Expert Evidence - Professor Bisby (21 November 2018 Pt 1 of 2)

Full transcript

00:06:02 good morning everybody welcome to today's hearing they're going to hear some more expert evidence about fire development and related topics yes good

00:06:14 development and related topics yes good morning Janet good morning mr. chairman I'm now going to call Professor Luke Bisbee please good thank you

00:06:32 I do solemnly sincerely and truly declare and affirm that the evidence I

00:06:47 declare and affirm that the evidence I shall give shall be the truth the whole truth and nothing but the truth good thank you very much professor sit down make yourself comfortable man yes sir

00:06:58 sir good morning professor Bisbee good morning can I ask you please to give the inquiry your full name my name is Luke Alexander Bisbee thank you now you have provided to the inquiry a preliminary or

00:07:10 provided to the inquiry a preliminary or interim phase one report dated the second of April 2018 I'll just give the reference to that that's lby are six zeros one with an accompanying video

00:07:21 zeros one with an accompanying video showing vertical flame spread on the east elevation of the tower at 2lb why are two I'll skip the six zeroes for convenience and you've I think now

00:07:32 convenience and you've I think now updated that report in a revised version dated the 21st of October 2018 is that right that's correct can that please be shown that lby s60 is won at page one is

00:07:49 shown that lby s60 is won at page one is that the first page of your updated report yes is that signature yours it is now you summarize the main updates that you've made at paragraphs 24 to 28 and

00:08:00 you've made at paragraphs 24 to 28 and I'm just going to summarize them aloud to you and see if you agree that my summary is accurate first an update to or to your original flame spread video yes and for new videos showing

00:08:13 yes and for new videos showing horizontal flame spread on the east north west and south facades of the tower that's correct and those are I think lby s three four five and six in each case preceded by

00:08:26 five and six in each case preceded by six zeros you also I think provided new updates on vertical and horizontal fire spread correct testing of hypotheses based on new evidence that's come to

00:08:37 based on new evidence that's come to light since April this year revisions of the hypotheses yes yes and I think you've updated your opinions to take account of ingress of fire and smoke taking account of the

00:08:48 fire and smoke taking account of the evidence from the bereaved survivors and residents I've added a new section yes thank you

00:08:54 thank you turning to the scope of your work briefly if I may your phase one report as we now have it sets out your preliminary conclusions on two main things is this right first of all the

00:09:05 things is this right first of all the ignition of the facade of the building correct and secondly fire spread - on a - and on the exterior of the building that's right now you've also been

00:09:19 that's right now you've also been instructed to provide a further report at Phase two of this inquiry and just correct me if I'm wrong about this but summarizing them that we'll cover first of all your final conclusions about fire

00:09:30 of all your final conclusions about fire spread - and over the exterior of the building yes secondly performance of the materials which formed part of the exterior of the building yes thirdly their respective

00:09:43 building yes thirdly their respective contributions if any to the spread of fire which would include I think is this right a review of testing by the BRE and other relevant testing bodies and also a review of the standard testing regime

00:09:56 review of the standard testing regime yes that's correct you're going to do that to the extent that we that we can yes to the extent that you can yes of course fourthly I think is this right you're also going to look at any issues relating to the mechanical response of

00:10:07 relating to the mechanical response of the reinforced concrete structural frame if relevant that's correct and finally recommendations about what if any changes could be made or should

00:10:18 if any changes could be made or should be made to the regulatory regime and Industry practice to prevent a similar incident from ever happening again in the future correct thank you very much now in your

00:10:29 correct thank you very much now in your report at section 1.2 this is page 12 you I think have summarized the structure of your report if we can please have that on the screen and

00:10:42 please have that on the screen and you've set out there and we can see it how you've organized your report running from a paragraph 70 section to technical

00:10:55 from a paragraph 70 section to technical background to paragraph 75 section 7 ingress covering geometry materials fire spread and spread over cladding in between at section 8 and at section 9 I just run

00:11:14 section 8 and at section 9 I just run into section 9 I think first of all you've set out your future of work as proposed for phase 2 and that's paragraphs 12:43 to 12 63 at page 2 6 4

00:11:31 paragraphs 12:43 to 12 63 at page 2 6 4 and just have that on the screen please

00:11:36 so just so that's there now you've I think set out also in your report a declaration at paragraph 90 if you can turn back to page 14 and I just want to

00:11:55 turn back to page 14 and I just want to make sure that you confirm these here now

00:11:59 now paragraph 88 89 and 90 and 90 and indeed 91 on pages 14 and 15 under the heading 1 point 6 statements can you confirm that those are

00:12:12 can you confirm that those are paragraphs which you stand by today yes thank you very much now at section 1 point 4 of your report at page 13 and

00:12:23 point 4 of your report at page 13 and I'm sorry to ask you to jump around a little bit you've set out at your relevant experience and qualifications and I'm not going to go through all those today everybody can look at those if they want to but can I just pick out

00:12:35 if they want to but can I just pick out of just one or two bullet points from them so that people in the room and watching us today can hear from you some elements of your your experience it's

00:12:46 elements of your your experience it's right isn't it that you are currently professor of fire and structures within the School of Engineering in the University of Edinburgh that's correct and you were formerly I think the head of research institute for infrastructure

00:12:57 of research institute for infrastructure and environment and royal academy of engineering research chair as well that's correct you are I think co-editor-in-chief of the fire safety Journal yes and you have I think extensive

00:13:09 and you have I think extensive experience of engineering research and consultancy of university teaching and promotion of public understanding of science and engineering that's correct you're a chartered structural engineer in the UK yes and a

00:13:22 structural engineer in the UK yes and a licensed professional engineer in Canada correct you are I think a fellow of the institution or Institute of fire engineers and the institution of structural engineers the International

00:13:33 structural engineers the International Institute for FRP and construction and institution of Engineers and shipbuilders in Scotland correct and I think you've got a number of awards for your commitment to high quality

00:13:45 your commitment to high quality engineering research and education and your dedication to the broader academic and research communities it spread to two general questions professor are the

00:13:56 two general questions professor are the factual matters that you set out in your report

00:13:59 report true to the best of your knowledge and belief they are does your report accurately set out your opinions on matters in respect of which you have been asked it does thank you now just to

00:14:15 been asked it does thank you now just to summarize where we've arrived at today with your evidence so far we've seen already that you provided a first report or preliminary report to the inquiry in April this year on the 20th of June this

00:14:28 April this year on the 20th of June this year you gave a presentation to the inquiry based on that report and you remember that of course yeah and people can see that if they want to and that presentation focused just to summarize

00:14:40 presentation focused just to summarize it in parts on concepts of flammability and fire spread and the different construction materials present on the facade of the building that's right and this is a continuation of that evidence

00:14:53 this is a continuation of that evidence is that right correct yes now I'm not going to go over the entirety of the detail that you've covered in your presentations in the past or indeed in this report but I am going to ask you

00:15:04 this report but I am going to ask you about a number of things first so you know where we're going a some questions about the materials installed on the facade and their performance in a fire and also your conclusions on fire spread

00:15:18 and also your conclusions on fire spread out of the compar and over the building and back into flats okay and I'm going to ask you to explain some of the aspects in which you've updated your sat your your earlier report now

00:15:32 your sat your your earlier report now I'm not going to ask you just so that we're clear about the cause and origin of the fire because that's been dealt with by professor Nev Nick Dade and dr.

00:15:43 with by professor Nev Nick Dade and dr. Glover but your conclusion if I can just look at that with you is at paragraphs 12 12 to 12 16 of your report which is

00:15:54 12 12 to 12 16 of your report which is at page two five nine if we can please have that on the screen

00:16:12 and at paragraph 8.1 you have summarized york or set out your preliminary

00:16:24 york or set out your preliminary conclusions at twelve twelve to twelve sixteen there and you say in twelve twelve that there is a high level of evidence to support the hypothesis that the fire started somewhere between the

00:16:37 the fire started somewhere between the edge of the cooker and the kitchen window in flat 16 and provided a figure now you may well label you now have a report from dr. Glover and we'll be hearing from him and professor Neve Nick

00:16:50 hearing from him and professor Neve Nick Dade it was also going to come to give evidence but in general do you agree with professor Nick Neve Nick Dade and dr. Glover's opinions on matters of cause and origin to the extent that I'm

00:17:03 cause and origin to the extent that I'm sufficiently expert in cause to agree then yes I do right and your report in

00:17:15 then yes I do right and your report in general again for clarification represents your initial conclusions on ignition of the facade and spread up the building based on the evidence that we have to date correct and I think it's

00:17:28 have to date correct and I think it's right that you expect to carry out further research and testing later in order to firm up your conclusions so as to be ready for Phase two you need yep and at this stage are you

00:17:40 you need yep and at this stage are you able to express any firm conclusions about the relative contributions of different materials on the facade to the rate and the extent of fire spread I think qualitatively yes in some cases

00:17:52 think qualitatively yes in some cases quantitatively is quite difficult right now I'm going to ask you please now to go to page 74 of your report and look at paragraph 290 and I'm going to ask you

00:18:06 paragraph 290 and I'm going to ask you one or two questions next about the familiarity that you have with the building after the fire so page 74 and

00:18:23 building after the fire so page 74 and at paragraph 290 and following you set out a summary of the materials and products presented in this section and

00:18:37 products presented in this section and you explained those and that's to 9 1 you say there were 6 unaccompanied post fire inspections of grenfell tower that I conducted the details of which provided in Appendix A of this report

00:18:50 provided in Appendix A of this report and then you said to 9/5 you say that you have not personally undertaken an exhaustive physical posts fire survey of the entire exterior or interior of all

00:19:01 the entire exterior or interior of all compartments of Grenfell tower that works been undertaken in part by inquiry expert dr. Barbara lanes team and also by the bre forensic team with an on and

00:19:13 by the bre forensic team with an on and on behalf of the MPS um just so that we can understand what investigations of the facade did you undertake at the tower during your visits so I have on

00:19:24 tower during your visits so I have on several occasions initially I went to the tower when there was no scaffolding external to the tower so we undertook investigations internal to the tower and

00:19:35 investigations internal to the tower and could only see the exterior of the tower bites from leaning or looking out the windows of the tower at that time subsequently we went back on several occasions once the scaffolding was in place and those specific occasions are

00:19:47 place and those specific occasions are listed in the noted table in the appendix and walk the scaffolding to the extent that we were permitted to typically based on health and safety considerations on site so I have on the

00:19:58 considerations on site so I have on the three or four occasions visited the exterior of the building at the lower levels say levels three through five or six on one occasion I walked every level of the building on the scaffold from bottom to top full perimeter up and down

00:20:12 bottom to top full perimeter up and down and then I've been back on two separate occasions to inspect the details of the architectural crown at the top of the building on two separate occasions that's correct and now in paragraph two nine fibers

00:20:25 and now in paragraph two nine fibers we've got there on the screen you refer to the work undertaken by dr. Lane have you relied on dr. lanes

00:20:37 you relied on dr. lanes survey of the building in any way in your work I think the only place where I've relied that uniquely on dr. lanes work would be in the identification of a

00:20:49 work would be in the identification of a specific product called pearl board where during her surveys she was able to identify the specific manufacturer of that product via some photographs that are in her report and so I relied on that as a

00:21:00 and so I relied on that as a confirmation of the supplier of those materials but I think it's probably the only specific location what I've done that here I see thank you well we'll come to pearl board later on and I think

00:21:12 come to pearl board later on and I think you were also present when cladding was removed by the police that's correct on two separate occasions yes and is it also right that you looked at cladding

00:21:23 also right that you looked at cladding removal photographs which were provided by the police that's correct yes some 12,000 photographs are you satisfied in your mind that these sections of cladding that you observed being removed

00:21:34 cladding that you observed being removed from the building were properly representative of the materials and the construction of the cladding over the whole building to the extent that it's possible to conclude that given that

00:21:45 possible to conclude that given that much of the cladding was destroyed in the fire and so it you know it's impossible to know with with certainty but I have no reason to suspect that there was significant variation yes and breaking that answer a little bit down a

00:21:57 breaking that answer a little bit down a bit more were you able during your work to consider or calculate the volume of different materials making up the facade that were just number one installed

00:22:11 that were just number one installed we've actually been stalled there I mean I've not done those calculations myself it would be possible based on the geometry of the cladding system to do that we have a sense of the respective

00:22:22 that we have a sense of the respective quantities of different materials from purchase orders and materials supplied to site but obviously we couldn't confirm definitively that the materials that were

00:22:31 that were purchased or sent to site were actually installed right will it follow from that answer that you were also not able to calculate or consider the volume of materials that disintegrated combusted

00:22:42 materials that disintegrated combusted melted or fell off during the fire that's correct only sort of in an approximate way by surveying the visual appearance of the building and I have done that that that

00:22:53 building and I have done that that that was that was my reason for wanting to do a walk of the full extent of the tower just to get a sense of the extent to which the insulation materials in particular we're still present and

00:23:04 particular we're still present and another means that I've used to try to develop that information is looking at all of the drone photos that were taken on various instances by various parties of various stages immediately after the fire and then during the months

00:23:15 fire and then during the months following the fire were you able to analyze of the material that remained on the building at the moment the fire was

00:23:26 the building at the moment the fire was extinguished what was later removed from the building as opposed to what remained on it I mean that was my that was my rationale for looking at the drone photos and requesting additional drone

00:23:38 photos and requesting additional drone photos to the extent that I could get my hands on them right it's very difficult immediately after the fire my understanding was that there was some health and safety concerns about debris continuing to fall off the building so loose debris and that some crews were

00:23:51 loose debris and that some crews were sent up in a basket and were pulling some of the loose materials off the building and that we may not have that information recorded in the drone photos that are available to us so I think in

00:24:02 that are available to us so I think in general yes that information is at least visually available through the drone photos with some caveats about some uncertainties and that is some work that we do intend to do it phase two I'm to

00:24:13 we do intend to do it phase two I'm to try to get a sense of the amount of insulation that was consumed in the fire in particular thank you and were you able to undertake any kind of analysis

00:24:25 able to undertake any kind of analysis or investigation into the depth and extent of charring of the insulation which was left behind on the building after the fire beyond a cursory visual

00:24:38 after the fire beyond a cursory visual examination no nothing systematic right would such an analysis have helped you in your conclusions that you've arrived at in your report I mean I think

00:24:51 arrived at in your report I mean I think it would be it would be interesting information to have one of the issues with that is is that the reason that I give in my scope of work the reason that I would be interested in the answer to that question in terms of charge eps and

00:25:03 that question in terms of charge eps and the amount of insulation remaining is that one of the questions that i'm interested in is the extent to which the predominantly PIR insulation within the cavity will have contributed to the fire spread mechanisms that we observe on the

00:25:14 spread mechanisms that we observe on the building one of the challenges with the using char depth or the amount of material remaining in that context is that we know that after the fire front past the particular location on the

00:25:25 past the particular location on the building we had the significant number of compartment fires burning within the building as a consequence of the ingress of the fire into the building and the consequence of those compartment fires is that you have fires venting from the

00:25:36 is that you have fires venting from the windows with significant external heat flux is applied to the insulation now that will continue to burn and char the PIR in the regions around the windows but that burning and charring of the PIR

00:25:47 but that burning and charring of the PIR is so far behind the fire spreads that led to that that it isn't telling me anything useful about the contribution to the fire spread mechanisms so whilst

00:25:58 to the fire spread mechanisms so whilst it's interesting I don't know I haven't looked at it yet and thought that that detailed about what information is available to us which is the topic we've been leaving for phase two I wouldn't be

00:26:09 been leaving for phase two I wouldn't be able to say how useful it would be I think it'd be interesting I don't have a huge amount of optimism that it's gonna be particularly instructive as regards fire spread mechanisms thank you now I

00:26:20 fire spread mechanisms thank you now I won't turn to a different topic namely materials which were to be found on the facade in your report you have identified a number of materials present

