Grenfell Tower Inquiry - Expert Evidence - Professor Bisby (21 November 2018 Pt 2 of 2). Professor Luke Bisby provides expert testimony analyzing the mechanisms of fire spread at Grenfell Tower, including vertical spread through ACM cladding, the role of PIR insulation, and the contribution of building geometry to rapid fire escalation.
00:00:56 you
00:01:12 you
00:02:56 I usually drinking you can give me something that you like [Music]
00:03:10 could be waiting for you to tell them we're ready
00:03:16 I need to repeat the triggering fest and it get a long dining to get that it's a
00:03:29 it get a long dining to get that it's a data point
00:03:43 right we're ready to carry on yes
00:03:47 Faysal is be before we start I'm going to repeat the trigger warning I gave before mr. chairman just before we think you stopped for lunch I'm going to be playing in a moment or two a part of
00:03:59 playing in a moment or two a part of your video your first video in video 1 showings fire spread up the East elevation of the tower in the early stages so people may find that
00:04:10 stages so people may find that distressing to look at there's also some audio which people may find distressing to hear so they need to absent themselves from this room or from the livestream while we play that before I go to that professor can I ask you
00:04:22 go to that professor can I ask you please to turn first of all to page 117 one one seven of your report and look at figure 58 now this sits within the part
00:04:33 figure 58 now this sits within the part of your report dealing with vertical fast bread and the early part of the fire and you identify this as a picture extracted from the video captured at 105
00:04:47 extracted from the video captured at 105 49 and you say flames visible that left of window inside compartment I just want to pick this up with you as a data point at this point
00:04:59 at this point 105 49 could smoke from within the compartment B heating up the uPVC windows surround causing it to deform yes
00:05:11 yes what about radiated heat from the fire oh yes yes now what I need to do then is to start the video and going to run it
00:05:24 to start the video and going to run it up to 111 and what I'd like you to do that is to signal when you want to stop and identify things that are important and the reason I want you to do that is
00:05:36 and the reason I want you to do that is that we've heard earlier that you have changed your opinion from between your first report in your second report and what I need you to do is to explain to me by reference to this video what we see which enables you to come to that
00:05:50 see which enables you to come to that conclusion and focusing particularly on the timing of the fan failing and also the timing and place of where we see melting droplets of polyethylene okay okay so
00:06:04 droplets of polyethylene okay okay so you're going to be over right okay all right and if you have to get back to anything we can do that okay so can we start please Paul
00:06:44 so I mean I just I just stopped it here because that's sort of coincident with the figure 58 that you showed me yes recently that's about at the same time so just again to see here that we do see some flaming that flaming does appear to
00:06:56 some flaming that flaming does appear to be confined to inside the flat still you don't see a lot of flames coming out the window you do see a bit of smoke coming out the window which equally could be heating the cladding above the window or
00:07:07 heating the cladding above the window or adjacent to the window admittedly to a limited extent do you know where the windows open or closed at this point my understanding is that the the larger pane the tilt pane is tilted inwards 40
00:07:20 pane the tilt pane is tilted inwards 40 50 millimetres a couple of inches and so I open at the top in an inward leap tilting position and that the window the smaller pane beneath the extract fan is open according to the witness
00:07:31 is open according to the witness statements approximately 10 inches I believe is what mr. committee committee says thank you so go ahead Paul
00:07:43 [Applause]
00:07:55 and they on the fire so clutch
00:08:02 I'll call overhead or graveyard shift but I've seen the eggs light the lorries your that is what not so much so I mean
00:08:16 your that is what not so much so I mean it's not a very good not a very good frame to stop on there unfortunately but um so you know at this stage again we can see flames inside the flats and again it's hard to say the extent to which those flames might be projecting
00:08:27 which those flames might be projecting outside the window so we still see a similar collision although the fire is clearly growing a bit in time as we go forward but still contained within the compartment you think of this it appears to be yes by this stage mr. arrow has
00:08:41 to be yes by this stage mr. arrow has says that it is it has exited the compartment although the earlier earliest point at which it could have done is passed at 105 can you comment on that I mean I think that the basis upon
00:08:52 that I mean I think that the basis upon which Professor torero is making that statement is related to a still image that does social show some falling debris from the window which could be
00:09:04 debris from the window which could be could potentially be droplets of polyethylene right burning and falling from the window but it's very very limited at this stage yes and you will
00:09:16 limited at this stage yes and you will have noticed in my report that we've we put that time where we would be more comfortable confirming that the fire was within the cladding and burning the polyethylene are closer to 108 109 in my
00:09:27 polyethylene are closer to 108 109 in my report yes yeah his his image is I think a 105 57 just for reference purposes its page 56 of his statement of his report
00:09:38 page 56 of his statement of his report let's continue okay yeah well I'll be pissed if that was my own top or sideways mud
00:09:51 top or sideways mud put up those states
00:09:55 Marty
00:09:58 ends
00:10:01 [Applause]
00:10:05 [Music]
00:10:10 anytime here yeah okay so in this sequence here around 107 51 and in some seconds after that what we see here is that flames are passing underneath the
00:10:22 that flames are passing underneath the fan mounting units it's hard to say whether that's through the bottom of the infill panel or some flames coming out of the open Oh inwardly opening window and you
00:10:35 Oh inwardly opening window and you immediately below the extractor fan it's also difficult to say definitively whether or not the extract fan is still in place here although it appears to be right and then I'll get you a pole to
00:10:47 right and then I'll get you a pole to just continue a little bit more please
00:10:53 sorry if you can go back a little bit apologies so there is a moment there just at the end of that clip so in that
00:11:08 just at the end of that clip so in that view there you can see a circular opening in the location where we would expect the extract fan to be does it appear to you that the extract fan is still in place no it would appear to me
00:11:19 still in place no it would appear to me on the basis of this that the extract fan has fallen out so and I so that that and unfortunately that could have occurred even before 105 49 it's
00:11:31 occurred even before 105 49 it's possible we just don't have very good views to be able to say definitively when the extract fan has fallen on this still frame you could see a circular orange disc but with a black bar across
00:11:43 orange disc but with a black bar across it might not tell you that the extract fan was still in place or not I think what we're seeing there the larger bright spot yeah is I think the opening
00:11:55 bright spot yeah is I think the opening where the extract fan would have sat so that is a hole through a window infill panel it's a circular opening through window info panel yes and the flames the little piece of flame that you can see under that I would suggest is either
00:12:08 under that I would suggest is either flames coming from the bottom of the infill panel or through the open window I've immediately below the extract fit yep okay go ahead
00:12:28 so here this next sequence you really just see the fire continuing to grow within the flat increasingly we see flames coming through the extract fan and through that either open or absent
00:12:41 and through that either open or absent window beneath the extract fan and indeed a little bit of flaming coming that it would appear through the tilt the inwardly tilting window no as well by this stage Oh 108 16 have we seen any
00:12:56 by this stage Oh 108 16 have we seen any falling burning material yet I don't I mean the aside from the still photo that Professor torero has used no significant and we should see it in a few moments
00:13:07 and we should see it in a few moments the reason I ask is if you go and I wonder whether as a way of having both on the screen at the same time if you go to figure 60 of your report at parent page one more nine that if it is
00:13:18 page one more nine that if it is possible to have faith on the screen at the same time but if you go to figure sixty you've got maybe we haven't arrived at it yet yeah so we'll see that yeah we will see that in a moment but if
00:13:29 yeah we will see that in a moment but if we continue there so fast quickly if everybody watches just the lower left-hand side of the window they should see some debris dropping down in a moment before we do that can you tell from this frame all the sequence which
00:13:41 from this frame all the sequence which leads to it what is combusting no right I couldn't say it's also noteworthy here that there does appear to be flaming
00:13:52 that there does appear to be flaming sort of more towards the left-hand side of the window although given that it's sort of shielded by the the view angle it's hard to say for sure right can we continue
00:14:20 deposit their poll so here you can see 109 34 and there you can now see sort of a semi continuous stream of lids
00:14:32 a semi continuous stream of lids particles from the lower left-hand side of the window right can I just ask you I'm sorry to just get back to the last into the last sequence I want you to look for burning falling material coming
00:14:44 look for burning falling material coming out of the window at that state before we get to 109 you can just look just go back to that let's play from there yeah we could see
00:14:57 let's play from there yeah we could see burning material yeah 101 Oh 8 119 what is that do you think I couldn't say is that it's it's possible that it's polyethylene it could also be things
00:15:08 polyethylene it could also be things that are coming out from inside the flat we have we have the parole board immediately above the window which I would expect to be burned or burning at this stage right and you have various
00:15:19 this stage right and you have various other things around the window that could potentially be burning the the droplets that we just saw falling are not falling sort of straight down in a very sort of dedicated seaming manner
00:15:30 very sort of dedicated seaming manner they're kind of a bit floating away from the building later on when we see the polyethylene the burning and ripping polyethylene that tends to be sort of a more vertical the particles are falling
00:15:42 more vertical the particles are falling with a bit more intent if you see what I mean yeah okay we can continue
00:16:09 dog
00:16:13 stopall so you did hear someone in the background there say it sounds like it's dropping down yeah so I would expect that they're commenting on things falling to the ground in this photo you
00:16:25 falling to the ground in this photo you can clearly see that the extract fan is now absent from the from the panel there's very clearly a hole there now and there's quite a lots of flame within the compartment and a little bit exiting
00:16:37 the compartment and a little bit exiting the compartment now we saw it was in this sequence I think actually the end of the last sequence the flowing dripping material would that do you say that's probably ethylene I think it's I
00:16:49 that's probably ethylene I think it's I think it's probable that it's polyethylene but I couldn't I couldn't possibly say if it weren't certainty where would it be coming from it would be coming given the location that it's dripping from it would be coming either
00:17:02 dripping from it would be coming either from the column Cosette to the left of the window yeah or from the spandrel Cosette immediately above and to the left of the window I would say or some combination of those two potentially
00:17:13 combination of those two potentially right and if it were coming from the column Cosette to the you say to the left of the window you mean to it as I'm looking as you're the outside yeah what
00:17:25 looking as you're the outside yeah what is the mechanism by which that polyethylene would have ignited at this point well as we've discussed we essentially have these two candidates
00:17:36 essentially have these two candidates and my two hypotheses B 1 and B 2 one is that the the the fire and hot gas gets into the cladding via the uPVC windows boards which we will have to assume have
00:17:48 boards which we will have to assume have have been removed in some way or because flame and hot gas are exiting the compartment via the extract fan panel or the open window and impinging on that
00:18:00 the open window and impinging on that column cassette immediately outside the window or immediately above the window so it could be either it to be honest and I do say this at some stage in my report I think that the only credible answer to that question is that it's
