asked today, I consider myself to be an expert very much in that field.
00:08:09 very much in that field. Thank you. Yeah.
00:08:10 Yeah. Um, and for module one, you provided the inquiry with a CV which we can find at BLP25015.
00:08:20 Yeah. Uh, and if we look on page four. Yes. Yep.
00:08:25 Yes. Yep. We've got your your CV there. And we can see your Arab roles and education there. I'm not going to go through them again. We've covered them previously. Yes.
00:08:35 Yes. At page five and onwards of this CV, you set out selected project experience in the second half of the page. Yeah.
00:08:43 Yeah. Including on page seven. Yeah.
00:08:45 Yeah. For high-rise residential buildings. Um and you've given us some examples there. Now, in terms of smoke control systems, can you summarize your
00:08:56 systems, can you summarize your experience in the design, specifying, reviewing, and commissioning of smoke control systems in high-rise residential buildings? Yeah. Yes, I can. So, this CV was produced specifically for module one.
00:09:08 produced specifically for module one. You'll see that in my other CVs, I've picked other projects or other um because I try not to draw in my existing clients into the inquiry. So I tend to
00:09:20 clients into the inquiry. So I tend to try and explain my experience a different way. So for smoke control only I consider I've had five years working full-time on this inquiry and 20 years
00:09:31 full-time on this inquiry and 20 years experience before that and I I've decided I can split my experience into three chunks as such. So the first third of my career was spent as a junior
00:09:42 of my career was spent as a junior engineer working for others, carrying out simple and complex smoke control calculations and working with mechanical engineers in Arab and outside Arab,
00:09:53 engineers in Arab and outside Arab, dealing with fan selection and other issues associated with smoke control in different types of buildings including high-rise residential buildings and other other high-rise the mid part of my
00:10:06 other other high-rise the mid part of my career. uh and again I can provide a full list of specific projects as needed. The midpart of my career I spent then in that level of seniority being responsible for writing the performance
00:10:18 responsible for writing the performance requirements for all different types of smoke control systems including in high-rise residential buildings in that particular period of my career. So that's coming up to the mid 2000s. Uh
00:10:30 that's coming up to the mid 2000s. Uh there was a lot of concern in Arab fire about the standard of smoke control systems in on the island of Britain and particularly how the you know numerical
00:10:41 particularly how the you know numerical modeling was or was not being done. And we had taken the decision to do numerical modeling on all our projects where possible. And because of quality
00:10:52 where possible. And because of quality concerns, I personally set up the fire and smoke modeling team in ARP in the UK. So that all our project analysis came through one expert team and I was
00:11:03 came through one expert team and I was responsible for that and that's actually how those persons were involved with the SEA. And then in the final third of my career which was in the years preceding the fire I have a very different type of
00:11:15 the fire I have a very different type of experience and that's because I worked on a a very significant multidisciplinary project with Arab where things were a little bit tricky and I had to become part of the
00:11:29 and I had to become part of the leadership of a of a commissioning team of a a a myriad of really complex systems including different types of smoke control systems including lobby
00:11:40 smoke control systems including lobby depressurization systems and after that I spent the majority of my career working in operational buildings or on construction sites either witnessing or
00:11:52 construction sites either witnessing or personally certifying the operational performance of systems and buildings. Okay. Thank you. So that's my experience as I find it and and and within that experience to
00:12:03 and and and within that experience to what extent did you have any involvement with existing or what might be called legacy
00:12:09 legacy um residential buildings. Um I have uh I tend to be brought in to existing buildings to look at the condition or the
00:12:23 to look at the condition or the defective condition of systems. And one of my last projects before I had to excuse myself from all projects was an estate of I'm frantically trying to
00:12:35 estate of I'm frantically trying to remember it was either 12 or 12 or 14 high-rise residential buildings with faulty smoke control system to protect the stair and to protect the extended
00:12:46 the stair and to protect the extended travel distance in the lobby. And that building's currently occupied so I don't want to give you the name here in public. Yeah. Okay, that's fine. Do you have any formal qualifications in in in terms of smoke control?
00:12:57 smoke control? Yeah, actually I was thinking about that. Um I heard you ask Mr. Lelay that yesterday. So I need to now explain to you the kind of degree I have which is an engineering degree from Trinity
00:13:08 an engineering degree from Trinity College Dublin. And it's I didn't appreciate it at the time, but it's actually a very unusual and indepth degree because you don't specialize in any one field of engineering until your
00:13:21 any one field of engineering until your final year. So for the first two if not three years I had to study fluid dynamics, thermodynamics, combustion, heat transfer and I sat a degree in mathematics in my third year and then in
00:13:33 mathematics in my third year and then in my fourth year I specialized particularly in structural mechanics. Thank you. Um I just think I should continue because I know people are a little bit worried about my experience. When I
00:13:44 worried about my experience. When I finished my degree, I then carried out the experiments for Professor Dale's seinal work on the flashover compartment fires and the behavior of the products of combustion in well well ventilated
00:13:57 of combustion in well well ventilated and underventilated compartments. And it's because of all of that experience coupled with my PhD which was about the effect of fire on structural systems that I was offered a job at ARP.
00:14:10 that I was offered a job at ARP. Okay. Thank you. Um, now have you yourself ever actually designed a smoke control system or have you always been part of a a wider project team that
00:14:22 part of a a wider project team that that's been involved in? So I just I let let us be clear what we mean by design. So as a fire safety professional, I am obliged to set the performance
00:14:34 I am obliged to set the performance requirements from, you know, concept up to detail design depending on your your obviously your contract. I'm responsible for those performance requirements and I consider
00:14:46 performance requirements and I consider that to be design. I know some fire engineers don't consider that to be design, but I vehemently disagree. When it comes to doing detailed drawings, you know, controls, equipment,
00:14:59 drawings, you know, controls, equipment, scheduling of components, etc. I absolutely don't do anything like that. And it falls into the experience of of different different
00:15:10 different different professional people. And for a for a say a mechanical smoke control system, what kind of professions would then typically be involved? Okay. Well, I'm used to working with a
00:15:21 Okay. Well, I'm used to working with a mechanical engineer during design if I'm lucky because again it depends on the contract you have. Okay. But where you can get really really involved, I would be working with the mechanical engineer.
00:15:33 be working with the mechanical engineer. I might be working with the architect and then hopefully I would get to work with the contractor and their their respective teams. Okay. Um, yeah, that's
00:15:44 respective teams. Okay. Um, yeah, that's for the design phase. Yeah. Oh, sorry. Excuse me. I also have to um work with the statutory authorities and any other parties who have an interest in why I'm
00:15:57 parties who have an interest in why I'm relying on that smoke control system in the particular project I'm responsible for.
00:16:03 for. Okay. Thank you. Now we'll come on to some more detailed questions uh about the design of the system at Grenellfield Tower but just help us with this at this stage. Have you ever come across a
00:16:14 stage. Have you ever come across a system which was similar to that which was installed at Grenfield Tower? So do you mean a lobby depressurization system? In essence, yes. Yes, I have. And I have personally
00:16:25 Yes, I have. And I have personally worked on projects with them. And I got um the we have a project records team at ARUP and I wanted to work out the percentage of the different types of system we tend to offer on our projects
00:16:38 system we tend to offer on our projects and lobby depressurization systems take up
00:16:42 up over onethird of the designs we offer to people.
00:16:46 people. Yeah. Thank you. Now, before we turn to some more specifics about the Grenell Tower smoke control system, I want to begin by asking you about the regulatory requirements uh which the system needed
00:16:57 requirements uh which the system needed to meet. Now, you've explained these in chapter 2 and onwards of your module 3 report and in some detail as well in your supplemental report. Um, would you agree that in simple terms, if one is
00:17:09 agree that in simple terms, if one is making changes to a building which do have to comply with the building regulations, the changes must either achieve compliance with the functional requirements in schedule one or result in the building being no more
00:17:21 in the building being no more unsatisfactory in relation to those functional requirements than it was before the changes. In relation to those functional requirements? Yes. Yeah. Now um can we agree that the functional requirements which were
00:17:33 functional requirements which were relevant to the smoke control system at Grenell Tower were B1 means of warning and escape um B5 facilities for the fire service access and facilities for the fire service but also B3 on internal
00:17:46 fire service but also B3 on internal compartmentation. Yes.
00:17:48 Yes. Thank you. Now um in section two of your supplemental report um you discuss some of your disagreements with Mr. delay about the
00:18:00 disagreements with Mr. delay about the regulatory framework which was relevant to the smoke control system and I want to start by looking at regulation 8 of the building regulations. [clears throat] If we could go to CLG301 9897
00:18:16 um and we these these are the building regulations 2010 and if we go to page nine we can see regulation 8 [clears throat] it's right at the bottom of that page
00:18:27 it's right at the bottom of that page it's headed limitation of require on requirements and it says there parts A to D so that would include B F to K and P except for certain paragraphs of schedule one shall
00:18:39 certain paragraphs of schedule one shall not require anything to be done except for the purpose of securing reasonable standards of health and safety for persons in or about buildings and any others who may be affected by buildings or matters connected with buildings. Now
00:18:52 or matters connected with buildings. Now [snorts] you deal with this in your supplemental report and you refer to it as a life safety requirement. Is that right?
00:18:59 right? Yes.
00:18:59 Yes. Yeah. And um is it your understanding that this provision imports a separate reasonleness test as distinct from what we see in the functional requirements
00:19:10 we see in the functional requirements themselves which building control will apply uh on projects where building work is covered by the regulations. A separate test. Yes. A separate reason test or a
00:19:22 Yes. A separate reason test or a separate test of latitude. Oh yeah. Well, I mean, if I'm understanding correctly, I'm not aware that there's multiple separate reasonlenesses as such. So, in my mind,
00:19:34 reasonlenesses as such. So, in my mind, I've always assumed that B1 to B5 as written are, you know, I'm allowed to read them and understand that they are relevant to to the life safety
00:19:46 relevant to to the life safety requirement. I'm I'm not aware and I anyway, I think I presume this is actually a legal matter, but I'm Yeah, thank you. So I'm just really so as a practitioner
00:19:57 practitioner I'm not aware that I have two reasonlenesses to deal with now. Okay. So I I read B1 to B5 the topline functional requirement as emanating or
00:20:11 functional requirement as emanating or you know I inserting into this regulation 8. I don't adopt two different tests. Okay. In practice if that's appropriate for me to say. Yeah. Ju just putting it maybe a
00:20:23 to say. Yeah. Ju just putting it maybe a slightly different way. Um do can we agree that the functional requirements themselves are often expressed in terms of reasonable standards of health and safety? So appropriate means of escape
00:20:35 safety? So appropriate means of escape or reasonable facilities for the fire service. That's B1 and B5. Yeah. Well, I understand that's what the authors intended. Yes. So that um there is some scope for
00:20:46 Yes. So that um there is some scope for building control bodies to decide what amounts to a reasonable standard of health and safety when they're looking at whether those functional requirements are met
00:20:55 are met a reason. Yes. No. Of course. Yeah.
00:21:00 Would you accept that what may be considered practical to achieve a reasonable standard of health and safety in a new building might differ from that which might be practical in a legacy or
00:21:11 which might be practical in a legacy or existing building? Yeah. potentially. It depends on the circumstances of the case. It's not one blanket.
00:21:19 blanket. Yeah.
00:21:20 Yeah. Problem. Some some existing buildings can be very easy to work in. Uh some new buildings are incredibly difficult to put together. You know, active and
00:21:31 put together. You know, active and passive fire protection measures that taken together can be easily proven to meet the functional requirements. So, so I I don't I probably should be
00:21:43 I I don't I probably should be absolutely clear that I don't at all agree that new buildings are easy and existing buildings are complicated and certainly I know I work in a company
00:21:54 certainly I know I work in a company where people employ us because their building is so complex. So I have a lot of experience about th those really challenging circumstances in new buildings when it
00:22:05 circumstances in new buildings when it can be very very difficult to find a solution that I am satisfied can comply with the functional requirements. Right.
00:22:13 Right. But yes, some existing buildings are very very difficult to work in. Okay.
00:22:18 Okay. Yes.
00:22:18 Yes. Now can we also look at regulation 11 um of the building regulations which is over the page at page 10. This is the power to dispense with or relax requirements.
00:22:31 requirements. Um, and it refers back to the power contained in section 81 of the building act 1984. And this makes clear that it's uh that power shall be exercises exercisable by the local authority.
00:22:42 exercisable by the local authority. Yeah.
00:22:43 Yeah. Now, you say in in your report at paragraph 2.5.3 of your supplemental report, we don't need to bring it up, that in your experience, it's extremely rare for a dispensation or relaxation of
00:22:55 rare for a dispensation or relaxation of functional requirements B1 to B5 either to be sought or to be granted. Is that right? Uh yes, that is my experience. But can let we should just be really
00:23:06 But can let we should just be really clear of what we mean by requirement. So that's the topline B1 English and I have no experience of someone going in and saying I'm not planning on complying
00:23:18 saying I'm not planning on complying with the functional requirement B1. People do need to apply for I don't want to miss you dispensation or relaxation about one of the provisions within that
00:23:31 about one of the provisions within that requirement [clears throat] not the requirement in full itself. That's what I mean. And it's a very common misconception in the profession that obs obtaining a relaxation or a
00:23:42 that obs obtaining a relaxation or a dispensation for a a component of that is intended to meet the functional requirements is a relaxation of the whole requirement in itself. A very common misconception.
00:23:53 common misconception. I see. So, have you ever come across any um situation in which a building control body did dispense or relax a a requirement for an entire functional requirement?
00:24:04 requirement? Absolutely not. Absolutely not. No. Mr. Lei um explained yesterday that the combination of these two regulations, regulation 8 and 11, effectively meant
00:24:16 regulation 8 and 11, effectively meant that there was a he called it a climate of latitude amongst building control bodies. gave building control some discretion, some flexibility in terms of
00:24:27 discretion, some flexibility in terms of the way they um required the functional requirements to be met. Now, have you come across that in your own experience? Okay, but sorry, I just because I have to be really really specific now because
00:24:38 to be really really specific now because of where we are. You said both climate and 8 and 11 read properly allows that and they're two very different things. Okay. Well,
00:24:49 Okay. Well, do you want me to give a view of that? Let's take them separately. Have you come across a a climate of latitude or a flexibility on the part of building control bodies to effectively do what they consider is reasonable in the
00:25:01 they consider is reasonable in the circumstances um and which allows a great deal of flexibility in the way the the functional requirements are interpreted. I don't want to single out building control here, but it is absolutely
00:25:13 control here, but it is absolutely clear. It was absolutely clear before this fire and I think you don't need expert evidence since the fire that there was a climate of you know
00:25:25 I I just worried about what word to use here you know a climate of worrying standards okay uh that can't be
00:25:36 worrying standards okay uh that can't be attributed solely to building control in the context of regulation 8 and regulation 11. It is not my understanding. Okay. And I'm not sure I've ever heard a building control body
00:25:48 I've ever heard a building control body say to me, I've taken eight and 11 together on and on that basis I have the following opinion. I've never heard someone say that to me. Okay.
00:25:57 Okay. I don't know if that's answered your question, but I think climate and then the facts around the regulations are two very different things. Yes. Have you seen any evidence in relation to all the smoke control uh
00:26:09 relation to all the smoke control uh documentation you've looked at on Grenville Tower that there was any dispensation or relaxation under regulation 11 considered by building control in this project? Well, not that I've read about.
00:26:20 Well, not that I've read about. Yeah.
00:26:20 Yeah. Yeah.
00:26:21 Yeah. Now, another area where you've expressed some disagreement with Mr. Lelay is about documentation. We saw and I put it to him yesterday that um at paragraph 8 of his report and
00:26:32 that um at paragraph 8 of his report and paragraph 875 he says there's no requirement in the building act or the regulations for persons to document how they achieve compliance. Now, in fairness to him, yesterday when when
00:26:43 fairness to him, yesterday when when pressed on this, he was saying, well, what I'm saying is it doesn't tell you the the extent of documentation that you need to achieve compliance.
00:26:54 need to achieve compliance. [snorts] Um, and potentially, you know, there would be a varying amount of documentation that you would need. Now, let's just take the simple point first. Is it your understanding that there is a duty on the part of those carrying out
00:27:06 duty on the part of those carrying out the works to show how they are going to comply with the building regulations? Yes, I do think it's a duty. Yeah. And is that because of I think you
00:27:17 Yeah. And is that because of I think you say this in your report, regulation 14 in particular, the full plans application regulation in the building regulations. Yes. And other duties designers have under different pieces of legislation.