00:26:31 identified a number of materials present on or within the facade of grenfell tower following the refurbishment and I'm going to ask you a number of questions about how those materials behave in a fire starting if I can with

00:26:43 behave in a fire starting if I can with the rana bond 55 PE that now can we begin please by going to page 78 of your report

00:26:54 and on that page we have a table table to which is entitled if we can just have that highlighted ACM product variants

00:27:07 that highlighted ACM product variants used in Granville tower refurbishment all at four millimeters total thickness and there are three products set they're set out with their different finishes

00:27:20 set out with their different finishes and colors as you can see and in the in the table you identify in the last column that the PE color that polyethylene color is different between

00:27:31 polyethylene color is different between column panels and some of the spandrel panels I think first of all is that am i right to identify that difference that's right the polyethylene in one case is

00:27:42 right the polyethylene in one case is sort of a clear translucent and the other case is black right and you say later in your report and I'll just give you the reference it's page 77 paragraph three one four there's no need to go to

00:27:53 three one four there's no need to go to it the testing is underway to establish whether there are any significant differences in terms of the fundamental material and reaction to fire properties

00:28:04 material and reaction to fire properties at this stage professor do you know or can you say with any confidence whether the different core color has any bearing on fire performance we've been doing thermo gravimetric analysis and

00:28:17 thermo gravimetric analysis and differential scanning calorimetry on those two core materials which are essentially tests to characterize the way these particular core materials respond to heating and looking for signatures that would indicate some

00:28:28 signatures that would indicate some differences between the two of them we've not found anything yet that I would consider significant as regards the performance of these materials and are you going to consider it do it continuing those tests of course yes and

00:28:39 continuing those tests of course yes and will you be able to report on that a phase two was built to report on that very early in phase two yes very good did the pattern of fire spread that you've observed from your visits to the

00:28:52 you've observed from your visits to the tower and from the flame spread videos that you've presented indicate the possibility beyond the negligible of any significant difference between these two colors of polyethylene

00:29:04 colors of polyethylene no I haven't observed anything that would lead me to believe any significant differences now I don't think in your table here which we can have back up

00:29:15 table here which we can have back up again table to page 78 you've identified anything on the surface of the aluminium but have you identified whether the ACM

00:29:26 but have you identified whether the ACM contained a powder coating on the surface I'm the the the the color of the external finish I'm not sure and if I'm

00:29:37 external finish I'm not sure and if I'm not sure if that is a PPC or powder coating

00:29:40 coating [Music]

00:29:41 [Music] aiiow Majan that the purchase orders would specify whether or not that is the case but you don't you haven't looked at that i'm the nature of the the painting

00:29:52 that i'm the nature of the the painting of the of the panels it's not something i've looked at specifically okay and again would that be something you're going to look at a Phase two I mean I hadn't I hadn't planned on it because I didn't observe any sort of surface effects on the exterior of the aluminium

00:30:04 effects on the exterior of the aluminium either during the fire or in any of the testing that we've done for instance cone calorimeter testing looking at our response to heat flux right so without any compelling reason to do so I wouldn't intend to there is a compelling

00:30:15 wouldn't intend to there is a compelling reason I would love to hear it okay well that leads me to this question what would in your experience would have powder-coating if there was one have had any impact on the spread of fire in terms of Splendor heat transfer I think

00:30:26 terms of Splendor heat transfer I think it I think it's hard to say I wouldn't expect a significant difference there are powder coatings tend to be very thin so the the mass of material is very small it could potentially have a minimal impact but I wouldn't I wouldn't

00:30:38 minimal impact but I wouldn't I wouldn't expect anything significant leaving aside powder coating on the surface have you identified whether these panels had any any adhesive between the aluminium

00:30:51 any any adhesive between the aluminium skin and the polyethylene filler or core I mean the product information for this specific product that indicates that the the aluminium skins if you like are

00:31:02 the aluminium skins if you like are bonded to the PE filler via a thermal bonding process I'm not entirely sure how that works or what that is but given

00:31:14 how that works or what that is but given that it's a thermoplastic material at the core

00:31:15 the core expect that would that would mean that you heat the thermoplastic so that it softens about on its surface and you bond the aluminium to it in that context and once it cools you have a bond but I've not been able to confirm that fine fine thank you can I just

00:31:27 fine thank you can I just are you finding this a bit difficult

00:31:31 I'll do my best yeah sorry sorry it's it's the way I am I apologize it's perfectly fine a

00:31:42 I apologize it's perfectly fine a paragraph for three one of your state of your report if I can please ask you to go to that it's a page a hundred you you

00:31:56 go to that it's a page a hundred you you say there the fact that thermoplastic polymers such as PE present particularly challenging behavior as regards his

00:32:07 challenging behavior as regards his reaction to fire has been well known and documented for decades and this fact therefore cannot in my opinion be considered at all surprising by any competent fire safety professional and

00:32:19 competent fire safety professional and then you go on at paragraphs four three two two four three four to identify what you described in the second line of four three two as decades old literature

00:32:31 three two as decades old literature being available and in four three three you identify and paper a paper written

00:32:42 you identify and paper a paper written in 1975 by murti and by murti Connery is that a partnership or is that absurd an individual that's co-author and is that the earliest date at which these issues

00:32:53 the earliest date at which these issues were documented or is there even earlier reliable literature there is even earlier commentary in the literature but those are some of the earliest papers that we could find that we're

00:33:04 that we could find that we're specifically dealing with polyethylene there are there's a little considerable earlier work looking at thermoplastics in general and in the next paragraph paragraph 434 you refer to the work of

00:33:15 paragraph 434 you refer to the work of Kherson and Pyun i think it is or maybe peon

00:33:20 peon matters for taking those two together the 1975 or 1976 work would that work be in particular be specifically known to

00:33:31 in particular be specifically known to competent fire safety professionals I would be surprised if most fire safety professionals a competent or otherwise we're specifically aware of those two papers but what about the principles in

00:33:43 papers but what about the principles in them I mean I think that the the general principle that a thermoplastic will melt and drip and burn quite vigorously is very clearly highlighted in any of the

00:33:54 very clearly highlighted in any of the reference text that one would expect a confident fire safety professional to have at least skinned if not know quite well so for instance Dougal Drysdales book on fire dynamics or the SFP handbook would be would be references

00:34:06 handbook would be would be references where they clearly highlight the risks associated with these materials and I would certainly think it reasonable to expect fire safety professionals to have some awareness of those references yes but if we can then turn to the next

00:34:17 but if we can then turn to the next paragraph of your report for 35 and have that on the screen and identify it you actually pick up your reference there to the SF PE handbook of fire protection engineering my question there is and you

00:34:31 engineering my question there is and you can you identify that I think in the footnote it was published in 1988 doesn't say say there is it fair to say that since 1988 there has been a

00:34:42 that since 1988 there has been a recognized body of opinion on the dangers of thermoplastic materials from a fire safety perspective absolutely now

00:34:53 a fire safety perspective absolutely now I want to turn to the details of the properties of polyethylene at page 101 of your report now at that page just

00:35:04 of your report now at that page just over the page you've set out table three and you've selected there as we can see the typical properties of low-density polyethylene and we can note the melting

00:35:18 polyethylene and we can note the melting temperature of polyethylene at 130 to 135 degrees centigrade and the surf and the surface temperature at ignition

00:35:30 the surface temperature at ignition which is the last but one entry at 377 degrees centigrade it is there any data about the time to ignition of

00:35:42 about the time to ignition of polyethylene I mean yes there will be Studies on the ignition of polyethylene which is where some of these data for instance surface temperature at ignition will come from one of the one of the

00:35:54 will come from one of the one of the issues with polyethylene is the with the orientation of the sample and the way that the fuel responds to heating and that it does melt and drip so it will depend on the particular configuration right can you give us a sense of time to

00:36:13 right can you give us a sense of time to ignition for low density polyethylene I mean I mean I will depend on the heat flux that you apply to it so you see in the table table three critical heat flux before polyethylene is listed at 15

00:36:26 before polyethylene is listed at 15 kilowatts per meter squared so that is that is the heat flux if you had a lower heat flux than that and you were to test it I presume that reference is using testing and what we call a cone calorimeter so a heat flux less than 15

00:36:39 calorimeter so a heat flux less than 15 kilowatts per square meter will not result in ignition of the sample within a defined period a period of minutes higher heat fluxes would cause ignition

00:36:51 higher heat fluxes would cause ignition but eventually the higher that heat flux the faster will ignite yes and are you able to give us a clue about its thermal inertia its thermal inertia is

00:37:05 inertia its thermal inertia is comparatively high in comparison for instance to a polymer insulating foam all right one of the reasons I've presented the data in these tables it's probably worth me mentioning it's not

00:37:17 probably worth me mentioning it's not because they necessarily represent definitive values in all cases for materials if we had additives or fillers or fire retardants we might get slightly different values so these are sort of ballpark reference values that I've

00:37:29 ballpark reference values that I've placed in the report to give an overview of the kinds of behaviors we can expect and the key thing to recognize there is that the thermal inertia of the polyethylene illidan's polyethylene you can see 0.43 yeah and

00:37:41 polyethylene you can see 0.43 yeah and you compare that to for instance PIR bottom of the same page point zero six yeah the the key message to take away from that is that there's an order of magnitude difference in the thermal inertia of those two materials and that's why I've presented themselves so

00:37:53 that's why I've presented themselves so I think it's important that we not focus on the actual values but we focus on the comparative nature of the values and that's why they've been presented and I should also points out that the work

00:38:04 should also points out that the work that we're doing at Edinburgh now is seeking to characterize specifically to the materials at Grenfell tower what these values are so for the actual materials that we have on site like

00:38:16 materials that we have on site like Renfield Tower say it will report that early in phase two thank you now I'm still focusing on PE as to the heat release rate which i think is good the

00:38:27 release rate which i think is good the rate at which any energy releases per unit time as a material burns expressed in watts kilowatts on anok megawatts you you've set out in your report that the

00:38:39 you've set out in your report that the heat release rate can be extrapolated to quantify a fire will quantify the size of any fire is that right yes and I mean that's typically how we quantify the

00:38:50 that's typically how we quantify the size of a fire yeah and it's I think it's for reference it's footnote 12 in your report on on page 23 we don't need to go to it my question is this knowing the approximate quantity and maybe this

00:39:02 the approximate quantity and maybe this is the problem but tell me knowing the approximate quantity of polyethylene in panels which were used on floors four to twenty three of the building are you able to quantify the size of the

00:39:13 able to quantify the size of the resultant fire no because it will depend on the amount of the material that's burning at any given instant in time so the more material that's burning the more heat release you'll get the less

00:39:24 more heat release you'll get the less material the less he release and so it's it's gonna be dependent on the the time at which you ask the question so early on the fire is gonna be quite small yes at some stage the fire is a very very

00:39:35 at some stage the fire is a very very very large fire to quantify that in any cut in any way that I would be able to defend scientifically it would be very difficult thank you now at paragraph

00:39:48 difficult thank you now at paragraph four six one just moving ahead if I can we come to section 4 point 12 this is page 104 where you deal with aluminium

00:40:01 page 104 where you deal with aluminium and its reaction to fire and you say upon exposure to heat aluminium will melt at approximately six hundred and sixty degrees centigrade now first does

00:40:15 sixty degrees centigrade now first does the physical evidence that you've seen from your surveys of the building suggests that this temperature was reached anywhere on the building yes I mean there is considerable evidence of

00:40:26 mean there is considerable evidence of melted aluminum and where would that have been from your observations I mean if you were to walk the surface of the

00:40:38 if you were to walk the surface of the of the scaffolding as I did you would see remnants of melted aluminium in most areas of the building and to be honest small droplets small pools bits of risa Lydda fied aluminium throughout the site

00:40:52 Lydda fied aluminium throughout the site yeah it's quite quite widespread yeah and wood melting aluminium itself as a taken as a single product have any

00:41:03 as a taken as a single product have any any effect will play any role in the extent and rate of fire spread I wouldn't expect it to no I mean aluminium is reactive but typically only in a finely divided powder form which is

00:41:16 in a finely divided powder form which is not what we have here right so does that mean that the the temperature at which aluminium is reached was relevant because of delamination away from the polyethylene you mean why have I

00:41:29 polyethylene you mean why have I bothered to mention this temperature yeah I mean I think I think yeah I mean I think because the aluminium for many materials that we find that Grenville Tower

00:41:38 Tower sorry many products that we find in Granville Tower the the aluminium is there and is providing some protection to the underlying combustible materials

00:41:50 to the underlying combustible materials so that's true for the ACM it's also true for the Celotex and the kingspan insulation products is true for the window infill panels all of which have aluminium skins of various thicknesses

00:42:01 aluminium skins of various thicknesses so it's important to understand the extent to which those protective layers will have remained in place as opposed to for instance if we had steel

00:42:13 opposed to for instance if we had steel skins of a similar thickness the outcome could potentially have been quite different this steel has a much higher melting temperature than aluminium so I put the value there to simply indicate

00:42:25 put the value there to simply indicate this particular weakness if you like of aluminium yes in that it melts at temperatures which are comparatively low yes it's interesting can I just ask you then just to pick up paragraph four six two on page 105 where you you make this

00:42:39 two on page 105 where you you make this point and you say there it's notable that aluminium also has a comparatively high coefficient of thermal expansion about twice that of steel or concrete so under heating as in a cladding fire it

00:42:50 under heating as in a cladding fire it could be expected to warp and deform under the influence of thermal gradients and differential thermal expansion with other materials this may lead to connection failures or to the opening up of cavities and products formed by an iminium sheets including ACM rain screen

00:43:01 iminium sheets including ACM rain screen cassettes are you able to tell us anything about the speed at which a this warping or deformation would occur once

00:43:13 warping or deformation would occur once aluminium had reached 660 degrees well I mean that's a difficult question the the it's a good question but a difficult one the warping of the aluminium will depend

00:43:25 the warping of the aluminium will depend on the rate of change of temperature so the thermal expansion is a is it you know the hot or something gets the longer it gets yeah right so that that

00:43:36 longer it gets yeah right so that that is relevant into an aluminium sheet of both because if the entire aluminium sheets take a two dimensional sheet of aluminium if it's temperature is increased the entire sheet wants to

00:43:47 increased the entire sheet wants to expand in all directions if the material that is behind the aluminium sheet has a different coefficient of thermal expansion you will generate mechanical stresses at the interface between the

00:43:58 stresses at the interface between the two materials which could lead to de bonding failure between those two materials additionally if you have a temperature gradient through your aluminium sheet ie the surfaces halt and

00:44:09 aluminium sheet ie the surfaces halt and the face which is against whatever the core material is is colder then that aluminium sheet is going to I'm curved as a consequence of the thermal gradient the external surface is getting hotter it wants to get larger

00:44:20 getting hotter it wants to get larger the rear surface is cold it doesn't want to get larger and that induces a curvature in the aluminium which again can induce mechanical stresses in your panel and could lead to opening up of the panel or some kind of failure so so

00:44:31 the panel or some kind of failure so so the thermal expansion is potentially quite important for aluminium in particular I'm gonna should point out that both concrete and steel also experience thermal expansion just less than aluminium a different temperatures

00:44:45 than aluminium a different temperatures the rate of change of the length is less significant for a given change in temperature for steel economy yes I see okay no can I send them to Al you glazed

00:45:00 okay no can I send them to Al you glazed which is the next product I just want to ask you about you cover that at page 95 of your report at page a paragraph 389

00:45:14 under Section four point nine point one

00:45:21 and you call you look well but the title of this part is window infill panels aluminium polystyrene composite panels and at paragraphs three nine four over

00:45:34 and at paragraphs three nine four over the page at page 96 and at page 402 paragraph 402 at page 97 paragraph 402 at page 97 you refer to these as al you

00:45:51 at page 97 you refer to these as al you glaze and you say that these are made of the same product the infill panels around the kitchen extract fans and the window in the fill panels are made of the same product name yellow case yeah yes

