Professor Luke Bisby provides expert testimony on fire testing standards, the development of combustibility classifications, and the fundamental problems with applying internal fire tests to external cladding scenarios.
00:00:27 good morning everyone welcome to today's hearing
00:00:30 hearing today we're going to hear further evidence from professor bisbee yes mr chairman good morning good morning members of the panel i now call back please professor bisbee
00:00:49 good morning professor i think i left your status as a witness slightly uncertain on thursday so just to
00:00:56 to make things clear would you mind making the affirmation again thank you
00:01:02 there are the words are on the screen for you
00:01:05 for you i do solemnly sincerely and truly declare and affirm that the evidence i shall give shall be the truth the whole truth and nothing but the truth thank you very much and please sit down and make yourself comfortable
00:01:18 yes sister mr chairman thank you professor welcome back uh we we are going to hear your evidence today in response to questions that i have for you we will take scheduled breaks in the
00:01:30 you we will take scheduled breaks in the normal way as we have throughout the inquiry with the witnesses can i just ask you please one thing that i always ask all witnesses and that is to keep your voice up to speak slowly and clearly so that
00:01:41 up to speak slowly and clearly so that the transcriber who sits over there to your right can get down everything you say on the transcript clearly sure now you've produced six reports for phase two of the inquiry um three of
00:01:52 phase two of the inquiry um three of which we referred to last week when we gave your when you gave your presentation and those dealt with the experimental work that you carried out so that was work package one and work package two
00:02:04 and work package two those were respectively lby wp wp1702
00:02:10 and lbywp
00:02:14 2701 respectively dated respectively 15th of march 2020 and the 15th of december 2021 and i'll call each of those the work package one report
00:02:25 package one report and work package ii report
00:02:28 ii report now the third report that you produced to the inquiry when you gave evidence last week was your materials testing report at lbynt
00:02:37 of the 24th of february 2019 updated on the 1st of june 2020 and that as i think you told us is to be ready in conjunction with your final phase 1
00:02:48 conjunction with your final phase 1 report 21 of october 2018 and that is to be found at lbys 601 in addition uh you've produced to the inquiry
00:03:00 uh you've produced to the inquiry another report and that is at lbyp 2
00:03:04 lbyp 2 6 0 1 can we please have that up on the screen
00:03:10 and we could see
00:03:15 we can see that
00:03:17 that that is the work package to system interact systems interaction reports and here on the screen now is phase two regulatory testing and the path to grenfell dated the 10th of
00:03:29 path to grenfell dated the 10th of november 2021 updated twice 4th december 2021 and 1st june 2022 this year and we'll call that your path to grenfell report
00:03:41 grenfell report and if we can go please to page 12 of that report you'll see paragraph 1.16 under the heading statements and there again are the familiar four-fold paragraphs setting out a
00:03:52 four-fold paragraphs setting out a number of matters which cover the statement um first are these your statements in relation to this report they are there and secondly you can see a signature at the bottom next to the date of the 10th
00:04:03 the bottom next to the date of the 10th of november 2021 is that your signature yes it is have you read this report recently i have can you confirm that the facts and the factual matters set out in it are true to the best of your knowledge and belief yes and can you
00:04:15 knowledge and belief yes and can you confirm that the opinions you give are your honestly held professional opinions yes and is it true that you provided your expert opinion in this report to the inquiry in the same way as you would have provided it
00:04:26 same way as you would have provided it to an english court that's correct yes can we then turn to another report which is lbyp2603
00:04:39 and this is titled entitled phase 2 bre reconstruction report and there's a signature there above the 10th of may 2022 is that your signature yes it is and can we go please to page 4
00:04:52 yes it is and can we go please to page 4 where we can see paragraph 1.1 and there again the four-fold statements about the report and the signature at the bottom next to the date again is that your signature yes it is uh and are these your statements about uh this report in
00:05:04 your statements about uh this report in particular they are and have you read this report recently i have and can you confirm that the facts and the matters set out in this report are true to the best of your knowledge and belief yes and can you confirm also that the opinions that you give in this report
00:05:16 opinions that you give in this report are your honestly held professional opinions yes and also that you provided your expert opinion in this report to the inquiry in the same way as you would have done
00:05:27 the same way as you would have done providing it to an english court that's correct right now lastly then please if we can turn to lbyp2
00:05:35 six zeros four we can see a report entitled phase 2 br 135 desktop assessment report and there's a signature there above the date
00:05:47 there's a signature there above the date of the 30th of may 2022. is that your signature yes it is uh can we turn please to page seven in that report paragraph 1.2 the four paragraphs we can
00:05:58 paragraph 1.2 the four paragraphs we can see there again above a signature against the date 30th of may 2022 is that your signature yes it is and are these statements here the statements that apply to this report yes and uh
00:06:10 that apply to this report yes and uh have you read this report recently i have and can you confirm again that the facts and matters set out in this report are true to the best of your knowledge and belief i can and can you confirm that the opinions that you give in it are your honestly held professional
00:06:21 are your honestly held professional opinions yes and is it true that you provided your expert opinion in this report in the same way as you would have provided it to an english court that's correct and can you confirm in relation to all of these opinions that i've shown
00:06:32 to all of these opinions that i've shown you this morning that your opinions and conclusions in them
00:06:36 them have not changed since they were produced to the inquiry that's correct now
00:06:41 now you've given evidence before including in relation to your experience and your fields of expertise and you've set those out in a cv that you provided in your final experts report for phase one at
00:06:52 final experts report for phase one at appendix e and i'll just push that up on the screen so that those who want to look at that can it's at lbys six zeros one
00:07:06 that's the final experts report uh and um if um people want to see um
00:07:13 um well perhaps we should go to your pastor grenfell point a report at lbyp2601
00:07:21 page 10.
00:07:26 lbyp2601 page 10. uh and here you uh the paragraph 39 under paragraph 1.4 and you summarize what you've already told us in the previous report i put up
00:07:38 told us in the previous report i put up on the screen and that runs over to page page 11. and what i want to do is just summarize briefly with you uh what you say about yourself first is it correct you are currently
00:07:49 currently professor of fire and structures within the school of engineering at edinburgh university that's correct uh and also within the same school the head of the research institute for research and environment uh infrastructure and
00:08:01 environment uh infrastructure and environment yes infrastructure and environment and i think formally you were
00:08:05 were royal academy of engineering research chair that's correct as well as arab chair uh they were linked and in the uk you are a chartered structural engineer correct and in
00:08:17 structural engineer correct and in canada a licensed professional engineer that's right and also a fellow of the institute of fire engineers yes institute of structural engineers yes it's international institute for frp and
00:08:29 it's international institute for frp and construction yes and in scotland the institute of engineers that's correct institution of engineers yes and i think you've advised various industrial and government research organizations in this country
00:08:41 research organizations in this country as well as in the us canada france switzerland and germany correct yes and that includes or included in relation to the development of design codes and guides internationally that's
00:08:53 codes and guides internationally that's right and i think you're also currently co-editor-in-chief of the technical journal fire safety journal correct and is it right that your current fire safety and your structural fire
00:09:04 safety and your structural fire engineering research is based on matters including building and infrastructure materials at elevated temperatures fire safe structural strengthening and rehabilitation materials and far
00:09:15 rehabilitation materials and far performance of external cladding materials products and systems correct and i think you've published peer-reviewed articles in those areas as well as in related areas including
00:09:26 well as in related areas including sustainable building design and engineering education correct and is it also correct confirm for me please that you've got extensive experience of engineering research consultancy and university teaching as
00:09:39 consultancy and university teaching as well as the promotion of public understanding of science and engineering that's right finally i think it's right to say that let me ask you you have received a number of awards for your commitment to
00:09:50 number of awards for your commitment to high quality engineering research and for your dedication to the broader academic and research communities yes yes
00:09:58 yes let's then turn to your phase 2 experimental work last week we had the benefit of hearing from you on 9th of june um a presentation to the inquiry on the
00:10:10 a presentation to the inquiry on the experimental work that you carried out as set out in work packages one and two yes yeah there was one matter which i think was an error which i just want to pick up with you before we go on to some questions about work package one and two
00:10:23 questions about work package one and two can we please go to the transcript from last thursday where you gave your presentation that's day two eight nine and i just want to take you within that please to page 179
00:10:41 that's day 289 page 179 thank you and if we go to line 21 you say there and you're just you're describing um the
00:10:52 and you're just you're describing um the experiments where you remove foil faces from the insulation products and if we pick it up at line 15 and you say of course we know that while there were exposed edges of insulation within the cladding system at grenfell tower most
00:11:03 cladding system at grenfell tower most of the insulation products whether rs 5000 or k15 had foiled faces in place in the case of the kingspan product again the foil facer is perforated i therefore repeated the above experiments
00:11:16 therefore repeated the above experiments but in each case i retained the foil on the front face of the insulation including having foil on the front face of the combustible mineral wool insulation now when you use the word
00:11:27 insulation now when you use the word combustible there did you mean combustible mineral wool insulation uh no i mean i i i almost certainly will have meant to say uh non-combustible mineral insulation although you know as
00:11:39 mineral insulation although you know as i said during my evidence uh any material that that has a heat of combustion strictly speaking is not non-combustible so it's the mineral is non-combustible from a regulatory
00:11:50 non-combustible from a regulatory perspective but not necessarily from a physical perspective yes thank you now i'd like to turn police to work package one and can we go to l b y p l b y w p one
00:12:03 l b y w p one seven zeros two page five paragraph twenty nine
00:12:14 and there you say this under the most severe heating conditions used in my experiments i observed short-lived surface spread of flame over the polyester powder coating of samples
00:12:25 the polyester powder coating of samples of reynabon pe acm are you able to say what the likelihood is that there was some surface spread of flame over the reiner bond pe acm in the early stages of the grenfell tower fire
00:12:37 early stages of the grenfell tower fire uh
00:12:39 uh i mean that's a very it's a very difficult question to answer uh the the footage that we assembled at phase one didn't show any obvious surface
00:12:50 one didn't show any obvious surface spread of flame over those panels in the early stages of the fire uh as the fire grew it's very hard to say where that spread of flame was occurring whether it was a consequence of burning of the polyethylene core or consequence of the powder coat so i mean
00:13:02 consequence of the powder coat so i mean that's a very difficult question to answer
00:13:05 answer the amount of energy that would be liberated uh by any burning of the surface coating would be very very small in comparative terms if you compare it to the amount of energy that can be liberated from the polyethylene core so
00:13:16 liberated from the polyethylene core so i i wouldn't think uh i think i intimated as such in my report i wouldn't think that that's a hugely significant observation um then if we look um at the heading
00:13:27 um then if we look um at the heading below that it says alu glaze window infill panels let's look at paragraph 33 there still on page five you say the alley glaze window infill panels are comparatively
00:13:40 window infill panels are comparatively easy to ignite provided that even a small area of xps foam is directly exposed to heating this is due to the low thermal inertia of xps foam
00:13:51 of xps foam it is noteworthy that the low thermal inertia is also the reason that xps fame is desirable as a thermal insulation in buildings now given the conclusions that you've derived from your experiments
00:14:03 derived from your experiments in relation to the allu glaze infill panels are you able to reach any conclusions on the potential contribution of the ignition of the allu glaze infill panels to the ignition of other elements of the facade
00:14:15 other elements of the facade uh again
00:14:17 uh again challenging to say definitively i mean the reason that that comment is is in there is because we have uh evidence uh from phase one from memory uh that suggests that the
00:14:30 from memory uh that suggests that the extract fans that were located within small pieces of infill panel essentially the same product uh in the kitchen windows of the flats uh flat six is all the way up the building
00:14:40 building that those extract fans uh felt softened and fell out quite early on in the fire and certainly the footage that we have from the fire of uh the kitchen window flat 16 early
00:14:51 of uh the kitchen window flat 16 early in the fire suggests that the extract fan had fallen out and there you know you can see a circular hole in that small panel of window info panel material
00:14:59 material if the extract fan falls out of that infill panel then around the circumference of the hole where the fan was sitting you will have had exposed
00:15:10 have had exposed xps foam insulation uh that foam insulation uh is quite likely to have both softened and melted and dripped and ignited uh and will have contributed to burning
00:15:22 uh and will have contributed to burning in that location and will have contributed to flaming that is likely to have impinged on the acm so that's quite a long-winded answer but i think the answer is it's certainly possible that um ignition and burning of the xps core
00:15:33 um ignition and burning of the xps core of the window infill panel that was holding the extract fan will have contributed to some extent and are you able to quantify that contribution uh no uh uh not in any sort of
00:15:45 uh no uh uh not in any sort of meaningful way uh uh you know other you have a you have a fire in the kitchen that is quite a well developed fire and is venting flames out the window and would have been regardless of the burning of the of the infill panel so i
00:15:57 burning of the of the infill panel so i i would say some some additional flaming some additional energy release quantifying that you know whether we're talking one percent or 10 percent or 20 i wouldn't be able to say with confidence moving on
00:16:09 be able to say with confidence moving on to celetex rs 5000 if we go to page six of this same report please you say this at paragraph 45 furthermore i have found that without in
00:16:20 furthermore i have found that without in italics without its aluminium facer celatex rs5000 is comparatively berry in italics very easy to ignite the pr foam core of celatex rs 5000 has very
00:16:33 foam core of celatex rs 5000 has very low times to ignition a direct consequence of its comparatively very low thermal inertia if
00:16:39 if rs-5000 had lost its aluminium phaser what is the likelihood can you tell us of the ignition of the pir foam if it came into contact with downward flowing
00:16:50 came into contact with downward flowing xps
00:16:53 xps um
00:16:54 um so you have downward flowing xps and you have uh
00:16:58 have uh celotex rs 5000 without a foil yes uh yeah i mean i think it's it's going to ignite uh it whether that ignition or the extent to which subsequent burning would be
00:17:09 which subsequent burning would be sustained
00:17:10 sustained is a more challenging question but i think you know these th this pir uh insulation uh without a foil facer when it's exposed to
00:17:20 to a heat flux of you know more than something in the range of 25 to 30 kilowatts per square meter uh for for any appreciable amount of time ignites very quickly as we saw in my uh
00:17:32 ignites very quickly as we saw in my uh where package one experiment so do we take from that answer that the um the relevant heat flux to make xps drip and flow would be enough to ignite
00:17:44 drip and flow would be enough to ignite unfaced rs 5000 uh again it would depend on the duration so it's not necessarily just the magnitude of the heat flux but i think if you've got if you've got burning dripping flowing
00:17:55 if you've got burning dripping flowing xps then you probably have enough heating to ignite uh celitex without a fourth phaser yes and what is the likelihood and that this i think flows from as it were from the
00:18:06 i think flows from as it were from the last answer but what is the likelihood of downward flowing flaming xps uh flaming xps coming into into contact with
00:18:14 with non-faced rs 5000 it it
00:18:19 it it in the geometry at grenfell
00:18:22 um
00:18:27 i i don't think that that likelihood is very high if i'm being honest i have to i would have to think quite hard about the configuration which i don't have in front of me the configuration of the
00:18:39 front of me the configuration of the uh so so the the the allu glaze window infield panels uh at grenfell tower sat within a system of aluminium rails that were that made up the window assembly so you essentially
00:18:50 the window assembly so you essentially have an aluminium aluminium framing around
00:18:53 around uh those infill panels so getting the xps out of the window infill panels notwithstanding my comments about the small panels that has the kitchen extract fans um you know there has to be
00:19:06 extract fans um you know there has to be a route for the for the xps to get out if you like of the aluminium framing you've got two aluminium sheets uh the xps between the two aluminium sheets would melt and start to flow and drip within the infill panel as it gets
00:19:19 drip within the infill panel as it gets to the bottom it finds an aluminium frame the extent to which it can come out of that frame will depend on a whole host of factors and then if it comes out of that frame where it goes i think you'd have to look very closely
00:19:31 i think you'd have to look very closely at that interface between the aluminium framing and the cladding below the windows uh from memory i think i i probably would consider that
00:19:43 consider that reasonably unlikely i think it would more likely uh
00:19:47 uh if the if the acm cladding were still in place beneath the window uh i think i would consider it more likely that that xps the melted dripping xps would flow
00:20:00 xps the melted dripping xps would flow over the outside surface of the acm from memory
00:20:06 memory and therefore not come into contact with rs 5000
00:20:10 rs 5000 um whether foil faced or not full foil faced at that point i mean event i mean eventually probably yes given that the acm is probably going to ignite and burn quite vigorously and disappear and eventually yes you're
00:20:21 disappear and eventually yes you're going to find some insulation there and certainly below the windows the way the the the way the celitex insulation was cut and formed within the cladding cassettes below the windows uh again from memory the top uh the top
00:20:34 uh again from memory the top uh the top edges of the insulation panels if you like
00:20:37 like uh did not have foil facers on them you know they were cut to an angle so that you get a sort of a downslope on the acm panel below the window um so if the acm were removed
00:20:48 um so if the acm were removed then you do have exposed celotex at that location beneath the window but it becomes a question of uh you know whether we're in an upward fire spread mode or a downward mode or or a lateral horizontal kind of mode
00:21:01 horizontal kind of mode uh if we turn police to page seven of this same report and gay please to paragraph 49 you say there from my experiments to date
00:21:09 date it appears that flat samples of celetex rs-5000 tested in isolation do not significantly spread flame horizontally in italics
00:21:20 in italics in the absence of an applied external heat flux additional experimentation is required to confirm this what additional experiments would be required to confirm that in your opinion uh i would want to do a lateral ignition
00:21:34 uh i would want to do a lateral ignition and flame spread type testing um both with and without the foil facer so it would be similar you know you could you could do something similar to a ps476 part seven lateral flame spread test yep
00:21:48 i mean i have to say based on our experiments what i what i expect you would see is that they would not spread flame