00:27:29 under different pieces of legislation. the onus is solely on us and it's a very I've already spoken about this several times it about the responsibility of designers
00:27:38 designers um to demonstrate with transparency and with you know knowingly communicate
00:27:49 and with you know knowingly communicate the meaning of what they're doing and the significance of it and I don't support at all the quite prevailing opinion that if someone doesn't notice
00:28:03 opinion that if someone doesn't notice you've done a good job right
00:28:05 right or discharged your duty satisfactoryy right
00:28:08 right I think and my my understanding also and certainly how we comport ourselves is in the event of something you know either legally or you know something some
00:28:19 legally or you know something some incident the onus will be on me as the designer not a member of the building control body particularly it would be me on me as a designer to be able to
00:28:30 on me as a designer to be able to demonstrate how I transparently and honestly and knowingly explained why what I was offering why and what it can
00:28:42 what I was offering why and what it can do in the event of a fire. And that includes when I know it won't be able to mitigate certain circumstances that a building control body might reasonably intrinsically expect.
00:28:54 intrinsically expect. Right. I see. Thank [clears throat] you.
00:28:58 Now um I also want to discuss with you regulation four of the building regulations which you've dealt with in particular in your supplemental report. And if we go to that supplemental report
00:29:10 And if we go to that supplemental report at BLP25043
00:29:14 page 65
00:29:21 if we look at 4.1.3 here you've cited regulation 43. So there it says building work shall be carried out so that after it's been completed in a any building which is
00:29:33 completed in a any building which is extended or to which a material alteration is made or any building in or in connection with a controlled service or fitting is provided extended or material altered or any controlled service or fitting complies with the
00:29:44 service or fitting complies with the applicable requirements of schedule one or where it did not comply with any such requirement is no more unsatisfactory in relation to that requirement than before the work was carried out.
00:29:55 the work was carried out. Yeah. Yes. And I I asked you briefly about this. So this is the no more unsatisfactory position and and that's often referred to as the non-worsening principle. Is that right? Yeah, it is. Sorry, can I just say
00:30:07 Yeah, it is. Sorry, can I just say something here as well? So we like in the inquiry and everywhere else, everybody always focuses on the no more unsatisfactory, but actually it's no more unsatisfactory in relation to that
00:30:18 more unsatisfactory in relation to that requirement. It's not no more unsatisfactory. And I think the additional words after unsatisfactory are actually extremely important in terms of certainly how I read that
00:30:30 terms of certainly how I read that regulation. So I think what you're saying is um and I think Mr. Lelay agreed you should read it like this that it's no more unsatisfactory in relation to that functional requirement before the work was carried out.
00:30:41 was carried out. Exactly. It's not just generally and that again is is a slightly prevailing culture in industry that if it's generally slightly better you know that
00:30:52 generally slightly better you know that the job is done and I long before this inquiry you know I have never shared that I don't believe that's how that regulation was written but it's not for me to say it's just how I read it in
00:31:04 me to say it's just how I read it in practice. Now in terms of non-worsening um Barl Menses the inquiry's building control expert explained in her evidence that she thought the appropriate comparator for building control would be
00:31:16 comparator for building control would be the existing system in its working state or at least how you believed it would work. That was her evidence. Do you agree with that?
00:31:27 agree with that? You know when you say believed how it how it worked. Yes. That
00:31:32 Yes. That my belief might be well Leave that to one side. Okay. So,
00:31:36 Okay. So, and and just focus on um do you agree with her that the appropriate comparator for building control if if taking a non-worsening approach or no more unsatisfactory approach
00:31:47 unsatisfactory approach she felt would be uh the existing system. So, the existing smoke control system but as it was meant to work it working state. Exactly. As it was intended to function at that time. Yes. Yeah.
00:32:01 at that time. Yes. Yeah. And um Miss Mens has also explained uh in her oral evidence that when assessing whether the building is no less compliant, the requirements of the regulations to which the altered building must be no
00:32:13 which the altered building must be no less compliant are always the current functional requirements of the building regulations. So B1 to B5 and not whatever requirements were or may have been in place at the time of original
00:32:25 been in place at the time of original construction. Oh yeah, sorry. I'm sorry. Can you just repeat that again? I think the point she was making in relation to the wording that you've just emphasized is no more
00:32:36 just emphasized is no more unsatisfactory in relation to that requirement. The point she made is that you're looking at it through the prism of the current functional requirements as opposed to any functional
00:32:47 as opposed to any functional requirements that might have applied back when the building was first constructed if they were different. If they were different. Yes. That that that was her evidence.
00:32:58 Yes. That that that was her evidence. Okay. And you're asking me if I agree with that. Yes.
00:33:01 Yes. So
00:33:04 I'm trying to frantically remember if the functional requirements have changed. I'd have to go back in and look at my report. My understanding is that it's the functional requirements at the
00:33:15 it's the functional requirements at the time. I need to understand and so what the system was intended to do at that time. And then I'm considering it also through this prism you described to try
00:33:26 through this prism you described to try and work out the the situation I find myself in I suppose or the
00:33:35 if there's a gap between what's required now and what was required back then I think is maybe what you're trying to ask me
00:33:42 me this is really a matter of construction of the regulations isn't it? Yes, I think it is. But um these are some questions that have been submitted and um I I I'm trying to explore what Dr. Lane's understanding is as a practitioner in
00:33:53 practitioner in So So yeah, exactly. Because that's a really complicated question and I am uneasy answering it. So in terms of working on one of my projects, I will look at the functional requirements at
00:34:04 look at the functional requirements at the time, understand what the designer needed to produce. I'll look at the functional requirements now understand what as a designer I need to produce and
00:34:15 what as a designer I need to produce and I will establish whether or not there is a gap between those two things or not. Yeah, that's helpful. That's about all I can say. Yeah, that's helpful. Thank you. Um now
00:34:28 Yeah, that's helpful. Thank you. Um now you you've suggested in your report that this non-wsening approach um requires a comparison to be made between the performance objectives of the original system and those of the new system. Is
00:34:40 system and those of the new system. Is that correct? Yeah. Yes. Do do you agree that there's no express reference to any such comparison with performance objectives within the
00:34:52 performance objectives within the wording of regulation 43 itself? I absolutely recognize that and but there's no other way to carry out the comparison I've just described to you.
00:35:04 comparison I've just described to you. Right. Thank you. Now
00:35:08 Now um let's just move on um to start thinking about the um the smoke control system at Grenell Tower and the the background to this. Um I just want to start with something um from Mr. Colin
00:35:20 start with something um from Mr. Colin Todd's report. If we could go to CTA 7001
00:35:26 7001 and look at page 64,
00:35:31 this was the report he prepared for phase one of the inquiry's work. And at 64, paragraphs 5.2.42, little 4. So it's in the middle of that
00:35:44 little 4. So it's in the middle of that page. It's the little Roman four beginning guidance on. Do you have that? M
00:35:49 M so he says this guidance on the provisions for smoke control in the common parts of blocks of flats was changed within the 2006 edition of ADB C paragraph 2.26 the previous philosophy
00:36:01 paragraph 2.26 the previous philosophy in relation to this matter was reversed. Previously the objective of smoke control in the common lobbies of a tower block was deemed to be the dispersal of smoke within the lobbies.
00:36:12 smoke within the lobbies. As something of a quote bonus, the smoke control would also afford protection to the common stairway. The philosophy described in the 2006 edition of ADB was
00:36:23 described in the 2006 edition of ADB was that the means of ventilating the common lobbies was to protect the common stairway, so supplementing the protection provided by the fire doors to the stairway. It was now noted as something of an aside, that the
00:36:35 something of an aside, that the ventilation also afforded some protection to the lobbies. Now it it do you agree with that basic summary of this shift in philosophy that
00:36:46 summary of this shift in philosophy that we we see in the approved documents over time? So, an emphasis on smoke dispersal historically and protection of the common lobby with some bonus protection
00:36:57 common lobby with some bonus protection to the stairway effectively flipping over to being protection of the common stairway being the primary goal with protection of the lobby being something
00:37:08 protection of the lobby being something of an aside. Do you agree with that? I I like it depends on so I I can't I understand the sentiment of the paragraph. Okay. But when the
00:37:22 of the paragraph. Okay. But when the smoke dispersal systems existed I I really think I thought I'd put this in my report. There was still some ventilation provision made to the stair. Okay. It wasn't without any
00:37:34 Okay. It wasn't without any consideration. and this switch then the philosophy with the the ventilating the common lobbies was to protect the common stairway. So so that's in that depends on the travel
00:37:45 so that's in that depends on the travel distance
00:37:45 distance right
00:37:46 right so it's not all the cases can I just in here I think what Mr. Todd is suggesting is that there was a switch from um making the
00:37:57 there was a switch from um making the protection of the lobby Yeah.
00:37:59 Yeah. the primary consideration. Yes.
00:38:01 Yes. With um a potential benefit to the stairs.
00:38:04 stairs. Yes.
00:38:04 Yes. To making the protection of the stairs the primary consideration. Yeah.
00:38:08 Yeah. And the protection of the lobby or the benefit to the lobby being um advanticious. Understood. But it's not for all travel distances. That that's the problem. So
00:38:19 distances. That that's the problem. So there's a body of buildings where where that's correct because the travel distance is within a limited distance and then there's a body of buildings where the protection to the lobby
00:38:31 where the protection to the lobby remained a relevant parameter for not just for protecting the staircase. Apologies. Okay. So, so remember the the dispersal systems were it's expressly
00:38:44 dispersal systems were it's expressly stated in in the CP3 standard and I think I've pasted that in to the supplemental report. It expressly stated the system was to in you know extend the
00:38:56 the system was to in you know extend the travel distance in the lobby. So the philosophical shift occurred but it's not in all cases. Okay. So it's a little bit more nuanced but that is true in
00:39:07 bit more nuanced but that is true in many cases. Thank you. Yeah, that's helpful. Um, if we could just look at paragraph 2.25 of ADB, if we bring that up, CLG5024
00:39:18 ADB, if we bring that up, CLG5024 at page 30,
00:39:22 that's ADB. It's the version that would have been in force when the refurbishment works carried out. Um, and if we could look at 2.25, 25.
00:39:33 if we could look at 2.25, 25. Uh, in the right hand column, smoke control of common escape routes. It says, "Despite the provisions described in this approved document, it's probable that some smoke will get into a common
00:39:44 that some smoke will get into a common corridor or lobby from a fire in a flat, if only because the entrance door will be opened when the occupants escape. Do you see that?" Yes. Now, does it therefore follow that one would not expect the lobby to be
00:39:56 one would not expect the lobby to be completely or even largely smoke free throughout the course of a fire in an adjacent flat, even if the smoke control operated um exactly as it was intended
00:40:07 operated um exactly as it was intended to.
00:40:11 That's a a very big all-encompassing um question. So, you're asking me if the lobby remains fully smoke-free. What did you say? or there will be some smoke in
00:40:22 you say? or there will be some smoke in the lobby even if a smoke control system designed to protect what is operating. Well, I suppose that's that's a potential um caveat to the question, but
00:40:33 potential um caveat to the question, but I mean,
00:40:34 I mean, let's assume Okay, let's assume there's a a travel distance of no more than 7.5 m.
00:40:39 m. Yeah.
00:40:40 Yeah. Um so, we're not into an extended travel distance situation. Yeah. Um, is it the case though that you you still wouldn't expect the lobby to be completely completely clear? No, it's not it's not
00:40:52 completely clear? No, it's not it's not No, it's not physically possible. And what you're trying to do is minim minimize the time period where that condition
00:41:05 is underway. Yes, I see. Yeah. So the presence of some smoke within a common lobby in the course of a fire um
00:41:17 common lobby in the course of a fire um would not of itself constitute evidence that the smoke control system was not operating as it ought to. I don't I'm sorry. I can't I think that question is too large for me to give a
00:41:28 question is too large for me to give a yes or no answer because there's so many different scenarios. I'm afraid to give a yes or no answer to that question. I see. Is that it's a kind of you know I I can't say if there's some smoke it
00:41:40 I can't say if there's some smoke it doesn't mean the system has failed. It's not one parameter or the other. Yeah.
00:41:44 Yeah. I I understand that the the the let's say to say the question in the positive that when a smoke control system operates satisfactorily
00:41:56 satisfactorily there there will be some smoke in the lobby. Yes. I can't do it in the reverse because it can be misconstrued. Okay. That's helpful. Now, let's just think back to the
00:42:07 Now, let's just think back to the original system design of the smoke control system at Grenville Tower when it was built. Yeah.
00:42:13 Yeah. Um, we can see a diagram of that in your phase one presentation. If we go could go to BLA 405481, page 173.
00:42:26 And sorry, we need to rotate this diagram. So this is the uh diagram that you came up with um when you first did a presentation a long time ago now.
00:42:37 presentation a long time ago now. Yeah.
00:42:37 Yeah. Uh into this uh system. Yeah. [snorts] And um Mr. Manne said at paragraph 18 of his second witness statement that this existing system was a natural
00:42:48 existing system was a natural ventilation system with a mechanical boost function. Now do you agree with that?
00:42:54 that? Yes I do. Yes I do based on my reading of Max Forom documents. Right. Yes. Thank you. Yeah. So, [snorts] um its first uh level of operation would be just as a natural system.
00:43:06 just as a natural system. Yes. Yes.
00:43:06 Yes. Yes. So, if there was a fire in a flat on a particular floor, you would expect naturally there to be some air flow coming up the south shaft passing through the lobby and then um
00:43:17 through the lobby and then um discharging some smoke up the the north shaft. Is that correct? Okay. Um,
00:43:24 Okay. Um, so the south shaft acting as an air inlet was as I understand things for when was when the system was in mechanical mode.
00:43:35 mechanical mode. I see. Yeah. Okay. So before the system was in mechanical mode, before any fans were activated by the fire brigade, what was the system designed to do in
00:43:46 what was the system designed to do in the event of a fire? Yeah, it was a smoke dispersal system. So to naturally ventilate the the lobby, right? And can you just give us your definition of a smoke dispersal system?
00:43:57 definition of a smoke dispersal system? Um, what do you mean by a smoke dispersal? The the smoke flows under its own
00:44:07 I was about to say capability, but that's wrong. The smoke as a function of the smoke produced from the specific fire, it should flow towards the um e
00:44:20 fire, it should flow towards the um e you know the extract points on that lobby.
00:44:23 lobby. Yeah.
00:44:23 Yeah. Yeah. So that was intended what to provide some protection to the lobby was it
00:44:30 it as I read CP31 1971 that's what it intended. Yes. Right.
00:44:36 Right. Um and then once the fire brigade arrived, it had a mechanical mode. Is that correct? Yes. If they chose, they were given a switch downstairs to I had understood to
00:44:51 switch downstairs to I had understood to start a fan at the roof and start the fan. I think it was down at at level three if you read the Max Forom documents. So you have mechanical inlet and and mechanical outlet,
00:45:03 and and mechanical outlet, right?
00:45:03 right? That's Yeah. Um Yeah. Yeah, Mr. Manne when he gave oral evidence the inquiry said he'd been told that the original system didn't have a supply fan at low south level and
00:45:14 have a supply fan at low south level and only an extract fan in the north shaft of the top of the building. Are you able to help us with um whether that's consistent with the documents you've read? No, I mean like I have the Max Forom
00:45:25 No, I mean like I have the Max Forom documents and and that's what they say. I'm assuming they had checked for themselves um that there was a fan at level three. Yeah. Um I know that Mr. Hansen did
00:45:36 Yeah. Um I know that Mr. Hansen did query
00:45:38 query the the you know in the very early discussions he asked that question that that's all that I know right okay thank you now in summary is it your view that the guidance which
00:45:49 it your view that the guidance which appears to have been used when Grenell Tower was first designed and built i CP3 1971
00:45:55 1971 included as performance objectives first of all the protection of common lobbies for means of escape second the protection of the stair for means of escape gape. And third, the protection to firefighters when using
00:46:07 protection to firefighters when using the common lobbies. Yes. Yes.
00:46:12 Yes. Yes. I think you set that out in your supplemental report um for the transcript that's at um BLP250 43 pages 71 and 72. Now, [clears throat]
00:46:23 Now, [clears throat] do you consider that all of those performance objectives were met by the original system, even though we know that it didn't comply with all of the guidance in CP3 1971, including most
00:46:36 guidance in CP3 1971, including most importantly, the shaft sizes were much smaller than recommended in that guidance. So, they were only 0.48 m squared instead of 1.5 m squared. So
00:46:48 squared instead of 1.5 m squared. So you're asking me if I know the system performed to the functional requirement at the time despite its design. Is that the question? Yes.
00:46:58 Yes. I how how I how like I have to assume that it did. How would I particularly know? I I don't know. Is there deeper context to the question? No. I think the point that's being made
00:47:10 No. I think the point that's being made is it's all well and good to say well CP3 1971 has those three objectives. Oh yes. Okay. But this seems to be a system which didn't actually meet those
00:47:21 system which didn't actually meet those objectives. Well, sorry. This is a system which didn't meet all of the CP3 guidance because it didn't have 1.5 m squared bents. Okay.