00:18:11 answer to that question is that it's going to be some combination of those two because no matter what the hot the hot gas and flames exiting the compartment are going to be heating the cladding externally and no matter what's
00:18:22 cladding externally and no matter what's you are going be getting heat through the windows around whether it's there or not and into the cladding it's a question of the relative importance of those two modes of heating the cladding and I I would be
00:18:33 of heating the cladding and I I would be very hard-pressed to say which one I think is dominant if that makes sense on the basis of the visual inspection of these videos on the basis of any of the
00:18:45 these videos on the basis of any of the evidence that I've seen yeah can you understand what I'm seeing some of these pictures if you look at one on the screen at the moment yeah we can take it
00:18:57 screen at the moment yeah we can take it to either the top of that brightly illuminated windows where the fan was the sort of circular opening yes and a bright yeah would it be right to infer from this and the previous films that
00:19:11 from this and the previous films that the large window which is to the left of the support when they would the fan as you stand in the kitchen the right on sue is not as heavily involved well it is not open so it is here it's there but
00:19:31 is not open so it is here it's there but I mean yeah the impression I get from what I'm seeing here and it's true for the earlier shots is that the fire is impinging on the as we view it from here
00:19:43 impinging on the as we view it from here left-hand window where the the fan was but not nearly so much on the right hand large window which which could be relevant for identifying the
00:19:55 could be relevant for identifying the point at which breakout occurs yes I mean the important thing to recognize in this view is that this smaller window here is an inward swinging window that opens like that and it's open ten inches
00:20:07 opens like that and it's open ten inches so it's essentially wide open so you're looking straight into the kitchen here whereas the right-hand window is closed from a visual perspective and so and it
00:20:19 from a visual perspective and so and it could have some soot deposition on it which is causing it to be slightly sort of frosted at this stage in the fire which is why it looks a lot darker yeah but it but it does appear to me that that there is more flaming to the left
00:20:32 that there is more flaming to the left of the window that is certainly something that is true that I asked because then I think you've suggested that the fire might have come out of the kitchen along at the top of the window
00:20:45 kitchen along at the top of the window rather than the side of the window to put it in rather generosity but if it came out at the top of the window it's going to be the top of the small window not the top of the large window it's gonna be the extract fan yeah the hole
00:20:56 gonna be the extract fan yeah the hole in the extract fan panel will be the primary route that I would suggest as well as the window immediately below yes yes thank you okay at this state different question but at this stage was
00:21:09 different question but at this stage was the XPS involved it appears to me that some of the flaming that we see around the extract fan infill panel will be associated with combustion of the XPS I would I would consider that highly
00:21:20 would I would consider that highly probable given that we have flaming and are gases there yes although as I've noted there's not a huge mass of material there so it could burn away quite quickly yes and then you're just left with two aluminium sheets yes
00:21:33 [Music]
00:21:38 [Applause] the Oscar
00:21:49 come away from that get over there boy
00:21:59 okay so here I've stopped the the video here because we can now see on the ground there is actually some burning debris on the ground it's rightly beneath the window my assumption would
00:22:10 beneath the window my assumption would be that that would be polyethylene that has dripped while it's burning forming a small pool fire on the ground yeah so at this stage 109 58 were reasonably certain that we have polyethylene
00:22:22 certain that we have polyethylene burning and melting within the cladding by some means yeah would that do you know whether that would be self-sustaining by this stage what was in within the cladding the cladding you
00:22:33 in within the cladding the cladding you know if if you have polyethylene burning and dripping out of cladding such as this and either you have a continued
00:22:44 this and either you have a continued source of external heat flux or you have a pooling of that polyethylene in the location where it's continuing to burning then yes I would say at this stage you would have a fire that we would expect to propagate if left to its
00:22:57 would expect to propagate if left to its own devices yes okay
00:23:16 Seifer gates the house guys don't make fires it's parents keep kids away alright yeah five again can you stop it
00:23:32 alright yeah five again can you stop it your fault I mean it's very difficult to see here through the trees but what we do see in this next sequence is you do see now quite a lot of smoke coming out of the compartment and quite a lot of flame coming out of the compartment as
00:23:44 flame coming out of the compartment as well go ahead
00:23:56 not even on Donna
00:24:08 lemon
00:24:19 yeah so here what's interesting is you see you can see now quite a lot of flaming below the spandrel panel it's difficult to say whether those flames
00:24:31 difficult to say whether those flames are emanating from within the compartments itself or whether that is an indication that we have polyethylene within that spiritual panel that's actually burning and dripping and burning lots of falls away the location
00:24:45 burning lots of falls away the location where you see a bright spot on the spandrel panel below the kitchen window flat 16 the only explanation I could give for that is that that is burning polyethylene on the surface of the
00:24:56 polyethylene on the surface of the spandrel panel the likely candidate for where that polyethylene would have come from would be the spandrel panel above the kitchen window above the kitchen window what about to the side to the left of the kitchen in the location that
00:25:08 left of the kitchen in the location that it is I think it's unlikely that it would come from the side and end up there right yeah ok
00:25:27 it's not yeah
00:25:33 lastly to pause this well you may be about to do it but you can see the fire in flames now hinging upon the 90 degree return of the aluminium panel above the
00:25:44 return of the aluminium panel above the kitchen yeah would that tell you anything about ingress of fire into the dark crack that we looked at earlier this morning behind which is exposed poppy I mean certainly at this stage I would expect flaming inside the the
00:25:57 would expect flaming inside the the cavity behind the ACM panel yes I would expect those flames to travel up through that gap yes
00:26:17 [Music]
00:26:26 I was hoping for [Applause] [Music]
00:26:35 right here go back a bit Paul if you wouldn't mind yes but I'm looking for a sort of one 13:31 that we see a little pulse of flame yes yes oh
00:26:50 see a little pulse of flame yes yes oh there so we start to see now this pulsing of flames those flames are exiting the gap the vertical gap between the first and second spandrel panels immediately above the kitchen window of
00:27:03 immediately above the kitchen window of flat the 16 which would indicate that you have some pyrolysis or evaporation of liquefied polyethylene within the cavity above flat 16 so that's behind the because there's something going on
00:27:17 the because there's something going on inside that cassette and the gases are coming out their heart they're finding oxygen and they're flaming have you seen any evidence visually or of that phenomenon before this point or in this
00:27:29 phenomenon before this point or in this particular Akron force our or in other cases the Grimpen I think this is the first time we see this happening specifically a gram fell in the footage that we have yeah and just before you
00:27:41 that we have yeah and just before you continue Paul what you'll see in a minute if this continues in just a couple more seconds you'll see a similar sort of licking or pulsing of flame slightly to the left which is along the the corner or the the reentrant corner
00:27:54 the corner or the the reentrant corner where the column joins the spandrel panel above flat 16 and you'll see that extent I think a little bit farther up go ahead yeah there it is so that's
00:28:07 go ahead yeah there it is so that's that's the joint between the column and the spandrel panel and again it indicates to me that there's something going on within those those cassettes at that location
00:28:21 beautiful evocative oh yeah
00:28:28 anywhere there yeah so so at this point I think it's quite clear that the cladding is involved the ACM cladding cassettes are involved and that that
00:28:39 cassettes are involved and that that this fire is likely to escalate up the building supported primarily by combustion of the ACM and the polyethylene so that's I think that's as
00:28:53 polyethylene so that's I think that's as far as we really need s to go here right and so sort of just to sort of say where that where does that leave me with respect to my two hypotheses probably the next question that was the next question yeah so so where it leaves me
00:29:06 question yeah so so where it leaves me with a situation that I have professor Toreros analysis which suggests to me that the gas layer in the kitchen is between 200 and 300 degrees Celsius most
00:29:17 between 200 and 300 degrees Celsius most likely and that we have flame impingement on whatever is going on inside the kitchen at that stage if we assume that the uPVC is physically
00:29:29 assume that the uPVC is physically absent then and if we assume that along with the uPVC goes the 25 millimeter thick PIR which is adhere to the back of the uPVC then we have epdm
00:29:42 the uPVC then we have epdm weatherproofing membrane which would provide negligible resistance to flame impingement and those types of gas temperatures and it would burn through quite rapidly and then we're into the back of the cladding and as Professor
00:29:54 back of the cladding and as Professor torero said yesterday at that point with flame impingement and those types of gas temperatures it's anyone's guess as to which material is sort of the first ignited material within the cavity
00:30:06 ignited material within the cavity outside the window I have flames and hot gases exiting I have impingement of those flames and hot gases directly above and potentially to
00:30:17 gases directly above and potentially to the left if I'm outside the building looking at the building of the window and at some stage we see polyethylene melted and dripping and falling from that region to the left-hand side of the
00:30:28 that region to the left-hand side of the window as I'm get it from the outside I think where that leaves us is in a situation where no matter how you look at this you have
00:30:39 no matter how you look at this you have some combination of those two heating mechanisms that are causing eventually the ignition of the cladding and the escalation of the fire spread of the building so I mean if you look at for
00:30:50 building so I mean if you look at for instance I'm just looking at this over the lunch break paragraph seven one three in my report I sort of finished this section on b1
00:31:01 I sort of finished this section on b1 and b2 this immediately below the paragraph but you read previously and I say indeed it's probable that some combination of the fire spread routes suggested in b1 and b2 conspired to
00:31:12 suggested in b1 and b2 conspired to cause the ignition of the initial ignition and sustained burning of the external cladding so that's kind of where I end up with it and even I guess I would like to say also with respect to this issue that for me it's almost a
00:31:27 this issue that for me it's almost a secondary issue I can understand why we want to get to knowing sort of more confidently which one it is but at the end of the day there's a there's a number of mechanisms by which cladding
00:31:39 number of mechanisms by which cladding of this nature rainscreen cladding of this nature could be ignited on the outside of a building and to focus too heavily on the specifics of what has happened in this particular fire scenario I think in in a way diminishes
00:31:51 scenario I think in in a way diminishes the importance of recognizing the clear risks that it presents under any scenario so I I wouldn't want to labor the point too much no I understand that and picking up seven one three and the
00:32:04 and picking up seven one three and the purpose of this exercise in a sense is to see if we you can come to an opinion with a reasonable degree of confidence about although they're combined
00:32:16 about although they're combined whether a b1 or b2 is the more likely yeah I mean I I think you can tell that I'm not enthusiastic to be drawn on this point I think at this stage if you
00:32:28 point I think at this stage if you really push me I would say that fire spread through the uPVC is ahead by a nose
00:32:34 nose all right yeah and let me try a different way when you are you're obviously looking at it from a visual perspective and forming