00:21:54 flame uh very enthusiastically at all yeah and in the fire at grenfell would the rs 5000 have been the subject of an applied external heat flux uh
00:22:04 uh can you repeat the question yes would the rs 5000 have been the subject of an applied external heat flux again it depends on whether we're talking about um
00:22:16 um it depends on where where the insulation is on the building obviously but i mean yes if you have a large external fire burning then you have a large heat flux yeah yeah
00:22:25 yeah yeah and the source of that heat flux would have been what in your view uh early in the fire it would have been um burning polyethylene from the acm um i mean very early in the fire as we're
00:22:36 mean very early in the fire as we're talking about the fire getting from the kitchen out into the insulation out into the cladding system itself uh that source of heat flux could have been the kitchen fire itself um you know i talked last week about the potential route of
00:22:47 last week about the potential route of fire spread through the side of the window and in that situation the kitchen fire would have provided the heat flux as the fire grows you've got most of the heat release as i said last week is probably coming from the polyethylene
00:22:58 probably coming from the polyethylene from the acm so
00:23:01 so in an upward fire spread mode um
00:23:06 um you're you're likely going to get the heat flux coming from that fire plume uh as the fire reaches the crown starts to go around the ground and you have dripping polyethylene down the building
00:23:18 dripping polyethylene down the building um then it gets slightly more complicated in terms of where do you have polyethylene collecting pooling generating pool fires igniting other materials etc at that point it gets complicated
00:23:30 at that point it gets complicated probably beyond the point that i could say for sure although in in every case uh
00:23:38 uh as i've said in every case my view is that the acm pe and the polyethylene the burning of the polyethylene is what's contributing uh the vast majority of that heat flux now
00:23:48 now i mean i should i should also say that of course as as the fire spread past flats in grenfell tower either up across or down the tower
00:23:59 across or down the tower it typically ignited fires within the flats
00:24:03 the flats and those fires then burned as you know typical if you like compartment fires ventilation limited compartment fires and you have fire plumes coming out the
00:24:15 and you have fire plumes coming out the window for extended durations of time given that the fire service couldn't do anything
00:24:20 anything about those fires so then you have a very significant external heat flux coming from the fire plumes generated by those fires over long periods of time now those
00:24:31 those those heat fluxes and those exposures of the
00:24:34 the cladding products uh
00:24:37 uh are on time scales that are typically much longer than than those that would be relevant to the external fire spread so so and under those i mean that's it's actually quite an important point you know
00:24:48 know after the fire when when we went to look at grenfell tower after the fire and we did you know a walk-around survey of the entire external surface of the building
00:24:59 entire external surface of the building once the scaffolding had been put around the tower and we we examined um uh the the insulation you know the extent to which the the insulation boards had charred or or been burned in
00:25:12 boards had charred or or been burned in the fire uh you know
00:25:16 you know the question is the the charring uh and of the insulation that you observe when you walk around the fire after the you know days weeks months after the fire has been put out to what
00:25:27 after the fire has been put out to what extent is that charring evidence of charring that will have occurred as the fire was spreading or to what extent is that charring that will have occurred as a consequence of the fires burning in the flats over
00:25:38 of the fires burning in the flats over long durations once the spreading had essentially occurred in the acm pe was long gone
00:25:44 long gone so it's yeah that's quite a long-winded answer to your question but i think i think it's important to think quite hard about
00:25:51 about the durations over which the materials and products uh that constituted the external wall arrangement uh the durations over which their burning occurred because products that release a lot of
00:26:04 because products that release a lot of energy very quickly are much more hazardous from an external fire spread perspective than products that might contain similar amounts of energy but burn very very slowly under different circumstances and that's you know it's a very important
00:26:15 that's you know it's a very important distinction yes thank you i'm sticking with page seven can we look please at paragraph 51 where you say this however the ease of ignition of celetex rs 5000 may be relevant as
00:26:28 celetex rs 5000 may be relevant as regards initial growth of the fire outside the kitchen window flat 16 where without protection from foil facer or aluminium tape at a cut edge it could have been one of the first or possibly the first cladding materials ignited
00:26:41 the first cladding materials ignited thus promoting ignition of other materials that were present at that location for instance the pe filler stroke core of the reynabond pe acm rain screen cassettes can you explain the mechanism by which
00:26:53 can you explain the mechanism by which the ignition of the rs-5000 may have promoted the ignition of the pe filler pe core of the raynor bond acpe acm uh i mean simply that if if
00:27:07 uh i mean simply that if if something ignites uh and starts to burn then it's gonna liberate energy that energy is is gonna go somewhere and if that energy goes you know into the acm so to speak uh heats the acm and starts
00:27:19 so to speak uh heats the acm and starts to to mobilize polyethylene which cannot ignite
00:27:22 ignite then
00:27:23 then that would be the mechanism you know the mechanism is simply that burning of the insulation liberates energy that could then be used to heat the acm and cause it's burning
00:27:33 and what about other elements of the facade
00:27:36 facade uh i mean you there were other things in in the cavity you had um you had the the the upvc window frames which would have been adjacent to that location which which can burn um you will have had
00:27:48 um you will have had epdm
00:27:50 epdm rubber membrane around that location which can also burn uh you had you know spray foam bits of timber various other things
00:28:02 timber various other things in the clouding system at that location so there's a variety of things that could burn in that location which is one of the reasons why i say you know
00:28:10 you know it's very hard to say
00:28:13 to say with any certainty what was the first item ignited and and
00:28:20 and and whether the first thing ignited would have continued burning in the absence of the other things is really difficult to unpick are you able to quantify the amount of energy that the rs 5000 would have allowed to be fed back to the other
00:28:32 have allowed to be fed back to the other clouding components uh i mean as i sit here you know if we're talking specifically about the configuration that existed at grenfell tower
00:28:43 grenfell tower i think no is probably i mean i certainly wouldn't want to attempt it as i sit here my work package one experiments do quantify that the types of energy
00:28:56 quantify that the types of energy release or heat release that we would expect from the various insulation products both with and without foil phasers under a range of heat flux conditions and all of that work suggests that the energy contribution from the insulation
00:29:09 energy contribution from the insulation products is quite small and that's probably the best quantification i could give you you know comparatively quite small if you compare against something like the polyethylene from the acm once it starts burning
00:29:20 from the acm once it starts burning right now you say quite small do i take it from that that you're not able to attribute a reasonably precise percentage
00:29:32 percentage uh i mean this is this is something that i've discussed within my team at edinburgh a lot um
00:29:40 one of the one of the challenges is of course we've performed experiments where we've quantified a number of things under a range of conditions none of those conditions are exactly uh what was at grenfell tower they are
00:29:51 uh what was at grenfell tower they are all representative of the physics but we can't say for sure what was happening at grenfell tower in the cladding it's one of the challenges when you go from from the lab to reality um
00:30:03 um i was discussing this point within my team quite recently because i expected i'd be asked this question and and you know the best i can say is that i think the contribution from the insulation
00:30:14 from the insulation uh
00:30:14 uh in that initial environment and even to the upward fire spread is is probably less than 10 of the overall contribution something like that i mean it could be it could be
00:30:25 like that i mean it could be it could be two percent it could be ten percent um
00:30:31 and before getting too hung up on figures are you able to say well there are two things first of all flowing from that last answer
00:30:40 answer does the answer to the question i've just asked you depend on where in the building and at what point during the fire treating it as a single entity
00:30:50 entity um
00:30:52 um you are looking i think so yes yeah i mean the work that i've the work that i've done uh today has focused pretty heavily on the up the upward you know the fire going from a small fire to a big fire in
00:31:04 going from a small fire to a big fire in an upward mode uh how the fire goes from uh from a small fire to a big fire in the in the lateral or the downward mode is is more complicated
00:31:16 complicated yes just pinning that down a little bit further if i can you you use the expression going from a smaller fire to a bigger fire doing the best you can with a particular point whether in timing or in
00:31:27 point whether in timing or in quantitative terms um maybe that's the point at which the the fire becomes out of control of any reasonable frs if that's a possible bridge point but but at that point
00:31:40 but but at that point what would have been up to that point the contribution uh
00:31:46 uh in percentage terms if you can of the rs 5000
00:31:49 5000 up to the point that the the fire is quote out of control yes and spreading quickly up the building yes less than 10 right
00:31:57 right and secondly less than 10 would you say that that was negligible or would you say that it was small but still materially contributive um
00:32:14 i mean i guess it again it depends what we mean by the contributive if you if we're i presume in your question that we're we're talking about the contribution of the installation via
00:32:25 the contribution of the installation via its combustion rather than the constellation the contribution of the insulation by its presence if you like yes because as i as i as i explained
00:32:38 as i as i as i explained last week when i gave my presentation the fact that the insulation has a very low thermal inertia and is very insulating is critical absolutely critical so if there had been no insulation there whatsoever
00:32:51 insulation there whatsoever uh whether kingspan or celatex or or mineral wool uh the outcome may have been quite different
00:32:58 different uh significantly different more than ten percent different the fact that that insulating material is also contributing energy
00:33:06 energy by its burning is is what i'm referring to the ten percent yes and that's probably quite an important distinction for me to make thank you for that clarification then let's turn to your report dealing
00:33:17 then let's turn to your report dealing with kingspan k15 page nine please paragraph 65.
00:33:32 page 9 same report page 9 paragraph 65. and you say there however the ease of ignition of kingspan k15 may be relevant as regards initial
00:33:44 k15 may be relevant as regards initial growth of the fire outside the kitchen window of flat 16 if it were present in this location where without protection from foil facer or aluminium taper to cut edge it could have been one of the
00:33:55 cut edge it could have been one of the first cladding materials ignited thus increasing the local heat flux and promoting ignition of other materials present for instance the pe filler stroke core of the rayna bond pe acm rain screen cassettes
00:34:06 rain screen cassettes are you able to describe for us the mechanism by which the ignition of the k-15 as you say could have promoted the ignition of the pe core of the rhino bomb peacm as well as the
00:34:17 the rhino bomb peacm as well as the other elements of the facade i mean i would i would give the same answer i gave previously for celatex effectively yeah
00:34:24 yeah and when you say could have been would you give the same answer in in response to the question of quantification uh that's right yeah yes
00:34:35 uh that's right yeah yes and if we go to page 26 of this report please
00:34:39 please page 26 you say this at paragraph 165 at the top of the screen unlike polyethylene both pir and phenolic polymer foam are thermosetting
00:34:50 phenolic polymer foam are thermosetting polymers i.e they will char on heating rather than melting and dripping or or flowing as a consequence it is the extent to which pir and pf foam ignite and spread flame over their surface that
00:35:02 and spread flame over their surface that is a primary interest along with the extent to which they do or do not continue to contribute to heat release and flame spread over the time scales relevant to consideration of external fire spread during the grenfell tower
00:35:13 fire spread during the grenfell tower fire
00:35:14 fire given the absence of melting dripping or flowing
00:35:18 flowing from uh pir and phenolic polymer foams what is the mechanism by which the pir and
00:35:25 and phenolic foams contribute to the external fire spread by insulating the cladding system and making sure that the heat is retained within the system and fed back to the
00:35:36 within the system and fed back to the acm which exacerbates the burning of the acm
00:35:39 acm and
00:35:40 and by liberating some admittedly small amount of energy via their own combustion uh potentially by spreading flame although i think the the flame spread characteristics are
00:35:51 flame spread characteristics are probably not that significant particularly if you had a foil facer in place
00:35:54 place yes now if we then turn to page 27 um
00:35:58 um paragraph 169 you say under the heading products and materials under investigation para 169 i decided however not to use the cladding products removed and retained from grenfell tower for my
00:36:09 and retained from grenfell tower for my phase 2 experimental program i made this decision because i felt that i would be unable to guarantee adequate control by others either of the chain of custody for these products or the specific origin of the various samples nor could i be
00:36:21 various samples nor could i be completely certain that the products had not been damaged in some way due to their installation on the tower their in-situ service experience some exposure to heating during the fire or mechanical damage during their removal
00:36:33 damage during their removal do you consider that as a consequence of that decision that you've described there
00:36:37 there you would have been unable to take account of any alterations or modifications to the cladding products which resulted from the manner in which they were installed or the means by which they were affixed to the facade of
00:36:48 which they were affixed to the facade of the tower
00:36:52 i mean none of none of the none of the experiments that i've performed
00:36:58 performed uh
00:36:59 uh in
00:36:59 in intended or or even tried to simulate or reproduce those issues in any way that i would say is directly applicable to grenfell tower we
00:37:10 directly applicable to grenfell tower we were much more interested in uh in understanding the the mechanisms by which the different behavior what the behaviors would be and then the mechanisms by which those behaviors would manifest in the product
00:37:21 behaviors would manifest in the product so i know i don't i don't think that's i don't think i would agree with that statement
00:37:27 right but um it is
00:37:32 focusing on the consequences of your decision
00:37:35 decision not to use the cladding products removed and retained did that materially or should that materially affect the conclusions no
00:37:48 so do we take it from that that you didn't think it was necessary to take account of the exposure of the pe core resulting from the installation of the product in cassette form uh in in the experiments that i
00:38:01 uh in in the experiments that i performed
00:38:02 performed um we we did certain things to the acm panels certainly in the work package 2 experiments that were intended to ask questions that were
00:38:14 were intended to ask questions that were relevant to whether or not the panels were installed in a in a riveted form or a cassette form so for instance as i showed in my presentation we we intentionally routed the rear face the
00:38:26 intentionally routed the rear face the face of the acm panel that was facing into the cavity in our work package two experiments because we recognized that the the opening up the separation uh the
00:38:37 the the opening up the separation uh the removal of the inside aluminium face in a cassette uh configuration would probably drastically affect the burning behavior
00:38:46 behavior and that's certainly something that we observed
00:38:48 observed we also performed and i didn't present the results of these experiments last week but we also performed some of the experiments that are presented in my work package to report
00:38:59 report where we uh intentionally uh if you like overly routed or overly riveted the acm panels so we performed experiments where we looked at the
00:39:11 experiments where we looked at the the time to escalation the manner of failure
00:39:15 failure heat release rates peak release etc where the acm panel in addition to being the baseline configuration that i showed during my presentation last week we added let's say rivets to the acm panel
00:39:28 added let's say rivets to the acm panel so we intentionally secured the inside face of aluminium to the acm panel so that we could see what the influence of that would be and we did that actually in a number of configurations so you know we riveted the entire panel
00:39:42 so you know we riveted the entire panel and observed what differences in behavior uh manifested in the experiment so we riveted only the top half of the panel and left the bottom half free to open up
00:39:50 open up we did experiments where we intentionally routed horizontal lines over the aluminium face on the inside of the acm panel to see what would happen if you had more exposed lines of acm core and
00:40:03 more exposed lines of acm core and smaller aluminium inside surfaces that could mobilize in a different way and we did observe differences in behavior so you know we've asked in those experiments i asked a number of questions that i think are relevant
00:40:14 questions that i think are relevant to understanding why the manner of fixing could matter and i think have pretty clearly demonstrated at least for myself
00:40:25 demonstrated at least for myself that um
00:40:27 that um the presence of rivets and routing uh it can be very important in terms of the
00:40:35 the time scales over which things occur now um
00:40:38 um two things first i i i think you're drawing a distinction which i may have blurred accidentally in my answer between workmanship and in
00:40:51 workmanship and in experience of the particular panels of grenfell
00:40:55 grenfell and just to be clear that's what you've excluded under 169 here is that right uh what i've what i've excluded under 169
00:41:06 if you like is the
00:41:08 the uh
00:41:10 uh the manufacturing and materiality of the products themselves so the concern that i'm i'm trying to express uh in 169 here is a concern that
00:41:21 express uh in 169 here is a concern that given
00:41:23 given given that there was a very significant fire at grenfell tower um and given that that fire lasted for hours and hours uh and given that there was a lot of downward mobilization of polyethylene
00:41:35 downward mobilization of polyethylene in that fire uh
00:41:39 uh you know there were significant portions of the building of the of the clouding system at grenfell tower that looked relatively undamaged let's say and the metropolitan police service took all of those products the undamaged
00:41:51 all of those products the undamaged products and they put them in a warehouse
00:41:53 warehouse and they used those products for experiments so that they could understand you know what products precisely had been used what classifications they would achieve etcetera etcetera the the metropolitan
00:42:05 etcetera etcetera the the metropolitan police service forensics team working with bre did a whole host of things to try to understand those products when it came time for us to perform the experiments related to my
00:42:16 to perform the experiments related to my phase two work at edinburgh the the question was whether we should ask the metropolitan police service if we could have a substantial amount of materials that they had stored that had come off the
00:42:27 they had stored that had come off the tower or whether uh whether that was whether we would be able to get from them
00:42:32 them uh a suitable volume of products that would allow us to undertake the work that we wanted to undertake recognizing we were going to need quite a lot of each of the products in order to perform you know the very large number of experiments that we ended up
00:42:44 of experiments that we ended up performing so
00:42:47 so the two concerns were one maybe that much a product wasn't available via the mps given that they needed some of it for their purposes uh and we certainly didn't want to deprive the mps of uh the product that
00:42:59 deprive the mps of uh the product that they would need in order to conduct you know criminal work etc uh and so if we're gonna so where do we get the product from uh and the answer is we get it from the corporate cps to the inquiry but of course uh one if one
00:43:13 the inquiry but of course uh one if one goes down that road one has to be sure that what one is given by the corporate cps is uh fairly representative of what was on the tower so that that's what i'm expressing there is you know we recognize that probably we're going to have to go to the corporate cps to get