00:47:30 Okay. So, could it have been a system which was deliberately designed perhaps not to meet all three of those requirements, but which building control nevertheless thought was satisfactory? That's that's
00:47:41 thought was satisfactory? That's that's the point that's being made. All of that is kind of speculation as far as I'm concerned. I did read I thought Miss Mens [laughter] was was quite clear on this actually and I'm sure I she was very clear on this. Um
00:47:54 sure I she was very clear on this. Um and I I I am happy to assume that at the time the dimensions the components and it was it was kind of slightly new engineering system at the time. I'm
00:48:07 engineering system at the time. I'm assuming it was deemed to comply with building regulations because it met those functions. And does that mean that um you you think
00:48:18 And does that mean that um you you think it's reasonable to assume that a performance objective would have included protection of the common lobby for means of escape at that time? Yes.
00:48:27 Yes. Yes, I do. Because of the travel distances and it was very clear at that time,
00:48:31 time, right?
00:48:32 right? Yes.
00:48:32 Yes. And is what you're saying that CP371, one of the new things it was doing was allowing extended travel distances in certain circumstances. Yeah, it it
00:48:43 in certain circumstances. Yeah, it it says that it it it says it in the at the start of the document, right? Yeah. Yeah.
00:48:49 Yeah. Now, is it possible to tell is it possible for anybody to tell in fact what level of performance the existing system would have had when working if one did a computational fluid dynamics model of it?
00:49:00 dynamics model of it? Right. Okay. And um how easy would that have been to have done at Grenell Tower? Could one have done that? Yes.
00:49:09 Yes. Right. Yeah. So you could have taken the existing system, the capacity of the fans, the size of the shafts etc. Yeah.
00:49:16 Yeah. And and done a calculation to to look at the performance of the existing system could you? If that information was available. Yes. Right.
00:49:24 Right. Yes.
00:49:29 And so just to be clear, is it your understanding that that existing system would have provided protection to the lobby? In fact would have actually provided something. No, but I can't like that. I can't.
00:49:40 No, but I can't like that. I can't. You're asking me to guarantee something. I'm sorry. I I don't want to sound disrespectful. How on earth can I do that? It It should have protected the lobby. I can't tell you that it would or
00:49:52 lobby. I can't tell you that it would or did every time. I'm not that's I'm No one can answer that question at the moment. So, it should have protected the lobby with the travel distances it had. And when you say protect the lobby,
00:50:04 And when you say protect the lobby, Yeah.
00:50:05 Yeah. What do you mean exactly? because you agree that there's going to be some smoke in the lobby or likely to be. Well, okay. So, so again, we're all postulating now in all different kind of scenarios. So, it should have protected
00:50:16 scenarios. So, it should have protected the lobby. So, there were tenable enough conditions to escape. Okay. There's no suggestion by me or anyone that any system produces
00:50:30 by me or anyone that any system produces this beautiful, it's a perception people have this, you know, something like this beautifully clear um space. That's not what happens in a real fire. You don't
00:50:41 what happens in a real fire. You don't need me to tell you that. Yeah. Okay. Turning then to the system that was actually installed at Grenell Tower. I just want to uh look at that. The the new Are we in the new the
00:50:52 The the new Are we in the new the the new system? Sorry. Yeah. Yeah, let's look at um your module 3 report. This is BLP25035
00:51:00 at page 260.
00:51:04 And here if we blow this up, it's quite an intricate diagram, but if we could blow it up so we can try and see it as clearly as possible. This is an illustration of the new smoke control
00:51:17 illustration of the new smoke control system and how it was meant to operate. Um so um unlike the old system, is this right? Instead what we got was an extraction of air or smoke at the low
00:51:30 extraction of air or smoke at the low level, the south level. Yes.
00:51:32 Yes. And continuing to have an extraction up the north shaft. Yes. So instead of it being a kind of what's been described as a pushpull, we're getting a pull pull. Is that sorry that
00:51:43 getting a pull pull. Is that sorry that a fair way of summarizing? Yeah. Yeah. And can you just help us um in general terms what kind of system this new system was? How would you describe it?
00:52:00 Do you mean outside as I've described it in my report? Well, I'll I tell you what, I'll come to some more. I've refer I called it a lobby depressurization system since April 2018
00:52:13 depressurization system since April 2018 if you go back and check. Yeah. And then in in my module three report, I thought I better use the phrase Mr. Mahoney used or Mahoney,
00:52:24 phrase Mr. Mahoney used or Mahoney, sorry. But they're they mean the same thing,
00:52:27 thing, right? Yeah. And is the is the primary purpose of this system, as you understand it, to extract smoke from the lobby?
00:52:38 lobby? Not as PSB designed it. No. Right. Because that appeared to be the thrust of Mr. Man's oral evidence that the key performance criterion was the extraction rate of 3 cubic meters/s
00:52:53 extraction rate of 3 cubic meters/s um from the lobby uh sorry through the stair door which was delivered by extracting through the north and south shafts.
00:53:01 shafts. Okay. I I understand the purpose of the system to be to produce an air flow through the open stair door in a particular condition.
00:53:12 particular condition. Yes.
00:53:14 Yes. Now, had you been designing this system or considering the design of this system, would you have had any concerns about relying on the existing location of the south shaft dampers for
00:53:26 of the south shaft dampers for extracting smoke given that they were low to the floor? We saw a photograph of this yesterday. In each lobby, the south shaft vents are low on the floor and the north shaft vents are higher up on the
00:53:37 north shaft vents are higher up on the floor. Yeah. Would you have had concerns about extracting smoke from low level within each lobby? Yeah. Well, I I would have noted that it
00:53:48 Yeah. Well, I I would have noted that it was unusual and um I don't really like doing this. I would have would have stuff, but uh we I we would have done a numerical model
00:54:00 we would have done a numerical model anyway. And certainly um with one or two of the more complex aspects in that lobby, I would have been more at ease um about say you know satisfying myself
00:54:13 um about say you know satisfying myself about the location of those points down near the floor through numerical analysis.
00:54:19 analysis. Right. You you said it was unusual. How unusual is it to have um vents which are extracting from a lobby like that at low level rather than Well, well, it's well, it's very unusual
00:54:30 Well, well, it's well, it's very unusual cuz the idea is you're extracting the smoke up at high level while whilst it's hot to try and maintain, you know, a safe walking space
00:54:42 you know, a safe walking space underneath it. Right. Obviously I am aware of projects in the world where people have attempted to extract downwards and it's a very tricky matter
00:54:53 downwards and it's a very tricky matter indeed.
00:54:54 indeed. Well that that's a slightly different point that I want to come on to. What about the extraction of smoke downwards through the south shaft so unlike the north shaft where you've got you know natural buoyancy or stack
00:55:06 got you know natural buoyancy or stack effect whatever various forces which might help in that north shaft. Yeah. Would you have had concerns about the in principle approach of trying to extract
00:55:17 principle approach of trying to extract smoke downwards? Well, I think it sounds extreme saying kind of concern. So, it's another parameter
00:55:25 parameter that's making this system. So, as a designer, it's another so sorry if the designer has made that decision. as a fire engineer, it's another parameter I
00:55:37 fire engineer, it's another parameter I need to be very sure about and that the consequences of it have been factored in to the wider design requirements. Okay. So like all engineers, you know, I'd be
00:55:49 So like all engineers, you know, I'd be up for the challenge. Okay. But to satisfy yourself about, you know, the slightly unusual case here, you in my mind, you have to do a bit more work to
00:56:00 mind, you have to do a bit more work to make sure it's not causing something that you may not expect. for example or you may not have seen before. Can I can I just ask you this? If you approach the uh the new system
00:56:11 If you approach the uh the new system Yeah.
00:56:12 Yeah. on the basis that the primary objective is to create an air flow through the stair door. Yeah.
00:56:20 Yeah. You the fact that the um south ducting and and the um vents are near the floor isn't going to matter for that purpose, is it? But what
00:56:31 matter for that purpose, is it? But what it will mean is you don't get the conccommatant benefit of smirk smoke dispersal or reduction. Yes. But also so so correct. Okay. But
00:56:43 Yes. But also so so correct. Okay. But the the other issue is to do with fan selection. Yeah. Okay. And I don't want to stray I've been very clear. I don't want to stray
00:56:54 been very clear. I don't want to stray too far outside here, but
00:57:00 picking a fan, picking a fan has to then incorporate all the different things that resist, you know, that cause resistance to the performance of that fan. And that
00:57:13 to the performance of that fan. And that is why you need to satisfy yourself that that route, the convoluted route or not the damper area and location. So you could say it's almost a non if if you
00:57:25 could say it's almost a non if if you wanted to imagine it, it's a nonsmoke layer problem cuz you're not trying to maintain a smoke layer. Um but it contributes
00:57:36 Um but it contributes I I mean from from my perspective, smoke control systems have so many different parameters that have to be balanced and some of the parameters have a negative effect on each other. That's what that's
00:57:48 effect on each other. That's what that's why I think they're actually quite difficult myself in practice. And so I the smoke layer point you make I I agree with but it has other consequences in the round
00:57:59 the round when trying to get this system to have all the components that fundamentally will be balanced. Okay. I I see that I mean I raised the point only because it was inherent in some of Miss Grange's
00:58:11 was inherent in some of Miss Grange's questions that it might be questionable to seek to be extract to seek to extract smoke from low-level vents. Yeah.
00:58:20 Yeah. Yeah.
00:58:21 Yeah. But if you're not setting out principally to extract smoke, that doesn't seem to matter much. But you won't get the same benefit as you will from extracting from from a higher level presumably.
00:58:32 from from a higher level presumably. Yeah. So, so again you see
00:58:38 then you have to get into why are you extracting the smoke and are you trying to maintain a clear layer la you know and on it goes. So isn't that so I'm sorry to interrupt but my understanding is that the the primary
00:58:50 my understanding is that the the primary purpose of this system is not to extract smoke is to create a flow through the stair door and therefore extracting smoke is a sort of secondary benefit. it's a secondary benefit. But I suppose
00:59:03 it's a secondary benefit. But I suppose um what you also have to try and make sure that you're not doing is causing. So if you're doing your numerical model, you might see that you're I and I'm this
00:59:15 you might see that you're I and I'm this this is just a conceptual opinion for me. I have not not done any calc, you know, I haven't done a CFD model. you may cause a condition in the lobby that
00:59:27 may cause a condition in the lobby that wouldn't occur if the the vents were at roof level and you need to satisfy yourself again. You're not causing a hazard that wouldn't have existed in another system and whether or not that
00:59:39 another system and whether or not that matters.
00:59:40 matters. Yeah, I see. Okay. Yeah. Yeah. It may not matter at all.
00:59:44 all. Yeah.
00:59:45 Yeah. Thank you. Thank you. If we could go within your supplementary report, please. BLP25043
00:59:54 at page 50. Now, in section 3.5 of of your supplemental report, you you've discussed the different types of smoke ventilation system available since 2011 and their recommended performance
01:00:06 and their recommended performance objectives. And if we go on within this at page 53 at table 3.2, to what you've done um and it's a detailed piece of work is you've
01:00:19 it's a detailed piece of work is you've summarized the performance objectives of different types of systems. Yeah. Does that make sense? So you've got a type of system down the left. Is the type of system intended to provide protection to the staircase
01:00:30 provide protection to the staircase during means of escape? Yes or no? Is the travel distance uh less than or equal to 7.5 m? And and because at the top you've asked is the system intended
01:00:41 top you've asked is the system intended to provide protection to the lobby in addition to providing protection to the staircase during means of escape phase. Yes. [snorts] And you've derived these objectives from statutory and other guidance. Is that
01:00:52 statutory and other guidance. Is that right?
01:00:52 right? Yes.
01:00:53 Yes. For example, from ADB or BS 91. Now um if we go to page 55, you set out some conclusions from this analysis. Um, [clears throat]
01:01:05 Um, [clears throat] and what what you say is is this. Um, so as derived through this table, it's at the top of the page. The performance objectives of a smoke dispersal system designed in accordance with CP371
01:01:16 designed in accordance with CP371 is to enable extended travel distances of up to 15 meters in the common lobby, but providing protection to the lobby and staircase for both means of escape and firefighting phases.
01:01:27 and firefighting phases. B. All the various types of system can be designed to provide protection to the staircase during the means of escape and firefighting phases. C. No published guidance specifically recommends the use of either a natural system or a pressure
01:01:39 of either a natural system or a pressure differential system to protect the common lobby where the travel distance is greater than 7.5 m. And you you've quoted the SCA guide 2015 which states
01:01:50 quoted the SCA guide 2015 which states that generally natural ventilation is not appropriate for corridors of this length. So the system provided should be mechanical. On that basis, these systems are unlikely to fulfill the performance objectives of the original system. And
01:02:02 objectives of the original system. And then you go on and you say BS91 um from 2011 and 2015 and both both SCA guides recommend a mechanical smoke ventilation system when protection is
01:02:14 ventilation system when protection is required to both the common lobby and the staircase during the means of escape phase where the travel distance is greater than 7.5 m i.e. meeting the performance objectives of the original
01:02:25 performance objectives of the original system installed at Grenful Tower. So, sorry for that slightly long um but but that's a useful way of summarizing uh your analysis. Now, you've told us in
01:02:36 your analysis. Now, you've told us in your reports that you consider that the system which was eventually installed at Granville Tower was most akin to what's called a mechanical extract only system as described in the 2015 SCA guide. If
01:02:49 as described in the 2015 SCA guide. If we could just look at that, this is a RBK 402932.
01:02:55 If we go to page 37
01:03:00 at section section 6.4.4, it's got a heading from 12. It's 2012. Is it? Sorry, I didn't see the front page. No, this is the 2015 guide. Sorry.
01:03:11 No, this is the 2015 guide. Sorry. Um, this is a mechanical extract only description. And um in briefly can you just explain
01:03:22 And um in briefly can you just explain why because there's a difference between you and Mr. Lei here. Mr. Lei says that this desri the description that most accurately meets this system is a mechanical extract natural inlet system
01:03:36 mechanical extract natural inlet system whereas you say that actually it's it's a mechanical extract only system. Can you just explain why you say that? No. Actually I what I said was I'm not
01:03:47 No. Actually I what I said was I'm not sure where in my report you are. I said that when the door is closed it's a mechanical extract only system and when the door is open the natural inlet comes through the open stair door. So and I
01:04:00 through the open stair door. So and I set all of that out in anyway it's both right. I see.
01:04:10 Now in your report, let's go to that. It's BLP25043.
01:04:15 Yeah. At page 41,
01:04:21 paragraph 3.3.17 of this report. Yeah. You refer to a specific warning in the SCA guide regarding mechanical ex extract only systems.
01:04:32 extract only systems. And you say there the SCA guide 2015 makes the following point. Mechanical extract only systems using natural leakage for replacement air are not suitable where extended travel distances occur unless specific consideration of
01:04:44 occur unless specific consideration of the risks is undertaken by the designer and approval obtained from the authority having jurisdiction. Yes. And you say the significance of this is that the SA guide 2012 stated
01:04:56 that the SA guide 2012 stated mechanical systems as described in section 64 may be designed to allow extended travel distances subject to agreement from the approving authorities. So you're picking up on a
01:05:07 authorities. So you're picking up on a um a difference between the two SCA guides.
01:05:09 guides. Yeah. Well, I'm trying to So that's correct. But also it's about having a a dedicated supply of inlets air in any condition. Yeah.
01:05:20 Yeah. And when you don't have a dedicated supply of in inlet air in certain conditions. Yeah.
01:05:25 Yeah. Okay. Now, can you help us as to do you know on what basis this warning was added for these specific systems in the SCA guide 2015? I have no idea.
01:05:36 I have no idea. You don't know? Well, I'm not I'm not in the SCA, so I can't answer that question. Yeah. But do you have any idea what No, I don't have any ideas cuz I'm not in the SEA and I don't know anything about it.
01:05:45 about it. Okay. So, you can't help us as to why they might have said that mechanical extract only systems using natural leakage are not suitable where extended travel distances occur. I can't factually explain why they put
01:05:57 can't factually explain why they put that into their guidance document. Okay. Thank you. Um but I'm sure it's clear from my report and all the other reports on this subject about [snorts]
01:06:09 subject about [snorts] how smoke behaves when doors are closed. Right.
01:06:12 Right. Okay. But I don't know what the SEA were doing. Now in terms of the design basis for the PSB design, if we could go back to your module 3 report BLP25035
01:06:23 and look at page 32 at paragraph 2.5.1,
01:06:32 you basically say that proposing an alternative solution to the provisions made in ADB 2013 such that it meets the functional requirements is termed an
01:06:43 functional requirements is termed an alternative approach. And then at 2.54 you say certain relevant characteristics of Greful Tower were pre-existing and did not follow the guidance within ADB 2013. In particular, a the position of
01:06:56 2013. In particular, a the position of the dry fire main which was in the lobby and not the stair and B the travel distance in the lobby was you've measured it at 10.5 m and therefore extended beyond the limit in ADB of 7.5
01:07:08 extended beyond the limit in ADB of 7.5 m. Is that right? So you're drawing attention to the fact that there were certain unusual characteristics of Greful Tower which were part of its existing situation. Is that correct?