00:46:02 yes now al you glaze I think is made up of extruded polystyrene or XPS sandwich between aluminium sheeting correct yeah and just for your just for our note that's figure 56 at page 96 there's no

00:46:15 that's figure 56 at page 96 there's no need to go to it well is that it that's it yeah now is it right that these panels that we see here

00:46:26 right that these panels that we see here are similar to the panels that were involved in the lacrimal house fire yes in terms of the type of product yes that's true in terms of the type of product is there any difference that you know about between the panels on

00:46:38 know about between the panels on Grenfell these panels on Grenfell and the panels on Lacan all house I've not specifically looked at the details of the panels that were installed on like in a house what about the Shepherd's caught fire yes I mean based on the the

00:46:52 caught fire yes I mean based on the the lfb presentation that deals specifically with the Shepherd's court fire which has been discussed here at the inquiry yeah on a number of occasions those panels appears to be quite similar to these panels yes and did the Ali glaze panels

00:47:08 panels yes and did the Ali glaze panels and I've called them that as a shorthand which were a Grenfell have exposed edges of XPS they were mounted within the

00:47:19 of XPS they were mounted within the window frame assemblies so the edges in general were not exposed no right I mean well let me just caveat that one

00:47:31 well let me just caveat that one instance where the edges became exposed which i think is a relevant instance is I'm sure we'll come to this at some stage today is that we know that the

00:47:43 stage today is that we know that the extract fans that were mounted within these panels in the kitchens of the refurbished refurbishment windows tended to fail quite early on when exposed to heating when those fans fell out of the

00:47:57 heating when those fans fell out of the mounting panels that they were sitting within which are these Ilia Claes panels as far as we can tell you then have a hole through in our glazed panels and obviously the inside of that hole has

00:48:08 obviously the inside of that hole has the exposed XPS showing right in that location yeah I was going to ask you that and in that instance just taking this point now is it your opinion that

00:48:19 this point now is it your opinion that that exposed s XPS foam within the circle previously in which the fan was previously mounted facilitated fire spread in any way I

00:48:32 facilitated fire spread in any way I mean that's that's certainly plausible I think it's important to recognize that the the XPS insulation is a low-density product so despite the fact that it

00:48:45 product so despite the fact that it looks like there's quite a lot of it there's 25 millimetres of that XPS as opposed to three millimeters of the PE for instance in the ACM panels the dense both the density and the heat of combustion of polystyrene in this

00:48:57 combustion of polystyrene in this configuration are considerably less than is the case for the PE so the total mass of polystyrene that's available here is actually quite small so even if we

00:49:09 actually quite small so even if we assume that all of that mass is consumed and to deliver energy to the fire and we're talking about a comparatively small quantity of energy you know a few percent not a lot a huge amount of the

00:49:21 percent not a lot a huge amount of the total right so in summary can you quantify the contribution that this material has exposed by the falling out of the fans had to the overall spread of

00:49:33 of the fans had to the overall spread of fire I if I were to assume that it all burns as efficiently as possible I could come up with sort of a back-of-the-envelope quantification yes

00:49:46 back-of-the-envelope quantification yes but given that under the conditions we would experience we don't know how complete the combustion of the material will have been it's difficult to do that in any way that would be scientifically

00:49:57 in any way that would be scientifically defensible but I mean we could do a sanity check on it and find that it's quite small thank you it sounds so you don't think it's likely to have been significant certainly as regards an

00:50:09 significant certainly as regards an escalating fire once the fire gets big when the fire is small I think it could potentially have contributed for instance to flaming out the window early on yes thank you well we'll come we may

00:50:20 on yes thank you well we'll come we may come we will come back to that in due course and before I leave this material can I ask you please to go to page 97 of your report paragraph four oh six and

00:50:32 your report paragraph four oh six and you quote here from the product literature for alley blaze

00:50:45 published by panel systems limited PSL and paragraph 406 it says there may be thought there are several basic queries in terms of the far performance of

00:50:56 in terms of the far performance of panels that may form part of designing the panel composition these may include glass one surface spread of flame fast outer building regulations non combustible core do you

00:51:09 regulations non combustible core do you know if any of those questions could be answered in relation to this material as you saw it installed a green fill out so

00:51:21 you saw it installed a green fill out so that so that statement has come from panel systems limited I believe that was one of the statements that they submitted to the inquiry I'd have to

00:51:32 submitted to the inquiry I'd have to check the reference to confirm that it may be from their position statement that paragraph four or five just above the section that you've quoted it says PSL do not manufacture a panel that has

00:51:44 PSL do not manufacture a panel that has been subjected to any independent fire testing so on that basis I would say no there is no evidence that this material would meet any of those subsequently listed requirements right if that

00:51:57 listed requirements right if that answers your question I'm not sure that it does to us it gives rise to the next question which is are you aware of any other far test data for this product well this material I should call it

00:52:09 well this material I should call it produced by anybody else no not specifically no I've never seen either BS 476 part six or seven testing which

00:52:20 BS 476 part six or seven testing which would be the tests that would be required for class one in class o for any other similar product no right there and then the second question that arises out of that is if you look at paragraph 407 the product literature says to

00:52:34 407 the product literature says to achieve a that's class one surface but of flame we may propose an aluminium skin to achieve be a poly isocyanate foam and foresee a lamellar mineral fiber do you know if any of those were

00:52:49 fiber do you know if any of those were present on the these panels at fell in either location certainly these panels do have an aluminium skin 1.5 millimeters thick or there abouts so

00:53:02 millimeters thick or there abouts so that would meet the requirement for four for point a but I mean I I find this statement slightly problematic in that

00:53:14 statement slightly problematic in that without actually performing the regulatory compliance tests I don't understand the basis for those propositions if you see what I mean I thank you

00:53:25 thank you now I mean I should say also that you know given that dr. Lane is commenting specifically on compliance issues I think it would be very good to put those questions to her tomorrow if possible

00:53:38 yes thank you now turning over to page 101 please you've set out there table 4 where you give it new tales some of the

00:53:51 where you give it new tales some of the properties of XPS and you cover there's a little bit just now and they're selected have you calculated the heat release rate of a unit of this XPS again

00:54:07 release rate of a unit of this XPS again it will depend on the nature in which that piece of XPS is burning so the you know the heat flux is subjected to the manner in which it's burning etc so know I mean I couldn't calculate the heat

00:54:18 I mean I couldn't calculate the heat release rate as I mentioned I could you know in a back of an envelope sort of sanity check sense I could tell you the amount of energy that it is possible to liberate from a piece of this material

00:54:30 liberate from a piece of this material but that would be the maximum conceivable value in reality it would be somewhat less than that how much somewhat less I'd be hard-pressed to to say now see and

00:54:41 hard-pressed to to say now see and comparing XPS and PE you will note that the thermal inertia that you've got in the last entry in the box under table 4 is na melts whereas for

00:54:55 under table 4 is na melts whereas for low density polyethylene PE you can see you've put a value in at Northpoint for 3 kilowatt square per second

00:55:08 what our or rub other any key differences materials of grenfell between the behavior of XPS and the behavior of PE under heating yes I mean

00:55:20 behavior of PE under heating yes I mean so the reason for the discrepancy which you've pointed out between Table three and Table four as you've noted in Table three we I've given a value for thermal inertia yeah in Table four I've just

00:55:32 inertia yeah in Table four I've just said not applicable melts the reason is it's very difficult to measure the thermal inertia for XPS under the conditions that we would expect in a fire because when exposed to heat it tends to sort of shrink away from the

00:55:45 tends to sort of shrink away from the source of heat as a consequence of its foam nature and it's low density I mean people may have experience you may have experienced this yourself if you hold a match up to a piece of this XPS it tends to sort of shrivel and

00:55:57 XPS it tends to sort of shrivel and shrink away from the heat which of course makes it difficult to measure its properties if it's sort of running away from you

00:56:03 from you where's the polyethylene which is higher density you can actually measure a useful value right so that the big difference is the density well the big

00:56:14 difference is the density well the big difference is the way that it responds to the heating the low density influences that baby yes I see okay if they're subject to the same heating conditions does that mean that XPS Woodlake would maybe this is perhaps not

00:56:27 Woodlake would maybe this is perhaps not the appropriate question but will it take longer to melt and form burning droplets than PE I would expect SPS to melt before PE as a consequence of its

00:56:40 melt before PE as a consequence of its thermal inertia which this despite me not giving a value in this table its thermal inertia at room temperature so it's insulating properties would be better than low-density polyethylene and

00:56:51 better than low-density polyethylene and non foamed polyethylene right which means I would expect its surface to heat up more rapidly than the surface of PE all conditions all other conditions being equal yes now dr. Lane has said that this product

00:57:03 now dr. Lane has said that this product made up some thirteen percent or so of the facade at Greenville tower and just for a reference that is paragraph eleven point seventeen point four at page 63 of

00:57:15 point seventeen point four at page 63 of her her report latest report are you able to agree with her about that I've not actually done a rigorous calculation but it seems about right yep okay is XPS ever in your

00:57:32 right yep okay is XPS ever in your professional academic opinion an appropriate material to use or a high-rise buildings such as Grenville Tower I mean that's a question that I would want to answer in the context of

00:57:43 would want to answer in the context of the overall fire safety strategy for the building it's conceivable that it could be used by someone who takes adequate account of its response to fire again

00:57:54 account of its response to fire again whilst my own remit for phase one is not necessarily related specifically to compliance assessment of various materials at Greenville tower this material is used in an insulating

00:58:07 material is used in an insulating capacity and a green filter our is above 18 meters my reading of approved document b would suggest that the materials used in that type of application should be classed as a 2

00:58:18 application should be classed as a 2 euro class in which this material would not be um so in that respect no it's not an appropriate material to be using in my view thank you but again I mean I think that would be an excellent question to put to dr. Lane tomorrow

00:58:29 question to put to dr. Lane tomorrow right now can I then turn to a different product which is the PIR insulation and you just do some general points first of

00:58:43 you just do some general points first of all you cover that at paragraph 4 3 8 on page 101 so we're on the same page and PIR as you can see is poly iso cyanurate foam was that present in the building in

00:58:57 foam was that present in the building in the form of Celotex insulation on the columns and in the spandrels yes and is it right that's the this product using that word in the advisedly

00:59:09 product using that word in the advisedly made up of PIR foam with a thin layer of aluminium foil both phases and in some cases with a glass fiber mesh as well within the foam and now at paragraph 438

00:59:25 within the foam and now at paragraph 438 you say

00:59:29 you say that in the second line the low thermal inertia of PIR means that it tends to have a comparatively low time to ignition and will support rapidly flame spread rapid flame spread and then you

00:59:43 spread rapid flame spread and then you give under table five the selected typical properties of PIR foam insulation and you can see the thermal inertia from a cone calorimeter of naught point naught six kilowatt square

00:59:55 naught point naught six kilowatt square per second can you describe the process by which this material and I mean the

01:00:06 by which this material and I mean the material PIR supports rapid flame spread

01:00:12 the so the the in order for flame spread to occur you have to have heating of the surface of the material which leads to pyrolysis of the material that results

01:00:25 pyrolysis of the material that results in the formation of combustible pyrolysis products adjacent to the material and if those pyrolysis products mix with air in the right proportions and you have either an ignition source

01:00:37 and you have either an ignition source or an appropriate amount of heat in that gas mixture adjacent to the surface you will have flaming and then you need the next piece of material to be exposed to

01:00:48 next piece of material to be exposed to conditions that are sufficient for that response to sort of snowball ignition to ignition to ignitions with the flame spreading along the surface so those are

01:00:59 spreading along the surface so those are the conditions under which you need or those the conditions you need to work for flame spread to occur one of the things that's important to mention about PIR is that it tends you tend to need an

01:01:12 PIR is that it tends you tend to need an external source of heat flux in order for that split flame spread to progress along a PIR material so a piece of PIR material left to its own devices in the absence of any heat flux being received

01:01:23 absence of any heat flux being received by it from an external source will tend to self extinguish and professor torero mentioned this yesterday yes that's PIR as a material if one then turns to

01:01:36 as a material if one then turns to Celotex as a product the question is does an aluminium foil covering on one or more phases affect the rate of flame spread or time to ignition yes I mean it

01:01:51 spread or time to ignition yes I mean it will I think that's one of the reasons presumably that it's there so it the the the aluminium skin will prevent the pyrolysis gases at least initially from exiting the surface of the PIR which

01:02:03 exiting the surface of the PIR which makes them available unavailable for combustion the surface of the PIR so that would prevent surface spread of flame and additionally when subjected to

01:02:15 flame and additionally when subjected to a radiant heat flux the aluminium will will essentially reflect some of that initial radiant heat flux and will prevent a surface heating of the PIR to some extent so that it's less likely that it will paralyze early despite its

01:02:27 that it will paralyze early despite its low thermal inertia would there be a difference of significance between rate of flame spread across uncovered or unfiled phases as opposed

01:02:40 uncovered or unfiled phases as opposed to the rate of flame spread within the material where there is a foil face when exposed to heat flux I would expect there to be a significant difference yes although I wouldn't be able to quantify

01:02:51 although I wouldn't be able to quantify that this at this stage now professor torero has said that PIR has the potential to burn for longer a long

01:03:02 potential to burn for longer a long period of time compared with other components of the Grenfell facade system and again a reference there that's his report at page 64 917 48 to 17 51

01:03:14 report at page 64 917 48 to 17 51 there's no need to go to it do you agree with that yes response yes do you think that that potential to burn for a longer

01:03:26 that that potential to burn for a longer period is relevant in any way to the re-entry of fire back into flats at Grenville tower

01:03:41 I mean everything everything that can burn that is everything that can burn that is there is rap is potentially relevant I wouldn't consider that to be dominant by any stretch of the

01:03:53 dominant by any stretch of the imagination I mean but the fact that it can pyrolyze and release combustible pyrolysis products must be relevant in some way even if a small one and again a

01:04:04 some way even if a small one and again a another general question I'm afraid but is the longest longer burning time professor terraria speaks in with which you agree is that is that relevant to vertical or horizontal fire spread

01:04:17 potentially to the horizontal but given the horizontal modes of fire spread that again I'm sure we'll talk about in some detail later I don't think it would play a significant role with

01:04:28 it would play a significant role with horizontal with with vertical I think the timescales of vertical fire spread are too short for the burning of the PIR to be that important now you've we've

01:04:45 to be that important now you've we've talked about cut edges and and faces that are or aren't exposed in the PIR and two questions about that first of

01:04:56 and two questions about that first of all would the fact that the Celotex as installed on the building with in parts cut edges so that they're exposed affect the reliability of the classification of

01:05:09 the reliability of the classification of this product for the purposes of the Building Regulations again I mean I guess that's partly a compliance question isn't it maybe I let these materials these materials are tested for

01:05:21 materials these materials are tested for classification with respect to the requirements of the building regulations both under the national classification system and under the european classification system in a way such that

01:05:32 classification system in a way such that they are protected by their foil phase when those tests are performed in in i in in all of the cases that would matter relevant to those classifications yes so

01:05:45 relevant to those classifications yes so so I guess that's a long-winded answer to the question yes it matters if the aluminium is not there right and is that because when the tests are done their tests done on PIR which is fully faced

01:05:57 tests done on PIR which is fully faced with aluminium and aluminium foil correct yes and and based on tests that I have seen I would I would say also that any joints are also sort of over

01:06:08 that any joints are also sort of over taped with aluminium tape when those tests are performed yes right second question is that is there any relevance in the difference in the thickness of

01:06:19 in the difference in the thickness of the aluminium foil on the PIR insulation compared with the aluminium skin on the rain screen when you're considering how readily each of those materials will paralyze that's a tricky one because of

01:06:34 paralyze that's a tricky one because of the differences in thermal inertia and density of the underlying materials the the aluminium skin on the cell attacks is much much thinner so I would expect

01:06:47 is much much thinner so I would expect it to heat up more quickly and therefore be removed more quickly than is the case for the ACM I think that's a fair statement yes right