00:43:26 have to go to the corporate cps to get the products and we wanted to be we wanted to have some confidence that what we were being given uh you know uh hadn't been fiddled in any way let's put it that way right but were you also seeking to eliminate error
00:43:39 were you also seeking to eliminate error in your own methodology by using products which had actually been used as a result of yeah i mean it's very very difficult to know with certainty
00:43:48 certainty if uh any particular piece of clouding that we might obtain from the mps was actually undamaged had not been altered in some way had not been heated in some way during the fire
00:43:59 way during the fire but that was much more about
00:44:02 the the thermal history of the sample than it was about the manufacturing or installation history of the sample yeah and the second thing just to draw out from what you've just been telling us
00:44:13 from what you've just been telling us is that there's a distinction between non-use of the materials actually used at grenfell tower which you've covered in paragraph 169 and what you've just said about that on the one hand and as it were pre-designed installation
00:44:26 and as it were pre-designed installation or fixing
00:44:27 or fixing methodologies use of bolts or rivets on the one hand or use of cassettes on the other which were the subject of analysis by your team that's right but not in so far as we
00:44:38 that's right but not in so far as we were attempting to recreate the conditions at grenfell tower we were simply attempting to understand yes and and can you tell us it's in your reports and your your data but can you summarize for us what you concluded as a result of
00:44:51 for us what you concluded as a result of the experiments done where rivets were applied
00:44:55 applied uh that the the presence of rivets substantially uh and obviously with all sorts of caveats about how many rivets and where and of what type et cetera et cetera
00:45:05 cetera but
00:45:07 but if if
00:45:08 if if one manages by any mechanism in one's installation of acm pe panels to prevent the aluminium skins from opening up
00:45:19 opening up either with rivets or with framing or bracketing or you know i'm aware that over the years in standardized testing of acm products sometimes little u-sections of metal were put round the edge
00:45:32 were put round the edge of panels
00:45:34 of panels to try to
00:45:36 to try to to keep the faces together um
00:45:39 um that that will improve performance now that
00:45:43 now that that will
00:45:45 that will in our experiments what that tended to do
00:45:48 do was to
00:45:49 was to make it take longer for escalation to full involvement of the acm to occur but
00:45:56 but you still do get eventually full involvement of the acm and you still deal you still do get um the same approximately the same total amount of energy release so
00:46:07 amount of energy release so the the presence of rivets would it or the presence of any mechanism that holds the aluminium skins together what it does is it prolongs the time until things go really bad until you get
00:46:19 until things go really bad until you get you know a lot of burning and you get this rapid escalation and that
00:46:24 and that that's
00:46:25 that's for me very relevant to a number of questions and pieces of evidence that the inquiry has heard you know the fact that riveted systems are apparently able to
00:46:38 riveted systems are apparently able to achieve a class b result in the euro classification system when tested in an sbi
00:46:43 sbi but a cassette system does much worse um
00:46:47 um the
00:46:48 the what's interesting about that is that if you let an sbi test
00:46:53 test run
00:46:54 run with with a riveted system my expectation is that eventually you would you would see the same result it's just that you know you because of the time scales that are involved you don't necessarily push the panels
00:47:06 don't necessarily push the panels uh
00:47:07 uh to that
00:47:08 to that to that point again within my team my colleagues will hate that i use this terminology because we argued about it quite a lot as we were doing the work but i started referring to these acm products as tipping point products and
00:47:20 products as tipping point products and so there's a moment uh where things go from not so bad to really bad and that and if you if you pass that point all bets are off and if you don't then things can
00:47:32 off and if you don't then things can sometimes look like they're not quite as bad as they might be a minute later um so that's one of the reasons these products are so dangerous is because they display this very volatile behavior
00:47:44 volatile behavior yes
00:47:46 yes thank you now um moving on to page 32 of your report
00:47:51 uh you um explain there in various places but let's pick it up a paragraph one uh eight four that you're aware that the celetex insulation boards used at grenfell were
00:48:03 used at grenfell were i think typically produced on uh two uh different production lines this is power one eight three before the hitchin and the henniker lines and uh at one eight four you say this celatex bar link lasers llp have
00:48:15 celatex bar link lasers llp have provided the inquiry with a detailed account of these differences i've not been able to quantify the possible influences of these differences on the reaction of the these two thicknesses of celatex rs 5000 products
00:48:26 thicknesses of celatex rs 5000 products to to heating aside from a brief comparative evaluation of the response of the rs5080 and rs 51 double zero product supplied to me
00:48:37 to me this comparison is presented in section 8.7.3
00:48:40 8.7.3 i do not however consider it likely that the temporal variation in manufacturing inputs straight processes is significant um
00:48:50 um what do you mean there by temporal variation
00:48:54 variation uh now okay yeah so i mean i'm not a i'm not a polymers chemist nor am i someone who manufactures polymer foams but you know the base chemistry of these products uh
00:49:06 products uh didn't change a whole lot you know it seemed to me in reviewing that information that there were you know little tweaks and changes and decisions made by the manufacturing operatives in terms of you know a little
00:49:17 operatives in terms of you know a little component here a little component there you know probably based on things like uh the temperature uh in the facility that day potentially ambient relative humidity and things like that that might influence manufacturing i don't know
00:49:29 influence manufacturing i don't know so i mean i would hesitate i was i would hesitate to put too much stock in that if if the inquiry feels that the the changes in uh let's say chemical
00:49:40 the changes in uh let's say chemical inputs to manufacturing process over time uh warrant uh investigation in terms of the possible outcomes for the resulting product then i would probably insist that the
00:49:52 then i would probably insist that the inquiry ask ask you know a polymers manufacturing specialist rather than rather than me but it's really the word temporal i was asking you yeah temporal i just mean in time you know um
00:50:03 i just mean in time you know um if if you look at the data that we were provided um again from memory it was quite some time ago i looked at this um you know there's there's little adjustments that are made to the manufacturing process in time right um
00:50:14 manufacturing process in time right um and i and i felt that that was probably unlikely to to significantly alter the outcomes of what we would observe if we took a piece of the product and tested it in some way you know that it's not going to vary significantly any
00:50:25 it's not going to vary significantly any of the reaction to fire properties that we looked at in my view you know heat of combustion critical heat flux for ignition those sorts of things i wouldn't expect to see differences yes i see now if we go down to page 58 of your report please let's
00:50:37 to page 58 of your report please let's look together at paragraphs 328 and then 330 on that page under the heading effects of melting and dripping and in 328 you say this in my phase 1
00:50:48 and in 328 you say this in my phase 1 final expert report i've identified that melting and dripping of burning pe filler stroke core material from raynabon peacm rainscreen cladding cassettes played a critical role in both
00:51:00 cassettes played a critical role in both the horizontal and downward fire spread experience during the grenfell tower fire i've also identified that xps foam insulation that formed the core material within the alley glaze window in fill panels may have been a secondary source
00:51:12 panels may have been a secondary source of melting and dripping thermoplastic polymer
00:51:16 polymer and then at 3 30 you say pir and phenolic foam insulations however are thermosetting polymers which will not melt
00:51:25 melt are you able to explain how your experiments in work package one or work package to quantify or measure the extent to which rs 5000 or k15 may have contributed to the downwards
00:51:37 contributed to the downwards spread of flame um
00:51:41 um i mean in a in a direct way uh
00:51:45 uh the
00:51:47 the the rs 5000 it in a direct way won't have contributed uh to the the downward spread in that you know the the rs 5000 product itself
00:52:00 the rs 5000 product itself isn't going to mobilize bits of of itself downward you know you're not going to get bits of of um burning
00:52:08 burning uh pir foam mobilizing downward and spreading flame by that mechanism obviously the extent to which those products insulate a cladding cavity where you might have other things burning is going to be relevant to the
00:52:19 burning is going to be relevant to the downward mechanism in that you know if you have more heating locally more melting of acm more mobilization of pe you're going to get more downward um
00:52:30 um for the so so for the cell attacks you know as in terms of the material the material that made up the core itself no direct involvement although contributory contributory involvement uh to the other
00:52:41 contributory involvement uh to the other mechanisms of downward i.e the melting of the polyethylene with respect to the um phenolic i would say largely the same thing with the with the the small caveat
00:52:52 thing with the with the the small caveat that
00:52:53 that we did observe um that the uh
00:52:57 uh the phenolic foam or the kingspan product did have a tendency to
00:53:03 to um to spoil to mechanic to become to come mechanically uh detached from the face of the insulation when we didn't have a foil face or there when there was no foil facial there to keep that material in
00:53:14 facial there to keep that material in place so you would you would observe pieces of um of glowing phenolic foam that would detach and drop downward that is a possible
00:53:27 that is a possible contribution to downward although again you know you're not talking a huge volume of material these pieces of material in the absence of an applied external heat flux would go out very quickly they wouldn't continue to flame
00:53:38 quickly they wouldn't continue to flame right so it's not a huge issue but it is you know it is a small distinction between those two products that i think is relevant right so just to be clear then
00:53:46 then your findings were that rs 5000 would not produce burning flaming debris of any kind but kingspan k15 would uh yeah i mean although i you know i
00:53:58 uh yeah i mean although i you know i would hesitate to say that kingspin k15 would would uh develop you know a lot of burning flaming debris i would say that we observed bits of glowing phenolic foam that would detach from the face of the sample and then drop downward yes so
00:54:10 the sample and then drop downward yes so it's a qualitative difference but you can't really say much about the quantitative difference that's right yes um then uh if we go please two uh
00:54:24 yeah well let me just ask you that um are you able to say or the ext comment on the extent to which melting pe may lead to the involvement of pir or phenolic foam into the fire through pooling
00:54:36 pooling uh significantly yes yes i mean i think pooling of pe on on surfaces um within and outside the clouding uh is was very significant at the grenfell tower fire yes now you showed
00:54:48 grenfell tower fire yes now you showed us last week very helpfully your drip tray in the work package two experiments uh when we saw that from the video in particular um are you able to make any analysis or
00:55:00 um are you able to make any analysis or assessment um for an experiment which which was designed identically to your work package two experiments but which replaced the drip tray you used there with an exposed edge of a sample of rs
00:55:12 with an exposed edge of a sample of rs 5000 or k15 or rockwool
00:55:18 you mean if instead of having a a steel drip tray
00:55:23 drip tray we have a
00:55:25 we have a a piece of insulation there yes so dripping
00:55:28 dripping molten dripping burning polyethylene falling onto unexposed rs 5000 or k15 or rockwool
00:55:42 no i i'm not able to say anything confidently about that we certainly didn't do it we certainly didn't try that to see what would happen uh
00:55:51 uh i i suspect uh that uh you know in that in that scenario uh you've got polyethylene dropping onto a very insulating surface
00:56:04 unless you've got mineral where the polyethylene might actually you know wick into the fibers and you know i have absolutely no idea what would happen under those circumstances um
00:56:15 um but the
00:56:16 but the one of the things that's interesting about the drip tray um that i didn't uh discuss last week is we when we were developing the experimental program
00:56:28 experimental program um as i mentioned last week the reason we had the drip tray was because uh in if you don't if you don't control if you like
00:56:37 like the pool fire that you get um
00:56:40 um the burning polyethylene pool fire that you that you get once the polyethylene starts to mobilize downward you get polyethylene going all over the place and you get um a pool fire that is very hard to control
00:56:52 a pool fire that is very hard to control the consistency of from experiment to experiment so the drip tray was created or was was placed in the rig so as to make sure that the pool fire we got was the same every time and we could ask other
00:57:03 every time and we could ask other questions that were perhaps more interesting in a in a more controlled way
00:57:07 way when we when we were doing our initial experiments to kind of um finalize the procedure that we were going to use in the exact setup we ran experiments where we had the drip tray but the drip tray wasn't
00:57:19 but the drip tray wasn't i didn't mention it again last week but the drip tray you have a steel ledge underneath the acm on top of the steel ledge you have a drip tray between the drip tray and the steel ledge
00:57:30 steel ledge we had a thin piece of ceramic paper which is essentially an insulating ceramic paper a couple of millimeters thick
00:57:38 thick when we ran an experiment without the ceramic paper we didn't it didn't escalate
00:57:43 escalate uh when we ran an experiment with the ceramic paper it did escalate and so we always use the ceramic paper now if we had left the burner in longer you know various other um questions we could have could have asked
00:57:55 questions we could have could have asked about the extent to which we needed an input of heat to make the experiments escalate but that fact
00:58:01 that fact indicates that or indicated that the extent to which the polyethylene in the pool fire was kept warm
00:58:10 warm was insulated itself as a pool fire was relevant
00:58:13 relevant so if you if you have the pool fire developing on a highly insulating surface then probably it's going to make matters slightly worse yes thank you now if we um then go to uh paragraph of uh paragraph 331 here same
00:58:26 paragraph of uh paragraph 331 here same page page 58 you say melting and dripping of polymer filler straight core materials can be expected to play significant roles in the responses to heating of both p e acm and value glaze window infill
00:58:38 p e acm and value glaze window infill panel since they will influence the extent to which the thermoplastic philistine core materials burn in situ at the sample location or rather in some other location once mobilized
00:58:49 other location once mobilized can you explain what you mean by since they will influence the extent to which the thermoplastic filler stroke core materials burn in situ at the sample location or rather in some other location once
00:59:01 rather in some other location once mobilized what do you what do you mean by that um i i mean that it matters i guess in simple terms i mean that it matters where the energy goes uh
00:59:11 uh or or if the energy goes if if so so these these materials the polystyrene the xps and the uh polyethylene
00:59:22 uh polyethylene are quite calorific materials they have a lot they have high heats of combustion and
00:59:29 and where and when that energy that's essentially locked up in the material uh is released matters so if you if you have if
00:59:37 have if if you have a lot of mobilization of the polyethylene uh the polyethylene in the cladding is no longer where it started and where it goes matters
00:59:48 goes matters you know
00:59:49 you know so you know if it if the polyethylene drips out of the cladding and into the atmosphere and falls through the sky and lands on the pavement at the base of the building which we did see some of that
01:00:01 building which we did see some of that uh then that the influence of that burning polyethylene on the clouding fire locally has been removed if however the polyethylene drips and
01:00:12 if however the polyethylene drips and pools
01:00:13 pools in the shelf at the bottom of a cloud and cassette uh you know the bottom these cladding cassettes on the tower certainly the spandrel panels you have uh if the face of the panel comes down
01:00:24 uh if the face of the panel comes down you have it comes in above the window and then there's a little lip up on the back of that cladding you've got
01:00:30 got essentially a perfect container for
01:00:33 for a pool fire of polyethylene in sitting in your cladding so every every every spaniel cassette at grenfell tower uh is essentially a drip tray for burning polyethylene on
01:00:45 drip tray for burning polyethylene on the inside on the inside of the cassette within the clouding system and that's looking at the foil facing looking at the insulation that's right yeah so you you you know you have
01:00:57 yeah so you you you know you have a very efficient um
01:01:01 um you have a very efficient system for creating
01:01:04 creating the worst possible fire uh in those cloud cassettes you know you have you have a you have a physical means by which to locally uh collect pool fires of burning polyethylene within your cladding so
01:01:16 polyethylene within your cladding so that that energy can be released locally in the worst possible way um
01:01:21 um for upward spread yep now um can we go to page 81 of this report please and go to paragraph 422 um
01:01:31 um you have um set out some graphs on that page under figure 32 measuring heat release rates for typical samples of acm
01:01:43 for typical samples of acm and at 422 you say this the
01:01:48 the the heat release rate is central to evaluating
01:01:53 um
01:01:58 yes um four two two the heat release rates from these small samples are comparatively low you say it is noteworthy the measurement resolution of the hr measurements made by the university of edinburgh's furniture
01:02:09 university of edinburgh's furniture calorometer is insufficient to provide high fidelity data for such low heat release rates however this does not affect the conclusions drawn from the data
01:02:20 conclusions drawn from the data now um
01:02:22 now um then you go on to say
01:02:30 um yes i think it's probably enough for my question is it your opinion that that a feedback loop existed during the fire at grenfell tower uh i mean
01:02:40 uh i mean yes most i mean there's always a feedback loop when a fire grows yes yes and are you able to identify the elements of the facade which would have contributed or created this feedback loop
01:02:51 loop uh
01:02:52 uh anything that had a heat of combustion will have contributed to some extent to that feedback loop right and
01:02:59 and what would that include identify the elements um
01:03:04 um i mean
01:03:07 i mean in order of of decreasing relevance let's i mean i can try to do that in order of decreasing relevance i mean the acm pe first and foremost uh the uh the insulation products
01:03:19 the uh the insulation products uh whether celatex or kingspan at any given location yes uh and then all you know
01:03:25 know all of it really any any um any timber that might have been there upvc window frames window surround insulation epdm membrane
01:03:36 insulation epdm membrane uh spray foam uh you know any anything that could burn will have contributed to some extent i mean however very minor in some cases but yeah
01:03:47 but yeah and if we go back to page 77 and look at paragraph 411 next uh you you say there as follows the heat release rate is central to evaluating fire hazard since it determines the amount of energy released
01:03:59 determines the amount of energy released from a material that is available to be transferred back to the fuel via convection and radiation thereby creating a positive feedback loop and possibly resulting in fire growth and or
01:04:10 possibly resulting in fire growth and or spread now the heat the heat release rate that you've generated um does that come from all of the components or each one combined
01:04:21 components or each one combined each one individually uh i mean the heat release rate that one measures when one observes a fire is going to
01:04:32 is going to uh represent typically you know if you're me if you're measuring the way we did it in in the experiments in the lab at edinburgh uh what we're measuring is the total heat release rate that comes from
01:04:43 heat release rate that comes from everything that may be burning so yes everything and when you say via convection and radiation are you describing there and i don't put words in your mouth but are you describing there the the effect of
01:04:55 describing there the the effect of heating
01:04:56 heating when a pool fire in a drip tray on the in so to speak on the inside of the um cassette on grenfell tower heats
01:05:07 heats the
01:05:08 the insulation and creates rising heat radiates but creates rising heat uh i mean i think uh where which paragraph is that in again 411.