01:07:22 Well, I didn't say they were unusual. Sorry, that was my work. Okay. Sorry. Yeah, they're just that that's just a the conditions. Yeah. Yeah. now was another relevant
01:07:35 Yeah. Yeah. now was another relevant pre-existing characteristic of Grenful Tower that um meant that it was difficult to follow for example the guidance in approved document B the small size of the builder's work shafts
01:07:46 small size of the builder's work shafts that went through the core of the building
01:07:50 sorry will you say that again sorry was another relevant characteristic of Grenell Tower the fact that it had these small existing shafts that were part of the original system
01:08:02 the original system in the in the well do you want in the in what context? I mean they were a known constraint. Is that what you're asking me?
01:08:08 me? Yes, I think that's the point that's being made that they were another known constraint and I've been clear I mean I actually I'm not able to tell where in which report this is from the screen but I've
01:08:19 report this is from the screen but I've been clear in my supplemental report because I was asked to be clear about constraints. Yes.
01:08:27 Yes. Yeah. So yes, the builder's workshops were of fixed size, right? Yeah. Would you agree with this that in the majority of cases, smoke control systems in high-rise buildings
01:08:39 control systems in high-rise buildings are bespoke solutions which have to be tailored to the particular existing conditions of the building? Yes.
01:08:50 Now, if we go to section 3.6 six of your supplemental report BLP25043
01:08:57 and look at page 56. In this part of your report, you've considered the project constraints as they were at the time of the primary refurbishment. Is that right?
01:09:09 refurbishment. Is that right? Um that's the title. Oh, the documents containing the constraints. Yes. Yeah. So, you've you've had a look at what were the project constraints as evidenced by the the primary documents.
01:09:21 evidenced by the the primary documents. Yes. [snorts] And we can see these you've set these out at table 3.4 on page 57.
01:09:27 page 57. And these included um
01:09:32 um the requirement to re if we look at I want to look at the left hand column sorry the requirement to reuse the existing smoke exhaust shafts which came from the employer's requirements. Yes.
01:09:45 from the employer's requirements. Yes. Yeah. Yes. Yep. Well, it's there's different description across under each document. Yes.
01:09:52 Yes. Yeah.
01:09:53 Yeah. And then over to page 58, you also refer to reusing the existing dampener openings.
01:10:02 openings. Um but you suggest that this was not specifically stated in the employer's requirements. Now, is that something that you consider ought to have been explored
01:10:11 explored or um
01:10:15 or um Yes. Do you consider that you ought to have exp someone ought to have explored whether or not uh reusing the existing damper openings was a constraint or whether something else could have been
01:10:26 whether something else could have been done with those openings? I if if the area of the openings were relevant to the design I was trying to carry out at the time and it was posing me a problem,
01:10:39 the time and it was posing me a problem, yes, you you would explore it. I think I I I've read that the opening those openings were like to me a constraint actually is contra was almost contractual. They tend to come with you
01:10:51 contractual. They tend to come with you know your constraints are imposed on you on a project. So that yes it should be explored
01:10:58 explored if it's causing you know a lowering of performance or a lowering lowering of flexibility in what you might like to provide in that building. Right now, in
01:11:10 provide in that building. Right now, in terms of other constraints, if we go over the page to page 59 and look at your paragraph 3.6.8,
01:11:18 you say this. You say, um, I found no documentation directing the design team not to locate the new south shaft fan in the rooftop plant room. Do you see that?
01:11:31 the rooftop plant room. Do you see that? Yes.
01:11:32 Yes. And you say uh at 3.6.9, 6.9. I do not know from the evidence either why it was decided that the south shaft extract equipment would be provided at level two and not on the roof, nor why extending
01:11:43 and not on the roof, nor why extending the south shaft to the roof level and placing the south shaft fan there instead was not either considered or the subject of a cost benefit analysis. Now, first of all, what documentation
01:11:55 Now, first of all, what documentation would you have expected to have seen which gave consideration to whether the fans could be located at roof level? What type of analysis would you have expected?
01:12:07 expected? Sorry. Yeah, I'm just kind of strugg slightly struggling to follow. So, are you asking me what documents I would have expected the design team to put forward or do you mean if the client was making it a constraint? I
01:12:19 making it a constraint? I I think um the former what documentation would you have expected the design team to have put forward if they felt that that was a constraint?
01:12:30 that was a constraint? I I [laughter] don't know. I don't I don't like I'm struggling to Do you mean the document type? I I don't know really what you mean. So I I can't be specific on what document type I can say that I
01:12:42 on what document type I can say that I would Do you mean like a word file with an analysis of I I don't really know what you're asking me. Well, I tell you what, let me give you some examples. I mean just an analysis of why they may
01:12:53 I mean just an analysis of why they may have needed to use the plant room, what might need to move. Is that what you're asking me? Yes. I mean, how the consequences of the equipment being moved, you know, how
01:13:06 equipment being moved, you know, how long that might cause temporary or per, you know, you know, time problems with um services not being available. um if you could do it in phasing or if
01:13:17 um if you could do it in phasing or if fundamentally it caused such an you you know to do with time movement of equipment and the consequences in an occupied building
01:13:28 occupied building you would have expected that would you if they were going to conclude that they couldn't put the fans at the roof level if if I was so I would normally either be instructed that I cannot use a plant
01:13:40 be instructed that I cannot use a plant room or where the decision falls to me and I have been in this position uh where the decision falls to you, you have to make a very careful decision if the consequences of not doing it
01:13:56 the consequences of not doing it are consequences you can accept as a designer. Is that a better way of putting it? So I have in a certain circumstance had to insist that a plant room was rearranged to accommodate a new
01:14:09 room was rearranged to accommodate a new fan. Yes. Would I like to do that on every project I work on? Absolutely not. And my clients definitely wouldn't like me to do it if that's what you're asking.
01:14:19 asking. Right. I think Okay. But it it I don't think you can simply say it's not possible without having worked it out for that specific building.
01:14:27 building. Okay.
01:14:29 Okay. I don't know really why you're asking. Well, I'd like to know, see if I understand what where we are here. M um are you saying this that at some point in the design stage
01:14:40 point in the design stage someone should have said or at least asked themselves the question wouldn't the new system work better if the extract fans were at the top of the building
01:14:49 building and then gone on to ask could we put them up there and if not why not yeah exactly I sorry that's why I'm just trying to and then I don't know would you write that down would you you know and and and can I just say that's
01:15:00 and and and can I just say that's perfectly common normal behavior behavior on on a project small or large you know um and then someone might have said it'll
01:15:11 and then someone might have said it'll be too expensive too disruptive yeah or no you know no way am I paying for that yeah whatever there and then an instruction will come from your client or you know I then in the circum in c in
01:15:25 or you know I then in the circum in c in other circumstances if I if I thought in a a different circumstance the the risk to life was so high.
01:15:34 high. Yeah.
01:15:35 Yeah. That the client had to understand by not considering this highly disruptive work, there were other consequences for them. They're the kind of conversations a fire engineer has to have sometimes.
01:15:46 engineer has to have sometimes. Okay.
01:15:47 Okay. Yeah. Yeah. I understand. So, look, what I want to do is is look at some just two email communications that occurred on this project with you. Um and and I think the purpose um of taking you to
01:15:59 think the purpose um of taking you to these is to to my main question will be is that adequate consideration of um using the plant room or not because I think the points been made that in fact on the project they did think about this
01:16:11 on the project they did think about this they did ask themselves the question. Yeah. Um, so if we could go first to JSW43580.
01:16:20 So this is an email from David Bradbury to Simon Lawrence within Ryden copying in Mr. Manne and it's the subject is Grenful Tower
01:16:31 and it's the subject is Grenful Tower AOV shaft to roof plant room. It's the 13th of February 2015 and Mr. Bradbury says sorry Mr. Bradbury's of JS Wright I apologize. So it's from JS Wright to
01:16:43 apologize. So it's from JS Wright to Simon Lawrence at Ryden. Yeah.
01:16:45 Yeah. And he says, "Simon, further to our conversation and following site visit yesterday, it appears we will have an issue penetrating through to the rooftop plant room and there are other concerning issues such as the asbestos
01:16:56 concerning issues such as the asbestos ceilings etc. Therefore, we would need to stay with the original plan of having one set of fans at the lower level and one set in the rooftop plant room." So that's the first email. And then if we
01:17:07 that's the first email. And then if we go to the second email, this is at sea3012828.
01:17:13 And this is an email from Simon Lawrence to Kevin Lamb and Ben Bailey of Harley copying in a number of others. Subject AOV louvers within cladding.
01:17:25 AOV louvers within cladding. Um, and what's being said here? Hi Kevin, in the last design meeting, we discussed louvers through the cladding panels for the AOV system. At that time, we had some ideas about the AOV design, which would have meant that we could
01:17:36 which would have meant that we could vent the AOV fans through the roof. Unfortunately, because of structural issues, we can no longer do this. So, we'll have to revert back to the original plan. I've attached several drawings indicating our intentions for
01:17:48 drawings indicating our intentions for you to incorporate within the cladding panel design above the curtain walling and entrance door. So the the point's been made that here are two emails from the project which would suggest that
01:17:59 the project which would suggest that consideration was being given to locating the fans at roof level on the south shaft. Um but it looks like consideration such as
01:18:10 as um the asbestos ceilings and have to penetrate through into the plant room um meant that it was considered too ownorous to do that. Now, um I
01:18:22 ownorous to do that. Now, um I appreciate it's a difficult question, but is that the kind of level of consideration you would have expected to have been given to that issue on site or would you have expected a more detailed
01:18:33 would you have expected a more detailed analysis, a more comprehensive analysis? Would you have expected a cost [laughter] benefit analysis um before that option was discounted? So, I I can see these two emails and I understand that that's what people were
01:18:45 understand that that's what people were speaking to each other about. I I don't know what the structural issues are. I don't know where the asbestos ceilings are. I can't remember. There was a third point in the first email. Sorry. Um,
01:19:00 point in the first email. Sorry. Um, at the risk of making myself very unpopular or more unpopular. Um, I am used to people telling me things, you know, I like I think I'm just going to
01:19:11 know, I like I think I'm just going to leave it. I think that's a very high level. Um, you know, I think this is between Ryden and P in JS, right? You said.
01:19:20 said. Yeah.
01:19:21 Yeah. So, the first one was between Ryden and JS, right? This one seems to be between Ryden and Harley. Yeah. So, look, I'll tell you what, I can't give you expert evidence on the basis of these two emails, but I note
01:19:34 basis of these two emails, but I note that they have spoken to each other about it. I can't see any detail that would allow me to understand if it was a correct assessment of the building or not and I don't think it's for me to
01:19:45 not and I don't think it's for me to say.
01:19:46 say. Okay. Thank you. Okay,
01:19:47 Okay, Mr. Chairman, I think that's a good moment to break if that's Yes. very well. Well, we'll take the morning break at that point. Okay.
01:19:54 Okay. Um, you know the drill. Please don't talk to anyone about your evidence while you're out of the room. No problem. 25 I should have said 25 to 12. Thank you. Thank you very much.
01:20:07 Thank you very much. [clears throat]
01:36:02 Would you ask Dr. L to come back in please? Okay.
01:36:15 All right, Dr. Lane, ready to go on? Yeah. Sorry, I was being a bit slow there. I'm really sorry. What I should have said was I've I've seen those emails and then I would expect on the
01:36:27 emails and then I would expect on the CDM risk register there would be a line item explaining what decision had been made and why and how the hazard had been assessed and was deemed to be acceptable.
01:36:40 acceptable. Okay.
01:36:40 Okay. Yeah. Okay. Thank you. Yes, it's great. Yes. Thank you. Now in relation to design options which were discounted by Mr. Mani of PSB. Yeah. [snorts]
01:36:51 Yeah. [snorts] Um I want to ask you whether in your view it was reasonable for him to discount the pushpull system as had been proposed by Max Forom. Um i.e.
01:37:02 proposed by Max Forom. Um i.e. replicating the original system or the original mechanical part of the system with a mechanical pushpull system. Now when Mr. Many gave oral evidence he raised a number of potential problems with a
01:37:13 number of potential problems with a pushpull system and I just want to list those out. He he said that that would include excessive pressure drop in the shafts. And he talked about, you know, the analogy of trying to get an old quart
01:37:24 analogy of trying to get an old quart into a pint pot. Yeah. Are they coming off in the screen? No, I'm just going to try and remember. Yeah.
01:37:30 Yeah. So, excessive pressure drop, velocity jets across the lobby which would push push smoke towards the stair. Yes.
01:37:37 Yes. And he said that a pushpull system is much more suitable for a a corridor system.
01:37:43 system. Yeah. Um given that you would get dead ends here with a pushpull given the eye shape of the lobbies. Yeah.
01:37:50 Yeah. Now um do you [clears throat] share his concerns about uh the possibility of putting a pushpull system into Grenful Tower?
01:37:58 Tower? So I think Mr. is it Mahoney or Mahan? I I thought it was he said mani. Mahoney.
01:38:06 Mahoney. Yeah. Okay. So I I understand. So the parameters Mr. Mahani raised are relevant for consideration. Um I didn't find any there's no evidence
01:38:19 Um I didn't find any there's no evidence available to me how he quantified those concerns
01:38:24 concerns the how he quantified those parameters and if they would indeed occur in the eyeshaped lobby at Grenful Tower. But they were relevant parameters to
01:38:35 they were relevant parameters to consider.
01:38:37 consider. Okay. Um,
01:38:40 Okay. Um, knowing what you know about the design process and how it evolved, would you have expected more consideration to have been given to a pushpull option at Grenell Tower? I think I I I I think that I would have
01:38:54 I think I I I I think that I would have expected more consideration by Max Forward first of all. Um, sorry, I shouldn't have used the word consideration. I would expect more analysis to have been done to bring some
01:39:08 analysis to have been done to bring some shortity
01:39:09 shortity to the situation that pushpull for at Grenful Tower was not a viable option in the first place and that um
01:39:20 option in the first place and that um before it was discounted. Yes. Yeah. And and when you say you would expect more analysis to have been done, can [clears throat] you just give us an idea of what kind of analysis you're talking about? Well, personally, I'm
01:39:31 talking about? Well, personally, I'm talking about a numerical model of of Granful Tower, and that's what you know, lots of people do that. That's been discussed at length yesterday as well. Right.
01:39:39 Right. Okay. And then that kind of it it kind of ends the it ends any speculation or assumption
01:39:50 speculation or assumption that, you know, a system is absolutely off the table or not. Right.
01:39:56 Right. Yeah.
01:39:56 Yeah. Yeah.
01:39:58 Yeah. Now, Mr. Lelay in his evidence yesterday, he said that if you're going to try and get a pushpull system to work,
01:40:05 work, yes,
01:40:05 yes, you would need bigger extraction rates uh for the system to be put in. And he said he doubted that that would be achievable with this system. Do you
01:40:16 achievable with this system. Do you agree with that? He doubted it would be achievable with sorry with a pushpull system generally or with the equipment installed in Granful Tower. Just generally I think in my understanding is in general he doubted that it would be
01:40:28 general he doubted that it would be achievable to put a pushpull system into Grenville Tower which had the bigger extraction rates that you would need for the system to work effectively. Yeah, I I I think that
01:40:41 work effectively. Yeah, I I I think that all of us would need to have done some numerical analysis to be definitive. And I think um the the bigger issue
01:40:53 And I think um the the bigger issue about pushpull is um
01:40:59 is um the direction the smoke travels. So, for example, when you think about flat 16, which we've been doing a lot in the last year, focusing in on what happened on the night, if you were, you know, the
01:41:12 the night, if you were, you know, the north shaft dampers were used um to extract the smoke there, flat 16 is in the perfect location for a so-called push pulse system. But if you take a
01:41:23 push pulse system. But if you take a different flat, the most remote flat um from the north shaft, unless you done numerical analysis, you couldn't satisfy
01:41:34 numerical analysis, you couldn't satisfy yourself what extent of hazard remained in that lobby as a function of how the smoke was behaving there. Okay. But I I
01:41:46 smoke was behaving there. Okay. But I I think um
01:41:49 think um there was nothing intrinsically wrong with deciding to use a lobby depressurization system and I think that's been kind of forgotten about really in my work as I see it. Um but
01:42:03 really in my work as I see it. Um but before discounting a pushpull system which does offer better protection in certain circumstances I I think more analysis should have been
01:42:14 I I think more analysis should have been done but we have to always remember the the shape of the lobby at Granful Tower is an is it's a well a H or an I or you
01:42:25 is an is it's a well a H or an I or you know whichever way you see it. Yes.