00:32:45 it from a visual perspective and forming your opinions based on what you see we you can see burning droplets work they were coming I think from the bottom of
00:32:56 were coming I think from the bottom of the window or is that that's where we see them exiting the window box yeah my question is is that not more consistent with b2 hypothesis b2 b2 being through
00:33:12 with b2 hypothesis b2 b2 being through the uPVC yes yes I mean perhaps but as we discussed earlier when I was pointing out the detail of the cladding cassette alongside the window the exposed edge of
00:33:23 alongside the window the exposed edge of polyethylene in that particular location is external to the cavity so that vertical line of PE yes immediately to the left of the window if I'm looking at
00:33:34 the left of the window if I'm looking at the window he's actually external so if it's if it is coming directly from that location then I I think we should sort of have to hold our hand in the air and say we don't know right now again I
00:33:46 say we don't know right now again I think that does depend on being able to see clearly enough where the droplets are coming from indeed and we can't because of the angle that we're looking at it and also the fact that if they were coming from above the window
00:33:57 were coming from above the window they're falling past the window which is itself highly illuminated by the fire does that make it more or less difficult to well if and if they are coming from above the window given the way that that
00:34:08 above the window given the way that that cassette is configured essentially it's a it's a box that goes like that you essentially have a trough internal to the cavity of that location and you're burning polyethylene is going to come
00:34:19 burning polyethylene is going to come out one and either end of the trough and the vertical cracks given that I would expect the predominant heating to be above the extract fan the left-hand side prefer no it's possible
00:34:30 prefer no it's possible but again I mean I don't know that we will ever know the answers to these questions try something on you we've treated the uPVC as a single a single entity but can you help us with the
00:34:43 entity but can you help us with the temperatures that Professor Toreros identified with apartment would it be more likely that the uPVC would fail and fall away and open up at the top as opposed to the bottom I think so yes if that is so
00:34:56 bottom I think so yes if that is so would it not also be the case that therefore there was a more likely ingress of far from the inside of the compartment through the gap created by the uPVC at the top by the window indeed yes and that would also therefore
00:35:07 yes and that would also therefore explain or could explain that or support rather hypothesis b2 indeed yes so that in fact although the flaming droplets might well have been coming from the the
00:35:18 might well have been coming from the the top end of the window jamb on the right hand side as you look at in fact the ingress of fire into the cavity could well have come through the uPVC there yes and indeed the way that her way that
00:35:31 yes and indeed the way that her way that the rail that holds the window framing onto the building terminates at that location would allow flames and hot gases exiting at the top right hand
00:35:42 gases exiting at the top right hand corner if you're inside looking out to access the spiritual panel as well as the column panel just above the window so yes yeah it's possible and putting into the mix that possibility
00:35:54 into the mix that possibility how would that then Square against the possibility of your hypothesis be one namely flame impingement directly through the gap left by the extract vent or the open window I don't think that
00:36:08 or the open window I don't think that would necessarily impact my previous statement that I would say you know via the uPVC failing is ahead by a nose but not by a significant margin right yeah I
00:36:20 not by a significant margin right yeah I mean it's important to say of course we also have the analysis by Professor torero
00:36:23 torero and he clearly has a preference I think in his report and dr. Lane also I think expresses a clear preference for the upzu PVC failing mode in her report the
00:36:38 upzu PVC failing mode in her report the only thing I would say and I'm sure that professor torero would agree with me on this is that his analysis as you've pointed out is a simplified analysis it's quite a straightforward quite a simple analysis and it doesn't take
00:36:49 simple analysis and it doesn't take account of for instance the perl board immediately inside the window and potential for that to burn in flame or the potential for the extract fan infill panel to to burn and provide some flames
00:37:02 panel to to burn and provide some flames as well so his model only deals with gas layer temperatures and flame impingement due to a ceiling jet from an object burning at some distance from the window so there are a number of assumptions inherent in all of this that we have I
00:37:13 inherent in all of this that we have I think we have to keep in mind yes and so that so hence my inability to be more confident with apologies no thank you can I just take you then back into your report at page 122 I want just to pick
00:37:26 report at page 122 I want just to pick up figure 66 there's actually page 123 I think it probably spends the - in fact
00:37:38 think it probably spends the - in fact you identify in the text at pic of 66th bottom of the page intermittent flaming between the spandrel cassettes above between level 4 and level 5 we saw that
00:37:50 between level 4 and level 5 we saw that on the video and you showed us that yep and also intermittent flaming at the vertex of the column and the spandrel is that more consistent with hypothesis b1 or with B - the intermittent flaming at
00:38:06 or with B - the intermittent flaming at the junction between the spandrels I would say it's more consistent with the flames venting hypothesis the flaming at
00:38:17 flames venting hypothesis the flaming at the column could be due to either of those hypothesis right under but under hypothesis b1 would one expect to see or the burning of the cladding directly or
00:38:30 the burning of the cladding directly or more directly above the window as opposed to on the side as we do I would expect that given the buoyancy of hot gases and the tendency for things to move in that direction yes so would that
00:38:42 move in that direction yes so would that not then tend to support hypothesis b2 over b1
00:38:48 or is that just short nose again I think so yes
00:38:52 so yes right I think we're now all right a similar question look at figure 68 a
00:39:04 similar question look at figure 68 a please this is thermal imaging page one to six of your report and you've set out the relevant thermal images at the
00:39:16 the relevant thermal images at the second person the second after the second pulse at 114 odd looking at this is is the picture that this that these
00:39:31 is is the picture that this that these show particularly figure 68 a the heat still wear after the second pulse sorry after the first pulse and then the absence of it after the second pulse is
00:39:42 absence of it after the second pulse is that consistent with your hypothesis be one that the fire vented out of the open window or the extract fan the hot spots
00:39:53 window or the extract fan the hot spots I mean as Professor torero discussed yesterday given the resolution these images it's difficult to say anything too conclusive about them that hot spot
00:40:04 too conclusive about them that hot spot in this image does appear to be approximately in the location of the extract fan panel which could indicate that this is a time and here we're at what about 114 yes
00:40:21 so it could just simply be the extract van paneled burning or it could be I
00:40:30 mean it could be anything burning in that location but it's in the approximate location of the extract fan panel I would say right right it does this evidence help help us in any way
00:40:41 this evidence help help us in any way decide as between hypothesis B 1 and B 2 not really in my opinion no moving on to some other evidence we have some evidence from firefighter Daniel Brown
00:40:53 evidence from firefighter Daniel Brown that after 1:20 a.m. so it's a little bit later he could see within the cavity behind the panels and could see far traveling up the building and here
00:41:05 traveling up the building and here you'll recall he leant out of the window and aimed his jet into them and he says in his contemporaneous notes and just for the record this is M et triple zero quadruple zero five two five one at page
00:41:18 quadruple zero five two five one at page three he says that the father was traveling in an upwards direction behind the cladding it was easy to see he says the material behind it was alight and traveling in an upwards direction
00:41:29 traveling in an upwards direction however the vast majority of the cladding remained in place in any attempts to extinguish simply bounced off and similar evidence later when he gave evidence an in his statement to the police in a more in afula form does that
00:41:42 police in a more in afula form does that help you again decide between B 1 and B 2 no because I think at that stage we're quite well along in the vertical progression of the fire at the padding and so regardless of how it started we
00:41:54 and so regardless of how it started we have a very well-developed fire in the planning at that stage another similar vein in a similar vein Charlie battery said in his evidence and this was his oral evidence in the transcript for the 28th of June the page 85 he said that in
00:42:08 28th of June the page 85 he said that in it once inside the room I could see the fire had vented because the window had gone again does that help you no I wouldn't say so what is that the glass too late it's too late yeah not with
00:42:19 too late it's too late yeah not with respect to ignition of the cladding an infinitive right I'm is it fair to say that the the if I would eventually have come out
00:42:28 come out fales window in any event I think yes I mean I think we have to assume when designing cladding systems of any type that a fire venting from a window is a
00:42:41 that a fire venting from a window is a likely scenario now you'll have seen professor Toreros views about your hypothesis be one and he says that that is highly unlikely and easily to be
00:42:52 is highly unlikely and easily to be disproved by testing what do you say to that I mean I would be happy to attempt to disprove it by testing with some
00:43:05 to disprove it by testing with some assistance in how I might do that professor ceramic having considered his report and hurting him give evidence yesterday do you disagree with professor
00:43:16 yesterday do you disagree with professor Terraria
00:43:18 Terraria in what respect in in reactive that statement yes yes I think I do I think I do hypothesis be clear
00:43:30 I think I do hypothesis be clear hypothesis well let me show you what he says so we're clear about yeah as your I'm asking you to agree with can you be shamed please JT OS six zeros well at page 46 paragraph lines 30 and 14 to 15
00:44:02 but he says hypothesis b1 was indicated by professor this B I think is this his most recent version of his report
00:44:14 most recent version of his report because I think he's referring to my original bead one he may well be in this thing I probably put onion here mutterings around me which i think i think this is referring that in the fire
00:44:26 think this is referring that in the fire starts in the extract philip orifices
00:44:31 now moving forward them into talk about direct flame impingement through an open window is it relevant having considered
00:44:43 window is it relevant having considered professor to areas reported also seen your own your own work based on the visual inspections of the video is it relevant that flames would have come out from a hot compartment into a relatively
00:44:56 from a hot compartment into a relatively cool atmosphere outside I mean certainly one of the consequences of venting outside is a cooling effect both on the gases and on the flames as a consequence
00:45:08 gases and on the flames as a consequence of the cold air entrainment that would occur yes would that have affected the ability of flames coming out of the oven
00:45:19 ability of flames coming out of the oven window all the gap left by the vent extract fan to impinge upon the ACM i mean potentially both but we have I mean
00:45:30 mean potentially both but we have I mean we see flames impinging on the ACM in the footage so them so we do know it's happened the question of the question is whether or not the time at which it happens which is admittedly two to three
00:45:41 happens which is admittedly two to three minutes after we suspect that we see involvement of the ACM cladding gives us enough confidence that that is the primary candidate for ignition of the cladding or whether that is a secondary
00:45:52 cladding or whether that is a secondary effect that happens after the cladding has already ignited from within the the the the you know the the the takeaway from me yes for me yesterday from professor arrows testimony with respect
00:46:03 professor arrows testimony with respect to all of these issues was that inside the compartment you have a hot smoke layer at two to three hundred degrees Celsius and you have flames impinging on the region near the window outside the compartment you have hot