01:05:21 paragraph is that in again 411. um i mean
01:05:25 yeah i mean i think i think 411 could be read
01:05:29 read almost without uh via convection and radiation you know those words are probably not necessary the key idea in that paragraph is that when you have heat release the heat release rate is telling you how much
01:05:41 release rate is telling you how much energy is being released per unit time and the more energy you have the more likely it is that that's going to feed back to the fuel and cause the fire to grow um the convection and radiation are
01:05:52 grow um the convection and radiation are just the specific heat transfer mechanisms by which that would occur yes i see yeah and if we go on then to page 104 of this report and look at paragraph 606
01:06:07 you say there three-quarters of the way down your screen after the reference to the video bisbee you say based on the experiments performed on 100 millimeters times 100 millimeter samples of rhino bond p e acm
01:06:19 millimeter samples of rhino bond p e acm and alu glaze i would estimate that the majority of the polymer mass lost from samples incorporating thermoplastics filler stroke core materials i.e 50 or more of the polymer mats lost in all
01:06:30 more of the polymer mats lost in all such down all such experiments to date was due to mobilization of these polymers downward i.e dripping or flowing
01:06:37 flowing what would have been the effect of a downward dripping or flowing of the polymer
01:06:42 polymer um
01:06:46 twofold uh i mean one it would have removed energy from the local site of burning and taking that energy somewhere else uh where else depends where the polymer
01:06:57 uh where else depends where the polymer goes uh and two uh you know it's
01:07:03 it's in these in the conditions we observed certainly for the acm pe that polymer is burning while it's going where it goes uh and so if it if it lands somewhere
01:07:14 uh and so if it if it lands somewhere else and it continues to burn which it appears to have done um then that's a pretty effective downward fire spread mechanism i mean that's that that's one of the reasons why at phase one i i really um
01:07:25 really um [Music]
01:07:26 [Music] uh focused in on the crown detail at grenfell tower um the
01:07:34 the the upward fire spread mechanism is you know pretty straightforward uh the
01:07:43 the the uh
01:07:44 the uh the lateral the horizontal fire spread mechanism at grenfell tower uh which is you know quite unusual in terms of things we've observed in other clouding fires that involve these products
01:07:56 that involve these products uh
01:07:57 uh i believe is a it's a direct consequence of the presence of the crown and the fact that the the crown provided a mechanism by which the fire could go around the building and then the downward spread from the
01:08:08 and then the downward spread from the crown is what effectively makes the fire go sideways um you know the the the the diagonal lines of burning that you saw on grenfell tower in the fire and those diagonal lines how they progressed around the building
01:08:20 around the building uh are simply a manifestation of the flowing of pe down from the top of the building as opposed to let's say a a classical lateral fire spread mode across the horizontal surface of a
01:08:31 across the horizontal surface of a product
01:08:33 product so i guess i follow are you able to quantify the contribution to the intensity
01:08:38 intensity or propagation rate of the fire um of the downward flowing or dripping polymer from renault bond or perhaps also with the alley glaze uh yes am i able to quantify it no i
01:08:50 uh yes am i able to quantify it no i mean not in any uh not in any useful way i don't think and i you know quantify with respect to to what um you know it i think i think that is the mechanism by
01:09:02 i think i think that is the mechanism by which the fire goes down and around the building i think in the absence of uh in the absence of polyethylene it simply doesn't occur you you just
01:09:14 it simply doesn't occur you you just simply wouldn't get the downward and horizontal in the absence of the polyethylene and if we go please to page 111 of this report paragraph 651
01:09:26 you say there i felt it was important to satisfy myself experimentally that the ignition and physical mechanical the physical straight mechanical deformations of celotex rs-5000 pir and
01:09:37 deformations of celotex rs-5000 pir and kingspan k15 phenolic fame insulations were broadly similar to the cases where they were exposed to heating on a cut edge rather than on a flat face with the foil facing manually removed what was
01:09:48 foil facing manually removed what was the importance of demonstrating the ignition and physical stroke mechanical deformations of the rs-5000 and k15 which you described in this paragraph
01:09:59 paragraph uh i wanted to make sure that
01:10:03 that uh what i what i felt from so so earlier this is a uh
01:10:09 uh the work package one experiment so the work package one experiments as i discussed last week we did experiments with and without foil phasers and we observed how the insulation products behaved under those
01:10:21 insulation products behaved under those circumstances but those experiments were performed by taking
01:10:26 taking sheets of insulation and essentially peeling off the the aluminium facers and so the surface of insulation that was exposed in those experiments was
01:10:37 experiments was the uh the front face uh of the foam panel with the aluminium removed now that
01:10:45 now that is probably but not definitively the same situation as you have at a cut edge of the polymer foam because of the way these products are manufactured
01:10:56 these products are manufactured because for the celatex rs 5080 product you have
01:11:02 you have uh as i mentioned at phase one you have um in-depth glass fiber meshes that are sort of in the insulation in depth within the foam um uh and also when you when when the
01:11:13 um uh and also when you when when the aluminium foil facer uh is somehow adhered to the foam in a way that you know we've not interrogated in any way so the peeling off may leave some residue of something there so there's
01:11:24 residue of something there so there's all sorts of reasons why um
01:11:27 um and and and you know i wasn't and we know that the locations in grenfell tower where we were concerned about the direct exposure of the polymer foam cores of the insulation products were
01:11:39 cores of the insulation products were situations where we had cut edges not where people had intentionally removed the facers by peeling them off so we just i just wanted to make sure that there was no
01:11:50 was no substantive difference in the behavior under those edge exposure conditions both because they were the ones that existed actually in the tower at grenfell tower and because the peeling of the aluminium
01:12:02 and because the peeling of the aluminium could potentially result in some differences in behavior but we didn't observe anything i thought was particularly different so you know that that work was really just confirmatory i just wanted to make absolutely sure we weren't missing something yes i see and
01:12:14 weren't missing something yes i see and if we go on the same page please to 657 at the bottom you say
01:12:19 you say for celetex rs5080 ignition occurs within one second of heating exposure and is followed by pyrolysis of the thermosetting pir foam with continued minimal flaming the
01:12:30 with continued minimal flaming the overall response is sufficiently similar in appearance to this product's response when tested in a face on heating condition without a foil facer that i do not consider additional characterization of edge exposure to be warranted i
01:12:42 of edge exposure to be warranted i consider that face on exposure data to be broadly applicable to edge on exposure what is the significance to the intensity or propagation of the grenfell tower fire of the response of the rs-5080
01:12:54 rs-5080 which you described there um
01:12:59 what those experiments showed
01:13:03 showed was
01:13:05 was that under pretty severe heating conditions that
01:13:11 that the behavior of the the pir foam core within the celotex product
01:13:17 product when you actually expose the cut edge was broadly the same as it was when we when we exposed the samples with the aluminium faces removed so you know all of the conclusions that that i drew with respect to
01:13:29 respect to the the no foil rs 5000 case in the work package one work are relevant so you know easy to ignite
01:13:39 charring reductions of heat release rates
01:13:42 rates you know
01:13:44 you know eventual cracking maybe a bit of ongoing combustion in the presence of an external heat flux but pretty low heat release rates all those sorts of things um were equally relevant to the side exposure right and then
01:13:55 exposure right and then mr chairman finally on this topic before we have the break if i may page 116 please paragraph 680 680.
01:14:06 680. you say
01:14:08 you say there based on my experimental work i have concluded that in most cases the majority of the pe file stroke core material is likely to have mobilized downward i.e dripped during heating this
01:14:19 downward i.e dripped during heating this is likely to have been accompanied by flaming of the downwardly mobile material and the formation of pool fires where it was able to collect on horizontal surfaces both within and outside the rain screen cladding system
01:14:31 outside the rain screen cladding system now there when you refer to downwardly mobile material are you referring just to be clear to the burning dripping flowing polyethylene core material yes absolutely yes and what effect would
01:14:43 absolutely yes and what effect would that burning dripping flowing material have on the propagation of the fire uh
01:14:50 uh it's gonna spread it it's gonna it's gonna grow the fire it's gonna spread the fire
01:14:54 the fire and pooling yeah i mean pooling of polyethylene means you're going to have a local pool fire burning with significant heat release that energy is going to go somewhere if it heats acm or insulation
01:15:06 somewhere if it heats acm or insulation it's going to contribute to combustion of those products and you're going to have a bigger fire and in relation to the horizontal edges you've described already very helpfully this morning the um the return internally into the cavity
01:15:19 um the return internally into the cavity of the cassette with the lip that retains flowing dripping melting polyethylene are there any other horizontal areas within the cavity
01:15:30 horizontal areas within the cavity other than that return
01:15:35 yeah i mean the so that that was with respect to the spandrel panels that i mentioned that the
01:15:42 the uh the column cassettes uh also have uh little returns on them not quite so not quite as substantial as the the spandrel cassettes and indeed at phase one
01:15:54 cassettes and indeed at phase one i presented some images and some video evidence where you can actually see polyethylene burning in the cladding system kind of between the cracks of the column cassettes um i think on those
01:16:07 column cassettes um i think on those horizontal surfaces you have pooling polyethylene you can see flaming in those locations in cassettes that look otherwise intact i mean the other look the other location um which
01:16:17 um which sort of you know ironically uh given the purpose
01:16:21 purpose of cavity barriers is on cavity barriers that will have been installed within the system you know these these cavity barriers
01:16:28 barriers kind of protrude horizontally out into the cladding cavity um they're made of a mineral wool insulation uh and you could have polyethylene falling onto the cavity barriers within the cladding
01:16:39 cavity barriers within the cladding system pooling there burning locally and making matters uh locally worse for the cladding system uh certainly for an upward fire spread mode yes and that's internally what
01:16:50 mode yes and that's internally what about externally where would the horizontal surfaces be externally well you have you have window you have window sills and various other uh locations such as that there weren't
01:17:01 locations such as that there weren't on the outside of grenfell tower there weren't actually a whole lot of horizontal surfaces on the outside of the cladding if you like even even the window sill areas were inclined
01:17:12 window sill areas were inclined downward as soon as you got outside the glazing there was almost immediately a downward slope to the um to the cloud and cassette yes
01:17:20 yes well thank you very much professor uh mr chairman is now a convenient moment for this morning i think it is thank you well uh professor bisbee i think it's time we had our morning break so we'll stop there we'll resume please at 25 to
01:17:31 stop there we'll resume please at 25 to 12
01:17:32 12 and uh you know the drill please don't talk to anyone about your evidence while you're out of the room certainly thank you thank you very much would you give the usher please
01:17:48 good thank you 25 to 12.