01:42:27 Yes. So I'm sympathetic there. Yeah. Sorry, I'm wondering who can help me with this. A a pushpull system would have had as its primary object what the the uh clearance of smoke from the lobby.
01:42:39 clearance of smoke from the lobby. It depends what you design it for. So, sorry. I know. Well, I'm so so putting that in the form of a question. Oh, right. Well, so so one, so all all
01:42:50 Oh, right. Well, so so one, so all all systems draw smoke. We'll have some smoke in the lobby, but you can design those systems. Okay. you you you you scale them to deal with
01:43:01 you you you you scale them to deal with the lobby or you know to deal with the tenable condition in the lobby or not. So it depends what you're trying to do. Well, let me explain why I asked the question. Uh it seemed to me that a system which involves putting air into
01:43:14 system which involves putting air into the lobby. Yes.
01:43:16 Yes. Would not be entirely consistent with a system whose object was to create a flow across the stair door. It's not consistent. Sorry. Sorry. Do you mean a pushpull system does something different?
01:43:27 something different? A push pull system. I could understand how that could be a smoke clearance from the lobby. Oh yeah, exactly. Yes. But it would not be consistent with the objective of providing uh any air flow
01:43:40 objective of providing uh any air flow from the
01:43:40 from the Oh, sorry. Well, so then you'd write a different spec to the one that PSB put forward. Is that what you mean? So your parameters that you would offer for a pushpull system are different to those
01:43:53 pushpull system are different to those that are offered as if that's what you're asking me. Not just different, but is the primary objective
01:43:59 objective different? Different. Absolutely. Oh, sorry. Sorry. Completely missing the point again. Yes, it is. So if you start with the um objective of protecting the stairs,
01:44:11 protecting the stairs, Yes.
01:44:11 Yes. rather than the lobby. Yes. Then a pushpull system doesn't sound to me as though it's an appropriate system. Why not? Why not? Sorry. Well, that's what I'm trying to understand. Uh I think I'm kind of slightly lo
01:44:23 Uh I think I'm kind of slightly lo losing you here. But your your Well, because it seemed to me that Well, if it's stopping smoke flowing out into into the staircase, isn't it doing
01:44:34 into into the staircase, isn't it doing something?
01:44:37 Well, it it may be it may be that if you can clear the lobby adequately. Yes, exactly. get smoke uh entering the stairs.
01:44:45 stairs. Yeah. Yes. That didn't [snorts] sound to me as though that was the objective. So, sorry. The a pushpull system can
01:44:57 So, sorry. The a pushpull system can clear smoke from the lobby at different a different time depending on how you design it, right? and can then be relied upon to keep the staircase clear and
01:45:09 upon to keep the staircase clear and potentially have a tenable condition in the lobby at certain times. So it was a a viable alternative so to speak if the configuration would have allowed it
01:45:20 configuration would have allowed it theoretically. That's why I I said to you at the start, that's why we we consider them, you know, remember I said, so when we're looking at our projects, they are a consideration, but
01:45:32 projects, they are a consideration, but they have to be viable in the circumstances of the case. Yeah. All right. Thank you. Yeah.
01:45:37 Yeah. Yeah. Um, now you've said in your report, in your supplemental report, that the the problem that Mr. Mani identified regarding pressure drop with a pushpull system could have potentially
01:45:49 a pushpull system could have potentially been dealt with by either a higher performance fan or increasing the size of the existing shafts. Yes. Yeah. Because Yes. And you found no evidence that a
01:46:00 And you found no evidence that a costbenefit analysis of such options was done. You also make that point. Yes. Would you have expected a costbenefit analysis to have been done of both a using a higher performance fan
01:46:12 of both a using a higher performance fan and increasing the size of the existing shaft?
01:46:14 shaft? I'd prefer to have seen a a a detailed pressure drop calculations satisfying all the
01:46:23 all the is you know the replicating the physical condition of granful tire to know that the fan was sized correctly. Right.
01:46:30 Right. Yeah. So is what you're saying you take it in stages and you do the calculations first
01:46:35 first to see what the pressure drop is. You see what situation you're in. Yeah. I see. Okay. Um
01:46:43 Um now Mr. Lei has said in his report if we could go to paragraph um 22 on page 17. So ly 701 page 17.
01:46:58 If we go to page 17, paragraph 22.
01:47:15 There we go. So I just want to read um a little bit of 22 and then 23 to you. So in the last three lines of 22 he says um consequently I consider that the system
01:47:27 consequently I consider that the system which focused on protecting the stair by using both shafts for me mechanical extraction was the most appropriate design response and at 23 he says I've not been able to identify any
01:47:39 not been able to identify any appropriate smoke control system design capable of installation within the constraints of the tower which could have explicitly addressed both the lobbies and the stair maintaining ing
01:47:51 lobbies and the stair maintaining ing tenable conditions in both at the same time.
01:47:55 time. Now, um do you agree with the the first point? Do you agree that a system which focused on protecting the stair was the most appropriate design response at Granful Tower?
01:48:09 The most appropriate in like in in what sense? You know, that there was no other choice and one couldn't think about Well, to be fair to Mr. delay. Let's
01:48:20 Well, to be fair to Mr. delay. Let's read what it says in the beginning of that paragraph. He says there were significant constraints present at the tower, including most pertinently the need to avoid intrusive works and using the existing north and south shafts. We
01:48:31 the existing north and south shafts. We saw you noted that in your report whose combined cross-sectional area was significantly less than that required for a compliant natural shaft system and the fixed geometry of the common lobby. So it's in that context I the
01:48:42 So it's in that context I the constraints that we've been discussing that he's saying that a system which focused on protecting the stair was the most appropriate design response but that so that's his opinion and I you
01:48:54 that so that's his opinion and I you know
01:48:55 know I think and I understand that opinion do you agree with it I think that it was one one available option
01:49:04 option right okay to you can make so to make that decision to protect the stair only was a valid, you know, it's a I understand it as a valid design choice.
01:49:16 understand it as a valid design choice. Yeah.
01:49:17 Yeah. But the the matter remains about the lobby in Grrenful Tower and whether or not it then also requires some form of mitigation. And I I mean I've gone on
01:49:28 mitigation. And I I mean I've gone on about this in my report at length. So if mitigation couldn't be delivered in within the the physical constraints of the tower and other and other constraints and this it was decided
01:49:41 constraints and this it was decided actively to protect the stair and explicitly help everyone understand that was the decision that was made. I've been clear that I understand that. Right.
01:49:51 Right. Yeah.
01:49:51 Yeah. Yeah. Um and he says in in that paragraph 23 that he's not been able to identify any appropriate smoke control system design capable of installation within the constraints of the tower
01:50:03 within the constraints of the tower which could have explicitly addressed both the lobbies and the stair maintaining tenable conditions in both at the same time. Now do you agree with that proposition? I I think that um
01:50:16 that proposition? I I think that um it's it would be better to do a numerical analysis before saying something that definitive. Right.
01:50:23 Right. Okay.
01:50:25 Okay. Now, um if we could go to your supplemental report again, BLP25043
01:50:33 at page 217, and I want to look at paragraph 9.250.
01:50:40 You say um in my opinion a mechanical extract and natural inlet from a stair lobby depressurization system could have been a viable option for insulation in Grenell Tower, but only if the designer
01:50:52 Grenell Tower, but only if the designer had decided that the performance objective for the system was to only protect the staircase during the means of escape and firefighting phases and not to protect the lobby by design. Is that right?
01:51:03 that right? Yeah, that's just what I've just And then you go on. You say this required an extract capacity and components with the relevant leakage roots factored into the design by PSB resulting in an increased system
01:51:14 resulting in an increased system performance. This was not done by PSB. Yes.
01:51:18 Yes. And and the point you've made in this supplemental report um to be clear is that you say you're not criticizing the type of system per se, but you are critical of the quality of the system
01:51:29 critical of the quality of the system that PSB installed. Yeah, it was a perfect Exactly. It's a perfectly common system type in a in a suite of options available to designers.
01:51:40 suite of options available to designers. Yeah.
01:51:40 Yeah. Yeah. But just to be clear, I if the designers had decided to protect only the staircase, your evidence is is it that others in Grimfield Tower needed to be made aware
01:51:52 Grimfield Tower needed to be made aware of that.
01:51:53 of that. Yeah. So when you pick that system, it can only protect the stair. Yeah.
01:51:57 Yeah. And you know, and again, just as per my report, etc. As far as I'm concerned, you know, this is this whole thing about the integration and the impact of all
01:52:08 the integration and the impact of all the different systems on each other and why you can't design any one system in in isolation. And I think that's kind of really for me anyway, it's really emerged in the really detailed review I've had to do on
01:52:20 really detailed review I've had to do on this system in the last two years. But there was a fire strategy for Granful Tower. It was an unsprinkered building. it was relying on this this stay put
01:52:31 it was relying on this this stay put condition
01:52:32 condition um
01:52:34 um and it was of in the 1970s stock you know it had all the characteristics of that time frame and it was important to consider what it meant if one took the
01:52:47 consider what it meant if one took the active decision to not protect the lobby by means of smoke control that meant someone had to take responsibility for mitigating you know understanding any
01:52:58 mitigating you know understanding any potential hazard in the lobby and mitigating it by a different way. And that is very much part of the duty of a fire engineer when writing their fire strategy. And then PSB can come along
01:53:12 strategy. And then PSB can come along and they understand for the particular building they're being asked to work on the parameters that they're operating within. Okay. And I'm used to, you know,
01:53:24 within. Okay. And I'm used to, you know, and they it's a reasonable expectation in my opinion. They they had every right to expect those parameters to be clearly set out for this specific building and
01:53:36 set out for this specific building and to know therefore what their system needed to do when it was integrated in with everything else in the building. It can't just operate in isolation.
01:53:47 can't just operate in isolation. Yeah. [clears throat] And is what you're describing the work that you would have expected a fire engineer to have done before PSB became involved? Absolutely. And then and that's how it does work. I'm I'm sure Mr. Lelay made
01:53:59 does work. I'm I'm sure Mr. Lelay made this clear as well yesterday. any any company like PSB can then take the fire strategy
01:54:07 strategy understand the the life safety purpose of the specific system needed in the building and then can make you know as far as I'm concerned more valuable give
01:54:21 far as I'm concerned more valuable give more valuable advice about which particular system type is relevant for the building. Yeah. And have you seen any any evidence that that work was done before PSB got involved?
01:54:31 involved? No, I didn't. And we've we discussed all of that. I can't even remember what module now when we were going through Exova.
01:54:37 Exova. Yeah.
01:54:37 Yeah. Okay. And and that's why um Anyway, yeah. And I'm going to come to a few more detailed questions about travel distances in just a moment, but just picking up on you now. You say that
01:54:49 picking up on you now. You say that there might have been mitigation that could have been provided to the lobbies given that you say that with these extended travel distances. Yeah.
01:54:57 Yeah. Can you just give us an example of in practice what what could actually be done at something somewhere like Grenful Tower
01:55:05 Tower to mitigate an extended travel distance if it existed? So this is then where the other systems come into play. So so and where where one design becomes even more
01:55:19 where where one design becomes even more reliant on some other active or passive measure. So if you if you decided that you could not mitigate travel distance at ground tower or that you did not need
01:55:31 at ground tower or that you did not need to with the smoke control system. As far as I'm concerned, my professional opinion is that the performance of the fire doors and the performance of the
01:55:42 fire doors and the performance of the dampers in the lobby, so the protective devices in the lobby become even more important. Okay. Than they they are because you're relying on them more than
01:55:53 because you're relying on them more than maybe when you know than when you're um designing a smoke control system. So the fire strategy and the documentation handed over to the responsible person,
01:56:05 handed over to the responsible person, it would be really explicit. The the smoke control system in this building is there for the following purposes and it is critical that fire doors are and dampers are maintained that to to the
01:56:18 dampers are maintained that to to the relevant standard. Would would it ever sorry
01:56:21 sorry I I don't like I don't know what I would have done on Granful Tower and it's a horrible question to ask anybody but I think that I I would have been prepared to contemplate something like that. Yes.
01:56:33 to contemplate something like that. Yes. And I appreciate you might flag that maintenance duties need to be taken especially seriously. That's one example you've given. But the damper performance the damper
01:56:45 But the damper performance the damper fire the damper Yes. fire performance in itself and the maintenance of them. All of these things are interrelated. And then if the fire engineer is relying on a system from PSB
01:56:59 engineer is relying on a system from PSB that it it where it's absolutely essential the fire doors have X performance and the dampers have Y performance. All of that needs to be explained. And and would you ever have a
01:57:10 explained. And and would you ever have a situation where you would deliberately increase the level of performance you expect from a fire door or from a damper as a mitigation measure? Yeah, I don't I I don't want to
01:57:21 Yeah, I don't I I don't want to speculate on that at the moment. That's kind of a live design query, right? I think in just sitting here today and having thought about it for a while, I I think just even acknowledging
01:57:33 while, I I think just even acknowledging the importance of those two life safety systems in itself is a mitigation. I'd have to really seriously think and
01:57:45 have to really seriously think and probably do some further analysis for an unsinklered building, right, about if I needed the standard to go up, but I haven't I haven't drawn that in here. And is that because what you're saying is those who are managing and
01:57:56 saying is those who are managing and maintaining the building would need to have that drawn specifically to their attention so that they were ensuring that they gave priority to the maintenance exa. Exactly.
01:58:07 maintenance exa. Exactly. Those components. Yeah. And that's this whole thing about doing things knowingly that I've been trying to explain today. You that's why you have to explain it. So you know I don't have an obsession with
01:58:19 don't have an obsession with documentation. I do have an obsession with explaining to people really clearly what is in their building and what it relies on and so their role in making
01:58:31 relies on and so their role in making sure it can be relied on when when the fire occurs. Okay. Okay. Thank you. Now on extended travel distances some more detailed questions. Now if we can go to your uh face uh
01:58:43 Now if we can go to your uh face uh module 3 report BLP25036
01:58:49 and I want to look at page 25. You say at um paragraphs 10,133
01:59:01 you say this um the mechanical extract only system as it's described in the SCA guide is a pressure differential system as a pressure differential must be maintained by the system in operation and then you go on mechanical extract
01:59:13 and then you go on mechanical extract only systems are agreed to be inappropriate for the protective purpose of means of escape and then you refer to your table above no consideration was given into this during the Grenell Tower
01:59:24 given into this during the Grenell Tower primary refurbishment. And then um if we look at the last row of table 55 that you refer to there on page 153.
01:59:33 page 153. Yeah.
01:59:41 [clears throat] there. Um, in this table with the SCA guide requirements under 64, you've quoted uh from the SCA guide where it says it's in the middle column,
01:59:52 says it's in the middle column, mechanical extract only systems using natural leakage replacement air are not suitable where extended travel distances occur unless specific consideration of the risks is undertaken by the designer
02:00:03 the risks is undertaken by the designer and approve approval obtained from the authority having jurisdiction. And in the final column you say, I found no evidence that PSB considered the effect of an extended travel distance on
02:00:14 effect of an extended travel distance on their design or that they considered how a mechanical extract system using natural leakage may not be suitable for such an application. Now has your view on that changed at all having heard the
02:00:26 on that changed at all having heard the oral evidence and the evidence of Mr. Lei yesterday? No.
02:00:32 No. Help us with this. If the designers had acknowledged the travel distances and acknowledged that they were extended, but said that they were still satisfied that the solution was appropriate given
02:00:43 that the solution was appropriate given the relatively limited additional distance that that involved and given that the primary objective was protecting the stair, would that in your view have been a reasonable approach if
02:00:56 view have been a reasonable approach if the designer had sorry go through? So if the designers had say if PSB had put in a paragraph in their technical submission acknowledging the travel distances that they were in excess of
02:01:07 distances that they were in excess of 7.5 m
02:01:09 7.5 m but said explicitly we're still satisfied that this is appropriate given the relatively limited additional distance and given that the primary objective is protecting the stair. Would
02:01:21 objective is protecting the stair. Would that have been reasonable? The primary objective for them is protecting the stair. Yes. Of their system. Okay. So I so I think that Exova should have written
02:01:33 think that Exova should have written down whether the travel distance required a mitigation or not and it you know directed PSB to considering you
02:01:46 know directed PSB to considering you know it it you know I would there should have been some kind of discussion and they did actually have discussions as I remember then it when they understood uh lobby depressurization system was let's
02:01:58 lobby depressurization system was let's say the best option within the constraints for the tower that that they would describe the I'll call it the consequences of relying on that system in the full
02:02:11 relying on that system in the full context of the fire safety strategy for the tower
02:02:14 the tower right
02:02:15 right okay and for PSB I would expect them you know I you know they do they do this a lot if that information wasn't available they they they needed to find out what
02:02:28 they they they needed to find out what the the you know what scope they were being asked to offer a system in. Right.
02:02:33 Right. Okay.
02:02:34 Okay. Now if if we go within your supplemental report to where we see some measurements of the travel distances. This is BLP25043
02:02:44 page 269. Yeah.