00:46:16 outside the compartment you have hot smoke which is venting from the compartments at a maximum of two to three hundred degrees Celsius and these as a consequence of venting now somewhat cooler than inside the compartment and the same with the flames you have flames
00:46:27 the same with the flames you have flames venting from the compartment impinging on the cladding however again somewhat less than inside the compartment so if we agree that the uPVC windows frame aborts absolutely are
00:46:39 uPVC windows frame aborts absolutely are absent then I agree with Professor torero that the most likely candidate is the hypothesis where the ignition happens via the side of the window through the uPVC as I've explained there
00:46:50 through the uPVC as I've explained there I I wasn't in the kitchen so I don't know for sure that the uPVC boards were absent I think it's likely but I wouldn't be able to say that it is definitive yes and as I said I think at
00:47:08 definitive yes and as I said I think at the end of the day it's some combination of the two now and what - excuse me
00:47:23 I want to turn next to a different topic which is initial spread up the East face if I can please professor and I'll start by asking you about internal
00:47:35 by asking you about internal firefighting and then I'm going to turn to external firefighting internal firefighting first of all do you agree in principle that there is a defined point in time at which compartment ation
00:47:47 point in time at which compartment ation in general terms is breached I mean compare yes yes is that point in time when smoke and all flames extend out of
00:47:59 when smoke and all flames extend out of the compartment of origin or is it as soon as any of the combustible components of the facade in the case of Grendel tower ignites it's it's the moment when any secondary fire
00:48:12 moment when any secondary fire compartment is compromised by hot smoke or flames what do you mean by secondary fire compartment so that the flat of
00:48:23 fire compartment so that the flat of origin is a fire compartment yes it's a fire rated box it's the most likely candidate for next compromised would be the flat directly above which is also intended to be a fire rated box given
00:48:34 intended to be a fire rated box given that fires aren't supposed to move from one fire rated box to another fire rated box I would say that compartment ation is effectively lost when flat 26 is compromised by the vertically spreading
00:48:46 compromised by the vertically spreading fire so not then is this right not then at the moment when the ACM panels ignite outside flat 16 I mean I think that one
00:49:02 outside flat 16 I mean I think that one could argue that but if the definition of fire compartment ation is that the fire is confined to a single compartment in a building so take I mean let's take
00:49:14 in a building so take I mean let's take the case of a fire in a building that doesn't have a cladding system that spreads flame externally and you have a fire in your kitchen the kitchen window is open or has an extract fan the fire
00:49:26 is open or has an extract fan the fire events from the kitchen window you do have hot smoke and flame exiting your compartment and impinging on the cladding above that flat but we wouldn't call that a failure of compartment ation
00:49:38 call that a failure of compartment ation unless the flat above their window breaks and the flames get in or whatever and then you have a secondary flat so for me the the if if the fire had gone
00:49:49 for me the the if if the fire had gone out into the cladding and the fire had spread in the cladding but no other flats in the building had been at all affected by that then whilst the fire has left the compartment of origin it
00:50:01 has left the compartment of origin it hasn't caused any other spaces in the building to be affected by the fire and that's the key thing with the compartment ation strategy the effecting of other spaces yes I said so for you a breach of compartment ation the line is
00:50:13 breach of compartment ation the line is crossed well as the way in the next fire box is breached not when the first fire box is breached that's what I would say yes right because in the ordinary
00:50:25 yes right because in the ordinary instance that you've indicated you don't know whether there's going to be a break-in in the flat above but the nature of this fire was such that once it was established in the cladding it
00:50:38 it was established in the cladding it was almost inevitable it's not actually inevitable it would I mean I agree in this case there is an inevitability but of course cladding isn't supposed to do this so I'm after
00:50:51 this so I'm after I guess I'm struggling to understand what the point of the question is I think the point of the question is to work out the people speak of compartment ation linked to stay put and it's part
00:51:02 ation linked to stay put and it's part of a bigger design principle in part I mean it's not for me to tell you but it's really a question of focusing on the point in time which we can all understand as what we mean by
00:51:13 understand as what we mean by compartment ation has been breached or lost I'm suggesting to you that it's lost when the components of the cladding
00:51:24 lost when the components of the cladding on the exterior a flat 16 in this particular case are alight I mean I I mean I can go along with that
00:51:37 I mean I I mean I can go along with that in this case but if we had if we had as I said if we had a building I had a different cladding system where some elements of the cladding system was combustible but it didn't result in a
00:51:50 combustible but it didn't result in a rapid escalation of vertical fire spread off the exterior of the building would we call that loss of apartment ation no I don't think we would right so I think it's the consequences that are the issue
00:52:02 it's the consequences that are the issue as opposed to the potential yeah consequences right it's what actually happens so when that flat about flat 26 becomes involved you
00:52:13 flat about flat 26 becomes involved you now have lost your your firebox you're sealed your fire rated box in your building yeah there's a question I was
00:52:24 building yeah there's a question I was going to ask you later on but I don't ask it's you now in your experience do you know of a cladding fire which is which is which has not resulted in flats
00:52:37 which is which has not resulted in flats in a high-rise building other than the flat of origin being breached that has not resulted yes no I'm adding fun which didn't break back in I mean not
00:52:48 didn't break back in I mean not specifically because we tend not to hear about them because they don't so they're not newsworthy in that sense right my my understanding from speaking to colleagues who work in the fire services
00:52:59 colleagues who work in the fire services internationally would be that it is reasonably routine to have fires in multi-story buildings that don't spread
00:53:10 multi-story buildings that don't spread to other fire compartments via the exterior it depends on the characteristics of the cladding system right don't you know we could we could think of a number of cases where that has happened and you have seen fire spread vertically where you didn't have
00:53:22 spread vertically where you didn't have a cm maybe you had window infill panels or some other type of cladding system that presented the fire spread risks but but we think we only know about them because that occurred which that makes
00:53:34 because that occurred which that makes sense
00:53:36 sense yes now I'm just good trying to get a feel for the inevitability which the Chairman has put to you oh well they come back to Grenville tower looking at
00:53:48 come back to Grenville tower looking at the geometry and configuration of this cladding structure was it in your opinion inevitable but once the cladding had ignited it would spread in the way
00:54:00 had ignited it would spread in the way you've identified and therefore inevitable that it would breach other compartments yes so in practical terms
00:54:11 compartments yes so in practical terms would it be right to say them actually compartment ation to all intents and purposes was breached once the timing was the light outside flat 16 sure
00:54:22 flat 16 sure noting my slight disagreement of that definition all right I'll go along with you external fire fighting moving ahead can I ask you please to get to look at a
00:54:37 can I ask you please to get to look at a video clip mr. chairman I'm not sure if I should keep repeating the trigger warning we probably is better I again repeat the trigger warning I'm going to be showing the professor he'll be
00:54:48 be showing the professor he'll be showing us his second clip lby is number two and this also will show pictures of the building on fire on the exterior and has audio attached to it some people
00:55:00 has audio attached to it some people will find it distressing and may need to leave the room or remove themselves from the livestreams will give people a few seconds before we show this and can I
00:55:11 seconds before we show this and can I ask Paul if we can move to sequence at 1:15 and 53 seconds
00:56:25 now I've shown you quite a bit of that in this clip we can see a covering jet but you can still see in the part we've frozen on being started up and aimed underneath the window from what you've
00:56:36 underneath the window from what you've seen professor that you've seen and analyzed all of the video clips that you've got and it may not be complete of course is this the first visual confirmation of the jet being in use yes
00:56:49 confirmation of the jet being in use yes now I don't need to take you to this but we have a document from the lfb which is there
00:56:55 there oh our are the operational report response report which has a time at 111 which suggests that the jet was being applied at 111 and that it was being applied above the window and have you
00:57:07 applied above the window and have you seen anything to support that that statement no I've not and in your opinion could earlier external firefighting in other words earlier to 116 that we've seen I have made a
00:57:21 116 that we've seen I have made a difference I mean that's a very difficult question to answer I think it's hard to say with any certainty the
00:57:32 it's hard to say with any certainty the the only evidence that I could bring to answering that question is that I've seen a number of cladding fire tests on large scale 9 meter high rigs where
00:57:47 large scale 9 meter high rigs where fires involving combinations of materials similar to this ie PIR backing insulation and an ACM PE rain screen in
00:57:59 insulation and an ACM PE rain screen in a fire that is developed and spreading up the cladding one to two stories not dissimilar to we see here although admittedly higher up in the air in this case I've seen those fires extinguished with relative ease in test lab scenarios
00:58:13 with relative ease in test lab scenarios now obviously noting that there could be significant differences between those systems and those scenarios not knowing the differences in terms of the firefighting kit that's used in order to do that in terms of the volumes of water
00:58:24 do that in terms of the volumes of water that are deployed by the hoses and the pressures etc etc but I have seen these these fires visually similar to similar to this involving similar materials extinguished in fire testing
00:58:36 extinguished in fire testing laboratories yes so and I think I think it it is not impossible in theory knowing what you do about the composition of the materials in this
00:58:47 composition of the materials in this cladding structure and their geometry in your opinion would spraying a jet above the wind a a flat 16 have made a material difference to fire spread by
00:59:00 material difference to fire spread by 115 am that's a very very difficult and I recognize very important question
00:59:13 again I would say it's possible but I you know I'm not a firefighter III I would not want to say one way or another for sure on the basis that the Jets
00:59:26 for sure on the basis that the Jets being applied from the ground would it have been possible for water to reach behind the cladding outside flat 16 weather in the column or in the
00:59:37 weather in the column or in the spandrels or indeed the spandrels above the kitchen if that is where there was fire I mean it's a ventilated rain screen facade it's meant to exclude rain
00:59:50 screen facade it's meant to exclude rain which would be water coming predominantly from above in terms of water coming from below one imagines that water could get into the cladding via the cracks and openings that we've
01:00:02 via the cracks and openings that we've discussed in looking at the configuration of the cladding whether the amount of water that one could get into the cavity and assuming that there's burning going on within the cavity would be sufficient to extinguish a fire a growing fire of this nature
01:00:14 a fire a growing fire of this nature again I think it's very difficult to say with any certainty I think it's possible but not it's not definitive possible but not definitive there's a range there in that would it be probable or improbable
01:00:26 that would it be probable or improbable I don't know well genuinely I couldn't say all right vertical fast bread if I can turn to that can I go first to your
01:00:39 can turn to that can I go first to your report at page 1 v 2 and I'm going to ask you to look please at paragraphs 4 7 8 to 450 sorry 7 4 8 750 I mean mr.