01:36:49 would you ask professor bisbee to come back in please thank you
01:37:04 all right professor are you ready to carry on i am yes thank you yes mr willett thank you very much mr chairman um professor can we now turn to work package two and the report which we'll find at l b y
01:37:17 and the report which we'll find at l b y w p
01:37:18 w p two
01:37:19 two seven zeros one
01:37:22 and there it is we looked at it very briefly earlier it's dated the 15th of december 2021 and if we gave please to page five paragraph 32 you say the combustibility of the insulation product
01:37:33 combustibility of the insulation product used has been shown to be of secondary or even tertiary importance based on our experiments when acm pe rain screens are used the combustibility of the insulation played an obvious role only
01:37:44 insulation played an obvious role only when large surfaces were unprotected by foil faces and with us able to support ignition and widespread surface flaming of the insulation does that mean that where foil faces were damaged or simply not present such
01:37:56 were damaged or simply not present such as on cut edges the insulation did support ignition and widespread surface flaming
01:38:03 flaming um
01:38:04 um yeah the data that would underpin that paragraph uh would be data where we looked at the amount of mass that was lost so maybe a
01:38:16 amount of mass that was lost so maybe a step a couple of steps back so as i explained last week when we when we performed these experiments we had the acm panel was mounted on a scale that sat on a on a load cell
01:38:29 that sat on a on a load cell and the insulation products were also mounted on a load cell uh so that we could measure them the mass loss with time as the experiments progressed um
01:38:39 um that enabled us to if you know how much mass is lost and you know what the heat of combustion of the thing that's burning is you can in in approximate terms figure out
01:38:51 in in approximate terms figure out approximately how much energy might have been liberated by that mass loss if you like so you can sort of figure out what the contribution of the different products is to the burning by using mass locks mass
01:39:03 to the burning by using mass locks mass loss as a proxy measure of energy release if you like um and when we did that comparison and looked at the loss in mass
01:39:14 looked at the loss in mass up to the point of escalation to full involvement of the acm what we found that the mass loss from the insulation was only significant uh when its foil phasor was removed and
01:39:26 uh when its foil phasor was removed and that in some cases the uh amount of energy that would have been liberated using mass loss again as a proxy for energy release would have been about the same as was
01:39:38 would have been about the same as was released from the acm so that that's where that comes from i don't know if that i don't know if that clarifies the point um
01:39:45 point um clarifies the question at all um well i was more interested really but thank you for that clarification anyway but i was interested in in the question of damage to foil faces um let me try it slightly differently is
01:39:57 um let me try it slightly differently is it the case that your opinion is that in you let me try again do you think that once the exterior cladding is on fire that damage to the foil facing is inevitable
01:40:08 foil facing is inevitable once i mean if if the acm pe is burning then uh the foil facer is going to be damaged and removed at some stage yes i mean we saw that in our
01:40:19 stage yes i mean we saw that in our experiments once you had once you had a significant amount of burning from the acm pe the foil facer was typically removed you know it would it would bubble and fray and melt and fall and fall off yes so does taking it step by
01:40:30 fall off yes so does taking it step by step does that tell us that at some point
01:40:33 point in the grenfell tower fire the foil facer ceased to be a protective against significant mass loss
01:40:41 loss yeah
01:40:43 yeah and therefore began to contribute to the total energy overall that's right i mean the yes but again that the you know when that happens in the process of
01:40:54 that happens in the process of escalation is is quite important so you know at that point the acm is already you know
01:41:00 you know well away let's say and burning uh quite well and in answer to that question you say it's an important question when
01:41:11 when did it happen or does it happen in the escalation process when is the foil face or lost yes the foil facers uh again from memory without watching all of the videos back
01:41:23 without watching all of the videos back i wouldn't be able to say for sure but from memory it's in that region when the escalation occurs either immediately proceeding or or as the escalation to full involvement of the pe occurs
01:41:35 involvement of the pe occurs now um
01:41:37 now um we may be able to trace this through a little bit more um can we go to paragraph
01:41:42 paragraph 49 on page nine please in this report you say that the condition that leads to rapid and irreversible fire growth has been identified as the mechanical separation or otherwise compromising of
01:41:53 separation or otherwise compromising of the acm's inner aluminium skin which exposes a large area of polyethylene to the fire in the cavity this results in rapid a rapid increase in the energy released from the fire and promotes rapid fire growth
01:42:06 rapid fire growth um
01:42:07 um is it the case that once the exterior cladding has obtained has attained irreversible fire graves which you describe here that will in turn cause the insulation
01:42:18 that will in turn cause the insulation uh to burn as well provided it's combustible regardless of whether it's foil-faced yes i mean i think in a fire
01:42:29 yes i mean i think in a fire i mean
01:42:30 i mean never say never uh but i think in a fire of of that intensity if you had an acmp rain screen burning adjacent to a foil-faced polymer foam insulation with a cavity then that insulation
01:42:44 with a cavity then that insulation is going to get involved in the fire definitely yes and then if we turn to page 63 figure 17 we can see at the top of the page
01:42:55 we can see at the top of the page some photographs taken off selections of photographs taken from experiment 21 and you can see the line burner there is the method of ignition do your experiments uh in work packages
01:43:07 do your experiments uh in work packages one or two quantify or measure horizontal flame spread from a single point of origin as was observed at grenfell
01:43:16 uh no no
01:43:18 no i mean i might
01:43:22 i mean i guess i might dispute horizontal flame spread from the point of origin as was observed at grenfell depending on what kind of horizontal mechanism we're talking about as well fair enough
01:43:33 fair enough given the small scale nature though of the experiments in work package two and the absence of a whole system test what conclusion if any can you reasonably draw regarding the contribution of the insulation to the
01:43:44 contribution of the insulation to the spread and the intensity of the fire which did occur at grenfell uh
01:43:49 uh the yeah i mean that is a very important distinction uh and something that's important to be clear about is that these experiments were focused on uh growth of a fire from a small fire to
01:44:00 uh growth of a fire from a small fire to a large fire in an upward fire spread mode the the consequent spread of the fire around and down the building is not addressed by these experiments it's very it's very important to be clear on that you know
01:44:11 you know one of the reasons um why i labored the point a bit in the first session this morning to say you know to explain sort of what my view of the downward the lateral and the downward is um associated with the with the burning
01:44:23 um associated with the with the burning of the polyethylene rather than uh you know what we might call a classical horizontal or lateral fire spread over the surface of a product and if we go to page one two one
01:44:34 and if we go to page one two one paragraph six four four
01:44:38 paragraph one two one
01:44:44 six four four at the foot of the page says this under the heading contribution of insulation to total release of energy it says the data presented in this figure of the total energy release that
01:44:55 figure of the total energy release that can be expected in cases where the cladding is allowed to burn without intervention until local burnout of the acm at which point the insulation also typically self-extinguishes notwithstanding my previous comments
01:45:06 notwithstanding my previous comments regarding ongoing smoldering combustion of the kingspan k15 insulation what is local burnout of the acm yeah i mean it's perhaps slightly
01:45:18 yeah i mean it's perhaps slightly imprecise words but what i mean by that is until the ace essentially until the polyethylene is not burning anymore at the location of the fire that we're interested in yeah
01:45:29 interested in yeah so basically the polyethylene there's no evidence of any further burning of polyethylene whether within the panel or or in the drip tray yeah right and there's in relation to the figures
01:45:40 and there's in relation to the figures of contribution played by and k15
01:45:45 and k15 of the total energy released until the end of the experiment i think we probably need the figures for those can we go please to first of all figure 33 on page 78
01:45:56 first of all figure 33 on page 78 let's have that up first you showed us this last week and then again perhaps have it side by side um
01:46:04 side um page one two three paragraphs six five five and six five six
01:46:12 uh you you you can't quite yes that's it we may have to scroll across that's it um
01:46:19 um you give you give figures there of 20 and 53
01:46:23 and 53 up to as maximums likely maximums in a worst case scenario for celatex rs 5000 in 655 and k15 and 656.
01:46:35 656. they're just taking that data and those opinions together is it right that these experiments were terminated at 20 minutes yes
01:46:45 yes now what would have been the impact on your conclusions about the fire at granville tower given that it went beyond 20 minutes
01:46:56 um
01:47:00 at the uh it's an interesting question at the at the end of the 20 i mean 20 minutes was chosen essentially arbitrarily because in many of the experiments
01:47:11 of the experiments uh anything that was was interesting that was going to happen had happened or everything had had gone out and there was no further combustion that we could observe from the rig beyond 20 minutes um
01:47:22 um so you know all the burning had ceased if you like um how i mean how that relates to the fire at grenfell tower as i mentioned earlier at grenfell tower as the fire spread uh around the building
01:47:34 the fire spread uh around the building it ignited compartment fires which then burned within the compartments for much longer um durations and so you had further thermal exposure to whatever products might have been left on the cladding due to the
01:47:45 been left on the cladding due to the fire plumes the insulation in particular so any insulation that would have been left
01:47:50 left after the the external fire had kind of spread away gone away the acm was gone um that burning was able to continue because you had fire plumes coming out the windows as a consequence of the flats burning
01:48:03 as a consequence of the flats burning um
01:48:05 um remind me of the question again sorry well no i'm not going to build on the answer i think which is what was the basis of the assumption that as you say in the last answer
01:48:17 that as you say in the last answer that
01:48:18 that anything that was going to anything interesting that was going to happen had happened within the first 20 minutes ah right yes so uh yes and i remember now where i was going with my answer the the the so in the case of experiments that
01:48:31 the so in the case of experiments that involved
01:48:32 involved the celetex product from memory uh
01:48:38 uh you know by 20 minutes everything had gone out there was no further combustion that was observable at all
01:48:45 at all uh in the case of some of the experiments with the kingspan product there was as i mentioned last week some ongoing smoldering of the insulation um that occurred uh and and actually in in some cases that continued
01:48:57 actually in in some cases that continued up to 20 minutes and at 20 minutes we just sort of called it and said okay well we're just going to stop at 20 minutes now if we had let it run whether that smoldering or the extent to
01:49:08 whether that smoldering or the extent to which that smoldering would have continued beyond the end of the 20 minutes is anyone's guess um you know the the intensity of smoldering tended to decrease with time so one imagines that eventually it would it would stop
01:49:19 that eventually it would it would stop um
01:49:21 um but but we don't know i mean one of the things one of the things that was was interesting uh about the experiments involving the kingspan product the k-15 product
01:49:29 product was that you know long after the acm uh had had burned away um and there was little evidence of any ongoing burning of the the polyethylene um you still see this smoldering
01:49:41 um you still see this smoldering combustion um on ongoing and you still and eventually what actually happens is is you get smoldering combustion essentially eats its way all the way to the back of the 100 millimeter thick kingspan product
01:49:52 100 millimeter thick kingspan product and you actually have smoldering combustion kind of coming out the back of the insulation panel in our rig uh so so that i mean that was something we didn't observe for the for the cell attacks right and where would that on on
01:50:04 attacks right and where would that on on grenfell tower itself if that had happened where would that heat have gone uh
01:50:11 uh at grenfell tower the insulation was butted up against uh the concrete of the building so it would have gone you know
01:50:19 you know to the concrete or would have been i mean it would have been slightly different because smaller combustion depends on the availability of oxygen and the extent to which energy is retained within the insulation i mean i mean to sort of
01:50:30 insulation i mean i mean to sort of highlight that point one of the things that we observed that was was interesting with respect to the smoldering was that the kingspan products when tested with the foil phaser
01:50:42 phaser seemed to smolder better if you like than when they were tested without the foil facer and that's because some of the foil face or inevitably remains in place
01:50:54 after some combustion and pyrolysis of the underlying polymer has has started and that foil facer kind of counter-intuitively once you
01:51:06 kind of counter-intuitively once you have some smoldering in the foam behind the foil facer the fall facer actually keeps heat in the smoldering foam and makes the smoldering worse so in that respect having the four-facer on the on the k-15 product actually made
01:51:18 on the on the k-15 product actually made the subsequent smoldering uh continue for longer than in the case where it wasn't there so it's a sort of a counter-intuitive result well it may not be counter-intuitive is it
01:51:29 it it would this be right that it actually has a double effect the presence of the foil facer protects the integrity and the combustion of the k15 for longer
01:51:40 combustion of the k15 for longer but once there's combustion but the four facing remains in place in parts
01:51:45 parts it lasts longer yeah i mean the the foil keeps keeps energy out but it also keeps energy in yes that's an even better way of putting the duality yeah now um
01:51:57 duality yeah now um as you've said you've said you use the 20-minute cut-off period just standing back and answering the question in very general terms
01:52:08 general terms as we've seen i think throughout the inquiry
01:52:11 inquiry the testing regime has tests which have termination times um in general what are those termination times based on
01:52:22 on what assumptions are made generally about what about a particular termination time i mean
01:52:29 i mean typically our experiments were terminated or we chose to terminate experiments when we felt we'd observed what was interesting to observe right in simple terms so i mean it is it is
01:52:39 it is you know essentially arbitrary uh but we would not i mean i i would i would never as someone who's interested in the way the world works i would never
01:52:50 way the world works i would never terminate an experiment uh if i feel i still have something to learn from it i mean that that's one of that's one of the really important things i i presume we'll talk later about the testing regime
01:53:02 about the testing regime and testing regimes associated with clouding products but you know that that's one of the kind of key messages for me
01:53:09 for me overarching relevant to the question about rivets versus cassettes and my comments about the sbi experiment if you if you test an ac mpe product in a in an sbi um
01:53:20 um and you test it riveted and it achieves some level of performance and you stop the test when you test a cassette and you achieve some level of performance and you stop the test
01:53:30 test um
01:53:31 um you're missing information when you stop that test in the in particular on the riveted system you're missing the escalation you're missing the you're missing the shock uh an alarm
01:53:43 the you're missing the shock uh an alarm of what these systems and products can do when they are pushed too far and that is a that is a problem with fire resistance testing with with standardized compliance testing is you because you because you you say you know
01:53:55 because you because you you say you know these tests are run for 20 minutes that that means that people can uh
01:53:59 uh people can manipulate their products to make it through the allotted time without you observing maybe something that you might like to observe if you really wanted to understand what was going to happen
01:54:11 going to happen so so in our experiment i mean that's a very long-winded way with apologies of answering your question but i do think it's an important insight is that if you want to understand how a product burns
01:54:21 burns then you should you should let it burn until you can't learn anything anymore and that's that that that's the criteria that we use
01:54:30 now thank you no that's helpful looking at grenfell itself uh as we know the fire there spread from immediately outside flat 16 to the crown
01:54:41 immediately outside flat 16 to the crown um in the 20 minute period but taking all of the evidence into account that you've seen is it your view and to tell me if this is not the case but is it your view that the contribution of the insulation products to the total energy released by
01:54:54 products to the total energy released by the acm pe cladding occurred after the local burnout of the fire by of the piece of the acmpe
01:55:10 i mean the interesting distinction in words here uh i mean i would i would and again i think the words that i've used in the report are imprecise um
01:55:21 um local i mean i i've used those words without defining what i mean by local burnout of the acm um
01:55:29 um what i
01:55:30 what i what i would mean by that is until there's no polyethylene burning anymore but i think perhaps the more relevant question
01:55:35 question or the better way of phrasing that would be to say until local burnout of the cladding
01:55:40 cladding of the cladding system uh because in some cases you did have ongoing combustion of the insulation beyond the point in time where there was no obvious burning of the pe you know it's quite hard
01:55:52 it's quite hard when performing these experiments it's quite hard to identify with absolute precision
01:55:57 precision when there's no more pe burning you know i think in the experiment that i showed
01:56:03 i showed uh last week i think it was uh the experiment was at 20 21 i think uh where i showed the full progression of the experiment highlighted some of the key moments and the the the i think
01:56:16 the key moments and the the the i think that the moment that we observed the last burning of pe and that was around 18 minutes of the 20 minutes whether
01:56:25 whether whether that is a consistent 18 minutes or whether sometimes it's eight minutes and sometimes it's 26 minutes um i would have to go back and look at the data to to know for sure i don't think it's i don't think it's a hugely
01:56:36 it's i don't think it's a hugely significant point because at the end of the day we're interested in how much energy
01:56:40 energy we're interested in how much energy is liberated by the cladding system and we're also interested in uh the time scales over which that liberation of energy occurs when you say cladding system in that
01:56:51 when you say cladding system in that answer do you mean do you mean the acm i mean the external wall arrangement construct the build up yes
01:56:57 yes right um now um i see
01:57:01 is is it
01:57:04 is it can you just help me um is it the case that energy released by the insulation products as part of that external wall buildup
01:57:11 buildup after burnout of local burnout if you like of the pe acm was not relevant to the nature and speed of the spread of the fire
01:57:22 the fire at grenville sorry could you ask that again yes um well we tried differently what was the contribution of the insulation uh
01:57:32 uh at grenfell tower after local burnout of the pe
01:57:44 i mean i would say pretty minor
01:57:49 i mean for the celetex products it stopped burning once the pe was gone the celetex wasn't really burning anymore uh for the kingspan product uh the burning that was was ongoing was much
01:58:01 burning that was was ongoing was much less severe you know smoldering and a little bit of flaming
01:58:05 flaming so yeah i mean i think not not very significant would be i mean i could i'd struggle to put a percentage on it but not very significant yeah now um if we go please to page one two seven
01:58:17 um if we go please to page one two seven i'll show you the paragraph it's paragraph 685 but you say there that the experiments show that the arrangements using non-combustible mineral wood insulation grew to full involvement of the pe
01:58:28 grew to full involvement of the pe called acm more rapidly than for the foil faced combustible insulation products now in light of that conclusion are you able to tell us whether the theoretical percentage contributions to total energy
01:58:41 percentage contributions to total energy release attributable to different types of insulation products provides any kind of reliable indication of the relative contributions of those insulation products to the speed and extent of flame spread
01:58:53 flame spread with apologies could you give me the first part of that question given the contribution given the conclusion that you've set out at 685 which is the combust non-combustible mineral insulation
01:59:04 mineral insulation grows to full involvement of the acm more rapidly than the foil-faced combustible insulation given that conclusion are you able to tell us whether the theoretical percentage contributions to
01:59:16 theoretical percentage contributions to total energy release provided by each individual insulation product provides any kind of reliable indication of