02:02:47 Yeah. Now um this is where you set out your measurements of the various travel distances. And on page 271, um, sorry it's on from this, we get the measurements at levels 4 to 23.
02:02:59 measurements at levels 4 to 23. And what we have is your measurement on the left hand side. Um, where we can see going from flat 4, we get a measurement of 10,
02:03:11 we get a measurement of 10, right? Is that 10.3? Yeah,
02:03:13 Yeah, 10.3.
02:03:14 10.3. Bit blurry. And you can see the path by which you've measured it. And then we've got Mr. lays measurement on the right hand side where he's got a path of 9.5.
02:03:25 path of 9.5. Yeah.
02:03:25 Yeah. And it's also recorded that the BR in their on-site investigation of Grenful Tower on the far right recorded that it was 9.3 I think there.
02:03:37 recorded that it was 9.3 I think there. Yeah.
02:03:38 Yeah. Now um
02:03:42 Now um you present this uh in your in your diagram just going back to your diagram um over an architect's plan of the floor. Does that mean back you sorry is it possible to just go back over please if we could just go
02:03:55 back over please if we could just go back to the left hand diagram which is your diagram. Yeah.
02:03:58 Yeah. This appears to be a studio e drawing. So it's an architect's drawing that you've put these distances on. Does that mean that you've calculated the distances from the plan or did you ever measure them yourself on site?
02:04:09 measure them yourself on site? Oh god, I can't remember. I don't think I measured them on site. I can't remember. I'd have to go back in and look at my report. Yeah.
02:04:16 Yeah. Um this so this is from my phase one report and just that's how I measured it at the time. I was thinking about the shortest distance from flat one to the
02:04:28 shortest distance from flat one to the stair because of some very complicated events that happened in some of the flat ones. And also I wasn't putting a massive effort into finding the shortest route possible from the furthest away
02:04:41 route possible from the furthest away flats cuz the cut off off point for me was 7.5 m. Right. Do you accept that you could measure it instead in the way that Mr. Lelay has measured it? I'm sure I could
02:04:52 Lelay has measured it? I'm sure I could get it right down there if I made a big effort.
02:04:55 effort. Right. Yeah. But do you consider that there's um any guidance which tells you exactly how you should be measuring these travel distances which is helpful as to whether you do it your way which is perhaps got
02:05:07 you do it your way which is perhaps got more slightly more right angles and more straight lines or whether you cut corners a little bit more. Is there any guidance out there that tells you how to do this?
02:05:16 do this? Not in Britain. Yeah. Right.
02:05:19 Right. Um,
02:05:25 and in so far as there's a difference between what the BR's measured and Mr. Lays measured and your measurement, um, to what extent does this make any difference to the conclusions that you
02:05:36 difference to the conclusions that you reach about the importance of um, highlighting the extended travel distances and addressing that as we've just been discussing? What difference? So does it make any difference that the travel distance might be 9.3 or 9.5 m to what you've
02:05:49 might be 9.3 or 9.5 m to what you've said in your report? Well, look, you know, the the cut off point is 7.5 and the longer you have to travel above 7.5 apparently the greater haz greater, you know, the greater the
02:06:01 haz greater, you know, the greater the hazard. I'm absolutely clear, Mr. Lelay helped. I think it's a few seconds extra just in pure walking time. Absolutely clear on on all of that. It's nothing
02:06:12 clear on on all of that. It's nothing like having to walk, you know, 50 meters or something, right?
02:06:17 right? Yeah.
02:06:17 Yeah. But but do you consider that that difference um makes any difference to the criticisms you've made of the failure by the fire engineer and the designers to give explicit consideration
02:06:28 designers to give explicit consideration to the travel distances in in their analysis at Grenell Tower? They are in excess of 7.5 and it merits uh [snorts] it merits consideration. I
02:06:41 uh [snorts] it merits consideration. I think people see that as some, you know, really a far more extensive point or criticism than certainly is in my mind. They're in excess of 7.5. It's quite a
02:06:52 They're in excess of 7.5. It's quite a simple matter to explain what that means, if it poses a hazard or not, and how to mitigate it. And I think it was actually a very simple thing to do at Granful Tower.
02:07:03 Granful Tower. Right. And can you explain why you think that was a simple thing to do at Granful Tower? Well, it's as we we discussed earlier, I've said to you that if the fire engineer had explained,
02:07:16 fire engineer had explained, they had [clears throat] taken the decision that protecting the stair only was the best course of action and had noted that there was an extended travel distance depending on how you
02:07:27 travel distance depending on how you measured it of I can't see the one over on the right hand side between two to under 3 m in extension. and this was their advice about whether that required
02:07:38 their advice about whether that required mitigation or not, the matter would have been resolved. Right. Okay. Thank you. Do you consider that the LGA guide 2011 on fire safety and purpose built blocks of flats
02:07:49 and purpose built blocks of flats provided relevant guidance for the consideration of travel distances in existing buildings at the time that the smoke control system in Grenell Tower was being considered by the design team?
02:08:03 Did consider relevant? But do you mean re well it's for the purposes of carrying out a fire risk assessment and then it comes down to as someone with
02:08:14 then it comes down to as someone with duties to dis discharge and design if you find the advice within that guidance adequate or not. Right. And is it right summarizing I want to try and summarize the view you've put forward in your supplemental
02:08:26 you've put forward in your supplemental report. You say in your supplemental report that the LGA guide is not intended to provide guidance for those seeking to comply with the building regulations as distinct from say the RRO
02:08:37 regulations as distinct from say the RRO or the housing act and that it's in itself it contains warnings about smoke dispersal systems which should have been heeded before relying on that guidance. That's is that
02:08:48 relying on that guidance. That's is that an accurate summary of your view? No, I I've said that, you know, what I've been trying to communicate is is that, you know, I don't consider it to be relevant to the building regulations. I
02:08:59 to the building regulations. I understand it exists and if one is deciding to read it and rely on it now after the fire because it didn't happen at the time of this project work then one has to take full consideration of
02:09:13 one has to take full consideration of what's in the LGA guide not pick out the one section which recommends certain travel distances right so I don't agree that it was relevant at the time and I don't agree that it's
02:09:24 the time and I don't agree that it's relevant now but if a person takes the decision to rely upon it. I think the least they could do is rely upon it in full. I don't agree that it's right in
02:09:35 full. I don't agree that it's right in the first place. Okay. Thank you. Now, a point that was made um by Mr. Lei yesterday and it's a point that's made in the LGA guide itself is that the 7.5
02:09:46 in the LGA guide itself is that the 7.5 maximum travel distance that we see in ADB and we see in BSL 91 was never intended to be a hard and fast rule that the moment you're 7.6 six mters and
02:09:57 the moment you're 7.6 six mters and you're just a little bit above that, then you've got to have a radically different approach. Yeah. Now, do you agree with that? So, um I don't think we'd be in this
02:10:10 So, um I don't think we'd be in this inquiry actually if people were taking a hard, you know, taking hard stops at the end of some of the rules and the approved documents. I think it is a measured approach, but the but it has to
02:10:22 measured approach, but the but it has to be in the round. So, you can't like I've heard lots of the witnesses talk about the travel distance wasn't long enough to worry about. In their minds, they're doing a little mini risk assessment and
02:10:34 doing a little mini risk assessment and deciding it's a hazard that doesn't matter. But if you're doing that in every single independent system as you go and never putting it all back together again, okay, that's where the
02:10:46 together again, okay, that's where the problem starts. So I'm not going to sit here and say that only for a 1 m travel distance at Grenell Tower etc etc. In fact I was really explicit ever since
02:10:58 fact I was really explicit ever since phase one that the extand extended travel distance doesn't seem to have posed a problem at level four that I have written that down. Um sorry I'm kind of going off on a bit of a tangent.
02:11:10 kind of going off on a bit of a tangent. So I understand that one can think about those rules but in the round taken together your duty is to assess the fi you know the final hazard the intrinsic
02:11:21 you know the final hazard the intrinsic risk at the end and satisfy yourself that taken together the fire you know the fire safety strategy can meet the functional requirements. Yeah. And when you're looking at those
02:11:32 Yeah. And when you're looking at those travel distances um do you assume that someone is passing through smoke? Is that an assumption you make when you're considering the travel distance and how excessive it is? Do you assume that the
02:11:43 excessive it is? Do you assume that the lobby might be smoke filled? Oh, well you Oh, right. Yeah. Since you think about different scenarios, right?
02:11:50 right? Yeah.
02:11:52 Yeah. Mr. Lelay has pointed out that the way you've traveled, the way you've calculated your um travel distance, if you go to the left hand side diagram again, might be more appropriate to um
02:12:05 again, might be more appropriate to um buildings like theaters or stadium where there's fixed seating and occupants are walking along a center line of seatways or gang ways. Now, what's your response to that? Is that right? Is it is it reasonable to
02:12:17 that right? Is it is it reasonable to assume that someone would walk a center line or wouldn't they in fact often if they know certainly if they know the building take a cut of a corner? Yeah. So as I said I measured this in
02:12:31 Yeah. So as I said I measured this in phase one. Uh I was actually mostly interested in the shortest distance. As I said, I didn't spend any time trying to find the absolute shortest walking
02:12:42 to find the absolute shortest walking route for a person because that's not what I was thinking when I measured my travel distance. Okay. Now, I absolutely could find the shortest possible line in in fact, I
02:12:54 shortest possible line in in fact, I give it a good go to get it under Mr. lays measurement, but I don't really think that's the whole principle behind thinking about the hazard to people when
02:13:05 thinking about the hazard to people when they're making their way from a flat door to a stair door in different fire scenarios. And should one assume that you might have some people doing that who aren't familiar with the building, so new
02:13:17 familiar with the building, so new occupants or uh visitors? Is that something that you might think about because
02:13:22 because doing hard? So, Mr. Lelay make the point in his um in his report that for most of the people at Grenell Tower, this lobby will be very familiar. So, it's a familiar travel. It's a lobby they're very
02:13:34 travel. It's a lobby they're very familiar with. They'll have traveled it many times. And that's relevant when you're looking at whether travel distances are excessive or not or too excessive. Do you agree with that?
02:13:52 I think that's a highly sophisticated
02:13:59 set of reasoning to attributed to a simple line drawn on a plan. Okay. Now, just thinking about the LGA guide, I've just got a few more
02:14:10 guide, I've just got a few more questions on this before we move on. Um, do you agree that whether or not this guidance was relevant to the tower, it might evidence industry practice regarding consideration of travel
02:14:21 regarding consideration of travel distances in existing buildings and when they were considered excessive? Yeah. So, first of all, the LJ guide wasn't used by any party when they were
02:14:32 wasn't used by any party when they were thinking about the fire safety strategy for Grrenful Tower. So, it didn't happen. Okay. and the LGA guide. I mean, I haven't really wanted to give a big massive opinion on my overall impression
02:14:45 massive opinion on my overall impression of the LGA guide. I gave evidence in a previous module about it. It may reflect some industry opinion, but it doesn't necessarily reflect all industry
02:14:58 necessarily reflect all industry opinion.
02:15:01 Okay. Thank you. in her oral evidence when she gave um evidence Miss Mensy said she said this had I been looking at it I wouldn't have raised the matter of extended travel distances being a
02:15:13 extended travel distances being a criteria which they would now have to address under the new proposals the refurbishment proposals now um I appreciate she's looking at it from a building control perspective that may be
02:15:24 building control perspective that may be a difference but um do you agree with her that um it's likely that many reasonable building control bodies wouldn't have expected uh these extended travel distances to
02:15:36 uh these extended travel distances to have been raised at Grenell Tower or require that to be a criteria which was addressed. I'm not sure Miss Mensy said she wouldn't expect anyone not to notice. She said she wouldn't have expected of that distance as I understand it. It
02:15:49 that distance as I understand it. It required mitigation from the smoke control system. Okay. Um, and if she, you know, it's not for me to, you know, um, I've I've read
02:16:01 for me to, you know, um, I've I've read what she said. Um, I think a simple acknowledgement and an explanation about how one's going to mitigate the travel distance or one has just satisfied
02:16:12 distance or one has just satisfied oneself that one does not need to is sufficient. I understand that people do a little mini risk assessment in their head and decide it doesn't merit a mention. I understand that people do
02:16:23 mention. I understand that people do that.
02:16:25 that. But is that is that reasonably acceptable practice to do that? Why would you why why would you not acknowledge it? That's the thing I don't understand. But you mean why would you not
02:16:36 But you mean why would you not why would one not simply just acknowledge it because it's a fact. And would acknowledging it have satisfied reasonably acceptable practice just acknowledging? I think it would show a proper understand. It would show
02:16:49 show a proper understand. It would show an understanding of Grenful Tower and that due consideration was being made to all the different aspects of it that
02:17:00 all the different aspects of it that needed to be protected or not in the event of a fire. But it it but I I I think my reading of all the different reports and the commentary on on my work
02:17:13 reports and the commentary on on my work is people have decided that I think this is the deal breaker here and that is not what I think. Okay. Now I want to ask you some more
02:17:24 Okay. Now I want to ask you some more detailed questions about the the system as it was designed. Um but but starting with um documentation for a moment. Now in your uh main module 3 report you set
02:17:36 in your uh main module 3 report you set out your comparison of PSB's technical submissions against for example the relevant SCA guide requirements for documentation. Um we do you do that just to help you
02:17:48 Um we do you do that just to help you with this. It's at BLP25035
02:17:52 page 148. If we could just bring that up. And this is at table 54 um where you're looking at the SCA guide 2012 and 2015. And you've got the
02:18:04 2012 and 2015. And you've got the information that ought to be included. And for example, two lines down, it's got the design criteria and performance objectives of the analysis, the scenarios investigated, details of the
02:18:15 scenarios investigated, details of the techniques used and related information, the results of the analysis, and a statement as to whether the design criteria objectives have been met. Yeah. Now um does that remain your view that the documentation that was prepared
02:18:27 that the documentation that was prepared in relation to this system was inadequate based on relevant guidance at the time?
02:18:33 the time? Yes.
02:18:34 Yes. Now um in terms of design considerations was the failure just in terms of documentation and producing documents to evidence the design or in your view does
02:18:46 evidence the design or in your view does it go further than that and do you have substantive concerns about the design? Oh sorry. Yeah. Yes. And I've Yes. As explained in my report. Yes. Now, Miss Menses concluded at paragraph
02:18:59 Now, Miss Menses concluded at paragraph 25 of her supplementary report uh for the transcript that references BMER 607 at page 7 that PSB's design for the smoke control system which was
02:19:10 smoke control system which was conditionally accepted by building control was a performance-based design for the lobby control system which was acceptable in principle but subject to proof that the system worked as
02:19:22 proof that the system worked as intended. Now, do you agree with Miss Menses about that? That it was in principle it was an acceptable system. So I I think so I I understand what Miss
02:19:36 So I I think so I I understand what Miss Manzy's meant was the parameters were familiar to her and the concept of a lobby depressurization is familiar and
02:19:48 a lobby depressurization is familiar and on that you know very high level basis yes that is acceptable. Okay.
02:19:56 Okay. Okay. I don't
02:20:00 Yeah, I don't know. That's Yeah, that's helpful. Um, now in his second witness statement, Mr. Mani said that he considered the 2 m/s criterion for air flow across the stair door.
02:20:12 for air flow across the stair door. Yeah.
02:20:12 Yeah. Was appropriate because although the system was not intended to operate in the same way as a class B pressure differential system in accordance with the relevant British standard for that the air flow the system was itself
02:20:24 the air flow the system was itself required to generate generate across the stair door in the circumstances set out in his submission was similar to that aspect of a class B pressure differential system. Now in your view
02:20:37 differential system. Now in your view was the 2 m/s air flow rate an appropriate performance criteria to provide reasonable protection to the stair.
02:20:47 stair. So it's a it's a it's a a a common number and a common performance objective and there's no dispute that it was you know an unusual number or the
02:20:59 was you know an unusual number or the wrong number. The issue is about when it's provided. Yeah. at Granful Tower and I think it's perfectly familiar um
02:21:11 um and you'll see it in all my um reports too. Yes. Yes. And I think what you then go on to point out in your report is that if you go to the SCA guides
02:21:23 if you go to the SCA guides um it provides recommendations regarding the need to consider different scenarios during both means of escape and firefighting which any properly designed
02:21:34 firefighting which any properly designed system ought to anticipate and address. Is that correct? Yes.
02:21:40 Yes. And is that because any such system needs to address what the foreseeable scenarios will be when the system is operating as intended? Yes.
02:21:50 Yes. And you in your reports you've drawn attention to the fact that both the 2012 and 2015 SCA guides provide some indicative examples of design conditions. Yeah. Including consideration of the stair and
02:22:01 Including consideration of the stair and flat entrance doors opening at different times for different durations. Yeah. During escape and firefighting, respectively. Is that right? Yes. Can we [snorts] just look an example of
02:22:12 Can we [snorts] just look an example of a typical timeline for a time dependent design? Um, this is in the 2012 SCA guide. It's a LFB3059241.