01:00:55 8 to 450 sorry 7 4 8 750 I mean mr. Miller if it's all right I'd like just haven't thought about what you just asked me I'd like to come back to it and add a comment if I may is the reason that I assume that those questions on
01:01:06 that I assume that those questions on external firefighting are a consequence of some comments that I've added to my supplemental report in terms of the observations I made about external firefighting activities in the early stages of the fire the reason that I did
01:01:17 stages of the fire the reason that I did that is because of the lfb document which states that there was a covering jet directed above the fire at around 111 that had no effect on the fire now
01:01:28 111 that had no effect on the fire now if that is the case then it's important that we know that and if that isn't the case then it's equally important that we know that the consequence both in terms of truth in this event and in terms of
01:01:39 of truth in this event and in terms of the fact that we have a large number of buildings in the UK from non-compliant cladding systems on them and I would expect that firefighting tactics would be influenced by whether or not an attempt was made and was proven
01:01:50 attempt was made and was proven effective or not in this context so that that's why I did and I think it's important to state that no no that that's obviously left a factual question open on the on the hypothesis that the
01:02:01 open on the on the hypothesis that the operational response report is correct and that a covering jet was applied above the window at 111 it may not have been for terribly long what conclusions would you draw from that if that fact if that was in fact I mean that would
01:02:12 that was in fact I mean that would indicate that it is potentially very difficult to extinguish one of these fires even if that's done very early on I mean keep in mind that at 111 the fire we could look at the video of the fire in that region and it's still quite
01:02:23 in that region and it's still quite small and localized it hasn't extended anywhere near when it has by 115 when we see the covering jet applied so if it is genuinely not possible to relatively
01:02:34 genuinely not possible to relatively easily extinguish a fire which at that stage at least visually is quite a small fire although admittedly in the cladding then that's an important piece of information as regards the safety of people who are potentially living in
01:02:46 people who are potentially living in buildings when complaint cladding on them yes now approaching it from a different angle as assuming that the fact has recorded in the operational response report at 111 is it's not a fact in other words didn't
01:02:57 is it's not a fact in other words didn't happen no covering jet above the window at that time what conclusions would you draw from that having seen the video that you've shown us of the progression of the fire that if there were a fire in
01:03:09 of the fire that if there were a fire in a building and the fire brigade were to attend that fire and they were to see a fire that looks not dissimilar to this and they were to be aware that that building kind cladding on it that was
01:03:20 building kind cladding on it that was not necessarily the cladding we would want on it if it was one of these buildings that's been identified with non-compliant cladding on it that they would attempt to spray the exterior of
01:03:32 would attempt to spray the exterior of the building potentially before they send a crew in which is what I understand prevent it one of the reasons they didn't spray in this case the exterior of the building was because of some operational rules that are followed
01:03:44 some operational rules that are followed in the fire service that you don't spray into a compartment where you may have colleagues inside for the sake of the safety of the colleagues inside so that may change you know a decision about what it is that you do first in that
01:03:55 what it is that you do first in that fire scenario maybe it would be better to put out the external cladding fire first to be sure that you've dealt with that and then to attempt to fight the fire internally or some combination of activities that might be a bit different
01:04:07 activities that might be a bit different which leads then I think just to confirm the question whereas before having done this little little secure this route if in fact it turns out that there wasn't a covering jet placed over this over the
01:04:18 covering jet placed over this over the window above the window flat 16 at 111
01:04:26 you is it right you can't say whether it's probable or improbable that effective external firefighting would have extinguished this fire I couldn't say you couldn't say you say it's
01:04:37 say you couldn't say you say it's possible but not definite but you can't tell me where on the spectrum between those two it is I mean my view is that in the absence of any information it's certainly worth a try right vertical
01:04:49 certainly worth a try right vertical fast bread I think I was showing you what's now on the screen seven just gone it's
01:04:55 it's about seven four eight to 750 and you've got regulation B for up there and you say the functional objective of b4 is
01:05:07 say the functional objective of b4 is that the external walls of the building shall adequately resist the spread of fire over the walls and from one building to another having regard to the height use position of the building and
01:05:18 height use position of the building and you say the functional objective was clearly not achieved of Grenville tower i think it's right that you haven't at this stage considered compliance with the guidance and approved document b
01:05:29 the guidance and approved document b have you have you not significantly no no you do though go on to say at paragraph seven five one and seven five two and particularly in seven five to
01:05:46 two and particularly in seven five to that on the and then picking it up in the third line of 75 - on the basis that that far compartment a ssin was not a credible component of any fire safety
01:05:57 credible component of any fire safety strategy once the refurbishment cloudiness and installed at Grenfell tower it follows logically that a stay put policy was also not a credible component of any fire safety strategy
01:06:08 component of any fire safety strategy once the refurbishment having had been installed and i'll show you that and
01:06:19 installed and i'll show you that and there are three I think reasons why you say that in terms of directions of fire spread upward downward and horizontal and those different theories underpin this basic thesis that a staple policy
01:06:35 this basic thesis that a staple policy was not a credible component of any fire safety strategy at Greenville after the refurbishment I mean the fundamental assertion that I'm making here is that if a fire is ignited in the cladding
01:06:46 if a fire is ignited in the cladding system such as this made from these materials under any circumstances we have to expect it to spread quickly and catastrophic Lee because of the nature of the materials involved and I'm on
01:06:57 of the materials involved and I'm on that basis is unreasonable to expect compartment ation to be maintained and on that basis it is unreasonable to have state policy in place now of course that relies on someone recognizing that
01:07:08 relies on someone recognizing that they've caught this material on their building his which is clearly not the case apparently here well yeah I recognize this is quite a strong statement but it you know it's in a sense a philosophical one yeah a
01:07:21 sense a philosophical one yeah a philosophical and and that's your opinion yes but it relies on this assumption that the people actually are aware of the cladding that they have on their building yes now I'm going to ask
01:07:34 their building yes now I'm going to ask you some detailed questions about your analysis of each of the three routes of fire spread upward first then downward and then horizontal if I can before I do that can I just ask you to look briefly
01:07:45 that can I just ask you to look briefly at Barbra lanes doctor lanes basic hypothesis this is BL as6 sorry five zero is 10 at page five and this is
01:07:57 five zero is 10 at page five and this is figures ten point two and ten point three of doctor lanes report
01:08:14 we could just have those up there that they're there for you she has identified six different pathways for fire spread you can see
01:08:25 pathways for fire spread you can see those in what's particularly in ten point two and then you've got the you also got F in ten point three I have
01:08:38 also got F in ten point three I have questions about a and D the columns they represent the two vertical channels I think that you say can played an important role in the fire spread on the night that's correct that's right is it now doctor lanes also identified a third
01:08:51 now doctor lanes also identified a third vertical pathway II you could see the yellow in Figure 10 - which I think is is via the insulating core panels which connect between the spandrel panels
01:09:02 connect between the spandrel panels would you agree with her I mean I would agree that those are continuous bands of material that can burn I'm not sure that
01:09:15 material that can burn I'm not sure that I would agree that I've seen either evidence or physical mechanism by which that is a direction of travel of a fire front if you see what I mean I do let
01:09:28 front if you see what I mean I do let you leave it aside fire front we may come back to that can I just ask you to be shown page 39 of dr. lanes report figure ten point three seven under
01:09:39 figure ten point three seven under paragraph ten point seven point two which is a photograph of the vertical fire spread up insulating core panels estimated time at 126 taken off YouTube
01:09:52 estimated time at 126 taken off YouTube Nash her view is that this image shows evidence of fire spread up the insulating core panels my first question is have you considered that as a pathway
01:10:06 I've I've considered the fact that the insulating core panels will burn yes well I don't I don't so so this is a
01:10:17 well I don't I don't so so this is a this is a photo that shows insulating core panels burning yes that is what she says it's not necessarily a photo that shows vertical fire spreads because we can't see which way the fire is going in
01:10:30 can't see which way the fire is going in a still image are for me yeah that might seem a bit pedantic but I do think it's an important point so I could I could I could assert that the insulating core panels have been ignited
01:10:42 insulating core panels have been ignited by Falling burning debris rather than an upward fire spread mechanism and on the basis of this image I don't think you'd be able to say that I'm wrong okay does
01:10:53 be able to say that I'm wrong okay does that make sense thank you does it make sense to me not I'm not saying that it isn't I'm not saying that I think it's difficult to assert that I'm weak we could discuss in
01:11:04 assert that I'm weak we could discuss in detail my fire spread mechanisms I suspect that we weren't yeah okay so you say you you say that all the bases of this photograph you couldn't you couldn't confirm to a degree of
01:11:16 couldn't confirm to a degree of confidence that the insulating core panels were a root of vertical fire spread
01:11:21 spread that's correct the insulating core panels burn or the the core material the XPS inside is a combustible material and it will burn under some conditions how
01:11:32 it will burn under some conditions how it is that any one of those particular insulating core panels that appears to be burning in this image came to be burning I think is this is almost a different question now I'm going to ask you please next to go to table 13 of
01:11:44 you please next to go to table 13 of your report at page 175
01:11:55 now you've got a table at the top of that page thirteen approximate upward vertical fast bread rates in the Grenfell tower fire as a function of building level and I think we can see is
01:12:09 building level and I think we can see is this right that in general the rate of spread gets faster as the flame front gets further up the building yes that's true and you can see that it takes it takes 80 seconds to go from level 10 to