01:59:25 of those contributions to the overall speed and expense of flame spread where you have a pe called acm system i i think what it tells us is as i said
01:59:36 i i think what it tells us is as i said last week i think what it tells us is that that contribution in comparative terms is relatively minor uh if if if it exists at all i mean obviously these i mean the the insulation materials are paralyzing they
01:59:49 insulation materials are paralyzing they are liberating uh flammable pyrolysis products those products in the presence of heat and oxygen are going to burn and so there is a contribution i mean you
02:00:00 contribution i mean you you cannot i mean it would be very hard to argue that there is no contribution uh
02:00:05 uh that contribution is probably comparatively minor but the other thing that
02:00:10 that you know it's important not to over simplify
02:00:14 simplify the
02:00:15 the i understand the question but it's important not to oversimplify the complexity of the heat transfer environment within the cavity and the complexity of the interactions between the acm and
02:00:27 interactions between the acm and whatever is facing the acm whether it's foil faced uh combustible or non-combustible or without the foil insulation and that you know that's really nicely
02:00:38 and that you know that's really nicely uh shown and this was the you know the biggest
02:00:41 biggest sort of um head scratcher if you like for us when we when we perform these experiments when you have to be careful to make sure i get this right uh when we tested the system with mineral wool insulation and we added the
02:00:53 mineral wool insulation and we added the foil the escalation occurred more quickly
02:00:57 quickly when we tested with the combustible insulation products and we added the foil
02:01:01 foil the escalation occurred less quickly and that's because the the
02:01:07 the extent to which the insulation products can
02:01:10 can can liberate energy the extent to which the surfaces of those products heat the extent to which the surfaces of those products reflect or re-radiate energy
02:01:21 reflect or re-radiate energy and the extent to which the surfaces of those products can be heated uh by convective rather than radiation rather than radiative heating you know the balance of all of those
02:01:33 you know the balance of all of those factors changes for each of those products so saying for sure oh it must have been the energy liberated by combustion is actually a very difficult thing to do so it's not i mean what i want to say is it's not
02:01:45 i mean what i want to say is it's not that simple it's actually very very complicated um but
02:01:51 but i do think it's fair to say that the contribution as i said last week that the contribution uh to the total energy release of the clotting system the external wall
02:02:03 of the clotting system the external wall arrangement during the course of the 20 minute duration of our experiments uh it's shown here in the in the graph that's on the screen uh
02:02:12 uh you know given that the the combustible insulations the three leftmost sets of data are not that dissimilar from the mineral data that the contribution from burning is comparatively minor when you compare
02:02:24 comparatively minor when you compare with some of the other factors the installation uh for instance now
02:02:29 now if we go back to page one two three we saw this earlier and looked at paragraph six five five and six five six um and there they are is it right that the percentage contributions to total heat release that
02:02:41 contributions to total heat release that you've set out there in relation to each of those products rs 5000 and k15
02:02:47 and k15 are calculated by expressing the heat released by the insulating product at the end of the experiment at an assumed 100 combustion efficiency which is divided i think by the
02:02:59 which is divided i think by the experimentally measured heat release by the acm
02:03:02 the acm and the incident at the point of local burnout which is earlier um
02:03:08 um i'd have to have to scroll uh sort of up in the report to see because we've made a number because there's we've made a number of comparisons um uh in terms of
02:03:20 uh in terms of some of those comparisons were based on the mass loss measured during the experiment some are based on the total mass measured at the end of the experiment i think in this situation we're talking about the total
02:03:32 we're talking about the total mass loss from the insulation products so
02:03:35 so to back up a bit before we ran the experiments we we measure the mass of the sheet of insulation that goes into the rig so we weigh it
02:03:45 weigh it at the end of the experiment we take that sheet of insulation off the rig we weigh it again the difference is the mass loss yes if you take that mass loss and you multiply by the heat of combustion you get the maximum conceivable
02:03:58 maximum conceivable uh amount of energy that will have been released by that product and that maximum conceivable assumes that the combustion is 100 efficient
02:04:09 efficient and i think that is the basis upon which these numbers given here uh in these specific paragraphs are calculated yes well let me try and help you if you get back a page please to page one two two on the right-hand side of the screen you
02:04:20 on the right-hand side of the screen you can see
02:04:21 can see um what the observations are that are the basis of figure 33 and
02:04:27 and the methodology you adopted there just to remind you of what it was
02:04:40 um yeah so that'll be based on the full 20 minutes yeah yes so the question is is it the case that your calculations don't compare like for like for two reasons
02:04:51 reasons but the first is that they mix different time scales one is you're measuring total mass loss over the full period of the test
02:05:01 the test but
02:05:04 but um you're also measuring um heat
02:05:08 heat released by the acm up to point of local burnout which is earlier on
02:05:16 um
02:05:18 i mean we did do the two different things yes but i think here we're just presenting the 20-minute mass loss as a maximum conceivable value right let me ask it slightly is there any
02:05:29 let me ask it slightly is there any material
02:05:31 material um
02:05:36 flaw in the assumptions where you are measuring um [Music]
02:05:43 [Music] heat release up to the point of burnout in relation to the acm but up to the end of the experiment through the mass loss in relation to the um
02:05:54 um insulating products um
02:05:58 um okay i think i see what's happening here so i think that figure 33 is presenting the
02:06:07 the uh
02:06:09 uh the the the area underneath the heat release curve if you like for the experiments whereas uh the numbers that we're discussing are based on the total mass loss from start to finish and the
02:06:20 loss from start to finish and the question is uh you know which of those is the fairer comparison i think is is the question well and yes and the answer is that the the
02:06:28 the total heat release in figure 33 is the fair question it is the
02:06:33 the when you take the the mass of the insulation at the start of the experiment you run your experiment and then you take the mass at the end of the experiment and then you assume [Music]
02:06:43 [Music] that all of that mass resulted in liberation of energy you are if you like being unfair uh to the insulation product because it's not the case that all of the mass
02:06:55 the case that all of the mass turns into energy right it it is the case that
02:07:00 case that uh the conditions in which that combustion is occurring are not those that would exist within a bomb calorimeter which is where you get the heat of combustion from where you have a you know 100
02:07:11 you know 100 oxygen and you have the most efficient possible combustion environment so now how how much less efficient the combustion environment in the cladding experiments that we ran is as compared
02:07:23 experiments that we ran is as compared to the bomb calorimeter i can't say uh but but i do feel that i've been quite clear in the way that i've presented those data to caveat it by saying these are the maximum possible values we could ever expect so this is
02:07:34 values we could ever expect so this is you know this is sort of the worst case scenario
02:07:36 scenario uh if we assume that all mass turns into energy this is as bad as it could possibly be in reality it's going to be somewhat less than that are you able to tell us
02:07:48 are you able to tell us whether
02:07:49 whether the amount of mass lost between acm burnout
02:07:54 burnout and the end of the experiment was material was
02:07:59 was significant
02:08:02 i mean potentially but only in so far as those are the words that i've used um you know
02:08:09 you know with respect to what happens on a building which is why we've done this uh then
02:08:17 uh then as i sit here i think probably in my report um if i had the if i had the opportunity to amend the report i would simply change the words from until local burnout of the acm
02:08:28 the acm to read until local burnout of the cladding
02:08:31 cladding right and then it would be fine i see so you said the answer is no i think there's no in terms of the out in terms of my conclusions no right and same question in relation to different combustion efficiencies as
02:08:43 different combustion efficiencies as between the ac mpe on the one hand and each of these combustion product insulation products on the other um
02:08:51 um are you are you not comparing light with like because you're mixing different combustion efficiencies yeah probably yep and does that have an effect or impact on your conclusions um
02:09:03 um no because i don't think that my conclusions are based on calculations that assume 100 uh
02:09:09 uh combustion efficiency no i don't think so
02:09:12 so is it the case that if instead um you did compare like for like by comparing the heat release contribution from the insulation using experimental combustion efficiency measurements at the same
02:09:23 efficiency measurements at the same points in time namely peak hr peak heat release that the percentage contribution in respect of the total heat release from the insulation components would be lower
02:09:35 the insulation components would be lower than you've said
02:09:38 it's entirely possible i'm not sure that that's a relevant question
02:09:45 question i mean we're not interested necessarily in just what happens up to peak heat release we're interested in how much energy is liberated at that location
02:09:55 location period i mean you know so it's not simply a question of what what happens until we get to the peak it's a question of what happens throughout the full duration uh of burning so uh i think yeah i think
02:10:07 uh of burning so uh i think yeah i think the answer is yes it's possible that that would that the
02:10:10 that the contribution of the installations up to that point might be less as a percentage rather than the numbers i've given but i just i don't i don't necessarily accept that that's a an important question now if we go to page 35 of your of your
02:10:23 now if we go to page 35 of your of your report here paragraph 239
02:10:28 we don't need to read at all um
02:10:31 um 239 i think starts at the top of page 30 6
02:10:40 6 and you identify the sorry the middle of 23 36 and you identify the mineral wool insulation and you say in the second sentence the specific product chosen was a rockwool duct insulation lagging product marketed
02:10:52 duct insulation lagging product marketed under the trade name duct slab and i think it's right that that was classified as euro a1 and non-combustible under the national classification system yes
02:11:03 classification system yes yep um as far as you are aware is that um a foil face insulin uh yes
02:11:12 uh yes and marketed in the uk as a rain screen insulation product yes i have i don't know if it's marketed as a rain screen insulation product i don't yeah i mean i wouldn't it doesn't really matter to me whether
02:11:24 it doesn't really matter to me whether it's how it's marketed what i'm interested in and what it is i'm interested that it's uh a non-combustible mineral with a foil facer right now um i want just to ask you one or two questions about eight four one four
02:11:37 questions about eight four one four we will come to the topic in more detail later but in relation to the tests done on uh done under 8414 part one carried out by the government following the grenfell tower fire is it right to say
02:11:48 grenfell tower fire is it right to say that the nature and rate of flames spread on cladding systems incorporating foil faced pir
02:11:56 pir and unfaced mineral fiber insulation behind pe called acm have been found to be comparable at large scale and at intermediate scale
02:12:08 uh could you remember that past me again with apologies uh yes um is it right to say given the tests done under bs8414 by the government after the grenfell tower fire in 2017
02:12:20 grenfell tower fire in 2017 um is it right to say that the nature and the rate of flame spread on cladding system cladding systems incorporating foil face pir and unfaced mineral fiber insulation
02:12:32 and unfaced mineral fiber insulation both in each case together with a pr a pe called acm rain screen have been found to be comparable
02:12:40 um i mean nature and rate i might i mean i don't know that we necessarily learn that much about the nature and rate from a bsa414 test would be the bait
02:12:52 from a bsa414 test would be the bait which would be the basis upon which that question is posed uh you know referring to the post grenfell from dclg tests i presume yes um
02:13:03 yes um it is the case that in those uh tests that the system with mineral wool uh
02:13:12 uh that that the test with mineral wool was terminated uh at a similar time than the tests with polymer foam insulation but uh
02:13:20 uh i think from memory in those experiments that the mineral wool was used without a foil facer the polymer foam insulations had foil faces so there's a mild distinction there right and is it right to say the
02:13:32 there right and is it right to say the same thing that the nature and rate of flame spread on chatting systems incorporating foil faced pir foil faced phenolic and unfaced mineral fiber insulation in
02:13:43 and unfaced mineral fiber insulation in all cases with pe cord acm rain screen have been found to be comparable in modelling
02:13:53 i mean i'm aware that some modeling work has been performed sponsored i believe by kingspan uh the the veracity of that modeling and
02:14:04 uh the the veracity of that modeling and the extent to which that modeling is is has been validated i think is a question that i've not looked at in very much detail i'm aware that the work has been done
02:14:15 i'm aware that the work has been done and i'm aware that the conclusions of that work have been to suggest that there isn't a major difference i mean professor torreira in his report has commented on that in some detail and i think those would be very appropriate questions
02:14:26 questions to ask him now having regard to all the available evidence you've seen including our own experiments are you able to provide us with an opinion about whether the nature and speed of the spread of the fire at
02:14:38 and speed of the spread of the fire at grenfell tower would have been materially different had unfaced mineral fibre insulation been used as the insulating product behind the pe acm
02:14:50 the insulating product behind the pe acm rain screen cladding instead of rs 5000 and k15
02:14:59 i can only i can only base an answer to that question on uh on the evidence that i have from the experiments that i've performed and as i said earlier today
02:15:12 and as i said earlier today my view is that the the combustibility of the polymer foam insulations which is effectively what this question is asking me
02:15:21 me it has pla we'll have played a role that was probably something less than 10 of the contribution to the to the escalation the spread of that fire in an upward fire spread mode uh beyond that
02:15:32 upward fire spread mode uh beyond that it's very difficult for me to say um uh one way or another yeah i think thank you very much now i'd like to turn next to a different topic and a different report your path to grenfell report of the 10th of november 2021 and
02:15:45 report of the 10th of november 2021 and let's have that back up please that is at lbyp
02:15:48 at lbyp 2 seven zeros one
02:15:53 and i just want to turn to page four in that and run through the table of contents with you when you set up the structure of your report and we can see there that it's divided
02:16:04 and we can see there that it's divided um into three parts each with references and an appendix a now part one is the is the purpose of testing yes and you you've set out there three categories of tests explaining the
02:16:16 categories of tests explaining the differences between them and giving examples of fire safety tests in each category yes yes all right so category one unrepresentative tests category two model tests and category three
02:16:27 model tests and category three technological proof tests then part two foot of the screen the path to grenfell and that's drawing together the various narrative threads relating directly to fire safety
02:16:38 threads relating directly to fire safety testing research and investigation as well as building regulations and the various pieces of associated statutory and industry guidance yes yes and just on that is it right that you
02:16:51 and just on that is it right that you you you begin that part of your report with an overview of the development of the building regulatory environment in england and wales starting in 1919 describing the deployment of particular fire safety tests within
02:17:02 particular fire safety tests within those regulations and the relevant guidance that's right yes and you also i think address a number of historic uk clouding fires on high-rise buildings offering i think analysis not only of the fire events themselves but
02:17:14 the fire events themselves but subsequent investigations into those fires such as nasally and garnic to the extent that i was able to yes yes and is it right that you also offer analyses of patterns of risk and vulnerabilities in fire safety which
02:17:27 vulnerabilities in fire safety which existed at the time of the grenfell tower fire in june 2017 as revealed by these different narrative threads yes that was that was what i attempted to do yes and and you discuss
02:17:38 attempted to do yes and and you discuss a number of what you call missed opportunities where the statutory guidance and regulatory compliance testing regime could have been made simpler or less permissive i think certainly yes
02:17:49 certainly yes and you've also got if you turn the page please to page five
02:17:54 um oh it goes on actually to part three closing remarks on page seven and appendix a on the same page which starts at page two six eight which is about regulatory capture
02:18:06 is about regulatory capture yes yes
02:18:08 yes yes uh and if we turn very briefly to appendix a at page 268 we can see that it's headed the purpose and evolution of fire safety regulation
02:18:19 of fire safety regulation and if we go in that to 14 to 1641 paragraph 1641
02:18:26 at the beginning you say
02:18:29 you say well i do not hold myself out as a social scientist or as holding any particular expertise in science and technology studies sts have had a demonstrated academic interest in the roles of regulation and education in
02:18:40 roles of regulation and education in fire safety engineering design practice and enforcement for more than a decade i've also published peer-reviewed papers in both areas as noted in section 31 and if you look at 1644
02:18:53 and if you look at 1644 you you you tell us that the evidence presented in this appendix also underpins some of my interpretation of the evidence that i present in parts one and two of this report however i've placed it in an appendix because i do not hold myself as an independent expert
02:19:06 not hold myself as an independent expert in this area um
02:19:08 um that that's right is it yes uh and uh you then offer some as we've seen some closing remarks in part three now i'd like to start with part one if i can and can we go please in that to page 13
02:19:21 and can we go please in that to page 13 paragraph 53
02:19:25 and we start with some simple propositions i hope you start the purpose of testing is to allow an individual or an organization to use the results of a test to make a claim about how a material product or
02:19:37 claim about how a material product or system will perform in a real in-service situation
02:19:41 situation and you say if you go on in the same paragraph a little lower down tests can never exactly mimic operational use of a technology because test designers seek to minimize
02:19:52 test designers seek to minimize uncontrolled variables and introduce instrumentation that would not normally be present the differences between a test and operational use means that quotes tests
02:20:03 operational use means that quotes tests get engineers closer to the real world but not all the way close quotes and that's a quotation from pinch 1993
02:20:12 1993 and if you go to paragraph 54 you say the key issue therefore is not whether a test is quotes realistic quotes quotes because it can never be completely safe but rather whether it is
02:20:23 completely safe but rather whether it is sufficiently quite representative close quotes as dana argues quotations since even the most realistic tests will always differ in some respects from the real thing engineers must determine which differences are quite significant
02:20:36 which differences are quite significant those quotes and which are trivial if they have to know that a test is relevant or representative and you quote from downer 2007. uh now um you use expressions um
02:20:49 uh now um you use expressions um there but
02:20:51 there but we'll come back to this point in relation to large-scale testing later but can you explain in summary why it is the case that the question is not whether a test is realistic but whether it's sufficiently representative
02:21:05 uh why is that a relevant point yes well can you explain the distinction reasons for your for your drawing it well
02:21:13 well i mean because of what it says uh in the first line of that paragraph uh which is the you know the purpose of testing is to allow an individual and organization to use the results to make a claim about how a material product will
02:21:24 about how a material product will perform in a real in-service condition and because one can never uh
02:21:31 uh one can never devise a standardized test that will reproduce exactly the end-use conditions of a product uh that just you know
02:21:41 know it's just not it's just not a practical approach to testing so one has to come up with a test that asks the questions that allow oneself to
02:21:53 asks the questions that allow oneself to make a claim about how the in-service performance is going to be recognizing that the test cannot reproduce reality so that so you know designing tests that ask the right questions
02:22:04 questions that are representative of the things that one wants to know about a product is is the trick with these with these tests if we go to page 15 paragraph 64.