02:22:25 And if we go to page 13 of this 2012 guide, here we can see a typical timeline for time dependent design. If we could have
02:22:36 time dependent design. If we could have the whole of that table up and you draw attention in particular, I think to the last four boxes um of this table. Is that right? Where what we see is uh you could have a situation where the
02:22:48 could have a situation where the apartment window breaks, the door to the stair opens, fire service arrival and remains open, the door to the fire dwelling opens, fire service inspection, and the door to the fire dwelling opens, fire service arrival. Is that right?
02:23:00 fire service arrival. Is that right? Yeah.
02:23:00 Yeah. And does that mean that it's a foreseeable scenario that you're going to have both the stair door and the flat door open at the same time? Yes.
02:23:08 Yes. As part of firefighting activities? Yes.
02:23:11 Yes. And I think we don't need to go to it. There's a similar table in the 2015 SCA guide. Now, um you've said in your report that you can't identify any time period in the early stages of the
02:23:23 period in the early stages of the Grenell Tower fire where only the stair door was open as per the systems design condition, i.e. is designed to achieve um 2 m/s with just the stair door open. Is that right?
02:23:35 just the stair door open. Is that right? Well, they gave a more nuanced actually description than that in
02:23:41 in I'm sorry, have I lost something in that in that general? Yeah, you said ever um or some some word like that. Sorry, I might have just heard that. So I said you know in my analysis of the door openings at level
02:23:52 analysis of the door openings at level four which is in section 12 somewhere. Yes.
02:23:56 Yes. I've explained the door opening and closing scenario. Yes.
02:24:00 Yes. For the first period. And is it your view that designing a system with just one single stair door being open with all other doors being closed was an
02:24:11 all other doors being closed was an unrealistic uh design assumption to make in the context of trying to when you've made taken all your decision about your components and everything else and you
02:24:22 components and everything else and you you've um worked out how to produce an air flow through the open stair door. Anything that weakens that or causes it to reduce means that you can't meet your
02:24:33 to reduce means that you can't meet your offer design target,
02:24:37 target, right?
02:24:37 right? Yeah. So, it's common to understand classic leakage roots when they're relevant. And and let's look at um section 7 of
02:24:49 And and let's look at um section 7 of your supplemental report. It's a BLP25043
02:24:55 page 156. I just want to look at what you say at paragraph 7.1.1 onwards. So you say this, once the performance objectives have been set for
02:25:06 performance objectives have been set for a mechanical smoke ventilation system, work on the technical specification can begin. The sizing of the components as well as their fire performance are in very basic terms the means by which the smoke ventilation system can meet its
02:25:18 smoke ventilation system can meet its performance objectives. Extract rates, air flow rates, leakage areas and pressure are the primary parameters governing the selection of the systems components. The Chartered Institute of
02:25:30 components. The Chartered Institute of Building Services Engineer Sipsy um the Cibi Guide and BS5588 1998 fire precautions in the design construction and use of buildings code of practice for smoke control using
02:25:42 of practice for smoke control using pressure differentials show the significance of inherent leakage paths. International guidance such as NFPA 92 and other handbooks etc. also explain
02:25:54 92 and other handbooks etc. also explain the methods of calculation for leakage paths.
02:25:57 paths. These range from gaps around doors to more significant leakage paths from protected spaces to the exterior of a building via open doors and windows. Methodologies for calculating leakage are provided at length in these
02:26:09 are provided at length in these publications. Also the extract fan performance the required air flow accounting for leakage and the associated pressure drop in the system then guides the selection of a fan of appropriate capacity for the building.
02:26:21 appropriate capacity for the building. The mechanical engineer includes estimates for leakage, frictional losses and component losses in the calculations for the specification of the fans and other system components. So that's um
02:26:34 other system components. So that's um your introduction to why am I right to to why you say it matters that you need to do these calculations to ensure that you've taken all of this
02:26:45 to ensure that you've taken all of this into account in your selection for example of your fan. Is that right? Now um Mr. Lelay in his supplemental report um has um if you go actually it's
02:26:59 report um has um if you go actually it's conveniently set out at uh page 157 in this report
02:27:07 if you go to 7114
02:27:11 uh you can see you've quoted him and what what he says is this. He says Dr. has also been critical in her phase 2 smoke control report of the absence of calculations considering the potential impact on the system from doors to flats
02:27:23 impact on the system from doors to flats on the fire floor, including the fire flat being open at the same time as a stair door. Such criticism is however not substantiated by an explanation or analysis of the competing resistance
02:27:34 analysis of the competing resistance pathways that would occur. I have included in part two some basic flow pathway calculations which confirm that flow from the stair should remain the path of least resistance even when a
02:27:45 path of least resistance even when a flat front door is open. A similar point was expressed by Mr. Mani and his oral evidence on and then he gives the transcript reference. So um pausing there what Mr. lays done is he's
02:27:57 there what Mr. lays done is he's retrospectively carried out calculations to consider the extent to which the flow through the stair might be compromised by leakage paths including open uh flat
02:28:08 by leakage paths including open uh flat doors and and open windows out to fresh air.
02:28:13 air. And um
02:28:16 And um you say in the paragraph um paragraph 7116
02:28:21 7116 below this you say this you say these equations do not support the concept of one path of least resistance and Mr. Lay's use of this term has the potential to mislead. Mr. path of least resistant
02:28:33 to mislead. Mr. path of least resistant argument admits omits that the air flow through the open stair door will always be reduced for this system type when other leakage paths are available.
02:28:44 other leakage paths are available. Now um just to be clear what exactly do you understand Mr. later mean when he refers to the flow to the stairs being the path of least resistant when the stair and the flat door are open
02:28:58 that it's preferential somehow. All always that there's more flow going through the stair than there is the flat door. Always. Yeah. Is that path of least resistance a
02:29:09 Is that path of least resistance a technical term that is defined anywhere in relevant standards or guidance documents? Is it a concept that you've come across? Yeah, I dealt with that in my report. if you want to turn to it. Yeah. Can you just summarize
02:29:21 Yeah. Can you just summarize whether that's a concept that you're familiar with from your work? I'm familiar with it and I don't agree with Mr. Le's uh wording there as I've explained in my
02:29:33 uh wording there as I've explained in my report. Yeah. Do you consider this it's a relevant consideration when assessing the performance potential of the system at Grenell Tower? How how do you mean? So is it is it relevant to ask yourself which is the preferential path?
02:29:45 which is the preferential path? Well, you're trying to work it. That's the whole point of doing a leakage calc. You're trying to work out where the leakage paths are and therefore where the resist this you know you know what's it called sorry path of least resistance
02:29:57 it called sorry path of least resistance is
02:29:58 is right. So I mean if one wanted to use that term. So is it a fair summary of of your position that what you're saying is the key issue here is about the size of the leakage paths or spaces and how you
02:30:10 leakage paths or spaces and how you calculate those and essentially that if various doors and windows are open then this will impact on the system's ability to generate air flow through the stair and what you need to do is calculate yes
02:30:22 and what you need to do is calculate yes what you've lost. Is that correct? That's correct. Yeah. Now let let's just look in more detail at the calculations um you've carried out. Um if we can go um within this
02:30:35 out. Um if we can go um within this report to page 163 and look at paragraph 7411. So what you've done is you've taken Mr. Lay's calculations. They're set out in that
02:30:46 calculations. They're set out in that table at the top. So we see what he's allowed. He's allowed for three different scenarios with different sizes um in particular of kitchen doors [clears throat]
02:30:57 [clears throat] and flat doors according to whether they're open or closed etc. And at 7.4
02:31:05 um what you've done I think is you've back calculated from the calculations Mr. Lay's done and you think that actually the stair door should be 2.07 07 m squared when
02:31:19 door should be 2.07 07 m squared when actually he's only allowed for 1.68 m squared.
02:31:22 squared. I thought it was the other way around. If you go sorry, we go to 7.4.14. So his Yeah, I can't see. You say Mr. Lelay appears to have
02:31:33 You say Mr. Lelay appears to have overestimated the size of the door to the stair. Yeah.
02:31:37 Yeah. And overestimated the potential air flow through this leakage path. Now, um the point Mr. Lelay said yesterday is that even if you correct that
02:31:46 that Yeah. uh it makes very little difference. That's correct. Do you accept that? Yes, I do. Right. So, that's a very minor point. Is is that fair? It has a minor um impact on the result.
02:31:58 It has a minor um impact on the result. Right.
02:31:58 Right. Yeah.
02:31:59 Yeah. Um and then is it right that what you've done, if you go to the next page, figure 74,
02:32:07 74, um is you've explained in in diagram form, uh Mr. Lay's three cases. So, and you've scaled the relative openings for us in this diagram. Is that right? So,
02:32:19 us in this diagram. Is that right? So, we can see Yeah, it's it's a it's a visualization. Yeah.
02:32:23 Yeah. Yeah.
02:32:25 Yeah. Um, and so we can see the point I just made that for some of the scenarios, you've got a partial door closure. For others, you've got open doors. Yeah. I'm trying to understand it for myself.
02:32:36 myself. Yeah.
02:32:36 Yeah. And you've got a consistent sized window opening in his scenarios. Is that right? Um you I prefer to see the numbers cuz this is just a visualization but yeah from just be better to look at the
02:32:47 from just be better to look at the table.
02:32:48 table. Yeah.
02:32:49 Yeah. Yeah.
02:32:49 Yeah. And I think um we can see it if we go to page 160 of this report and I don't think there's any dispute about the methodology um between you and Mr. delay that effectively what you have to do in car
02:33:02 effectively what you have to do in car calculating these leakage paths is calculate some of them in series and some in parallel depending on the nature of the space you're dealing with. Is that right? Yeah.
02:33:12 Yeah. And if you go over the page I think Mr. Lelay said there was a helpful illustration of that calculation at figure 7.2. Yeah.
02:33:21 Yeah. Here. So for the flat, you have to take the openings in series to work out what you're getting in terms of leakage through the flat door. Yeah.
02:33:31 Yeah. You do the same for the the stair door because you've got a permanent open roof vent and then the stair door. But then in order to look at the total effective leakage area to the lobby, you then take
02:33:43 leakage area to the lobby, you then take those in parallel. Yeah.
02:33:50 And then um effectively you calculate that the majority leakage is still the stair door but there's also some leakage from the flat door. And if we could go to figure
02:34:01 flat door. And if we could go to figure 76 at page 168 of this report. What you've done here is you've come up with some other scenarios. Is that
02:34:13 with some other scenarios. Is that correct?
02:34:13 correct? Yeah.
02:34:15 Yeah. um where you provided your own calculations of the effective leakage area with some different openings assumed. Is that right? Now, how did you decide on those three scenarios? Can you help us? You've
02:34:27 scenarios? Can you help us? You've chosen three slightly different ones to Mr. Lei.
02:34:30 Mr. Lei. Yeah. So, I I looked at 1.35 m squared is the kitchen window and in the chairman's report, I think it was heard to break it. I think was about 115
02:34:44 to break it. I think was about 115 23. This is all marked up in my report. If you do you want to show the image? Yes. I think if you go to table 72 page 16
02:34:54 16 is a smaller portion of the kitchen window and then the not applicable is where I've worked out the area of window beyond which it has no further effect.
02:35:05 beyond which it has no further effect. Yes. And if we can go um to table 74 of page 170.
02:35:14 page 170. This table um sets out your calculations versus Mr. Lay's calculations. Is that correct?
02:35:20 correct? Yes.
02:35:21 Yes. And what we can see is that um the percentage flow from the leakage path. Mr. Lei has his calculations there at the bottom.
02:35:32 there at the bottom. Yeah.
02:35:33 Yeah. So for his three scenarios, the percentage flow from the flat reduces by 21% 9% 7%. But for your three scenarios, you've got them decreasing by 21% 49%
02:35:46 them decreasing by 21% 49% 55%.
02:35:48 55%. Yes.
02:35:49 Yes. Well, not not Yeah, not decreasing. Sorry, notreasing, but the understood. Yeah, different different percentage. Sorry. Different percentages. higher percentages of flow from the frat front
02:36:00 percentages of flow from the frat front entrance door leakage path compared with the stair
02:36:03 the stair Yeah.
02:36:04 Yeah. leakage path. Is that a better way of saying it? Yeah.
02:36:07 Yeah. Yeah.
02:36:09 Yeah. Um
02:36:12 now, one of the queries that's been made Yeah.
02:36:16 Yeah. um is whether you're assuming that the whole of the kitchen wall in your third scenario is missing. The whole of the kitchen wall. Yeah. If you look at page 169,
02:36:27 Yeah. If you look at page 169, no. Okay.
02:36:30 no. Okay. Where we've got your Yeah, this is a good illustration. No.
02:36:34 No. So, if we can look at figure 76 at the bottom of this um Yeah.
02:36:38 Yeah. page. Yeah. Here you've got Mr. Lay's three cases on the right in visual form and your three cases on the left. And we can see for example
02:36:48 example that all your doors are open. You haven't got any partially closed doors. Yeah. You've got a bigger window in case one, a much smaller window even than him in case two. Yeah.
02:36:58 Yeah. And then in case three, it looks like the whole wall is gone, not just the window.
02:37:04 window. Yeah.
02:37:04 Yeah. Now, um, is that right? Is that the calculation you've done to assume that the entire wall is missing? No.
02:37:11 No. Well, can you explain your case three then for us? Yeah. So, it's just a just poor visualization. I as I said I calculated we'll have to go back to do you want to show the
02:37:23 go back to do you want to show the equation of the paths in series please? Yes. So um you find that um
02:37:34 Yes. So um you find that um you you showed it to me there. Yes. Sorry I'm just a picture just before I say what I'm going to say might help.
02:37:39 help. I think it's at page 164.
02:37:46 Yeah. Sorry. No, it's earlier than that. 160. Yeah. You know that image the Is it not 7? Yeah. Here 16. Is it that is that one? Okay. Is that one in series? Yeah. So So if we blow up the bottom half of
02:37:58 So if we blow up the bottom half of that.
02:37:58 that. Yeah. So um if you take A1 as the flat entrance door, A2 as the kitchen doors I've done and then A3 as the area of
02:38:13 I've done and then A3 as the area of window that's broken because it's a one over it's a one over the square of a number one over a squared it be it eventually becomes an asmmptote. I don't know if you're familiar with this and I
02:38:25 know if you're familiar with this and I am a bit embarrassed saying this out loud actually. it becomes asmmptotic. I don't even know if that's the right phrase. And beyond four meters squared, it has no further effect on AE.
02:38:38 it has no further effect on AE. And I'm happy to I mean it I can just give you my spreadsheet if everyone can interrogate it for themselves. But beyond 4 meter squared, um no matter
02:38:50 beyond 4 meter squared, um no matter what you put in that third term, ultimately it has an almost minuscule effect on AE. Right. Okay. So, it's a a numerical thing and so it should look like 4 me squared and
02:39:03 so it should look like 4 me squared and beyond. It's not meant to be the whole wall is gone. Right. And where did the 4 me squared come from? Is that the largest the number when you when you plot out when you plot out the window changing
02:39:15 when you plot out the window changing from zero up to whatever you you see the graph turn and that's how you know. I see. So what you're saying is 4 me squared is the point at which it doesn't
02:39:26 squared is the point at which it doesn't matter how big the window and in in the old days because I'm an old lady when I had to get approval for leakage paths instead of arguing or trying to convince someone you know I
02:39:39 trying to convince someone you know I promise you this tiny piece of glass only will break in the event of a fire. You would instead agree a leakage path based on the number beyond which it had no other effect. That was the easiest
02:39:51 no other effect. That was the easiest thing to agree and that's what I used to do the old days. And if we can go to figure um 7 um six
02:40:02 And if we can go to figure um 7 um six again I think it's a page 168
02:40:13 sorry 169 maybe. Yes that figure again. Yeah.
02:40:18 Yeah. Can you just explain why you consider that your three scenarios are scenarios that also are reasonable scenarios to take into account in terms of the performance of this system?
02:40:29 performance of this system? Yeah. So I I mean I was trying to you know explain why leakage through an open flat door and a broken window matters
02:40:40 flat door and a broken window matters and then I was trying to show that the smaller the quantum of glass you know say at the kitchen or on the external wall the smaller it is you know
02:40:52 external wall the smaller it is you know the less contribution that that leakage path makes. Um that's I was trying to show the range of change it has on the leakage path through the flat door and as I said I
02:41:05 through the flat door and as I said I mean the the the big yellow box it doesn't really help understanding the one over number squared situation but you know I um and I picked sorry
02:41:17 but you know I um and I picked sorry case one is the window as it broke in the kitchen you know you can see that in my report that's the area that was the broke I think It's 115 in the chairman's report. Case two is that small piece of
02:41:30 report. Case two is that small piece of glass that's marked up in my report from the start of the fire. And then the point I'm making here for case three is that from 4 meter squared on it, it doesn't just doesn't matter.