01:07:02 have you done any testing to determine the time and conditions under which the foil on the PIR would peel away or remove itself in comparison with the foil on the on the p on the panels no

01:07:14 foil on the on the p on the panels no could that be done it could be done I'd have to think very hard and for longer than I have at the moment what we might get out of that in terms of useful

01:07:25 get out of that in terms of useful information but turning to phenolic foam insulation that's another product I want to it material I want us to ask you about and is it right that that phenolic

01:07:36 about and is it right that that phenolic foam insulation was present on the building in the form of kingspan insulation on some spandrel panels that's correct and that I think was used on upper floors is that right I think

01:07:50 on upper floors is that right I think I've seen it photographed on some of the lower floors as well as during my walk around on a few very localized locations on the upper floors yep is it fair to

01:08:02 on the upper floors yep is it fair to say that it has similar properties to PIR in terms of its ability to support rapid flame spread in a general sense yes and can you comment on how it would

01:08:13 yes and can you comment on how it would have contributed to the fire on the upper floors where it was used if that happened no I mean in a similar manner to what the things I've already said about about PIR right now I think you've

01:08:26 about about PIR right now I think you've also referred to other types of insulation which were used in the building around the windows can I take you to paragraphs 30 so 337 and 338 on pages 81 and 82 of your report you at

01:08:43 pages 81 and 82 of your report you at the bottom of page 81 pick up the fact that there was a 25 millimeter thick foil faced PIR polymer foam insulation board manufactured by Celotex specific

01:08:55 board manufactured by Celotex specific product name yet-to-be-named and a3 380 25 millimeter thick foil faced polymer foam insulation board manufactured by kingspan product name specifically named yet to be confirmed

01:09:07 specifically named yet to be confirmed and now dr. Lane has identified these as respectively Celotex TB 4000 and king spam Therma pitch TP 10 have you any

01:09:20 spam Therma pitch TP 10 have you any reason to disagree with dr. lane about her okay I've no reason to disagree and do you know what materials those types of insulation are comprised of if those should be PIR materials I believe yes

01:09:32 should be PIR materials I believe yes turning next then to a new material pu foam polyurethane foam page 102 of your report it's table 7 under Section four

01:09:45 report it's table 7 under Section four point ten point one point five I can just ask you to look at that please middle of the page you've I described pu foam as a synthetic thermoset polymer

01:09:58 foam as a synthetic thermoset polymer flex will all rigid and then in the table you've identified the properties just in general professor is it your opinion that pu foam has similar

01:10:11 opinion that pu foam has similar properties to PIR and phenolic foam in terms of its ability to support rapid fire spread in general yes yeah it's sort of ballpark yep ballpark yep is it

01:10:24 sort of ballpark yep ballpark yep is it a big ballpark or a small ballpark quite a small one I would say Yeah right next product aluminium windows page 94 if I can ask you just to skip back to that please under Section four point nine

01:10:36 please under Section four point nine paragraphs 386 and 387 you've been able to identify now that the windows used in the refurbishment this is paragraph 386

01:10:47 the refurbishment this is paragraph 386 assumed based on the available evidence to be what you've set out there metal technology's 5.20 high thermally broken and iminium windows and your conclusions

01:11:00 and iminium windows and your conclusions about that product at 387 in the next paragraph is that the aluminium alloys won't directly contribute to fire

01:11:11 won't directly contribute to fire development and can be expected to have melting temperatures exceeding 660 degrees

01:11:17 degrees question is would those aluminum windows deform at a lower temperature the the loss of stiffness

01:11:29 temperature the the loss of stiffness and aluminium prior to melting yes there would be some I would imagine I mean I'd have to reference a technical literature to know for sure but I would imagine

01:11:40 to know for sure but I would imagine you'd start to see loss of mechanical properties or you know anywhere above 300 Celsius something like that yes what proportion of mechanical properties you'd lose at what temperature would be

01:11:51 you'd lose at what temperature would be something that I'd want to to do a bit more homework on before answering I suppose the question really is it at what temperature would you expect this these windows to deform sufficiently to

01:12:03 these windows to deform sufficiently to fall out a very difficult question to answer because it depends on the nature of the fixings the way they're held in there the loads that they're subjected to the restraining forces that the

01:12:15 to the restraining forces that the structural frame imposes back on them given that the window frames are trying to expand more than the concrete that they're attached to so that's an extraordinarily difficult question to answer right is it necessary thing to answer it for the purposes of your

01:12:27 answer it for the purposes of your reaching final conclusions at phase 2 I mean my remit for phase 1 is is interested in the ignition of the cladding and spread over the cladding by

01:12:38 cladding and spread over the cladding by the time that window aluminium window frames falling out and off of the building becomes an issue the the fire front is this is already gone yeah so I think in terms of timescales for me it's

01:12:50 think in terms of timescales for me it's not a relevant issue you know and there's certainly no evidence that these windows the window frames were falling out of the building that I'm aware of as the fire was spreading thank you

01:13:02 the fire was spreading thank you next item extract fans which you've covered on page 98 if we could please turn to those under Section four point

01:13:14 turn to those under Section four point nine point two paragraph four one six we've covered at four one three two four one seven and I just want to pick up what you say at four one six you you say

01:13:27 what you say at four one six you you say that the video and photographic evidence collected both during the fire and also post fire site investigation along with a number of inquiry witness statements see section 7.4 suggests that

01:13:38 statements see section 7.4 suggests that the kitchen extract fans were in many cases the first components of the window assemblies including frames glazing units infill panels and extract fans to fail and fall away during the fire this

01:13:49 fail and fall away during the fire this is the case both for the in the case of the fire exiting the compartment of origin in flat 16 and in the case of external fire attack due to external fire spread elsewhere and on the cladding now are you able to identify

01:14:06 cladding now are you able to identify what these extra fans themselves made of I mean there I mean the mechanical extract fencer obviously they're made of a number of different materials but the

01:14:18 a number of different materials but the key materials that are sort of holding them in place if you like are a polycarbonate ABS blend as far as I can tell yes I do have I do have a number of these fans at the University of

01:14:31 these fans at the University of Edinburgh and we've been subjecting bits of the fans of the testing to try to determine precisely what they are they are marked as PC abs with markings on the various components which is a polycarbonate ABS blend yes and you

01:14:43 polycarbonate ABS blend yes and you paragraph four one seven if we can just have that highlighted on the screen you you give us some details about that PC ABS and now this material itself

01:14:55 ABS and now this material itself I think you've analyzed in a bit more detail in your report that page 104 if I could just ask you to go to that you've got a table 9 on that page where a table

01:15:10 got a table 9 on that page where a table 10 where you've analyzed the selected typical properties of neat ABS plastic and neat PC plastic respectively first

01:15:21 and neat PC plastic respectively first of all do you know whether these fans what do you play whether the PC abs in these extract fans at green filter were neat in the way you've read them so the

01:15:33 neat in the way you've read them so the reason that I've presented those two tables for what is effectively one material if you like is that the way PC ABS works based on my understanding you

01:15:44 ABS works based on my understanding you know I'm not a polymers chemist is that it's a it's a physical blend so you have some some polycarbonate thermoplastic and you have some ABS thermoplastic and you just physically

01:15:56 thermoplastic and you just physically mix them into a mixture in some relative proportions to one another and you end up with a PC abs blend which is the polymer that you end up with now so the respective proportions of abs and PC

01:16:07 respective proportions of abs and PC will depend on the particular properties that you're interested in for your particular component so whether you want a surface whether you want a durable surface or a tough surface or a product

01:16:18 surface or a tough surface or a product that's resistant to cracking or a bit more amenable to being pushed around you can play with the proportions of the two components so and I don't know so that the products are marked as PC

01:16:30 so that the products are marked as PC abs but I don't know what proportions those two components are in would it be relevant to your work to know those proportions I think I mean we're trying to find out via testing at the inverse

01:16:41 to find out via testing at the inverse of Enver what those proportions are I mean I was thinking about this this morning funnily enough over breakfast and it would be I mean if if the manufacturer of those fans can tell us

01:16:54 manufacturer of those fans can tell us that would be very useful yes would it be would it help you know what likely temperature these extract fans would deform and fail it would it would

01:17:06 would deform and fail it would it would to be a sort of a secondary check on the the testing that we're doing ourselves at Edinburgh so we are subjecting samples of the materials from these fans to what's called dynamic mechanical

01:17:18 to what's called dynamic mechanical analysis at the University of Edinburgh where we actually measure the mechanical response of the material as it is heated and cooled so we are actually measuring those reductions and mechanical

01:17:29 those reductions and mechanical properties at Edinboro and so some of those data were presented yesterday during the questioning of Professor Aaron says the answer that knowing those proportions would assist you in your work I think so yes yeah I don't I don't

01:17:40 work I think so yes yeah I don't I don't think it's critical but it would be nice it would be nice to know yes does that mean that you're not able to say as that now what the likely temperature at which these extract fans the fans would deform and fail I mean the testing that we've

01:17:52 and fail I mean the testing that we've done to date in the testing or the the data that were presented yesterday when when Professor torero was giving evidence so the data that were presented yesterday were data that we obtained at

01:18:03 yesterday were data that we obtained at the University of Edinburgh using tests on the specific fans that were used at Granville Tower those those tests indicated essentially a total loss of

01:18:15 indicated essentially a total loss of mechanical properties before you reach a temperature of about a hundred degrees Celsius which is clearly quite a low temperature in the context of a fire Thank You professor mr. Chairman I get

01:18:27 Thank You professor mr. Chairman I get to turn to a different product or material I should run it is that a convenient moment for a short break I think it is yes Bisby we're going to have a break now okay I have to ask you please not to

01:18:41 okay I have to ask you please not to talk to anon about your evidence when they're out of the room and we'll start again at 25 pass to them all right so if you like to give you the official carton

01:19:04 25 plus 11 please

01:28:59 alright ready to carry on yes professor I'm on to turn now please to the uPVC windows surrounds we know from your report that uPVC was installed around

01:29:11 report that uPVC was installed around the windows during the refurbishment correct yes and I think you've set out on page 103 of your report if we can go to that please table 8 which shows the select C typical

01:29:22 which shows the select C typical properties of PVC rubber membrane which is under the heading which starts the page before at paragraph 447 under Section four point ten point one point

01:29:34 Section four point ten point one point six polyvinyl chloride the table there shows that you PVC has a low melting point of between 75 and 105 degrees

01:29:45 point of between 75 and 105 degrees centigrade and we can see that there can I ask you we can keep that on the screen if we can please Paul but can we also have up on the screen the report of

01:29:57 also have up on the screen the report of Professor torero at page 41 where there is a diagram his figure 9 on page 41

01:30:13 is a diagram his figure 9 on page 41 that's J TOS six zeros one and we sit on the lower part of the page there professor and he says that that shows the mechanical properties of uPVC as a

01:30:26 the mechanical properties of uPVC as a function of temperature the modulus in Blues is related to the elastic modulus of the material the plot indicates that the material beginners to drastically lose stiffness at approximately 60 degrees losing 80 centigrade by or

01:30:40 degrees losing 80 centigrade by or losing 80 centigrade by 80 centigrade in 100% there should be 80% by 80 centigrade and 100% by 90 centigrade tests were conducted at the University of Edinburgh and the data was provided by Professor Bisbee first of all can you

01:30:52 by Professor Bisbee first of all can you confirm that you're the source of that data set that's correct and secondly do you agree with Professor Toreros use of this diagram of the data in this diagram I do thank you now do

01:31:06 in this diagram I do thank you now do you agree in general terms that the dangers

01:31:09 dangers differently the risks inherent in use of uPVC windows surrounds a Grace and two combustible materials is well-established could I have that question again yes riddles do you agree

01:31:21 question again yes riddles do you agree that the risks inherent in the use of uPVC material adjacent to combustible material is well-established um I

01:31:33 material is well-established um I wouldn't say that no I mean I think you mean uPVC specifically next to combustible materials ie the use of you PVC essentially to provide a fire a fire

01:31:44 PVC essentially to provide a fire a fire barrier to combustible materials well can let me show you something um can I should ask pleased the witness to be shown

01:31:52 shown CTA are six zeros 18 at page three this is a BRE report from 1992 after the nasally Heights fire and page three you

01:32:12 can see under the heading fire damage if we can just have that expanded all the cladding on the 11 stories was destroyed on one vertical face note that the

01:32:23 on one vertical face note that the splayed corners were also damaged figure 3.1.3 fire spread vertically up the cavity behind the cladding melting the aluminium supports and also attacking the window reveals via the strand board and uPVC frames does that tell hope it's

01:32:38 and uPVC frames does that tell hope it's I can ask it this way does that tell us anything about the risks of using you PVC surrounds adjacent to combustible materials I mean I I would query what

01:32:49 materials I mean I I would query what specifically is meant by you PVC frames in this context those that might mean the actual window frames are even made from your PVC as opposed to the boards that surround the window opening which

01:33:01 that surround the window opening which is the case we have a grim filter so I'm not I'm not certain we're talking about necessarily an apples-to-apples situation in this case but I mean I think it's I think it's clear that that uPVC is very well known to soften and

01:33:15 uPVC is very well known to soften and lose mechanical properties at temperatures that are low I think I've quoted you know typical service temperature limits in the range of 50 degrees Celsius so and and you know the manufacturers of VP VC products will

01:33:27 manufacturers of VP VC products will quote these values in terms of service temperature limits so if a service temperature limit for a product is limited to 50 degrees Celsius then anyone who has false about it would recognize that temperature substantially

01:33:40 recognize that temperature substantially higher than that are going to be problematic and if you're relying on this material to provide any sort of performance in a fire you ought to be in my opinion deeply suspicious of the ability of UPC uPVC to provide it I

01:33:51 ability of UPC uPVC to provide it I think that would be fair yes okay good night before and leave this can I just take you then to figure three point one point four which is referred to in this report at page five now it's not the

01:34:08 report at page five now it's not the most wonderful picture we've all we've got but this is a detail of the window damage and Leslie Heights does that tell you professor does that tell you anything about the risks inherent in using uPVC window surrounds

01:34:21 inherent in using uPVC window surrounds adjacent to combustible material it's hard I mean it's very difficult to say from this photo I mean based on this photo it it looks to me like what we're

01:34:32 photo it it looks to me like what we're talking about is it the the window frame itself is made from uPVC so that you know the piece of frame that actually is enclosing the glazing and the I mean I

01:34:45 enclosing the glazing and the I mean I haven't read the report in detail but it may be that that warning that comes in the paragraph that was put up previously is suggesting that when a uPVC windows frame is subjected to heat from an externally escalating fire that the

01:34:56 externally escalating fire that the failure of the glazing will happen earlier by having not read the report I wouldn't be able to say for dinner yeah fair enough now putting that away going back to Professor Toreros report can I ask you to be shown page forty

01:35:09 can I ask you to be shown page forty forty four of his report please and and specifically lines twelve sixty six to twelve seventy one where he identifies the lower and upper

01:35:21 where he identifies the lower and upper bounds of temperature which would affect you PVCs behavior in can I summarize

01:35:32 you PVCs behavior in can I summarize this in general terms do you agree that the heating of uPVC by smoke generated by 300 kilowatt fire so 140 and 220

01:35:43 by 300 kilowatt fire so 140 and 220 degree centigrade will result in the loss in a loss of mechanical strength within a approximately five to eleven and a half minutes but I mean it's

01:35:54 and a half minutes but I mean it's certainly plausible yes I haven't I you know I don't want to do the calculation myself to verify that to say definitively yes but it's certainly plausible I see a turning then to page 47 of professor Torres report I just

01:36:08 47 of professor Torres report I just want to show you five lines in the middle of that page that's 1344 to 1349 if you could just look at those and he says and he's picks up your report and

01:36:24 says and he's picks up your report and then in line one three four seven says none of these components would have ignited with the temperatures attained by the smoke layer therefore the conditions that will lead to direct impingement of flames on these materials needs to be analyzed do you agree with