01:12:21 takes 80 seconds to go from level 10 to 13 but it takes only 15 seconds to go from 19 to 23 that's correct traveling at a rate of Northpoint 1/7 meters a second yes now you I think say
01:12:36 meters a second yes now you I think say and this is paragraph 8 for 7 just under that you do say that this is similar to vertical flames spread up a solid-fuel
01:12:48 vertical flames spread up a solid-fuel surface it's the last sentence of that paragraph yeah I mean on a solid-fuel surface you would expect an exponential increase in the rate of spread based on
01:13:01 increase in the rate of spread based on the available research yes now when you say a solid-fuel surface could you just explain what you mean by that by that so the the scientific literature on
01:13:13 the the scientific literature on vertical fire spread dating back many decades people have been running experiments on vertically oriented fuels so that we can try to understand the physics of the vertically upward
01:13:24 physics of the vertically upward concurrent fire spread mechanism obviously if you want to understand something that is actually quite complex in terms of the physics even for a a
01:13:35 in terms of the physics even for a a vertically oriented fuel that is totally homogeneous is a single material doesn't melt doesn't drip doesn't flow doesn't warp you know it's a very well behaved
01:13:46 warp you know it's a very well behaved material even studying upward concurrent fire spread on that very simple case is extremely complicated in order to reproduce the physics and you know I was at I was at a conference two weeks ago
01:13:58 at I was at a conference two weeks ago where the keynote lecture was by a chap who is still trying to do this the very simple case and then you bring a second surface and you have a cavity and you just sort of put his hands in the air and said forget it
01:14:10 the air and said forget it you know the models that we have even the most advanced models can't do this at this stage so it's important to recognize the complexity of the science that we're dealing with here but but the theory of that the experiments for those
01:14:21 theory of that the experiments for those that case of the really quite well behaved fuel show that as the fire spreads up you will get so the fire spreads up but of course the bit that started burning is still burning so your
01:14:33 started burning is still burning so your fire is getting effectively bigger and bigger as the fire spreads at some stage you'll run out of fuel where it started and then you've got like a moving band of fire potentially right but as the fire is growing and the heat release
01:14:45 fire is growing and the heat release rate as a consequence is growing as the amount of burning surface is growing there's a snowballing effect the more heat you have the more preheating of the material above you get the more preheating you get the faster the fire
01:14:57 preheating you get the faster the fire will travel vertically upwards and you get this exponential increase in in fire spread rate now obviously at groennfell tower we don't have a well-behaved fuel in the matter that I just described we have a fuel that has aluminium facing on
01:15:09 have a fuel that has aluminium facing on it in places we have multiple fuels interacting with each other we have an external surface we have a cavity we have burning dripping melting falling we have deformations we have window openings we have all sorts of
01:15:20 openings we have all sorts of complexities that we would have to account for if we wanted to model this in any meaningful way but nonetheless what we have is a vertical surface with distributed fuel on it and we observe a
01:15:31 distributed fuel on it and we observe a similar outcome which is a growing fire vertically which causes this exponential increase in the rate of fire spread so it's just to say that that exponential increase in fire spread is not unexpected it is supported by the
01:15:42 unexpected it is supported by the physics that we understand in general terms now I think you agree is this right with Professor torero that the flame spread that was observed at
01:15:53 flame spread that was observed at Greenville tower was not as rapid as that which was observed at the address in Dubai the progression of the upward spreading fire was significantly faster
01:16:04 spreading fire was significantly faster at the address fire yes and that was also wasn't it a cladding fire involving polyethylene filled ACM I mean based only on media reports yes based on it yes now a UI UA
01:16:16 yes now a UI UA to identify any reasons why the vertical flame spread at grenfell was slower than that observed for example the Dubai tower the address no I mean I could I
01:16:30 tower the address no I mean I could I could postulate some things but they would be speculative the one thing that one does observe at the address fire that one doesn't observe that Grenfell is that at the address fire the address
01:16:42 is that at the address fire the address fire based on media reports I think started at the 20th floor of a building that is much much taller than Greenville tower it needs to be pointed out yes on a sort of a terrace and then started to
01:16:57 a sort of a terrace and then started to spread vertically so in the case of that fire and there was no external fire fighting on the terrace early on so in the case of that fire all of them melting dripping burning polyethylene that fell fell onto the terrace and
01:17:09 that fell fell onto the terrace and generated a large pool fire at the base of the vertically spreading fire which keeps the heat release rate at the base of the fire strong and indeed grows which then feeds the fire vertically
01:17:21 which then feeds the fire vertically spreading fire which would be one explanation for an increased rate of fire spread in that scenario now at Grenfell tower you don't have a pool fire burning at the base of the building because you've got Murphy and Cornelius
01:17:32 because you've got Murphy and Cornelius as evidenced in some of the videos and whenever they have a burning debris on the ground beneath flat 16 you actually will see them take their hose and direct
01:17:43 will see them take their hose and direct it at the burning debris they put it out and then they keep spraying the building so the formation of a pool fires prevented a Grandville Tower that's one possible explanation of a number that we could come up with but again the combination of materials I don't know
01:17:55 combination of materials I don't know what backing insulation was used within the cavity at the address maybe you know PIR of all the backing cavity installations we might choose PIR is one
01:18:07 installations we might choose PIR is one of the least combustible of those materials and he might choose it could have had XPS insulation it could have had styrofoam or something yeah now moving ahead and moving ahead you say in
01:18:19 moving ahead and moving ahead you say in your report and this is page 169 I don't think I need to go to it that you say the flames reached the roof at 127 58 all there abouts there abouts
01:18:30 at 127 58 all there abouts there abouts yep and you we conceived my picture or diagram of one page 170 but perhaps we
01:18:44 diagram of one page 170 but perhaps we ought to look at that this is figure 99 so photograph captured at 127 42 that the crown was involved in the fire by this time is this about the earliest
01:18:56 this time is this about the earliest moment when the crown was involved over there is it was near there or there about hello there bounce I mean I would say give or take two three minutes I'm looking at this image is there anything you can take from it which tells us
01:19:07 you can take from it which tells us anything about the mechanism for fire spread at that at the top of the building
01:19:12 building not as yet I would say I mean I think we do see it later in some of the videos and some of the photos but there's all the basis of this photo no now you've got I think five hypotheses of vertical
01:19:25 got I think five hypotheses of vertical fire spread which you cover under Section six point one point six of your reporter page 177 and following and you conclude at paragraph eight five nine if
01:19:38 conclude at paragraph eight five nine if I can just ask you to look at that that page one seven eight you just highlight that please Paul you say that of all the
01:19:51 that please Paul you say that of all the or all of the available evidence presented thus far in Section six of this report strongly supports hypothesis c1 I consider the presence of PE filled ACM rainscreen planning cassettes to be fire considerable margin the most
01:20:03 fire considerable margin the most important factor contributing to up to a vertical fire spread and indeed two external fire spread generally during the Grenville tower fire now we'll look
01:20:14 the Grenville tower fire now we'll look at some of this in a bit more detail but dr. Lane's opinion is that the columns on the building were the principal root for vertical flames spread do you agree
01:20:25 for vertical flames spread do you agree with her yeah yes Eddie are you able to explain the mechanism by which flames were drawn into and up the columns
01:20:35 yes I mean I think it's a combination of mechanisms I wouldn't say it's necessarily one distinct mechanism I think they're combination of factors the respective contributions of which are
01:20:46 respective contributions of which are difficult to quantify I mean that's one of the reasons why I've taken a very mechanistic and systematic approach to dealing with this issue via a number of specific hypotheses which look
01:20:58 specific hypotheses which look individually at the various factors that we know can influence vertical fire spread now we know that cider eyes-open state intumescent cavity barriers were installed in the cladding system
01:21:09 installed in the cladding system have you considered whether a different type of cavity barrier might have made a difference to vertical fire spread whether in through the columns or the spandrels in the manner that the cavity
01:21:20 spandrels in the manner that the cavity barriers were assuming that the same installation was used ie the cavity barriers were broken at cladding rails etc etc yes for example I wouldn't
01:21:32 etc etc yes for example I wouldn't expect no I wouldn't think there would be any significant difference necessarily right yet um mr. chairman I've got an eye on the clock which I personally should have had earlier it's 20 past 3:00 this might be an appropriate time for a
01:21:44 this might be an appropriate time for a short it doesn't get a look at this see - after the break we're gonna have a short break now please don't talk to anyone about what evidence when you're
01:21:55 anyone about what evidence when you're out of the room and we'll come back top of three okay
01:22:09 good 3:30 please
01:36:56 I think he's on his way mister
01:37:16 sorry about the delay no problem believe that inmate ready to go on now yes yes professor I'm sorry about that can I before I get back to hypothesis C to just ask you a question about the
01:37:29 to just ask you a question about the application of water to the cladding and was this cladding ice a cladding rate the rain screen hydrophobic it in the sense that it repels water as a matter
01:37:40 sense that it repels water as a matter of course I mean that's the purpose of it so yes one would hope yes yes therefore would it matter whether or not a day covering jet was applied from
01:37:52 a day covering jet was applied from above or below the reason I made a distinction between above and below is because of the the the nature of the
01:38:03 because of the the the nature of the openings in the rainscreen cladding so I mean I could demonstrate with a figure if that's a useful thing very quickly so if we go if we look at perfect so I mean
01:38:16 if we go if we look at perfect so I mean if we look at figure 19 and that's page 46 of million for page 46 yes just as an
01:38:28 46 of million for page 46 yes just as an example that's showing the joint between column cassettes rain when you're coming