02:41:41 doesn't just doesn't matter. Yeah.
02:41:41 Yeah. Um what the area of the window is, but where you choose a very small number for that third term in the equation um obviously it has a much bigger effect.
02:41:53 obviously it has a much bigger effect. Yeah. If we could look at page 166 and figure 75 where we see some of the markings up of Oh, yeah. Great. Thank you. Yeah. So, I think this is what you you wanted to look at.
02:42:04 to look at. Yeah. Just to try and show that they bore some resemblance to the kitchen. But remember, as a designer, you know, you don't know where the fire is going to start.
02:42:15 to start. You don't know if it will be beside one particular window or the other. And you certainly shouldn't be trying to guarantee some kind of you know impossible to promise quantum of
02:42:28 impossible to promise quantum of glazing.
02:42:29 glazing. Yes.
02:42:29 Yes. And that's why I was trying to explain about this asmmptotic condition. It's the safest route to take as a designer and with obviously some argument about obviously the the doors and if you want
02:42:42 obviously the the doors and if you want them open at a little slit or if you're prepared to accept that there are some there are reasonable cases where those doors are held fully open. Yeah. Is it your evidence that a
02:42:53 Yeah. Is it your evidence that a reasonably competent designer of these systems ought to be looking at a a best case through to a worstc case scenario as you've done in in your three cases?
02:43:04 as you've done in in your three cases? Yeah. And I think you know um Mr. Lelay touched on this as well yesterday. So there's best and worst cases when you're looking at air flow. And then as he explained yesterday, there is also best
02:43:17 explained yesterday, there is also best and worst cases when you want to look at the fire and the quantum of products it produces out in the lobby depending on the type of system you're designing. So
02:43:28 the type of system you're designing. So so it isn't just you have scenarios and you you know you resolve them for leakage. Sometimes there's other scenarios for different reasons. you also have to take due account of but for
02:43:39 also have to take due account of but for this system these these are the most important scenarios. Thank you. Yeah. Now, if we go to figure 77 of your supplemental report, so staying with this report, page 172,
02:43:52 this report, page 172, what what you've done in um sorry, 173, I beg you pardon. What you've done in this diagram 77 is you've plotted the levels on the left
02:44:04 you've plotted the levels on the left hand side and the velocity uh at the bottom.
02:44:07 bottom. Yeah.
02:44:07 Yeah. And then we've got the 2 m/s line uh identified in red. and you've plotted onto this uh the different velocities uh assuming certain things. Now the the
02:44:19 assuming certain things. Now the the gray line is actually what was measured during commissioning. So the gray line yeah so it's very important we are clear on this
02:44:28 on this each gray line is the product of a particular measurement at on some unknown date in well not an unnown date
02:44:39 unknown date in well not an unnown date in a particular set of circumstances floor by floor by floor yeah and they they that's the only commissioning data that I have available to me
02:44:50 that I have available to me yeah I think I've said the same thing as you sorry I wasn't meaning to No, that's fine. And then we've got in orange, we've got effectively Mr. one of Mr. Lay's cases, which is a flat door
02:45:01 Mr. Lay's cases, which is a flat door opening of 1.75, a kitchen door opening of 1.5, and a window opening of 0.25. Yeah, they're actually they're my three they're my three cases actually cuz you
02:45:12 they're my three cases actually cuz you know Mr. Le doesn't he has the I think from memory so I prefer to see the table his door is much the kitchen's much smaller as well I think. Yeah. And then we've got your worst case scenario which is the yellow.
02:45:23 scenario which is the yellow. Yeah.
02:45:23 Yeah. Uh which is assuming just a stair door velocity and a flat door opening and a kitchen
02:45:30 kitchen and then this this the the four this condition the four meters. Yes.
02:45:35 Yes. Yeah. Which is the maximum beyond which doesn't matter. Yeah. Yeah. I see. Now um so but it's right and the point's been made including by Mr. delay that
02:45:48 been made including by Mr. delay that for example if you look at level four even with your uh worstc case scenario the system is very close to achieving the 2 m/s
02:45:59 the 2 m/s yeah so
02:46:05 it shows that when I apply a reduction to the flow rate recorded on that day it's very close to that value recorded
02:46:16 it's very close to that value recorded on that day. But you know that I have a lot I don't I'm I don't agree that this data has been proven to demonstrate the system in
02:46:28 been proven to demonstrate the system in its very final condition before it was handed over. But on this graph, yes, it's absolutely correct. So that's for level four. But we can see as we go up, there's almost a slight
02:46:39 as we go up, there's almost a slight pattern emerging whereby the higher you go up
02:46:41 go up Yeah. Um
02:46:44 Yeah. Um it it's not so take level 23. Yeah. It's not achieving your conservative estimate.
02:46:52 estimate. Um I don't actually sorry I don't consider it to be conservative. Sorry. Yeah. You your best case of your three
02:46:58 three that the one of my scenarios. Yeah. Yeah. Um and then you can see actually I kind of wish I had presented these separately now but you can also see
02:47:09 separately now but you can also see um the way the flow rates at level three the in whatever circumstance that level three data was obtained are particularly
02:47:20 three data was obtained are particularly high and the change between um four and up and then the new floors three and down. Yes.
02:47:28 Yes. Okay. So then obviously my percentage reductions just follow that pattern. Yes. I see. Yeah.
02:47:35 Yeah. Yes.
02:47:36 Yes. And I suppose I'm bound to have to say that as a designer, you know, I have a duty to get every floor right, not hope that the one floor I may or may
02:47:47 not hope that the one floor I may or may not have got right is the floor that the fire started on. Yes, I see. Now, should PSB have carried out these kind of calculations that you I'm assuming I'm assuming that they
02:47:58 I'm assuming I'm assuming that they would do that all the time. Have you seen any evidence that these calculations were carried out on Granful Tara? No. No. Um,
02:48:09 Um, now Mr. Lei said yesterday in his evidence, well, okay, that's looking at the air flow through the sto through the stair door. Yeah. But that's ignoring other positive
02:48:20 Yeah. But that's ignoring other positive effects of this system which you've got to take into account and that includes smoke extraction, smoke dilution and the flow velocity that you might get across the [clears throat] lobby. So it's over
02:48:31 the [clears throat] lobby. So it's over simplistic just to focus on the 2 m/s. Okay.
02:48:35 Okay. Now what's your response to that? I I think that um PSB designed a system to produce a flow rate and I don't know when that flow rate was possible.
02:48:48 when that flow rate was possible. and and had these calculations been carried out by PSB and had had they got this kind of data yes suggesting that with some of the scenarios you're not achieving your 2 m/s
02:49:00 achieving your 2 m/s what would you have expected PSB to have done about that you know what what's a reasonable response by a designer if you get this kind of data once you've done
02:49:11 get this kind of data once you've done your calculations uh I I don't really know what you So assuming you mean if they got these answers or do you mean they did their calcs? They put assume they've done the calculations and
02:49:22 assume they've done the calculations and they've worked out that for some of the levels with certain scenarios you might not get your 2 meters per second. Yeah. Well, they'd have to go back and look at all sorts of different parameters and work out how to
02:49:34 parameters and work out how to Yeah. And and what would be the the the top three things you would be going then to look at in your system? Well, you know, it all at the end of the day, it all comes down to what the performance
02:49:47 all comes down to what the performance of your fan is. And the we're back to pressure drop, the fan performance, and trying to overcome any resistances, including these leakage paths so that
02:49:59 including these leakage paths so that you can get your the right velocity through the stair door. Uh I'm I'm not an expert in twiddling around with the systems on, you know, I'm not an expert in that. Yeah. And is
02:50:10 I'm not an expert in that. Yeah. And is one of the reasons you say that your scenarios are more realistic that that's what you would expect during firefighting operations to have doors fully open because Mr. Lei had some
02:50:21 fully open because Mr. Lei had some doors that were partially closed and he made the point for example that the kitchen door would close in a certain direction and that might mean it's less likely to be fully open. I so I understand all of that. So we're
02:50:32 I so I understand all of that. So we're applying knowledge of what happened the night of the fire. Okay. We I'm looking at designing a system when you don't know what's going to happen. You don't
02:50:43 know what's going to happen. You don't have the lux well luxury is a terrible word. You don't have the benefit of knowing what may happen in the event of a fire. You've to design your system so it can do what you're saying it's going
02:50:55 it can do what you're saying it's going to do for a reasonable range of scenarios. And that's how I've gone about this. I understand that Mr. and others are really focused on the night of the fire only and those parameters
02:51:09 of the fire only and those parameters and what that might mean. I'm looking at this as a a system and there was a duty to design it and how one goes about
02:51:20 to design it and how one goes about doing that and it's a I think that's a really important distinction retrospectively trying to work out the consequences of that design in the really specific
02:51:33 that design in the really specific circumstances that we may or may not be able to derive the night of the fire. I see it as two totally different things actually.
02:51:41 actually. So does it follow that um you don't accept that it's acceptable for example to look at level four here and say well we've got hang on we've got almost 4 and a half m/s
02:51:53 almost 4 and a half m/s through the stair door at level four and if we even if we have that and assume we only get half of that we're still almost at 2 m/s that that point's been made by
02:52:04 at 2 m/s that that point's been made by Mr. and it's been made understood and actually one of the main reasons why I did this work was actually because of an exchange the chairman had with Miss Menses about this data and I
02:52:16 with Miss Menses about this data and I thought it was an extremely important exchange because the presumption was this data represents the system I'm going to call it the at the moment of
02:52:27 going to call it the at the moment of handover when absolutely everything was finished everything had been tweaked and balanced the final set of appropriate cause and effect testing had happened and there was a moment in time when you
02:52:40 and there was a moment in time when you go this is my data that is the actual purpose of commissioning by the way that I could take that data out now and say to you these gray lines represent the
02:52:51 to you these gray lines represent the system as I as I designed it and we we can't say that if we could I'd be happy to have a a bit of an argument maybe if someone was asking me my opinion about
02:53:04 someone was asking me my opinion about the events of the night. I'm giving my opinion on a design and whether or not it met the functional requirements of the building regulations. Okay.
02:53:13 Okay. Okay. I hope that's probably a bit rambly, but I think so. Can I look at um Mr. Lay's recent statement? It's a LA703 at at page 14.
02:53:28 And I want to read to you what he said at paragraph 70 and 71. He says in her report, Dr. Lane refers to reports produced by cult which relate to the
02:53:39 produced by cult which relate to the protection of stairs by a smoke control system similar to the system by which I mean they employed extraction from the lobby with inlet via the stair. As noted in Dr. Lane's report, the cult reports were relied upon for smoke control
02:53:51 were relied upon for smoke control system designs in residential buildings. The cult report states that protection to the stair was achieved when the mass flow rate drawn through the door when their smoke control system design was
02:54:02 their smoke control system design was operating was 1.9 kg/s which for ambient air through a 1.6 m square single leaf door opening would equate to a flow velocity of 1 m/s. Yeah,
02:54:12 Yeah, this matches the velocity shown in the computer modeling images in the report. And then he goes on. He says, "Hence either a flow velocity significantly less than 2 meters/s alone can prevent
02:54:24 less than 2 meters/s alone can prevent smoke movement to a stair or a lower flow rate in combination with the other mechanisms extraction and dilution can achieve a combined effect which results in a lower flow velocity being necessary
02:54:37 in a lower flow velocity being necessary to protect the stair. My my experience suggests that the latter is the case. But I think what Mr. lay saying is that based on a lot of information that others have have done other studies that
02:54:50 others have have done other studies that have been done on similar systems in fact as long as you're getting one meter per second through the stair door that's that's enough and it's going to give enough protection to the stair
02:55:02 enough protection to the stair but what's enough you know so the code report actually I don't have it to hand and I certainly don't know it off by heart but there's a reason why it goes on to recommend a higher
02:55:13 on to recommend a higher flow rate. And I think the big difference here, and I don't know that I need to go on about it so much, is Mr. Lei is trying to justify the performance observed on the night of the fire. I'm
02:55:25 observed on the night of the fire. I'm giving my opinion on the system as it was designed. Okay. Okay. It is of course obvious if you get some kind of flow rate through the stair
02:55:37 some kind of flow rate through the stair door, it might do something. But that's I I'm I'm looking at what the design the design set out to do something and I'm explaining what I have found about
02:55:49 explaining what I have found about whether or not it it it was it actually was designed that way. Okay. Okay.
02:55:55 Okay. I understand. Well, well, actually this whole thing about what actually happened on the night of the fire is quite dangerous territory to get into because there's so
02:56:06 territory to get into because there's so many parameters that may or may not have impacted that system. Um, yes,
02:56:13 yes, that we start to talk about surely it gave us 1 m/s and that was fine. Okay.
02:56:18 Okay. Okay. But Colt actually went on to up increase that parameter [clears throat] and I'll I'll check the report at lunchtime. Yeah. Okay. Now, one point I want to put to you is that we know that
02:56:30 want to put to you is that we know that what Mr. Manne did was he worked out what he needed the extract rate to be. He said he needed that to be at 3.2 m/s and then he added based on his extensive experience, he added 50% for leakage to
02:56:43 experience, he added 50% for leakage to be added to that and that get gets you to 4.8 and in fact the fans were rated to provide 5.6 six um cubic meters uh extract the the the
02:56:56 um cubic meters uh extract the the the south fan gave you two uh cubic meters per second and the the the north fan at high level gave you 3.6 hence 5.6. Now why isn't that an
02:57:08 hence 5.6. Now why isn't that an appropriate way of doing this? Mr. Man is clearly experienced in these systems. Uh he he he obviously has has experience to draw on. Why isn't it acceptable for someone in that position using that
02:57:20 someone in that position using that experience to to to add on something like 50% for leakage and then ensure that your fans can can give you the air flow that you need that way.
02:57:31 need that way. Yeah. But that's leakage innate in the building construction. You know the build I pres like so I don't know how Mr. Mahoney quantified
02:57:45 don't know how Mr. Mahoney quantified all the different things that cause resistance in his system. Leakage through the builder's work shafts, you know, twists and turns. I I don't know how he did that. It's normal to have
02:57:56 how he did that. It's normal to have that set out. Um when he said he factored it up for leakage, I understand that. I don't know how he satisfied himself that for Grenful Tower that was sufficient. Do do you ever
02:58:09 that was sufficient. Do do you ever think though it's it might be reasonable to rely upon somebody's extensive experience in in just instinctively knowing how much leakage you need to allow for with
02:58:20 much leakage you need to allow for with these systems. But we have to be careful about which leakage we're talking about. Okay? Because there's leakage through all different routes. And I don't know if when he factored things up, he had already worked out from his last job
02:58:31 already worked out from his last job that he knew about leakage through a broken window. I haven't seen anything like that. and instinctively knowing how a complicated smoke control I think you're asking me if that's a reasonable
02:58:43 you're asking me if that's a reasonable design or reasonable professional behavior is yes I am I am well I don't think so I don't think so I think I've made that perfectly clear instinctive I have all sorts of
02:58:54 instinctive I have all sorts of instincts and I'd imagine that lots of them end up being terribly wrong you know we as designers you have these duties under multiple regulations if nothing else where the obligation is to
02:59:06 nothing else where the obligation is to demonstrate, you know, this was an existing building with
02:59:12 with all different characteristics and one needed to work out if they were being incorporated into the design for the tower. Okay. And I don't know how
02:59:24 the tower. Okay. And I don't know how you do that instinctively. Okay. Just one final short point before we break. Um Mr. also said that you might have got your stair vent size wrong in that you'd assumed 1 m squared
02:59:37 wrong in that you'd assumed 1 m squared and he thinks it might be bigger. Is that something that you um can respond to? Have you had a look at that? Uh no, and I won't be looking at it either. Yeah, because
02:59:47 because Well, because I mean I think I don't know when we checked that on site. We checked the drawings. Uh I don't know why he's decided it's bigger. [clears throat] Okay.
02:59:56 Okay. And as far as I'm aware, I'm finishing my work today. Okay. So, do you do you accept that you might have got the stair vent size wrong?
03:00:03 wrong? Well, I'm surprised no one's noticed it in the last 5 years. And if he could just mark up maybe he did this. Did he show a marked up drawing or something? No, he he just said she's assumed 1 m square and it's bigger.
03:00:14 square and it's bigger. Well, if he wants to pop along a drawing with the incorrectly measured stair vent onto it. I'll have a quick look at it. No problem. Okay. Thank you, Mr. Chairman. I think that's a good moment for our lunchtime break.
03:00:25 break. Yes. So do I. Thank you. We'll stop there for lunch. We'll resume at 2:00, please. And again, no discussing of your evidence. Yeah, no problem. Thank you very much.
03:00:40 Thank you, Miss Graange. 2:00, please. Thank you.