01:36:36 needs to be analyzed do you agree with that yes would you agree that the dimensions of the kitchen in flat 16 were sufficiently small that he that you PVC would have failed wherever the fire had been in that

01:36:47 wherever the fire had been in that kitchen yes although I mean I'm basing that opinion on the analysis provided by Professor torero absolutely thank you for that clarification do you also agree that given the low temperature of smoke

01:36:59 that given the low temperature of smoke you would need direct flame impingement on combustible elements around the windows below wall behind the uPVC if we assume that the smoke temperatures are going to be 300 Celsius or lower yes in

01:37:11 going to be 300 Celsius or lower yes in accordance with professors Toreros analysis then yes I would agree yes you know I should have could clarify I should have qualified the question in that way but thank you for that turning to the related question of of

01:37:23 turning to the related question of of adherents do you agree that glue and silicon sealants which we use to install uPVC windows surround are also flammable

01:37:34 uPVC windows surround are also flammable yes do you know from your own work at what temperature those materials would ignite no I've not been able to confirm precisely what those materials are as

01:37:46 precisely what those materials are as yet when again we're doing testing on those materials in Edinburgh we hope to be able to say so soon thank you assuming smoke at a hundred degrees centigrade would that in your

01:37:57 degrees centigrade would that in your opinion Professor open a direct path for flame spread into the planning structure via the UPV seed of deformation I mean

01:38:10 via the UPV seed of deformation I mean that's a difficult question to answer uPVC as we've discussed uPVC does soften at relatively low temperatures but it

01:38:21 at relatively low temperatures but it doesn't turn to a flowing liquid in the way that for instance polyethylene will it i believe professor arrow you just

01:38:32 it i believe professor arrow you just sort of said it turns to sort of gumgum yes i would say you know it goes floppy to use the technical lingo so it doesn't it doesn't flow typically although it

01:38:46 it doesn't flow typically although it can semi flow in a very viscous way under certain heating conditions so the rate at which it is heated matters in terms of what you get after it's heated uPVC is a very interesting material because in some cases and we have we

01:38:58 because in some cases and we have we have evidence of this on site that grenfell tower in some cases under some forms of healing which we don't know you see the uPVC remains essentially white

01:39:09 see the uPVC remains essentially white and drips and almost flows like a molasses or something from certainly from the head of the window in cases and in many cases on the jamb in other cases

01:39:20 in many cases on the jamb in other cases I would I would imagine cases where it's subjected to higher heat fluxes under a shorter duration time the uPVC will into mess which means that it it chars and

01:39:31 mess which means that it it chars and bubbles and becomes sort of a black expanded char so it's very difficult and and it's and and also it it will also under some circumstances in the manner I

01:39:43 under some circumstances in the manner I described

01:39:43 described for XPS as a consequence of that charring and swelling it will also shrink to some extent so the combination of it going floppy it potentially

01:39:54 of it going floppy it potentially dripping under some circumstances or it potentially swelling and forming a char means it's very difficult to say it's affinity what will have happened to that uPVC no that's quite a caveat I admit

01:40:05 uPVC no that's quite a caveat I admit the short answer is I think it's it's it's certainly plausible and potentially likely that if you had the the uPVC heated to temperatures around 100

01:40:16 heated to temperatures around 100 degrees Celsius that yes you would open up a gap adjacent to the window yes it's gonna press you a little bit you say certainly plausible and

01:40:27 you say certainly plausible and potentially likely doing the best you can sitting here with what degree of confidence would you say that assuming smoke temperature of a hundred degrees centigrade that would open a path into the cladding I mean if you

01:40:39 path into the cladding I mean if you said assuming a temperature of 200 or 300 degrees centigrade I would be more confident so is it right that your confidence level gets lower the lower

01:40:50 confidence level gets lower the lower the temperature of course of course yes okay but at 100 which is what the which is our bet yeah not yeah no I mean I think I think it's likely that we will

01:41:02 think I think it's likely that we will have had I mean well we know from having looked at post fire photos in particular of the building in apartments or in flats that were not subjected to very

01:41:13 flats that were not subjected to very severe fires but where the fire was creeping in from the outside in the later stages of the fire we know that the weak point in the window surrounds is is that gap to typically to the right or left of the

01:41:25 typically to the right or left of the window yes and so yes I think I think that's that's a likely weak point one more on this aspect of C can you help with the adhesives they've just told me that the

01:41:38 adhesives they've just told me that the adhesives are sort of materials that will

01:41:43 will the polymeric materials if you contemplate a uPVC board fixed by adhesive to something else and you've

01:41:55 adhesive to something else and you've got smoke impingement and let's take the hundred degree centigrade bigger how's that going do you know how that's going to affect the adhesive I mean the issue there is that in order to affect the

01:42:07 there is that in order to affect the adhesive the the heat would have to get through the uPVC you know to the adhesive so the adhesive is going to be in a sense insulated by the uPVC but if

01:42:18 in a sense insulated by the uPVC but if we assume that the uPVC manages to get to a hundred degrees Celsius and then the adhesive gets 200 degrees Celsius I presume the question is saying does the adhesive fail and the board simply falls over as a consequence of adhesive impossibility that is certainly a

01:42:30 impossibility that is certainly a possibility and again whilst I I haven't yet confirmed the specific nature of the adhesives used I expect the adhesive was used that was used as some type of an acrylic adhesive we're doing tests at

01:42:42 acrylic adhesive we're doing tests at Edinburgh we will do that the the types of tests that we would need to do in order to understand similar aspects of the response of these materials as we have already done for the uPVC so that's

01:42:54 have already done for the uPVC so that's a question we should be able to answer at some stage as a layman I'm getting this picture of a a uPVC board which has gone soggy if you like has no mechanical stiffness left being held on to

01:43:07 stiffness left being held on to whatever's behind it by an adhesive which is also starting to degrade yeah and again I think I think yes I agree

01:43:21 and again I think I think yes I agree with you but you know the uPVC boards don't weigh that much in comparative terms they're not super high density of products so the forces to which those

01:43:33 products so the forces to which those adhesives would be subjected are not immense and they are they tend to be quite strong adhesives at ambient temperature so even if they lose virtually all of their mechanical properties they may still have sufficient properties to hold something

01:43:45 sufficient properties to hold something in place so it's very difficult for me to say absolutely the uPVC falls away absolutely we have a hole next to the window I think it's likely I you know I'm a I'm a cautious guy so I

01:43:57 I you know I'm a I'm a cautious guy so I wouldn't want to say absolutely I suppose gravity plays its part because depending on where they're fixed of course yeah yeah of course thank you very much yes can I now turn to EPDM

01:44:11 very much yes can I now turn to EPDM rubber which stands for ethylene propylene diene monomer rubber which you cover on page 103 at paragraph four point ten point one point seven correct

01:44:24 point ten point one point seven correct me if I'm wrong professor that this material was used as the weatherproof membrane in the window assembly act that's correct at the size of the windows yep now at paragraph 450 on this page just

01:44:35 now at paragraph 450 on this page just under that heading there you say that no specific details are available regarding the combustion properties of EPDM these will be studied by laboratory based testing of phase two for the specific

01:44:47 testing of phase two for the specific EPDM identified at Grenfell nonetheless do you agree that it is a thermoplastic material which would burn and melt it

01:44:58 material which would burn and melt it will it will burn it doesn't melt and drip it will burn in situ now dr. Lane has got some values for this material she says and I this is a reference only

01:45:11 she says and I this is a reference only that is her report in Section 10 at pages 11 and 12 under paragraphs ten point three point eleven and twelve she

01:45:24 point three point eleven and twelve she says that it will ignite at temperatures between 180 and 378 degrees centigrade does that sound about right to you I mean it's a big range this is apparent

01:45:35 mean it's a big range this is apparent that is a big range and I think that's probably a consequence of the the variations in manufacturing this particular product which is one of the reasons why I've not provided data in my report but I think that range is

01:45:46 report but I think that range is certainly plausible yeah now okay there was it was there adhesive used to bond the EPDM to the concrete structure yes it appeared to be some kind of

01:45:58 yes it appeared to be some kind of mastic adhesive but again I couldn't identify it you couldn't identify it but from your knowledge of mastic in general that also be flammable I I would expect so but I would want to check and would

01:46:10 so but I would want to check and would you expect so because it was a it's a polymer I presume it's polymer based right okay um next materials spray foam now you could take this I think quickly

01:46:21 now you could take this I think quickly but in your report at page two five six if I can jump ahead to that you set out there at paragraphs 1192 1194 some

01:46:35 there at paragraphs 1192 1194 some evidence that you've summarized from the BR the BS our witness statements and oral evidence about pre-existing gaps in the window framing and in particular

01:46:46 the window framing and in particular some evidence from some residents that additional thermal silica was used by writing to fill up the gaps around the windows of which residents have given

01:46:58 windows of which residents have given evidence that they complained now 1192 you say in the penultimate line that the additional foam and/or silicon was used

01:47:09 additional foam and/or silicon was used in affection in some cases to address the problem was that use of the additional thermal and or silicon potentially significant in terms of the ingress of either smoke or fire back

01:47:22 ingress of either smoke or fire back into flats I mean it's very hard to say I mean I think it's so there's sort of a double answer on this point in it if we're talking about if we're talking

01:47:34 we're talking about if we're talking about ingress of smoke and that smoke is relatively cool cool to such an extent that it doesn't affect the polymer foam that's been sprayed in place then one

01:47:45 that's been sprayed in place then one can imagine that the presence of that foam would be helpful as regards ingress of smoke however if the smoke is sufficiently hot or if you actually have fire then that spray foam that

01:47:57 fire then that spray foam that particular products which is most likely a polyurethane would provide essentially zero resistance to the spread of that fire through the gap yep have you been able to analyze or test in

01:48:08 have you been able to analyze or test in any way the foam or filler that was used to stop up the gaps around the windows in parts of Grenfell does that works underway at the minute Edinburgh yep thank you

01:48:20 now whether gaps which you identify in the evidence here were not effectively stopped up with that effect the ingress of smoke or fire certainly smoke fire it

01:48:34 of smoke or fire certainly smoke fire it would depend on the mechanisms by which the fire was coming in there potentially yes right that next product or item is Perl board I could take this very

01:48:46 Perl board I could take this very quickly you've covered legacy Perl board which was identified in the building at page 85 of your report if we can just jump back to that please

01:49:08 now is it right just in general terms the pearl board is a polyurethane foam board covered with a paper covering correct and that it formed part of the

01:49:19 correct and that it formed part of the original construction of Grenfell tower above the perimeter of the windows in each flat that's my understanding yes it's shown as an existing feature on some of the architectural drawings for

01:49:30 some of the architectural drawings for the refurb it's also present below the windows on the external wall of the building covered with a layer of plaster board right now on page 85 at paragraph

01:49:42 board right now on page 85 at paragraph 387 you can you say that you don't believe that it's it played a central role in the spread of fire once the external cladding ignited however it may have played an as-yet undetermined role

01:49:53 have played an as-yet undetermined role in fire spread and growth within the compartment of origin do you mean flat 16 or do you mean all flats into which the fire then entered in this sense in

01:50:05 the fire then entered in this sense in this instance I mean flat 16 was it was the presence of pearl board a route or mechanism by which fire could break back into flats or propagate within them once

01:50:16 into flats or propagate within them once it had come back in given its location in a band

01:50:20 in a band I believe 350 millimeters in width around the exterior wall of the entirety of every flat that I'm aware of in the

01:50:32 of every flat that I'm aware of in the building then that pearl board on the ceiling would be one of the first combustible materials that a fire coming into the flat through a window would find as it was coming in so I think I

01:50:45 find as it was coming in so I think I mean not withstanding the materials around the actual window itself so in its so its potential there is a potential that that could have been the first material ignited within a

01:50:56 first material ignited within a compartment where fire is spreading into it whether that is significant in terms of all the other combustible materials within that flat and the very severe fire certainly an upward fire spread

01:51:08 fire certainly an upward fire spread that we would expect I think is hard to say very good a couple of slightly more stray questions have you identified during

01:51:19 questions have you identified during your survey of grenfell tower the use of any polyethylene gripper rods or stays around the window detailing for example to hold the aluminium frames in place

01:51:31 to hold the aluminium frames in place there are I did observe during the deconstruction of the cladding at lower levels of the building and the undamaged sections when I was on-site with the

01:51:42 sections when I was on-site with the Metropolitan Police and the BRE forensic team what I would call what looked to be polymer sort of shims or pucks that have

01:51:54 polymer sort of shims or pucks that have been used to position the window frames within or onto the cladding rails or the winter aluminium rails that are holding the windows in place I'm not entirely sure if that's what that question is

01:52:05 sure if that's what that question is getting at I'm not entirely sure what a polyethylene gripper rod is if I'm being honest but there are certainly little bits of polymer shim that seemed to have

01:52:17 bits of polymer shim that seemed to have been installed in sort of an improvised manner to get the window exactly where they want it and have you been able to form any view about whether those shims or pucks as you described them

01:52:29 or pucks as you described them contributed in any way to the spread of fire or smoke I mean the the the mass these are quite small shims so the mass of material that's present is quite low

01:52:40 of material that's present is quite low I wouldn't expect any significant impact in terms of the available fuel or that sort of thing I suppose it's it's plausible given the role that they appeared to be performing that lots of mechanical properties of

01:52:52 that lots of mechanical properties of those shims could lead to loosening of the window frames themselves under heat but that's that would be speculative right you know have you seen any evidence that then I have not seen any evidence of that happening thank you I'm

01:53:05 evidence of that happening thank you I'm not going to turn to a different topical together coming away from materials and turn and I'm going to turn to the geometry of the building and the presence of cavities and channels in the

01:53:17 presence of cavities and channels in the structure

01:53:20 structure and to see how and where some of those materials we've been discussing this morning professor fit in can i start by going to page 41 of your report and showing you paragraph three point two

01:53:33 showing you paragraph three point two point four you you've summarized in that paragraph there and we can see it the

01:53:44 paragraph there and we can see it the paragraphs two three two two three three and two three four the three main sets of materials present to her cladding system the four face polymer PIR insulation product the ACM

01:53:59 polymer PIR insulation product the ACM panels and the cavity barriers and you've provided some sketches that figures sixteen to nineteen at pages 43

01:54:10 figures sixteen to nineteen at pages 43 to 46 of your report and it will come to those in a bit more detail shortly

01:54:21 those in a bit more detail shortly can I start there by taking you to page 47

01:54:28 we'll start with with PE and exposed edges this is figure 20 on this page page 47 and you've identified this in

01:54:43 page 47 and you've identified this in the text next to figure 20 is the detail of edge of spandrel section a cm external cladding cassette from level 4 of Greenville tower outside flat 16 provided to you by the NPS and you're

01:54:56 provided to you by the NPS and you're going to say what it is and then you say note multiple cut edges directly exposing PE filler material both at the flat and even more so beveled edges of the panel and also along the re-entrant

01:55:08 the panel and also along the re-entrant internal corners can I just ask you to unpack that a little bit for us and just explain these edges first of all can you point out where the beveled edges are

01:55:19 point out where the beveled edges are for us you can get up if you want referring to is this edge this edge here where so for instance comparing to this

01:55:30 where so for instance comparing to this edge this edge the the cut across the panel is perpendicular yes here that cut is at an angle right so you just the reason that I felt that was significant to mention is just that it exposes a larger surface area of polyethylene at

01:55:42 larger surface area of polyethylene at that location yes it's not immediately obvious to the naked eye looking at this photograph yes say so they just said we're really more for the transcript so that the inner edges of the aluminium

01:55:54 that the inner edges of the aluminium that we could see on figure twin um figure 20 are set back from the outer edges so the bevel is an angle from the bottom to the top right yeah and similarly with the upright there from

01:56:05 similarly with the upright there from the inner to the outer there's an angle what kind of angle is the bevel do you know is probably somewhere around 45 degrees I would say just for memory