01:38:40 column cassettes rain when you're coming down like this the reason this joint is configured in this ways to prevent the rain from getting inside the cladding do you let air get in to ventilate it but if you're from down here and you're spraying up one imagines that you could somehow get some water in right okay but
01:38:56 somehow get some water in right okay but in general the fact is that since of the very large majority of this face shot is rain repellent or water repel its kind of repel water yes so the actions of the fire of the fire brigade and external firefighting
01:39:07 fire brigade and external firefighting are is this right likely to have little effect if the cladding system is still intact again that it doesn't have holes
01:39:18 intact again that it doesn't have holes having opened up in it then yes I would I would agree with that this may be a completely wild idea and they tell me but if you could get above the fire and put water down the cavity
01:39:31 the fire and put water down the cavity do any good I wouldn't want to hazard a guess that way one imagines it couldn't make matters worse I wouldn't want to say the extent to which it would make
01:39:42 say the extent to which it would make matters better thank you now turning to hypothesis C and can I take you back please to the foot of page 178 and the
01:39:54 please to the foot of page 178 and the top of page 179 of your report where you set out hypothesis C we could see at top of page 179 what you say there you say the presence of combustible PIR thermal
01:40:05 the presence of combustible PIR thermal insulation within the external cladding system significantly contributed to the rate and/or extent of upward vertical fire spread observed at Granville tower can you explain the mechanism by which
01:40:17 can you explain the mechanism by which it contributed right well it's important to say firstly that that is the hypothesis that I'm testing rather than a statement if you see what I mean it is I then come
01:40:29 if you see what I mean it is I then come later to a conclusion on that statement later in that section you do H on page 180 but to answer your I don't think it's important to know that those are those are stated as hypotheses rather than in facts or conclusions if you see
01:40:41 than in facts or conclusions if you see what I mean you're right and I'd jump to stage but perhaps in my mic my ego okay okay to move on but but the the the the physical mechanisms as you like by which
01:40:53 physical mechanisms as you like by which the PIR the primary physical mechanisms sorry the primary physical mechanisms by which I would think the PIR could contribute to warn see upward vertical fire spread would be both the PIR is a
01:41:07 fire spread would be both the PIR is a combustible material so when exposed to a heat flux that is sufficient to reach the pyrolysis temperature it will paralyze it will release combustible pyrolysis products those combustible pyrolysis products could contribute to
01:41:18 pyrolysis products could contribute to an increase in the local heat release rate of a fire yeah so they so the extent to which that pyrolysis will occur and contribute is unquantified at this stage but that's one potential mechanism they could exacerbate he
01:41:29 mechanism they could exacerbate he release rate and thus accelerate upward the fire spread absolutely and the other mechanism is that these materials are very low thermal inertia materials which
01:41:40 very low thermal inertia materials which essentially means that the surface temperature of the PIR will rise very quickly when exposed to an external heat flux and that hot PIR surface will radiate heat back at the ACM panels and
01:41:53 radiate heat back at the ACM panels and effectively will insulate the cladding compartment or inside the cladding and that could cause the well it prevents loss of heat from the system thus
01:42:04 loss of heat from the system thus potentially accelerating the upward flame spread as compared with a backing insulation that is less thermally efficient or ie has a higher thermal inertia but again the the degree to
01:42:17 inertia but again the the degree to which that potential assistance to upward vertical fire spring could be quantified at this stages is it's not good yeah we don't know yet yes now on
01:42:28 good yeah we don't know yet yes now on the basis of the mechanics of potential contribution which you've referred to would the insulation the PIR have contributed to the initial heating of the of the aluminium panels and
01:42:42 the of the aluminium panels and particularly the PE within it I mean anything that keeps heat in the system has a low thermal inertia material would will contribute to a higher rate of temperature increase of anything else in
01:42:53 temperature increase of anything else in the system yes so would it follow from that that if there were no such insulation or no such combustible insulation the vertical spread of the fire would have been slower in its
01:43:04 fire would have been slower in its initial stages it's a slightly hypothetical question but if the cavity were not insulated and in any way it would lose heat more rapidly and therefore yes I will go along with that statement
01:43:15 statement or if it were insulated by something that was wholly non combustible if there is such a thing well it's important not to mix ideas here so the combust ability
01:43:26 to mix ideas here so the combust ability is related to the additional heat release resulting from pyrolysis in production of combustible pyrolysis products the low thermal inertia is
01:43:37 products the low thermal inertia is about heat loss to the system so the one the one situations about heat production and the other situation is about reducing heat loss and they're independent independent mechanisms so it's important that we consider them differently so we
01:43:48 that we consider them differently so we could imagine if the backing insulation has a higher thermal inertia there's less thermally efficient as an insulator that yes there would be additional heat losses to that system and the vertical
01:43:59 losses to that system and the vertical progression of the fire would be slowed my personal view is that in the context of the the presence of the polyethylene that that would be hugely overshadowed
01:44:11 that that would be hugely overshadowed by the fact that you have polyethylene in the system which is freely burning right so again and as Professor torero said a number of times yesterday this is a hugely complex issue and quantifying
01:44:24 a hugely complex issue and quantifying the relative contributions at this stage is very very difficult and we hope to do a lot of work at Phase two to try to quantify these things but at this stage I couldn't say yes I see and just to be clear about that is it possible in
01:44:35 clear about that is it possible in theory at least and for phase two work to quantify the difference between a rate of vertical fire spread with the insulation not burning not paralyzing as
01:44:48 insulation not burning not paralyzing as opposed to the rate of vertical fast bread with the insulation paralysing yeah I mean we yes we already have a work underway at the University of
01:44:59 work underway at the University of Edinburgh to try to look at the respective influences of these two issues contributing pyrolysis products how that effects vertical fire spread compared with low thermal inertia and
01:45:10 compared with low thermal inertia and insulating the system and how that affects vertical fire spread although I should say for cavity cladding systems that from a research perspective are far simpler than what we find on rental
01:45:21 simpler than what we find on rental Tower right yeah that leads in I think to a related issue that paragraphs have eight seventy seven and eight seven to
01:45:34 eight seventy seven and eight seven to eight seven nine to eight seven seven eight seven eight nine seven nine on page 180 you refer to a large scale test carried out by D CLG as it then was in the weeks following the Grenville tower
01:45:46 the weeks following the Grenville tower fire and you say these demonstrated that the use of PIR insulation within the rainscreen cavity did not obviously exacerbate escalation of vertical fire spread
01:45:56 spread and you explained why and then you say late seven nine it should be noted that the PIR used in these tests was as far as I've understood from the available reports protected from direct flame
01:46:07 reports protected from direct flame impingement by foil facings or foil tape ie the joints and cut edges were not exposed within the cavity in these tests as appears to have been the case of Granville town now just just expanding
01:46:20 Granville town now just just expanding on that first of all what in your opinion was the utility of the CLG or D CLG tests in determining whether the PIR as installed at Grenfell tower
01:46:32 as installed at Grenfell tower contributed to the rate and extent of vertical fire spread given the ladee file facings we've seen on the edges at gren film what is the utility of the the
01:46:47 gren film what is the utility of the the D CLG post-grant felt tests specifically with respect to the ground for town yes it simply illustrative in that what
01:46:58 it simply illustrative in that what those tests show is if you have an ACM PE rain screen that the test regardless of the backing insulation escalates vertical fire spread very very quickly
01:47:10 vertical fire spread very very quickly and that I mean that is really the only reason I've presented that information in this report right other than that I would think they don't have much utility are you able to tell whether it makes a difference that the assembly used in
01:47:21 difference that the assembly used in that test did not have cut edges of PIR I couldn't say one way or another okay do you know whether in those tests the department used a riveted ACL panel rather than a cassette panel I believe
01:47:32 rather than a cassette panel I believe that those were riveted would that make a difference there is some information and again I'm not dealing with compliance in my phase one work but there is some information I believe that
01:47:43 there is some information I believe that we've received to the inquiry which indicates and that's a riveted system as regards class of product classifications under standard testing I think
01:47:57 under standard testing I think specifically through the test that we call the single burning item test that the riveted system performs marginally better than the kiss that system the reason for that I would
01:48:08 that system the reason for that I would presume is because a riveted system is riveted through both phases of the aluminium and they're held more tightly in place and it prevents them from opening up but I've not tested that that theory in it okay moving to a slightly
01:48:21 theory in it okay moving to a slightly different issue in terms of the state of the building after the fire when you did your surveys did you see areas of where the ACM paneling remained intact there
01:48:35 the ACM paneling remained intact there even though there was extensive charring of the insulation behind it no it's possible I didn't see it right you didn't see it did you see any areas on
01:48:46 didn't see it did you see any areas on level three where there was widespread charring to a to a death and where the damage to the PE was highly localized and more severe on the inner face than the outer face the damage to the
01:48:59 the outer face the damage to the dependently the pesach paneling was more severe on the inner face I've not observed that now right did you see any evidence low down on the corner
01:49:10 see any evidence low down on the corner columns where such deposits at the joint in the panels might suggest that the fire was burning internally rather than within the paneling I didn't see that
01:49:21 within the paneling I didn't see that low down on that the column tips there's a typically quite a bit of evidence of melted dripped polyethylene which is solidified in that location but I didn't see any suits for at least I didn't notice it right your next hypothesis is
01:49:34 notice it right your next hypothesis is hypothesis see three at page 180 I'll take this quickly this is continuous vertical channels and extensive internal cavities and your conclusion is at eight