02:22:15 paragraph 64. um you explain that as follows uh testing for fire safety needs to achieve two main purposes first and most importantly it should enable regulations that achieve societal objectives with
02:22:26 that achieve societal objectives with regard to safety second it needs to be practical in operation providing reasonably consistent results without being overly burdensome in cost and time and then at 65 you say the first of
02:22:37 and then at 65 you say the first of these purposes hinges on attaining a useful correspondence between test results and real-world performance in principle it doesn't matter whether a chest is realistic solomon is useful in this regard
02:22:48 this regard now just pausing there what do you mean by a useful correspondence with real world performance as distinct from a test which is realistic uh you know a test that tells you something that you
02:23:00 a test that tells you something that you can make use of in order to achieve satisfactory fire safety outcomes what's the difference between that and realism um
02:23:12 well well realism is not is not it's not practicable that i mean that's the that's the kind of um that's the kind of uh compromise that i'm alluding to in this section uh
02:23:25 i'm alluding to in this section uh you you can't have a test that would that would realistically that would that would simulate end-use conditions for every product so you have to have a test that tells you something useful i mean
02:23:36 that tells you something useful i mean uh there's there's a nice expression about models right which is that all models are wrong but some models are useful
02:23:45 useful you could say something similar about uh about fire tests you could say you know all all all fire tests are unrealistic and some of them are useful don't follow then let's go to page 19
02:23:58 then let's go to page 19 and at the top of the page there you identify during the period 1932 to 2017 three categories of fire tests used within the regulatory system
02:24:10 within the regulatory system uh in place within that period and you say that there are there are unrepresentative tests model tests and technological proof tests now that taxonomy there is that your own or is it
02:24:21 taxonomy there is that your own or is it one that's articulated and recognized in the literature no that's uh that's a local taxonomy if you like it's it's mine it's yours well mine along with colleagues who i was working
02:24:32 along with colleagues who i was working with on this report so graham spinardi who i've mentioned in appendix
02:24:37 grenfell specific your work specifically correct i see yeah now am i right to understand that it's important to understand the difference between these types of tests the purpose of developing them and what they were intended to measure or demonstrate in order to
02:24:49 measure or demonstrate in order to understand the limits of their credible use and application i i mean yes i think it's important to think about what these different types which is why
02:25:00 what these different types which is why this taxonomy has been written down in this report i think it's important to think about different types of tests the basis upon which they were developed how realistic or representative they are
02:25:12 how realistic or representative they are and therefore what response what burden of responsibility lies with those people who use those tests and it would be right also to say that certain relevant fire safety tests in
02:25:24 certain relevant fire safety tests in the uk
02:25:25 the uk were implemented and used in in practice in the period before grenfell in ways which did not align with the intention the logic and the limitations of the tests themselves that's my view yes yes
02:25:38 tests themselves that's my view yes yes uh and we'll come to some specific examples of that shortly but um is the reason for that non-alignment regulatory influence is that one of your
02:25:49 is that one of your rationales i think uh uh but by regulatory influence you mean the influence of regulatory processes by industry for instance or
02:26:00 industry for instance or well is it the case it was a bit of a cryptic question perhaps
02:26:05 perhaps is it the case that because um
02:26:09 um because the deployment of these tests within statutory guidance and practice specifically adb gave them a specific status that might have tempted people to ignore or perhaps
02:26:20 tempted people to ignore or perhaps misunderstand their applications
02:26:24 i think the answer the limitations yeah i mean i think i think i would say yes to that i think you know it's clear it's clear that um that the way people were
02:26:36 um that the way people were it seems clear that the way people were thinking about what
02:26:41 what following the recommendations of a proof document be was doing
02:26:45 was doing would indicate a misunderstanding of of well certainly this taxonomy of tests and the way that tests should be viewed you know for instance uh the idea that
02:26:57 uh the idea that one passes one sorry the idea that one performs a bs8414 test takes the data from the bs8414 test has those data classified in accordance with br135
02:27:09 br135 and gets a free pass to use that combination of cladding products in any variation on any building uh is a is a in my view a misconception of what that test is and what it's for
02:27:21 of what that test is and what it's for and how it should be used yes now um
02:27:24 now um turning to the first category therefore unrepresentative tests um you um
02:27:31 um you um can you describe for us in summary the main properties or characteristics of unrepresentative tests
02:27:38 these are these are tests that are typically very small and they are tests that give you a piece of information uh which
02:27:48 uh which is used to try to make some claim but which is
02:27:51 which is essentially totally non-representative of an end-use condition which is why you know why i've called them on representative tests so they're you know they're tests where you ask a question the way you ask the question is totally
02:28:02 the way you ask the question is totally unrepresentative of any sort of
02:28:05 sort of real construction application right now if we go to page 29 in this report and let's look together at paragraphs 140-143
02:28:20 no yeah thank you that's it 140-143 there um you've set out the tests above uh above that at paragraph 133 which we
02:28:32 above that at paragraph 133 which we could just scroll up we can see you've got the bsa bs476s and the the bs ends there the oldest of which dates from 1970
02:28:44 1970 and you've set out a list of um characteristics of paragraph 139 to 143 there
02:28:53 are the tests that you list under that category those which deal with combustibility
02:28:59 um so part four part 11 118 yes they are yes yep yes and and i think you then provide an overview of the history of the development of combustibility test methods
02:29:11 combustibility test methods uh at page 20 para93 and you say that that is the did you describe you describe that as the potential of a material to burn is that correct correct so that when you say
02:29:22 correct correct so that when you say combustibility that's what you mean is it
02:29:25 it uh
02:29:27 uh in in in the context in non-regulatory terms yeah um combustibility to mean would mean yes the potential of a of a material to burn so you know that
02:29:39 so you know that in in in non-regulatory language combustibility would be a material that can react with oxygen and and thereby liberate energy in the form of heat and light
02:29:51 form of heat and light strictly speaking so anything that has a heat of combustion is strictly speaking combustible now
02:29:59 now so combustibility is if you like an on off switch uh it either is or it isn't in regulatory terms uh the regulatory system chooses to
02:30:11 uh the regulatory system chooses to blur that a bit um and and decide that some materials that have a very very small amount of combustible content i.e content that
02:30:23 combustible content i.e content that could react with oxygen and relief energy
02:30:27 energy can be deemed to be non-combustible that that doesn't that doesn't make them non-combustible it means they are deemed to be such
02:30:38 am i right to understand that by 2017 there were four independent test methods by which a manufacturer could demonstrate that the product was quotes non-combustible close quotes
02:30:49 non-combustible close quotes yeah that would be referring to the four that are listed before the listed yeah and if we go on to page 23 or back to page 23 at paragraph 109 you we don't need to read it all out because it's quite long but is it right
02:31:00 because it's quite long but is it right that you conclude from your review of the evolution of those various different test methods that both the definitions of quotes non-combustibility close quotes and the thresholds chosen for those definitions
02:31:12 thresholds chosen for those definitions are arbitrary yeah
02:31:15 yeah yes can you yes and um specifically we go to page 24. paragraph 116. i think you ex is it right that you explain that there
02:31:27 is it right that you explain that there and in the third line you say there is no particular reason why the criteria for flaming should be set at zero seconds five seconds or ten seconds these are arbitrary decisions made typically by committee on the assumption
02:31:39 typically by committee on the assumption that the precise value selected does not particularly matter with regard to the expected in-service fire safety outcomes that's right yeah so so you know what these
02:31:48 these these um
02:31:49 these um [Music]
02:31:51 [Music] i mean i should probably say semi-arbitrary rather than arbitrary uh you know these these lines in the sand that get drawn on you know the permissible heat of combustion for for a product to
02:32:02 heat of combustion for for a product to be or sorry for a material to be considered non-combustible or limited combustibility uh those decisions get taken by you know committees of people uh who who decide
02:32:14 committees of people uh who who decide where those lines should be drawn under the assumption that something that would that would fall foul of those lines would burn too much and something that would not would would not burn too much but those are those are judgments that
02:32:25 but those are those are judgments that are made by by people you know it's not a
02:32:28 a it's not a scientific truth so to speak now in the third line just before that sentence you say at least partly arbitrary and then you go on to identify the timing criteria for flaming
02:32:40 the timing criteria for flaming are there any other criteria which you would say were arbitrary um
02:32:48 all of them uh i mean
02:32:51 i mean our
02:32:52 our are
02:32:53 are at least partly arbitrary you know so in the
02:32:57 the in the part 4 and part 11 tests the the chamber that the sample is lowered into is heated to 750 degrees celsius why why 750 degrees celsius why not 600 or 900
02:33:09 750 degrees celsius why not 600 or 900 and the answer is because they they tried a bunch of different temperatures when they were developing the test and they decided that 750 told them sort of what they wanted to know uh going to 900 was probably a bit
02:33:20 uh going to 900 was probably a bit difficult because it's quite hard to get something to 900 going to 600 maybe didn't quite get things hot enough to observe the behaviors that you're interested in um so i mean that's that's an example the size of the samples the shape of the
02:33:32 the size of the samples the shape of the samples are they cuboid are they cylindrical um
02:33:36 um if you look at the the bomb calorimeter tests uh the the the 1716 iso 1716 for instance and you look at where the euro classes decide to draw the line between
02:33:49 classes decide to draw the line between a1 a2 and b those decisions were made by a committee of people sitting in conference rooms in brussels deciding where that line should be drawn
02:34:01 deciding where that line should be drawn um yeah so in that you know in so far as these are these are committed decisions taken by individuals they are arbitrary they're not based on science which is what i mean you know they're not
02:34:12 what i mean you know they're not as i said before it's not a fundamental scientific truth it's a decision that's taken i think yes that's clear can we go then to 224 on page 45 page 45 paragraph 224
02:34:26 and you say um there the non-representative tests were used largely as set out above the thresholds were set at a conservative level the tests were relatively sensitive to detecting the degree to which a material
02:34:37 detecting the degree to which a material or product may or may not burn however the regulatory influence of this category of tests was limited as regards their application to combustible cladding materials and products um that
02:34:48 cladding materials and products um that last sentence are you able to clarify what you mean there um
02:34:53 um well if um if we're thinking about [Music]
02:34:58 [Music] the for instance the euro classification the european classification system so the european classification system uses um
02:35:07 uses um uh iso
02:35:09 uh iso well the bomb calorimeter test and the drop test similar to 476 part 4 or 11
02:35:15 4 or 11 to define uh a1 and a2 classifications which are you know the the non-combustible limited combustible classifications once you get down into b
02:35:28 classifications once you get down into b and lower down bcde uh those tests aren't relevant anymore um because the products don't well they're not non-combustible or limited combustible so so the different differentiation between
02:35:39 the different differentiation between the combustible products is made not on the basis of the potential energy contribution on heat combustion it's made on the basis of their reaction to fire in a in an sbi predominantly yeah i
02:35:50 fire in a in an sbi predominantly yeah i follow
02:35:51 follow so you're really just focusing on the upper end of the scale in that sentence yeah i mean what i'm what i'm trying to to to tease out there is that um the heat of combustion
02:36:02 combustion is used to draw a line that those who those who drew the line considered to be based on my assessment i wasn't in the room
02:36:12 room uh based on my assessment quite a conservative line you know a a material that has a heat of combustion of less than two megajoules per kilogram
02:36:23 of less than two megajoules per kilogram to use my sort of language from last week it's not a very burning material and no matter no matter what you do to that material the amount of energy you're going to liberate is comparatively small and so uh you you
02:36:34 comparatively small and so uh you you you know you could have drawn that line at 10 megajoules per kilogram or 30 megajoules per kilogram uh but they didn't they chose two um and the reason is because they wanted a conservative line
02:36:47 a conservative line despite the fact that they were acknowledging that they were allowing some contribution to burning just very very small right and you say that consideration doesn't apply once you're in but once you're down into b c d and
02:36:59 in but once you're down into b c d and yeah i mean i you you could you could have defined b c d and e you could have said well something can only be something it can only be given a b if in addition to achieving x and y in the sbi
02:37:11 addition to achieving x and y in the sbi test
02:37:11 test it has a heater combustion less than 15 or something but they didn't do that right they just they set heat heated combustion aside once they were down into the the lower ratings and i'll let uh let's turn then to the
02:37:22 and i'll let uh let's turn then to the model tests which is the second category of fire tests that you describe am i right to understand that that small scale model tests are modeled on and underpinned by larger scale research based on a more
02:37:33 based on a more on more realistic scenarios typically yeah i mean that's the way that that i've outlined them here is it right that those scenarios those scenario tests are intended to be representative of real fire hazards which might be present in
02:37:45 fire hazards which might be present in real buildings the models that are chosen as the basis for the model test yes
02:37:51 yes and the measurements in those small scale tests are intended is this right to correlate with the outcomes observed in the more representative scenario tests that's right the hope when developing a model test is that one
02:38:03 developing a model test is that one takes uh
02:38:05 takes uh a model that is relevant to the fire so the the the best example is the single burning item test uh in the european classification system i mean the bs-476 part six fire propagation test is also
02:38:18 part six fire propagation test is also a pretty good example both of those test methods the classifications that drop out of them are linked to a fire burning in the corner of the room
02:38:29 a fire burning in the corner of the room um so the model uh that is the scenario uh
02:38:35 uh is the fire burning in the corner of a room uh
02:38:38 room uh and then the hope is that you can make a test that isn't that doesn't require the burning of a fire in a room to infer
02:38:47 to infer what would happen if you use that product in a room with a fire in the corner and then and then you don't have to you don't have to burn a room every time you want to know the answer you can do a bs four seven six part six
02:38:58 you can do a bs four seven six part six test instead and still differentiate between products in a way that is faithful to what would occur in the room yes and i think you you your report gives
02:39:09 gives three three tests which fall into that category the bs476 part six bf476 part seven
02:39:16 seven uh and the sbi test en13501.1 um now i think each of those tests have been described previously by the inquiry to the inquiry by dr lane and others so
02:39:27 to the inquiry by dr lane and others so we don't need to go through the the methods or the apparatus or the associated classification systems but i just want to ask you one or two specific questions is it right that
02:39:37 that and i think it is right there for all three sets of tests they can only be strictly applied to products rather than materials unless a product is homogenous strictly yep yeah yes um
02:39:49 strictly yep yeah yes um can you explain and this may be a very basic question but what is the difference between a product and a material
02:39:58 i mean that's quite a i mean we i'm sure we could argue this point um all day when i think about it it has to do with the homogeneity homogeneity of the sample um so you know
02:40:10 homogeneity of the sample um so you know a product is going to be uh is often going to be something that is made up from different materials and in the context of this inquiry the most important case would be like a layered a flat layered product like a full face
02:40:23 a flat layered product like a full face foam insulation or an acm uh product uh so if you take for instance uh foil-faced uh insulation you've got a
02:40:34 foil-faced uh insulation you've got a polymer foam that is that is a material and you've got aluminium foil faces those are materials now it's slightly muddy in that case because the foil faces certainly of the kingspan product are not just foil there's fibers and various
02:40:46 not just foil there's fibers and various other things in there but
02:40:50 but you know and so for an acm product the aluminium the aluminium skins are a material
02:40:56 material the core or filler is a material polyethylene and so the product is a is a composite but you could have a you could have a product that is also a material so um a high pressure laminate cladding panel
02:41:08 a high pressure laminate cladding panel which is
02:41:09 which is uniform in composition throughout homogeneous and composition throughout is just the panel of a material right yes now um you you say in your report um that
02:41:22 you you say in your report um that uh and this is paragraph 178 on page 38 but
02:41:26 38 but you you say that the these tests can only be strictly applied to products use the word strictly there why is it that those tests are to apply to products
02:41:38 to apply to products strictly rather than materials what's the basis for that uh be because what you're doing in the model test is trying to assess
02:41:49 model test is trying to assess uh
02:41:50 uh how
02:41:51 how how products are going to how products are going to perform in a model scenario and what is relevant to the model scenario is not necessarily uh the material response but is the product
02:42:02 material response but is the product response you know it's the you know you you've developed a model of a room the reason you've the reason you've got a room
02:42:09 room with a fire in the corner is because you want to understand what's going to happen in rooms lined with that thing if there's a fire in the corner right you want to understand how quickly that fire is going to grow and whether that
02:42:20 fire is going to grow and whether that fire is going to progress the flashover so there's there's no point taking uh you know the core of an acm and testing it on its own in a room corner test
02:42:31 corner test because that's not representative of the end use condition it's not sufficiently representative of the unused condition it's not helping you answer the relevant question
02:42:39 question if that makes any sense i see um but i'm really after the distinction between products and materials why can or why do these tests only apply
02:42:50 why can or why do these tests only apply strictly to products and not to homogeneous materials i think because they're model tests because they are tests that are supposed to be asking questions about uh performance of products in
02:43:03 uh performance of products in fire scenarios you know in in the in the scenario that you used to develop your test uh and we know that part six says so but part six of bs476 actually says that it
02:43:14 part six of bs476 actually says that it applies to products that's right um but and the logic what is the logic though i know that it's a model test but but just to say that it's a model test explains why it only applies to