01:56:17 degrees I would say just for memory right no I mean I should I should point out that this is this is one example of a cut edge on one specific piece of spandrel cassette that I was given so I

01:56:29 spandrel cassette that I was given so I have no way of knowing if that is a uniform detail yes thank you now from your knowledge partly following up that good last question would this kind of

01:56:40 good last question would this kind of configuration or this kind of feature being present on every ACM cassette on the tower it's hard to say yeah have you any reason to think it wouldn't be well

01:56:53 any reason to think it wouldn't be well I mean to me that the question is is really where would it be if you see what I mean because on this particular panel it's only along this one particular edge all the other edges are cut at 90

01:57:06 all the other edges are cut at 90 degrees I don't know the rationale for that bevel existing in the first place from a constructibility perspective so I don't know why whoever cut and folded

01:57:17 don't know why whoever cut and folded these cladding elements has used a beveled edge at that location so it's hard for me to say what other locations might have the beveled edge I mean I

01:57:29 might have the beveled edge I mean I pointed out because it's something we observe in the photo I think it's significant because we do it we do see some more polyethylene in that location as I'm sure will discuss later I don't necessarily think that those

01:57:40 I don't necessarily think that those exposed lines of polyethylene have a primary role in terms of the flame spreads in any case so I pointed out of interest but I don't think it's a hugely

01:57:51 interest but I don't think it's a hugely significant detail if that's a helpful thing to say yes the other feature you point out in your figure 20 is the reentrant internal corners the word reentrant might be confusing because he

01:58:04 reentrant might be confusing because he used it in a different context when we come to the panel the panels on the column but do you mean by the re-entrant the-the-the well you what you point out they're arranged inside the inside lower

01:58:16 they're arranged inside the inside lower edge and is that is that lower edge exposing peb simply because of the way in which this cassette was folded over and and shaped yeah my understanding of

01:58:29 and and shaped yeah my understanding of the way these cassettes are shaped is that you take a flat panel of the ACM sheet and then you route a groove into the back face of it and then you fold along that line so you removes the aluminium skin and

01:58:41 so you removes the aluminium skin and you remove a certain amount a certain volume of the polyethylene which allows you to get a nice straight fold line in your cladding cassette yeah you know in the same way that you might score a box in order to make a box yes now a

01:58:54 in order to make a box yes now a paragraph 2 for 1 on page 42 of your report you explain the importance of this folding and exposure of a PE and we

01:59:06 this folding and exposure of a PE and we could see what you say there but but in simple terms does this mean that exposed returned edges that go into the does this mean that they go into the cladding

01:59:17 this mean that they go into the cladding rails which are then voids which run up the length of the spandrel what it what it means is that at that at the edges of

01:59:29 it means is that at that at the edges of a cm panels you will always have exposed polyethylene and on the insides of the boxes along every fold line it will also have exposed polyethylene which means

01:59:40 have exposed polyethylene which means that there are multiple routes to expose that polyethylene directly to heating or flaming and probably more importantly there

01:59:46 there multiple routes by which melted polyethylene can exits the ACM panel and then flow to other places yeah now do these return edges which are exposed in the way we've seen either the beveled

01:59:58 the way we've seen either the beveled ones or the or the or the return edges do they fit into the cladding rails not sure I follow you mean as the cladding

02:00:10 sure I follow you mean as the cladding cassettes are hung onto the cloud at Yale's yes within the cladding rails you will have exposed edges of ACM yes and we know because you've said it that these those cladding rails provide voids

02:00:21 these those cladding rails provide voids which run up the length of the spandrel yeah at the length of the spandrel and in some cases along the side of the column and the column tip as well yes my next question yes and that annex

02:00:32 next question yes and that annex paragraph 243 of your report while we're on this get you abled and I know this is more going to be phase 2 but are you able at this stage to identify any

02:00:44 able at this stage to identify any obvious risks in that kind of installation the the hanging of the cassettes on the rails in that way with

02:00:56 cassettes on the rails in that way with exposed PE I mean yes that I mean those those rails as installed it Grenville tower they also break through cavity

02:01:07 tower they also break through cavity barriers as I'm sure we'll also discuss you know later so you have routes where flames and hot gases can move up through the cladding and in doing so expose

02:01:18 the cladding and in doing so expose those exposed edges as polyethylene to heat perhaps as importantly if even if the spread of the cladding rail is not what we're particularly worried about if

02:01:30 what we're particularly worried about if the ACM cassettes on the whole is exposed to heat and you have the polyethylene becoming liquid within the ACM cassette what that means is that some of that polyethylene is going to

02:01:42 some of that polyethylene is going to exit the ACM cassette within the cladding rail which then provides a route for that polyethylene to flow down right as well absolutely and I think we can make this clearer actually by

02:01:53 can make this clearer actually by reference to figure 16 page 43 if you can go to that that that is your I think as you're drawing isn't it that's correct yep and it's a horizontal section detail so we're

02:02:05 horizontal section detail so we're looking at it as it were from above at the a at the join between the concrete expendable beam in the concrete column so at the at the return if I can call it that then you can shut you show the ACM

02:02:18 that then you can shut you show the ACM rain screen cassettes handle section turning at right angles of fitting into the aluminium Craddock cladding rail and you've put void there the expo does this mean that the exposed edges of the ACM

02:02:33 mean that the exposed edges of the ACM rain screen cassette are sitting within the void in fact there are two of them there that's correct does that mean that there are therefore exposed PE there is exposed PE material

02:02:45 exposed PE there is exposed PE material sitting in that void correct and that if it burns drips and melts it will drip down the void down the rail that would be my expectation yes yes now can I ask

02:02:58 be my expectation yes yes now can I ask you to look at page 50 just picking this up and running with it a bit further we can see a photograph figure 23 on that page is that at the same location that

02:03:12 page is that at the same location that compares with figure 16 on page 43 what's been looking at yes yes although the load of graph is perhaps a bit confusing given with multiple elements of the cladding system have been removed

02:03:24 of the cladding system have been removed yes on the left-hand side of that photo certainly and but looking at the well if you can identify from that photograph the return element that runs into the

02:03:36 the return element that runs into the cladding rail you eight are you able to do that yeah can you just do that for us please so I I imagine what you're talking about is this line along the side of the spandrel cassettes yes and

02:03:48 side of the spandrel cassettes yes and there's this small cover strip of ACM which is sort of adhered to the side of that yes and then there are this these bars here that are running side to side in the cladding rail the the cassette

02:03:59 in the cladding rail the the cassette has sort of hook shape out to the side and it hangs on to it right and that cuts outside is all exposed yes I see now is that photograph

02:04:11 exposed yes I see now is that photograph representative of what you would find a I suppose the above and below the but the kitchen window of flat 16 yeah

02:04:23 the kitchen window of flat 16 yeah from from level 4 to the top of the building right I mean it to the extent that we can confirm that given the damage of the upper levels yes right I'm sorry I may have to make make you get up again but can you also point out on this

02:04:35 again but can you also point out on this photograph where the cut edges of PII are insulation would be in this location

02:04:46 are insulation would be in this location well maybe we can do it yeah so so it's better it's more obvious at the location next to the window as opposed to to next

02:04:58 next to the window as opposed to to next to the spandrel yeah so it's more obvious slightly up here in this situation and it's worth it's probably worth pointing out that this construction detail that's shown on this

02:05:11 construction detail that's shown on this slide with the two layers of the PIR foam on the spandrels section sort of framing into that's interesting a configuration of cuts in the PIR here where they join yes into the 100

02:05:22 where they join yes into the 100 millimeter the depth on the columns because of the configuration of the building it would appear that that's quite a straightforward thing to actually do from a constructability

02:05:34 actually do from a constructability perspective yes it's given the geometries that we're dealing with here it seems that whoever installed the cladding an insulation was able to to cut the insulation to kind of fit in the way that I've shown it here yeah

02:05:46 way that I've shown it here yeah adjacent to the window which I guess is a different figure ruin your plan mr. Miller it's harder to it's there's more

02:05:58 Miller it's harder to it's there's more variability next to the window in terms of how that was installed but having said that you have essentially foil here you have foil here that is a cut edge yes PIR you have foil along this surface

02:06:11 yes PIR you have foil along this surface and along this that is a cut edge that is a cut edge yes I see I think in short terms the two layers of PRF foam insulation that you can see in your drawing and not actually

02:06:22 can see in your drawing and not actually physically visible in the photograph but the the angle PIR foam insulation attached to the column is these little oh yes oh these two are here and here

02:06:33 oh yes oh these two are here and here how I sleep just barely visible yes I see this one is coming sample here yes I said that's correct if we look on the photograph there's a label on path showing what's described

02:06:45 label on path showing what's described as foil face polymer foam insulation board column section it's the second direct looks as though it's identifying a cut edge that is a cut edge yes so

02:06:57 a cut edge that is a cut edge yes so this here is a cut edge however that underneath in so what you would have found here is cavity barrier here and

02:07:08 found here is cavity barrier here and then you would have found another piece of the pie are coming down here so you would have here these this edge would have been butted up against a cavity barrier and below the top surface would have been butted up against the cavity

02:07:19 have been butted up against the cavity barrier thank you and I think just while we're at it now you can actually see the voids is this right created by the grooves in the concrete columns that's

02:07:31 grooves in the concrete columns that's correct yeah so right so yes you can see the surface of the pre-existing concrete columns are not flat we're not flat yeah you have these sort

02:07:42 we're not flat yeah you have these sort of vertical channels in them it's worth saying that in some locations on the building that I've inspected there has been an attempt made apparently to close those at the locations of cavity

02:07:54 those at the locations of cavity barriers with spray foam in other locations not so as is shown here with spray foam the spray foam yeah right

02:08:07 I'm just returning to the subject of exposed PIR sort of PE edges can I ask you to be shown please figure 1026 in

02:08:22 you to be shown please figure 1026 in Barbara lanes report no that's that is BL AAS five zeros ten at page 26 and

02:08:37 BL AAS five zeros ten at page 26 and this is paragraph ten point four point eight of doctor lanes report and you see

02:08:49 eight of doctor lanes report and you see on the right-hand side of that figure the photograph we were looking at earlier with the beveled edges on the left-hand side of that figure there is a location photograph identifying where

02:09:00 location photograph identifying where one would find those gaps on the building and dr. Lane has related the beveled edge to the edge of the panel as

02:09:11 beveled edge to the edge of the panel as you consider it under the return at ninety degrees back above they'll be head of the window and you see that yep do you agree with that I do does that

02:09:22 do you agree with that I do does that tell us that in fact they were exposed polyethylene edges open to the atmosphere yes

02:09:40 now can I ask you next to turn could put that away go back to your own report at page 44 figure 17

02:09:59 now that shows the geometry of the cladding system at the junction of a window unit and a column on the east face is that is that right that's correct now there's a photograph I think

02:10:10 correct now there's a photograph I think we can relate to this so if Paul we can keep this on the screen and go please to page 55 of your report there's a there's a photograph

02:10:21 report there's a there's a photograph there which is figure 27 B and we've got a we've got a similar photograph as we had before under a and under B we've got

02:10:32 had before under a and under B we've got a different photograph and can you can you help us with this first of all in the photograph is this representative of what you would find adjacent to the

02:10:45 what you would find adjacent to the kitchen window of flat 16 yes and on this photograph and using both the photograph and the diagram can you help us where would the exposed edges of a cm

02:10:58 us where would the exposed edges of a cm panel be in that assembly exposed edges of a cm panel are just there at the tip comes in here yes and that the wreath at

02:11:11 comes in here yes and that the wreath at this corner here internally you would have an exposed reentrant corner now just of that little elbow joint I think you'll point out in yellow in

02:11:22 I think you'll point out in yellow in just here in Figure 17 so you would have that routed joint there to create the fault I see and that is that like the what you call the return edge in the photograph we looked at earlier correct

02:11:34 photograph we looked at earlier correct a different angle yes exactly are any of the voids that you can see in the diagram figure 17 relevant to far spread in this figure I

02:11:48 relevant to far spread in this figure I mean yes I mean one issue that is a bit of a sticking point is you can see that I have kind of lightened this piece of

02:12:00 I have kind of lightened this piece of polymer foam a PIR foam insulation and that's because the condition of the insulation boards in that location adjacent to windows

02:12:11 in that location adjacent to windows over the building is variable so we don't always find that piece of foam existing so in some cases this piece of foam that I have here which is a small

02:12:22 foam that I have here which is a small piece that's cut to basically feel a very small awkward bit of cladding next to the window is just not there and indeed yesterday I believe professor Terra was shown a picture where this

02:12:34 Terra was shown a picture where this this piece of board has been cut square and it just comes up and it just stops yeah and there's no piece of insulation here that's from dr. lanes report and

02:12:46 here that's from dr. lanes report and and we see variable configurations of the cuts in the in the PIR boards certainly in the lower levels of the building so it's hard to say with any certainty at a given location what the

02:12:58 certainty at a given location what the condition was at that location and certainly outside flat 16 there's so much damage that I couldn't tell you outside flat 16 if this piece of foam is there if the board is cut is this acute angle like this or if it's kind of right

02:13:09 angle like this or if it's kind of right angles I just can't say no now just focusing on the exposed edge of the the PD panel exposing the PE you identified

02:13:22 PD panel exposing the PE you identified the elbow joint but at the top which I think was the first edge you identified of the yellow hatched aluminium fixing sorry

02:13:33 sorry ACM panel just exactly which edge is exposed can you point that out you mean just just here there's just just there it's that little tiny edge

02:13:44 just there it's that little tiny edge and is that sitting in a void no it's sitting as you can see in this picture barely the the detail alongside the

02:13:57 barely the the detail alongside the window yes it's very difficult to see but you can see that you have the window frame yes which is the darker gray and then you have a secondary element here which is a little metal angle which is connected to

02:14:10 little metal angle which is connected to the window frame and then the ACM panel is riveted through or screwed through that l-shaped channel so the exposed edge of polyethylene here

02:14:21 the exposed edge of polyethylene here alongside building though is actually external to the L so that it's just there

02:14:26 there along that line does that mean that it would be visible or tangible from within the flat it's quite close to the frame

02:14:37 the flat it's quite close to the frame so it will probably be quite difficult to get a look at it but in principle yes okay but it's exposed to it's exposed to the air it appears that way so is this right that there is actually an exposed

02:14:49 right that there is actually an exposed longitudinal edge of some three millimeters of PE facing into each flat at that location about what five will

02:15:00 at that location about what five will save centimeters perhaps less from the window frame provided there's detail as shown here is consistent over the building which is a hard thing to verify I understand that so but but on this gap

02:15:12 I understand that so but but on this gap that may vary the this construction detail I've not been able to find on any drawings submitted to the enquiry by anyone so it appears to be an improvised

02:15:23 anyone so it appears to be an improvised detail in some respect right that could be wrong and of course material might come to light but but I I've not seen this shown on any drawings

02:15:38 have you considered the role that that exposed PE and that precise location would play in the initial ignition of the rain screen on exit of the fire by

02:15:53 the rain screen on exit of the fire by whatever route from flat 16 yes we'll come back to it yeah figure 19 I'm sorry figure 18 I thinks the next

02:16:05 I'm sorry figure 18 I thinks the next one we need to look at page 45 I think this shows the geometry of the cladding at the column tip is that right that's correct yes and if you go back I'm so sorry to make you jump around but if you go back next to the page on which we

02:16:17 go back next to the page on which we were looking at the photographs page 55 look at the figure twit look at figure 27 a just a flip between them if we could have faith of those on the screen please pull at the same time figure 18

02:16:29 please pull at the same time figure 18 on the left hand side if you can what doesn't matter figure 27 a on the left hand side if you can put figure 18 on the right hand side thank you first of all is this to your knowledge or on your serve a

02:16:41 knowledge or on your serve a representative of all the columns in the tower certainly columns that are on the faces of the tower at the corner columns you have a slightly more complicated