02:43:25 only applies to products and not materials is somewhat circular what's the what's the underlying rationale for the distinction
02:43:35 with respect to the part six test
02:43:38 six test the underlying rationale i mean i don't know again i wasn't i wasn't i wasn't there i wasn't born yet um when that part six test was developed i think in the 1950s uh originally
02:43:49 i think in the 1950s uh originally um but the rationale from my perspective is that
02:43:54 is that the the
02:43:55 the the taking the part six test as an example the part six test is asking questions about
02:44:02 about the ability of a product to contribute energy
02:44:06 energy to a fire so it's asking questions about the amount of energy that a product will liberate when heated in a compartment fire within a room and about
02:44:15 and about the
02:44:16 the uh the
02:44:18 uh the time scales over which that occurs uh mr chairman you look like you want to say something well it struck me listening to this exchange that maybe one ought to be thinking in terms of the test is only designed to be applied to
02:44:30 test is only designed to be applied to products it's a test that was conceived in order to test products would that be right
02:44:39 right i yeah i mean i again i wasn't there but that based on my understanding of what the test is what it does and the questions it asks and answers i would agree with that certainly and i i think mr millett's question was perhaps slightly
02:44:50 perhaps slightly um
02:44:52 um tempered by the fact that you use the words can can only be applied to products
02:44:58 products it can be applied to any material that you choose to apply it to i assume so go for it
02:45:04 for it wood for example or even a pir insulation board without any foil facer you could put through this test you you could you could put well you can that
02:45:15 could you could put well you can that would be an immodest product yeah yeah i mean certainly you could put anything you like through the test yes absolutely whether putting that thing through the test makes sense in terms of the
02:45:26 test makes sense in terms of the questions you want answers to in terms of the regulatory outcomes that would uh would eventuate is this maybe a secondary question right but i mean i think where i was going in my answer to mr millet was to say that
02:45:40 my answer to mr millet was to say that that the reason that i think these products can only strictly or credibly be applied or to these tests can only strictly or credibly be applied to products in the case of the part six test is that if if one is interested in
02:45:51 test is that if if one is interested in understanding the contribution of a product to a fire in a room the perfect example is within the
02:46:02 the perfect example is within the evidence to this inquiry um that
02:46:06 that for instance there were installation manufacturers kingspan who were performing bs 476 part 6 tests on the foil facers alone
02:46:17 with some notion that
02:46:21 you know getting a class o rating for the foil facer meant that the product with an underlying insulation would be classo
02:46:30 classo uh
02:46:31 uh and that is just utterly absurd because i mean not least because the facer has perforations in it but because the underlying foam insulation will contribute
02:46:42 insulation will contribute to the fire that you get in a room which is the model scenario that you're interested in assessing so to test the foil facing on its own is just completely and utterly nonsensical and and you know could never be defended in
02:46:53 and you know could never be defended in my view
02:46:54 my view so that i mean that that's sort of why i say that it's so that we don't get situations like people testing foil faces on their own um and claiming that that tells them something useful about the reaction to fire for product
02:47:06 the reaction to fire for product unless of course you're selling foil now
02:47:10 now just picking up your example which i think is one you've used in your report actually at um page 180 at paragraph 994 let's go to pyro995
02:47:23 where you
02:47:25 you uh say this bearing in mind the logic of the third way it is my understanding the tests might be undertaken in this way in order that a claim could be made that the surface of the k-15 was class naught despite the
02:47:36 of the k-15 was class naught despite the fact that the product as a whole was not such an approach would allow kingspan to generate the appearance of a product being classed north and thereby generate the appearance of compliance with approved document b and
02:47:48 compliance with approved document b and hence the appearance of compliance with paragraph b4 of the building regulations i note that i would consider this practice to be utterly indefensible both by any manufacturer and or by any compliance testing laboratory who
02:48:00 compliance testing laboratory who knowingly undertook and reported such testing
02:48:03 testing and then you have a footnote at 537
02:48:09 in my opinion the bs 476 part 6 testing standard is absolutely clear you say in italics absolutely clear that the part six test method is to be used
02:48:20 the part six test method is to be used to assess the fire propagation performance of quotes products uh or italics products i am not aware that kingsman sell aluminium foil faces on their own as distinct products for the construction industry
02:48:32 the construction industry and then if we turn the page please to the foot of page 81 and so i do not understand how either kingspan or any competent testing laboratory could undertake bs
02:48:43 testing laboratory could undertake bs 476 part 6 testing on this basis i am aware of the view approved document b could be interpreted so as to indicate that quotes the surface of any composite product place crate can be assessed
02:48:54 product place crate can be assessed independently of the rest of the composite product i consider any such claim to be patently absurd in discussing the test specimens to be used in bs 476 part 6 the testing standard explicitly states that quotes
02:49:07 standard explicitly states that quotes 4.2.2 products of normal thickness 50 millimeters or less shall be used to full thickness and
02:49:13 and quotes and quakes 4.2.3 for products of normal thickness greater than 50 millimeters the specimen should be obtained by cutting away the unexposed face of the product to reduce the thickness to 50 plus 0.3 millimeters the
02:49:26 thickness to 50 plus 0.3 millimeters the product in this case is kingspan k15 foil phase phenolic foam insulation and so i consider itself evident that the foil facer must be tested alongside a phenolic foam backing uh you go on to say with measurements
02:49:39 uh you go on to say with measurements regardless of the specific definition of class nor given in approved document b now and that's a long footnote um addressing um a potential interpretation
02:49:51 addressing um a potential interpretation of the
02:49:52 of the regulations and approved document b and is your reasoning based on your scientific experience
02:50:01 or or just on a reading of the language my reasoning for for what for for the assertion for the assertion that it's absurd to test the fourth pressure alone correct
02:50:11 correct uh
02:50:13 uh i mean i would argue that you don't that you don't need much experience to make that assertion frankly i mean i i i as you can sense from the language i've used here when i discovered that this was going on i was absolutely
02:50:26 was going on i was absolutely incredulous i could not i could not believe that this was going on i simply i refused to believe that it was happening
02:50:33 happening uh until i saw the evidence so
02:50:38 so yeah i mean i guess it's based on my my my
02:50:41 my my my technical knowledge but i think to me it's plainly obvious that you just can't do that now
02:50:48 now am i right to understand that for all three of the model tests uh bsa bs 476 part six and seven and the sbi tests
02:50:58 sbi tests there are four of them i think in total actually um which you talk about in this part of your report the real fire relevance the reference scenario is a fire growing inside a compartment or a room or a corridor within a building
02:51:11 room or a corridor within a building that's right not an external wall correct now
02:51:17 now we know um that national class naught achieved by a combination of results from tests carried out under part six and seven of ps476
02:51:27 ps476 or after 2002 euro class of the euroclass regime class where the classification is recommended in adb for external walls over 18 meters in height
02:51:40 over 18 meters in height do you know why do i know why do you know why or do you know the rationale for using class naught
02:51:51 for using class naught as a classification regime or class b as a classification standard for an external wall given the reference scenario was a fire inside a room or a corridor
02:52:03 corridor no i don't know why i i mean
02:52:07 i mean it's a
02:52:08 it's a it's a it's a it's a very important question um and i'm
02:52:13 and i'm uh i'm a bit surprised that i have to say no i don't know why i mean i know why the tests uh came into existence and i know how they came into existence and i know
02:52:24 i know you know the structures of the committees and the experimental underpinning research and all of those things
02:52:29 things why class naught was
02:52:33 was was able to
02:52:37 persist let's say
02:52:39 let's say for so long uh within the english regulatory system i don't know i mean i have some views i presume we'll talk which i've intimated
02:52:50 presume we'll talk which i've intimated about in this report uh
02:52:52 uh but no and and with respect to the uh the european classification system um you know in the development of the european classification system
02:53:03 european classification system uh you know from the late 1980s through until 2002 when they when they became um when they were when they were inserted into the approved document
02:53:14 into the approved document a proof document b uh
02:53:17 uh there were based on my understanding of what was going on in those years there was an understanding or at least a hope that um a classification system for
02:53:28 that um a classification system for products
02:53:29 products that was based on different reference scenarios that would be relevant to external clouding uh would also that that would occur that's that you know that that an activity would be undertaken
02:53:40 an activity would be undertaken in order to define a classification of products that would be more relevant to a reference scenario involving external cladding but that never occurred why that never occurred is a very important question and i don't know the answer to
02:53:51 question and i don't know the answer to it right
02:53:52 it right thank you let's go to page 39 of your report then paragraph 193
02:54:04 and you start at 189 by identifying three important conclusions which can be drawn from the development of the model fire tests first at first
02:54:15 of the model fire tests first at first you say they were created on the basis of underpinning research and a body of knowledge second the classification threats
02:54:21 threats thresholds were essentially arbitrary in terms of fire safety outcomes and then third all of the tests were developed on the basis that the relevant hazard was a fire growing inside a room or corridor
02:54:33 or corridor and then at 193 you say none of the above test standards was designed or originally intended to represent the fire hazards that might be presented by a fire impinging on the external cladding of a building or its
02:54:45 external cladding of a building or its potential for escalation the reference scenario
02:54:49 scenario quotes on quotes was used was and is far removed from the circumstances of a cladding fire potentially resulting in promotion of external fire spread and my question showing you all of that is this
02:55:01 question showing you all of that is this why does that matter
02:55:05 why does it matter it it matters because the
02:55:10 the physics that we are interested in that govern the way a fire grows and spreads on the outside of a building are
02:55:21 on the outside of a building are very different than those that would be experienced inside a room i mean to give you to give you one example all of those tests that i've uh that i've discussed previously
02:55:33 that i've discussed previously the the maximum heat fluxes to which the the product samples would be exposed would be considerably less than we would expect in a cladding fire scenario if you have a fully developed fire venting from a compartment so the products are
02:55:45 from a compartment so the products are not exposed to representative heat fluxes would be just one example of one of the differences but the you know the the
02:55:53 the the scale the mechanical issues um i mean professor terrero i think outlined a whole host of reasons why clouding systems are
02:56:04 clouding systems are are complicated uh in his presentation last week and all of those all of those factors are relevant i i mean i would i would also
02:56:15 i i mean i would i would also just add that um i also i i mr mill have also noticed that the screens have gone blank this is mouth confusion i wasn't going to stop you but i mean i think it's also worth noting that that you know it's important
02:56:26 noting that that you know it's important for me to say that
02:56:29 just because uh just because a test is based on a model scenario that is not the
02:56:37 the scenario that you're interested in doesn't mean that the test has no value um
02:56:44 um you know it's not that these it's not that bs 476 part six part seven uh sbi tests tell you absolutely nothing of interest they have the potential to tell us lots of interesting things about the
02:56:55 us lots of interesting things about the way products behave when they are exposed to fire um they are out but they're not asking the question in a way that is immediately relevant to the scenario that we're interested in and to me what's what you know which is what i
02:57:06 what's what you know which is what i would say about all experiments or test methods rather what's important is not uh you know criticizing this test or that test because it you know uses a different model scenario but but but how
02:57:18 different model scenario but but but how how are people using the outcomes of these tests how are people understanding the questions that these tests are asking
02:57:25 asking how are they using their understanding of how these tests are performed and their understanding of the outcomes to make decisions about what is okay or what is not okay on the outside of a building so it's it's about
02:57:37 building so it's it's about we have a mantra in in my research group at edinburgh which is you know the test is the test uh it's what people do uh with the test that is it's worthy of
02:57:48 uh with the test that is it's worthy of our scrutiny or more more worthy of our scrutiny so so i wouldn't want to get too hung up on that uh reference scenario business it's important to be aware of it it's important for the people who use the
02:57:59 important for the people who use the tests to be aware of it but it it doesn't mean that the tests are useless so i and i would be quite careful about saying that yeah i understood let's let's see if i can just explore this just a little bit more can
02:58:10 explore this just a little bit more can we go please to page 174 um and go in that to paragraph one paragraph 958 there you say the reference scenario for the european and
02:58:21 reference scenario for the european and notably also the national material product classifications is a room with the materials straight products in question uses internal linings by contrast the relevant scenario for vertical spread on the external wall as
02:58:33 vertical spread on the external wall as nationally represented by bsa414 or similar testing is the impingement of the plume from an already large fire on the external cladding then you say this in italics these two scenarios represent fundamentally
02:58:45 scenarios represent fundamentally different thermal and mechanical conditions to the exposed materials stroke products now
02:58:54 now you say they're fundamentally different the question is whether those fundamental differences matter in other words does the fact that the class naught or sbi tests
02:59:05 class naught or sbi tests might tell you something
02:59:09 does does it matter that they are telling you something in the context of the application of the relevant product to the external wall build-up as opposed to a room
02:59:21 to a room yes
02:59:21 yes it does matter
02:59:25 but what matters is not
02:59:29 is not what matters is not that it's different what matters is that the person who is using what is observed the outcome
02:59:40 what is observed the outcome uh
02:59:42 uh thinks about the extent to which the differences might matter given that they're going to use that result for some other purpose if that makes sense maybe quite a mild
02:59:53 that makes sense maybe quite a mild distinction but isn't that partly because the circumstances in which the test is
02:59:59 test is carried out brings with it a host of undefined factors which do actually have a bear on the outcome so if you light a fire on the inside of a building in a
03:00:11 fire on the inside of a building in a room
03:00:12 room you've got various factors in play and the fire on the outside is subject to different factors so you're not actually going to be comparing
03:00:21 comparing the same things absolutely and and and and what's important
03:00:26 important from my perspective is is that the people the practitioners who are using these
03:00:35 these tests
03:00:36 tests have some understanding of that have some
03:00:40 some have some understanding of what you know where did this test come from i mean to give you the example of the tests on foil facers and and my disbelief that that was going on uh i immediately
03:00:52 uh i immediately sort of asked myself who on earth was running these tests who on earth was performing tests on foil phaser stapled to calcium silicate board on behalf of kingspan
03:01:04 on behalf of kingspan and and didn't know to ask the question what are you guys doing this is not this is not appropriate and who's who signed these reports off recognizing
03:01:16 signed these reports off recognizing what was going on and didn't say well hang on this is not appropriate that you cannot be doing this right um and i'm still not sure i know the answers to those questions you know uh
03:01:27 answers to those questions you know uh but but but that's the issue the issue is not that that a bs 476 test is never useful the issue is that like somebody somewhere within this process of of building regulation and oversight
03:01:40 of of building regulation and oversight needs to be the person who stands up and says no this is not okay we cannot be doing tests like this and that didn't happen
03:01:47 happen and that's that's the issue just going to the differences though do the fundamental differences between the thermal and mechanical conditions for a room corner test sbi or the or the
03:02:00 for a room corner test sbi or the or the um the
03:02:01 um the part six and seven tests on the one hand and the
03:02:05 and the use of the product on the external wall of a high-rise building did they go so far as to invalidate the assumptions of the underlying research and reference scenario
03:02:19 in other words did the fact that the product was going to be used on the external
03:02:25 external wall of a high-rise building um mean that the differences between its application there and it's and the circumstances in which it was tested were so fundamentally different
03:02:37 were so fundamentally different um that the assumptions underpinning the test
03:02:39 test uh were inapplicable
03:02:43 uh i mean i think the the assumptions
03:02:52 i mean i can only answer this question in a more general way i don't believe that it is ever okay to blindly apply the results of a compliance test
03:03:04 so if someone wants to take results from a test that was developed on the basis of a fire burning within a room
03:03:13 room and they want to take the product assessed on that basis and put it on the outside of a building then yes they absolutely must think about
03:03:22 about the ways in which their application of the product might differ from the test scenario in which it was evaluated and and and yes if you're going to use a product that is tested on the inside of
03:03:33 product that is tested on the inside of a room with a small fire burning in a corner
03:03:36 corner and then you say okay well now i'm interested in how that product is going to react when it's vertically oriented on the outside of a building and exposed to a plume from a post-flashover compartment fire
03:03:50 very very different scenarios and yes you better you better think very hard about whether the assessment from the room corner test or or the model that's based on the room corner test is relevant and probably it's not
03:04:02 test is relevant and probably it's not in a bunch of ways i have one question flowing from that mr chairman may i ask it before i call for the break all right mr limit what is there in approved document b
03:04:14 in approved document b when it presents class not as the applicable classification standard or class b for the applicable classification standard in diagram 40 which tells you the building designer that you have to ask yourself those questions
03:04:31 in approved document b
03:04:37 i mean off the top of my head now you've asked the question i'd want to go back and read through a proof document b i can't point to a specific clause that says that i i
03:04:47 i i but
03:04:49 but i don't necessarily believe that a proof document b is obliged to say it that's a
03:04:55 that's a matter
03:04:56 matter but thank you professor mr chairman is now a convenient moment for the break yes i think it is mr lip thank you very much
03:05:02 much we'll break that so we can all get some lunch professor we'll uh come back please at five past two and usually discuss your evidence with anyone while you're out of the room
03:05:13 you're out of the room thank you thank you very much
03:05:22 thank you mr millet five folks too please
03:05:33 you