02:16:52 you have a slightly more complicated detail right because those columns are not sort of triangular they're more sort of half squares yes yep but in principle yes it's essentially the same detail okay now on that assembly can you

02:17:04 okay now on that assembly can you identify for us please the location of the exposed edges of ACN there the tip

02:17:16 the exposed edges of ACN there the tip there at the tip this is a little infill piece of ACM so there sorry so they're there they're there here and here and

02:17:28 there they're there here and here and you say here in here at the top and the acute angle that the the inside the return of that acute yeah because it's been grooved because it's in order to fold it yes it's a yes

02:17:39 it's in order to fold it yes it's a yes so so we can can we take it actually any fold of ACM paneling which we can see in this and indeed other configurations

02:17:50 this and indeed other configurations results in exposure of PE that's my understanding of the way to manufacture yes good so we have I think one two three four five six identification identified locations of exposed PE in

02:18:03 identified locations of exposed PE in the nose assembly correct I call it that and again are any of the voids in this diagram relevant to fire spread I mean

02:18:15 diagram relevant to fire spread I mean all the words are relevant to fire spread but specifically this void here within the channel so this cladding rails you can see in this photo here hmm it's coming off the tip of the column

02:18:28 it's coming off the tip of the column yeah it's it's got this u-shaped feature with the bar going across and this cladding rail here at the column tip is a continuous board which runs all the way from the base of the building right

02:18:41 way from the base of the building right the way to the roof along the column tip yes unobstructed and the cavity barriers are all cut around that rail as you can see here actually quite a nice picture the way the cavity barrier has been cut

02:18:53 the way the cavity barrier has been cut in this instance no guarantee that they're always cut exactly this way but clearly there's no way to have a cavity barrier continue through that you shape channel thank you the next one is figure

02:19:09 channel thank you the next one is figure 19 on page 46 of your report I'm not sure we've got a Co relative photograph to put with it but this is some vertical

02:19:21 to put with it but this is some vertical section detailing the typical geometry of horizonte' joints between the ACM cassettes a long vertical column lines as how you described it more or less is that again

02:19:34 described it more or less is that again is that representative of all the columns in the tower as far as I can tell yeah right including the corners yes

02:19:43 yes yes in principle yeah now on that assembly can you identify for us please where the expose Edge's of ACN would be this is so this is a vertical section through the

02:19:54 is a vertical section through the cladding panels yes so you have exposed edges of polyethylene I mean certainly right at that location yes just there this location is here yes at that

02:20:08 this location is here yes at that location right there and then along these edges although in section that's not unnecessarily an edge that we're interested in no now in the third of

02:20:24 interested in no now in the third of those which is the right angle we can see moving from left to right and bottom to top we're just below the Wiggly arrow

02:20:37 to top we're just below the Wiggly arrow is the exposure of PE on the exterior again open to the air yes yes it will be and that runs transversely does it it

02:20:48 and that runs transversely does it it would run across it runs across yeah

02:20:52 right I'm not sure you pointed this out but would there also be a transversal running across exposure of PE in the

02:21:03 running across exposure of PE in the inside of the right angle joint in the void the rainscreen capital oh you mean below yeah just that exactly here and there yeah I mean I mean I should say at

02:21:14 there yeah I mean I mean I should say at this point that this one here I'm saying yes on the basis that every fold I've ever seen at an ACM cassette has a routed cut yes given that we don't have a photo and I can't see it in my head

02:21:26 a photo and I can't see it in my head right now that is something I would want to check to verify to be certain yeah but I can't think of a way they would make that cut without doing it thank you I'll check right now you've identified

02:21:45 I'll check right now you've identified these pictures as but and you say I think that these are particularly important to vertical fire spread dr. Lane and I'll just summarize her opinion I hope accurately she has identified the

02:21:56 I hope accurately she has identified the rainscreen cavity in the column as itself a route for fire spread do you agree with that potentially yes you say potentially is that Wow I mean it will depend it will

02:22:08 that Wow I mean it will depend it will depend on the effectiveness of the cavity barriers within that cavity at preventing vertical fire spread within the cavity to the extent that the cavity remains a cavity as the fire grows which

02:22:21 remains a cavity as the fire grows which wouldn't be for very long under a very high heat flux right I follow you know quite quite quickly the rain rain screen cassettes are deforming or gone or burning and you no longer have a cavity

02:22:32 burning and you no longer have a cavity which kind of defeats the purpose of having a cavity barrier yeah yeah I'm sure we'll answer that that answer might actually answer the next few questions I've got on this topic but let's see how we go can I ask you please to be shown

02:22:45 doctor lanes report section 10 that's BL as50 10 page 16

02:23:00 and this is figure 10.13 where I thought which I she says as a 3d image of fuel

02:23:13 which I she says as a 3d image of fuel ventilation heat available within the column cavity of ground filter to support combustion and I think you answered a question about that if I can show you the bottom of the page and the

02:23:26 show you the bottom of the page and the text there she says an open state cavity barrier does not initially fully closed the cavity the particular cavity barriers installed in Grenville tower were designed to leave a 25 millimeter

02:23:38 were designed to leave a 25 millimeter gap between the outer surface of the cavity and the outer face of the cavity barrier and she explains why the outside face of the horizontal cavity barriers lined with an intermezzo material visible as the black strip in Figure

02:23:49 visible as the black strip in Figure 10:17 which will be may need to look at it we need to which is intended to activate under heat and expand to close the 25 millimeter gap therefore initially in a fire the entire column

02:24:00 initially in a fire the entire column cavity over the entire building height was fully connected do you agree with that conclusion yes does that mean that

02:24:12 that conclusion yes does that mean that there would be a continuous cavity up the column with the cavity barriers in an unreacted state yes

02:24:25 now if you look on a figure 1090 at 10:19 in her report that's page 20

02:24:42 she explains there that rainscreen cladding panels can distort when heated either through heating of the panel itself or by failure of the supporting fixtures this can allow further gaps

02:24:54 fixtures this can allow further gaps between the cavity barriers and the rain screen panels to form do you agree with that yes and does that will that also provide a route or further route or exacerbated route to fire spread by way

02:25:06 exacerbated route to fire spread by way of bypassing the cavity barriers absolutely yes and of course all of this is predicated on the assumption that the cavity barriers are installed as per the

02:25:17 cavity barriers are installed as per the recommendations of the cavity barrier supplier which may or may not be the case understood can I then show you also page 21 of her report at section ten point three point four zero and figure

02:25:31 point three point four zero and figure ten twenty and she says there and there it is the perform this is the text above it we may need to have both the drawing and the text pool if we can just she

02:25:44 and the text pool if we can just she says there that the performance of the cavity barriers in restricting the spread of fire was also compromised at the nose of the column due to the specific geometry of the ACP in support bracket as illustrated in Figure 10 20 a

02:25:56 bracket as illustrated in Figure 10 20 a gap where the horizontal cavity barrier was not present existed at the nose which provided another route of fire spread past the horizontal cavity barriers do you agree with that absolutely yeah and I mean the mat is

02:26:08 absolutely yeah and I mean the mat is the same thing shown in Figure 22 of my report in a photo that I pointed out previously so yes it's precisely the same gap that we've talked about before right and then finally on this question of exposed

02:26:21 finally on this question of exposed polyethylene edges and their route will their assistance in fire spread will role in it can I ask you please to go to figure 40 of your report at page 68 and

02:26:36 figure 40 of your report at page 68 and you'll see that that's a photograph of from site inspection during cladding deconstruction outside a typical kitchen window on level 4 looking vertically upwards is that do you think so far as

02:26:50 upwards is that do you think so far as you've been able to ascertain representative of the assembly outside flat 16 as regards the cavity barriers yes oh as regards all of the components

02:27:01 yes oh as regards all of the components that you can see there I mean my experience of having looked at the way the cavity barriers were fitted into the awkward spaces this being one example is that it was sort of improvised on a

02:27:12 that it was sort of improvised on a case-by-case basis I wouldn't necessarily say that that I mean I as I say I haven't done an exhaustive survey of every remaining cavity barrier installation on the building so it'd be hard to say but I but my gut feeling

02:27:25 hard to say but I but my gut feeling having looked at a lot of them is that they vary right in terms of identification of exposed edges of polyethylene would you be able to identify where those exposed edges would

02:27:37 identify where those exposed edges would be when looking at this picture I'm sorry to make you get up yet no that's fine so there's some exposed edge along here yes along there here they're not

02:27:51 here yes along there here they're not there and you would have had a column cassette coming in here and being joined to this so along this line on the outside of the angle now can I just ask

02:28:03 outside of the angle now can I just ask you to stand still sorry still stand sorry just help me above the extract fan which sits in its it's panel you can see

02:28:17 which sits in its it's panel you can see a gap where the rain screen panel returns back on a horizontal plane towards the vertical plane of the window

02:28:28 towards the vertical plane of the window set and we've blended up there for you you can see the dark edge but below can you help us whether there would be any exposed polyethylene in that location not so this corner that is forming this

02:28:42 not so this corner that is forming this line

02:28:43 line yeah shadow behind is not an exposed edge but the photo that we have that showed the bevel previously yes shows you the back of this yes so you have a

02:28:54 you the back of this yes so you have a slight upturn here so there's a fold and it's going sort of that way into the screen yes sort of yeah big and interesting I would say and on the top

02:29:05 interesting I would say and on the top of that you have exposed edge of so so I see so underneath this as it were moving horizontally into the building and then coming up vertically and then coming it

02:29:16 coming up vertically and then coming it as it were back out again you've got a horror you've got a flat exposed lengthways surface of polyethylene so you have a you have a flat surface of exposed polyethylene which is horizontally looking up exactly yeah

02:29:28 horizontally looking up exactly yeah right

02:29:33 and that gap there that we see the dark thick the dark line we were just looking at a moment ago is that is that an opening yes so anyway my does to provide ventilation to the ventilated rain

02:29:44 ventilation to the ventilated rain screen system in place it's it's intended to be an opening does that mean that any flame emanating from the window set wherever it is on the windows they could get up through that crack and melt

02:29:58 could get up through that crack and melt or allow or melt or burn the exposed poly abysses absolutely yep I'm now going to turn to a different feature of

02:30:11 going to turn to a different feature of the building professor which is covered by you at paragraph three point two point four point two of your report on page 58 which is the column top and

02:30:29 page 58 which is the column top and architectural crown details and can I start by diving into page 61 within that

02:30:40 start by diving into page 61 within that section and bigger 32 which we have there on the screen this is I think is this right a drawing of the crown detail

02:30:51 this right a drawing of the crown detail that's correct and I mean it's a design drawing of the crown detail I was going to ask you it looks as if it's come from the from CEO say it's a design driver

02:31:04 the from CEO say it's a design driver there's also can I just have that on the screen at the same time is something else I get to show you and it's an image in dr. lanes report and that's B la s50

02:31:16 in dr. lanes report and that's B la s50 is 10 pages 47 or 40 or 47 to 49 and this is figures 10:46 10:47 and 1048 the product I'll get them all on the screen

02:31:27 product I'll get them all on the screen but starting with figure 1046 to start with if we can can you tell us how that relates that

02:31:38 drawing that 10:46 relates to the original design drawing in terms of how the right hand drawing relates to the left hand right yes

02:31:50 left hand right yes I mean they're showing essentially the same thing the right hand drawing is showing a vertical section through the crown detail whereas the the left hand is showing a front elevation of the

02:32:01 is showing a front elevation of the crown detail right and it when we look at the blue part the profile cladding panels linking column cladding to top of crown could you just help us with the orientation and geometry of that of

02:32:13 orientation and geometry of that of those panels right okay so so you're referring I should point out that I'm colorblind so I mean it so could you refer to this yes I am I Blues are good for me so we're generally alright so

02:32:26 for me so we're generally alright so this section here would be the top of a column and that on this drawing would be this piece here or this piece yeah yes I

02:32:37 this piece here or this piece yeah yes I see I see okay and is that is that you can see what from the drawing that's been a magnified two lines coming down vertically at an angle what what does that signify that's just showing the way

02:32:49 that signify that's just showing the way that the panel is folded in order to create the architectural detail that we see in the room I think so it's the the original reinforce concrete columns that sit behind these are tapered back yes

02:33:01 sit behind these are tapered back yes it's just an architectural detail and so the cladding panels were tapered back in line with the concrete although it's worth mentioning some distance from the pre-existing on this the pre existing concrete stops at a lower level yes okay

02:33:12 concrete stops at a lower level yes okay thank you

02:33:13 thank you the next figure is 10:47 if we can just look at that please

02:33:23 and that shows the presence of combustible rain Obon cladding panels formed into fins where would they sit can you tell us where they would sit in relation to the figure of 32 so these

02:33:39 relation to the figure of 32 so these panels here yeah the red red is not a good color for me the red ya are essentially these vertical slats yes I

02:33:52 essentially these vertical slats yes I see leave dr. Lane refers to them as fins

02:33:54 fins yes she does fin with fins I call them sea channels ah this Technic that is that was a question I had fine that answers that and 10:48 is the next the next drawing which is yours the same as

02:34:07 next drawing which is yours the same as the same drawing there and it is there any signe well first of all is it the same drawing looks like appears to be although the one in dr. lanes report has been marked up by somebody at some stage

02:34:18 been marked up by somebody at some stage along the way is there any significance in that drawing in that secret in the marking up I've not no I don't think so right okay now is there in general terms

02:34:29 right okay now is there in general terms is there any installation sitting behind the details we can see at the top of the columns at the top of the columns no the installation is terminated above the

02:34:42 installation is terminated above the level of the the windows at the top floor is there any installation at all within the crown detail no what about cavity barriers no is

02:34:53 no what about cavity barriers no is there an aluminium coating before we go on is there any insulation behind look again the top there spandrel panels looking at the previous drawing reported

02:35:09 looking at the previous drawing reported Mirza there might be I believe yes but that it terminates before reaching the actual line of the roof there yeah yeah

02:35:22 actual line of the roof there yeah yeah could be wrong I want to check that well I think we might better see it I didn't make a note of the number of the red and blue drawing but it's certainly indicated on the drawing whether its

02:35:34 indicated on the drawing whether its presence on site you may be able to see it in part in figure 33 on page 62 of

02:35:50 it in part in figure 33 on page 62 of your report that may help no I mean I should point out at this point that the figure sorry the figure that was

02:36:02 figure sorry the figure that was previously on the right from dr. lanes reports that showed essentially the same section as being shown on the left from my report right I don't know what that is if it's possible to bring it up okay

02:36:14 is if it's possible to bring it up okay I do think it's important to point this out actually no sir it's a colored version in Figure 33 the colored version

02:36:25 version in Figure 33 the colored version of my figure 33 yes yes exactly

02:36:31 if you so yes that that note the one you have just there a second that one yes so that figure there unfortunately I was

02:36:43 that figure there unfortunately I was not aware of its existence before seeing dr. Lane most recent report so that only became available to me recently the figure that you had put up a moment ago mr. millet which was from my report my

02:36:54 mr. millet which was from my report my figure 33 yes you can see that it does not include the details below the coping that goes over the side of the roof yeah so it's just important for me to

02:37:05 yeah so it's just important for me to state that that that's helpful so it's a in fact looking at or using Flickr for 10.4 47 in dr. Lane's report at page 48 to section 10 you can is this right you can actually see where the installation

02:37:16 can actually see where the installation stops and therefore there's no insulation behind the fins or any other part of the architectural crown details that's correct right and I think that answers the the Chairman's question but

02:37:27 answers the the Chairman's question but there is also an aluminium flashing that we can see which in Maine are able to see this it's in a thing green it is Gray's it thanks to us hey did you know

02:37:42 Gray's it thanks to us hey did you know about that aluminium flashing over the top of the installation yes I knew about the flashing but I wasn't aware that the drawing shows PIR insulation underneath

02:37:53 drawing shows PIR insulation underneath on the drawing that I've used my figure 33 that's denoted in the design drawing

02:38:00 as it's very small print but it says WSP ply bonded inside coping to reduce sag so that's indicated as an aluminium sheet with essentially a moisture

02:38:13 sheet with essentially a moisture resistant plywood bonded to the underside to reduce its sag and so we had always assumed that was the detail in that location on the roof right in light of this new drawing I've asked to

02:38:26 light of this new drawing I've asked to go back to site and have a look myself subject to that later visit are you able to identify on figure 10 47 where the exposed edges of polyethylene might be

02:38:37 exposed edges of polyethylene might be within the ACM in the crown detail in the ground detail I mean there's there everywhere the better the better the better drawing is my figure 34 34 yes

02:38:50 better drawing is my figure 34 34 yes let's go let's go to that and they did a photograph of figure 35 this is page 63 of your report yes okay

02:39:01 of your report yes okay so yes so just just for us can you just show us where yeah so you need to get back up I figure there before yeah

02:39:12 back up I figure there before yeah so that expounded so yes I mean it's worth saying what you had in this detail is you have aluminium C shaped channels yes so these are this is these are vertical elements so this is a section

02:39:24 vertical elements so this is a section horizontal section through the crown so you have essentially C shaped channels running vertically like fence posts they have cladding they have bolts running across them at various Heights and then you have essentially the inverse shape

02:39:36 you have essentially the inverse shape made out of an ACM slotting onto those rails and that just sort of new you end up making a essentially a fence of a CM

02:39:47 up making a essentially a fence of a CM and aluminium same shape C channels as you go along the crown detail so this is this piece here is the column cassette we hold on top cassette framing in to

02:39:59 we hold on top cassette framing in to start the crown detail yes and then you just have a repeating sequence of these C shaped channels to continue across until you get to the next column you have exposed edges at this corner at

02:40:11 have exposed edges at this corner at this edge yes alright this corner this hinged at this edge at this corner the next corner that edge so just basically and on you go across all the way across

02:40:24 and on you go across all the way across so you have a lot of expenses presumably these are just vertical C channels in this view yet in reality these cassettes

02:40:35 this view yet in reality these cassettes are box shaped so they have tops and bottoms like there are sets yeah so they have they have a bottom that returns and at the top that comes over the top where

02:40:47 at the top that comes over the top where they have returned at the bottom is a cottage yeah it's an innocent imagine imagine a cardboard box that doesn't have the flaps on it anymore yeah yep and at the top the same

02:40:59 yeah yep and at the top the same the top set yes so you've got every edge music is exponents on the inside face of the crown yes yes thank you and in fact

02:41:12 the crown yes yes thank you and in fact I think you get a visual image from power 34 so I figure 35 on the same page does that show us that's we can have that expanded pool please does that show

02:41:23 that expanded pool please does that show us the sea channels yeah the crown elements in this figure extremely badly damaged

02:41:30 damaged this is immediately above the flat sixes incidentally this is where the fire will approach to come up the building sits the northeast corner correct yes correct so here you can see these are the

02:41:43 so here you can see these are the aluminium sea channels those and then these very badly damaged and warped pieces of aluminium are aluminium skins of the pre-existing ACM cassettes having

02:41:56 of the pre-existing ACM cassettes having gone up there and looked at them the polyethylene is is essentially gone there's some residue but the polyethylene has either burned or melted and dripped down from those and the sea

02:42:09 and dripped down from those and the sea channels are they's the indentations which can move away from the camera in in vertical grooves that we can see there these yeah these are the C channels yes so so the the ACM elements

02:42:20 channels yes so so the the ACM elements have been removed by the fire the aluminium sea channels are quite massive they're quite thick I think the three millimeters thick aluminium so they're quite sort of beefy elements for the

02:42:31 quite sort of beefy elements for the fire and nothing to prevent horizontal propagation no no I mean I mean quite the opposite yeah did this arrangement

02:42:44 the opposite yeah did this arrangement at the crown because you called it an architectural crown did well let me ask you an open question what do you mean when you use the expression architectural crown I mean that the only

02:42:56 architectural crown I mean that the only function of the crown that I can ascertain is that it was a visual and aesthetic feature of the building and therefore it's an architectural feature of the building as opposed to having some specific engineering functionality

02:43:09 some specific engineering functionality no it wasn't it wasn't required there was already parapet beam and a safety grating at roof level so it served no purpose other than an aesthetic purpose as far as I can tell I mean if we have evidence

02:43:20 can tell I mean if we have evidence otherwise I'd like to hear it but as far as I can tell it's purely an aesthetic feature right and we'll come back to the role of the crown in fast bread later in your evidence dr. professor can I then

02:43:31 your evidence dr. professor can I then turn to the question of Windows now at page 73 of your report you have summarized the materials that you have identified as used in the window sets at

02:43:45 identified as used in the window sets at paragraphs 279 2 2 8 4 and then at paragraphs specifically to 82 to 83 and

02:43:59 paragraphs specifically to 82 to 83 and to 8 for itself and then into 285 you explain what happens if any of those are or all three are penetrated for any reason now it's dr. Lane's opinion and

02:44:14 reason now it's dr. Lane's opinion and she's good to go to attend to give evidence so we'll have to wait to see what she says but it's her opinion that once there was a localized fire near the window the majority of materials around the window had no potential fire resisting

02:44:26 had no potential fire resisting performance I've summarized her opinion do you agree with that I'm and I wouldn't use the word no I would say very little yeah it's a very little potential fire resisting before correct oh yeah

02:44:37 oh yeah and she's also concluded and this is paragraph nine point seven point six on page 48 of section nine of her report once there was an a once there was a fire in a flat anywhere near a window

02:44:50 fire in a flat anywhere near a window there was a very high likelihood that it would break out of the flat into the cladding do you agree with that I mean I guess it depends what one means by very high likelihood but I would say it's likely yes right okay that wood cavity

02:45:04 likely yes right okay that wood cavity barriers around the window have made a difference at all it's difficult to say because I you know to be honest and I have thought about this I'm not sure how

02:45:15 have thought about this I'm not sure how one would

02:45:16 one would put a cavity barrier around windows installed in this manner so you know I don't it's almost an impossible question to answer because I can't imagine how one would actually achieve what one is

02:45:28 one would actually achieve what one is attempting to achieve by putting a cavity barrier around a window no I understand can I then turn to the topic of spread out of the compartment now you which is

02:45:41 out of the compartment now you which is a different topic all together you've based your analysis on your understanding of the way different materials react in a fire and secondly

02:45:52 materials react in a fire and secondly the available video evidence the visual evidence from video and photographs that you have that's correct yeah the evidence I'm using with respect to these questions of fire spreads is

02:46:04 to these questions of fire spreads is predominantly visual evidence yes now have you had an opportunity to consider dr. lanes and professor Toreros analysis of spread out of flat 16 in their

02:46:16 of spread out of flat 16 in their respective reports yes although not in any sort of very deep way I've read the reports although admittedly under quite short time constraints now we know the

02:46:27 short time constraints now we know the professor torero who gave evidence yesterday explained that he's carried out some modeling I think he might describe it as simple modeling to assist with analysis of how the fire fire broke

02:46:39 with analysis of how the fire fire broke out of flat 16 am i right in thinking that you yourself haven't carried out a similar analysis that's correct do you agree with professor torero that in order to have direct flame

02:46:51 in order to have direct flame impingement on to the ACM panel sitting outside flat 16 you would need a fire of

02:47:02 outside flat 16 you would need a fire of something like 830 kilowatts within the flat no if if I understand what

02:47:14 flat no if if I understand what Professor Toreros said yesterday if I were to attempt to summarize what Professor arrow said yesterday after quite a lengthy discussion about these issues its it would be that the gases ex

02:47:27 issues its it would be that the gases ex that that that his preferred fires between 60 and 300 kilowatts yes based on his analysis of the compartment that the largest of those fires is going to provide smoke layer temperatures in a

02:47:39 provide smoke layer temperatures in a non past post flashover scenario at a maximum of about 300 degrees Celsius but he seems to be leaning towards somewhat less than that say 200 degrees Celsius and so that the

02:47:51 say 200 degrees Celsius and so that the gas is exiting the compartment via the window or the extract fan panel or any other means are going to be in that range two to 300 degrees Celsius for his preferred fire and that you will also

02:48:05 preferred fire and that you will also get flames exiting the apartment exiting the the flat for a 300 kilowatt fire that is sufficiently close to the window

02:48:17 that is sufficiently close to the window so that you what you're getting coming out of the flat is hot gases to a 300 degrees Celsius as well as flames exiting the compartment while flames

02:48:29 exiting the compartment while flames essentially a ceiling jet inside the compartment with some flames exiting the compartment and so the eight 850 I think megawatt fire or kilowatt fire is not

02:48:42 megawatt fire or kilowatt fire is not necessary in order to have flames coming out the window that was I could be wrong but that was my understanding after the lengthy discussion yesterday the yeah the question I think is do you agree that in order to have direct flame

02:48:54 that in order to have direct flame impingement on to the ACM panels above the window through an open window so as to be able to ignite them you would need a fire of the magnitude of 830 kilowatts

02:49:05 a fire of the magnitude of 830 kilowatts no I think if you had a fire of 300 kilowatts that was sufficiently close to the window you could have flames going out the window right in in your work an analysis of fast breath have you taken

02:49:18 analysis of fast breath have you taken professor Toreros modeling into account no because I mean only to the extent that it was presented in his initial phase one report and only as a sort of

02:49:29 phase one report and only as a sort of sanity check on what is possible as opposed to having done any detailed analysis of it right and what about dr. lanes analysis same question no I had not considered that okay well

02:49:42 no I had not considered that okay well that's

02:49:43 that's I'll ask you questions about those as we go along let's go a little bit further into some detail if we can in your your your first report that you provided in April this year you know I think

02:49:54 April this year you know I think identified three hypotheses for fire egress exit from from flat 16 and I'm not going to take you through those in detail but just to summarize them if I can for our record there are at pages

02:50:07 can for our record there are at pages 128 to 129 paragraphs five seven five five seven nine and five eight two and I think you had three hypotheses B 1 B 2 and B 3 B what is this right B 1 this

02:50:20 and B 3 B what is this right B 1 this fire spread out of the complaint via the infill sandwich panel within which the extract found was mounted or the extract found itself igniting the cladding adjacent to the window of flat 16 that's B 1 yep what

02:50:33 window of flat 16 that's B 1 yep what was B 1 B 2 was the fire spread from inside the kitchen due to flame impingement from the internal fire venting through the window opening

02:50:44 venting through the window opening leading to the burning of the external cladding and then right that was B 2 originally yep yeah and then B 3 was fire spread via the different parts of the internal window structure being

02:50:55 the internal window structure being penetrated by fire allowing so fire spread directly into the back of the cladding cavity from within within the flat 16 kitchen that was B 3 yep right now you've now carried out further work

02:51:07 now you've now carried out further work as I understand it and have reformulated your hypothesis into two B 1 and B 2 am i right in thinking that b 1 is now an amalgamation a blend of your original

02:51:19 amalgamation a blend of your original hypotheses B 1 and B 2 and your first report that's correct yes I mean be one in the first report was essentially assigning the extract

02:51:30 was essentially assigning the extract fan a causal role yes and I so I think it probably would be fair to say that the original B 1 has just vanished because we have insufficient evidence I think to support that hypothesis now

02:51:41 think to support that hypothesis now right and B 2 who reflects your original B 3 so far getting through the materials in the sides of the window frames and getting

02:51:50 getting adding their way correct yeah now they say essentially b1 is now out through a hole in the window and b2 is out through the materials in the site in the side will run yes in layman's terms yes okay

02:52:05 will run yes in layman's terms yes okay now I think you've updated your conclusions and I just want to show this to you

02:52:09 to you it's page 147 of your report please and if you go to that you can see a paragraph 712 you say paragraph page 147

02:52:29 paragraph 712 you say paragraph page 147 that's okay that's the first report we want lby s the most recent report lb r lb why is six zeros one page 147 yes

02:52:47 lb why is six zeros one page 147 yes thank you pay paragraph 712 you say there is insufficient evidence to accept or reject hypothesis b2 a present on a balance of probabilities I consider hypothesis b2 to be equally

02:53:00 I consider hypothesis b2 to be equally equally likely as hypothesis be one above now it looks from that and I may be wrong but it looks from that as if you've changed your your your view

02:53:11 you've changed your your your view because in your original report you said that beat what is now b2 or was originally b3 was your most likely by a considerable margin is that right yes

02:53:25 considerable margin is that right yes effect can you just explain why you've changed your view essentially because additional evidence has come to light since I submitted that report at the stage that I submitted my initial phase

02:53:37 stage that I submitted my initial phase 1 reports earlier this year the visual evidence that we had from outside the compartment of origin didn't show any external any significant external

02:53:49 external any significant external flaming prior to obvious escalation of the cladding fire whereas some really key pieces of video evidence came to light through the iaws

02:54:01 light through the iaws submissions subsequent to that work which shows that in those two three four five minutes that are critical when the

02:54:14 five minutes that are critical when the fire starts to escalate there there is external flaming coming out of the kitchen window and so it is it is possible that that flames venting out

02:54:26 possible that that flames venting out from that window could have ignited the ACM panels previously I had no visual evidence to confirm that that was what we had had seen in addition to that that

02:54:37 we had had seen in addition to that that that the new video also shows evidence of melted dripping and burning polyethylene on the spandrel cassettes immediately below the window of flat 16

02:54:48 immediately below the window of flat 16 which would indicate significant exposure of the spandrel cassettes above the window which would tend to support an idea that or a hypothesis that flames

02:55:01 an idea that or a hypothesis that flames venting the window and eating the spandrel panel directly above the window could have been a mechanism by which the cladding fire gets going right yeah that

02:55:12 cladding fire gets going right yeah that makes sense so in short further video evidence correct yes now again we're going to spend a bit of time just analyzing that just to understand fully what it is and

02:55:23 just to understand fully what it is and I will be showing you some parts of your newly updated fire spread video I'm not going to do that yet given the time and mr. chair well I'll do is I think to

02:55:35 mr. chair well I'll do is I think to start with the still photographs as we go through it and then perhaps take the video immediately after the lunch it's something we could do the alternative

02:55:46 something we could do the alternative would be to break a bit early yes so it's not too disruptive I think that's

02:55:57 it's not too disruptive I think that's sensible

02:55:58 sensible actually if I may say say very good right now I think we should break now that I can I may be able to go take it slightly more quickly by reference solely to the video as opposed to the photographs can I actually just ask the

02:56:09 photographs can I actually just ask the professor which would be more illustrative for the purposes of view explaining your your opinion the video with pauses all the photographs figures 58 and following in your report page by page 58

02:56:27 following in your report page by page 58 is at page 1 1 7

02:56:42 I mean I think either would probably

02:56:49 either one would work right the videos are perhaps more interesting well let's get that which we certainly use more interesting in which case mr. chairman I'm gonna ask you to rise now if we may

02:57:00 I'm gonna ask you to rise now if we may but I'm gonna give a trigger warning now and when we come back yes in the usual way to which we've been accustomed and that is this that we are going to be looking at video of fire spread on the

02:57:11 looking at video of fire spread on the exterior of Grantville tower in in the period just after 1:00 a.m. and some people may well find this distressing there's also audio that accompanies it they may find that distressing and say

02:57:23 they may find that distressing and say if anybody who is watching or present in the rooms not run to see that then they should not come back at 2:00 o'clock will not be present in front of the live stream at 2:00 o'clock when we resume but I will repeat the trigger warning at that stage says that convenient it is

02:57:35 that stage says that convenient it is certainly I mean can we afford to take the extra five minutes can come back at 2:00 o'clock most unlikely I think we'll do it any way I can to break down

02:57:46 do it any way I can to break down professor have some lunches on please don't talk to anyone about your evidence while you are out of the room and we will start thinking it too

02:58:08 two o'clock please