01:49:47 cavities and your conclusion is at eight eight eight I think which is that you say this is page 181 at the time of writing I'm not aware of any definitive evidence that continuous vertical channels and extensive cavities which
01:50:01 channels and extensive cavities which have been shown to exist within the refurbishment external cladding system of Granville Tower played a role in promoting or accelerating upward vertical fire spread now just taking that a little bit slowly first of all
01:50:12 that a little bit slowly first of all when you say definitive what do you mean I guess I mean I couldn't say for certain but it plays a
01:50:23 couldn't say for certain but it plays a role that thing that would significantly accelerate the vertical fire spread I are you able to say on the within a range of probabilities whether the
01:50:34 range of probabilities whether the continuous vertical cavities and channels on the columns played a role some role in the fire spread vertically alright yeah I mean yes I think it's
01:50:45 alright yeah I mean yes I think it's likely like me I think it's likely that they did yes and I think I do I think I do come to that at the end of that section eight nine six I believe I think
01:50:56 section eight nine six I believe I think I say on a balance of probabilities given the available video evidence an oral testimony along with the known importance of vertical channels I consider it likely that these features contributed although I can't quantify to
01:51:09 contributed although I can't quantify to this stage yeah are you eight you so you're not able to say how likely I think it's very likely that they contributed to some extent I think it's a little it's almost certain that they contributed to some extent right whether
01:51:20 contributed to some extent right whether that's you know one percent worse or 50% worse I wouldn't be able to say this stage no I see okay say the difficulty you have is not the likelihood of the contribution it's the extent of it it's a significant to that contribution to a positively yes yes hypothesis c4 which
01:51:35 positively yes yes hypothesis c4 which is prevailing wind you can reject and you have hypothesis c5 which is your last one on vertical fast bread relates to the specific overall geometry of the building and you cover that at paragraphs 903 and following on page 182
01:51:48 paragraphs 903 and following on page 182 and you explain what the geometry is and you say it paragraph nine eleven on page 183 in the pre pronouncement line it's
01:52:01 183 in the pre pronouncement line it's not possible to definitively to determine well and what should I picked up the complete conclusion that perhaps is nine twelve you say on the basis of
01:52:13 is nine twelve you say on the basis of the available evidence it's not possible to accept or reject hypothesis hypothesis c5 however in my opinion it's plausible to suggest that the presence of the protruding column wing wall of the Hannibal degrees could have played as yet on
01:52:25 degrees could have played as yet on quantified role in promoting up rap rapid upward vertical fire spread additional work would be required to Phase two to confirm and quantify this now to what level of sort of confidence
01:52:42 now to what level of sort of confidence are you able to say that the presence of the protruding column wing wall did play a role well so the physics at play here's two effects one effect is that
01:52:55 here's two effects one effect is that having the fire confined within a corner even if it's not a right angled corner it does two things it it changes the way
01:53:06 it does two things it it changes the way that fresh air is entrained into the fire which it means essentially you're gonna get less air entrained into the fire at its base because there's restricted access to the fire because of its confinement that has an effect of
01:53:19 its confinement that has an effect of elongating the flame as the flame searches for more air in order to continue burning so you have flame elongation in a in a confined area which would exacerbate upward vertical fire
01:53:30 would exacerbate upward vertical fire spread in the same way as confining a fire within a cavity causes flame extension and the other effect of course is that if you have a flat wall then the
01:53:41 is that if you have a flat wall then the wall looks out and sees the cold world if you have walls at some angle to each other then part of what the one wall sees is the other wall which is hot and you get a reradiating effect which
01:53:52 you get a reradiating effect which causes the temperatures to increase locally which again will exacerbate vertical fire spread so I think it's you know I think plausible is perhaps not as strong as I ought to have used I think it's very likely that there will be some some effects but again quantifying it is
01:54:03 some effects but again quantifying it is the challenge and I'm not aware of any work in the letter in the technical literature that looks at wing walls at angles other than 90 degrees so the extent to which that is important I couldn't say this stage at this stage
01:54:15 couldn't say this stage at this stage but can further work be done a face to other work to be there definitely be done I have a I have a project planned yes right okay just picking up a couple of points of detail paragraph 906 within that
01:54:28 detail paragraph 906 within that hypothesis you refer to column lines offering continuous and unbroken vertical lines of combustion rainscreen cladding along with bustable PIR in sedation and ie vertical
01:54:40 bustable PIR in sedation and ie vertical lines of available fuel unbroken by windows and you then say this created a continuous and uninterrupted vertical fuel bed to support upward vertical fire spread and will have influenced ie increased the propensity for upward
01:54:51 increased the propensity for upward vertical fire spread you and I think refer at you you referred at footnote 56 to section four point nine point one but
01:55:06 to section four point nine point one but can I take you to page 32 of your report
01:55:16 shall then think of something we've looked at today it's figure eight it's within three section three point one of
01:55:27 within three section three point one of your report professor and it's it's a drawing effectively from Celotex can you
01:55:40 drawing effectively from Celotex can you identify where the continuous vertical lines of combustible cladding and PIR insulation are by reference to that drawing
01:55:49 noting my previously stated colorblindness I think they're pink sections left and right hand sides if they were to continue vertically up and down outside that image right and those
01:56:01 down outside that image right and those would be the continuous bands that I'm referring to okay now keeping a finger in that and I'll just uh perhaps I'll just do this but by telling you at 9:07 on page 183 you refer to spandrel lines
01:56:13 on page 183 you refer to spandrel lines offering continuous number ik and horizontal lines of combustible rainscreen cladding along with combustible PIR insulation within the rain screen cavity ie horizontal lines
01:56:25 rain screen cavity ie horizontal lines unbroken around the full perimeter of the building at all levels from level three and above and you say that created an uninterrupted horizontal supply of fuel capable of supporting horizontal fire spread by a number of different
01:56:36 fire spread by a number of different routes and mechanisms sorry number of routes and mechanisms again claim back see figure eight on page 32 can you identify those very briefly does the blue section the blue sections yeah now and to end to be fair they're
01:56:50 yeah now and to end to be fair they're continuous and uninterrupted only because the columns also provide a means for them to pass by the column if you see what I mean yeah absolutely now finally I'll not put fire spread dr. Lane says and we don't need to go to
01:57:02 Lane says and we don't need to go to this unless you want to and it's it's her report at paragraph ten point four point twenty at page 28 she says that the cladding rails for spandrel panels provided a route for
01:57:15 spandrel panels provided a route for vertical fire spread because they by potentialy bypass the cavity barriers do you agree with her I do right I can now turn to downward fire spread and you
01:57:26 turn to downward fire spread and you cover that at section six point two of your report starting on page 184 and is it right professor that downward spread in your opinion is caused by two things
01:57:37 in your opinion is caused by two things one the melting and running downwards of the polyethylene and second opposed flow flames spread yes with the the first of
01:57:48 flames spread yes with the the first of those being the dominant one right the melting and running down was of PE correct now you've a defined I think a post flav flames spread in your report
01:57:59 post flav flames spread in your report on page 184 in footnote 58 and I take it that that that's the definition that
01:58:10 that that that's the definition that you're using what role in general terms did opposed flow flames spread play in the downward spread of fire in Contra distinction to melting and dripping at
01:58:22 distinction to melting and dripping at Granville tower at Greenville tower I think likely to be a very small and potentially insignificant role right now
01:58:32 your view I think is that you can see downward fire spread the earliest along column lines it's correct right and that's parent one power of nine to
01:58:44 and that's parent one power of nine to six at page 189 can I just take you through a number of figures from that part of the report starting at page 190 we can just jump ahead to that and start with start with figure 110 and
01:58:58 and start with start with figure 110 and I'm gonna run through from that to figure 114 over three pages if you go through starting with 110 you say there
01:59:09 through starting with 110 you say there it's a extract from a video captured at approximately 250 and it appears to show dripping material on downward far spread at the corner of column a5 and the North
01:59:20 at the corner of column a5 and the North Face so that's the center of the northeast corner is is it yeah can you and you identify the drip burning dripping burning material there just hanging down on the right row
01:59:31 just hanging down on the right row that's the northwest corner northwest corner is the northwest corner yeah yes okay then you've got is it the same corner
01:59:44 then you've got is it the same corner wave in the next photograph downward fire spread those is one a continuation of the other yes and in fact in one of my videos it'll be either the North Face
01:59:55 my videos it'll be either the North Face video or the West face video we there is video footage of this hmm which is far more instructive to be honest yeah then the images but the images tell the story if you like and yes the tooth the two
02:00:07 if you like and yes the tooth the two things I would highlight there is that along the right-hand side of that corner column you see a clear downward fire spread if it was a video you'd see progression of that fire front down the column and you also see the lines of
02:00:20 column and you also see the lines of lights that are on the column there's sort of one line and then a secondary line slightly further below yes that story heights and those are the horizontal breaks in the cassettes along the column and I believe that what we're
02:00:32 the column and I believe that what we're seeing there is pooling of burning polyethylene on that little shelf that I showed previously in my diagram yes as the as the polyethylene drips down inside the columns so just on this
02:00:44 inside the columns so just on this picture if you could point that out and they have to get up and sorry to make you do that just pick that up yeah it's sort of here yes and here yes and you see it actually on every column on the building where we
02:00:56 every column on the building where we have video evidence you see this occurring you see these lines light up ahead of the obvious external fire spread and so you have this progression of the dripping polyethylene down and it cools locally on horizontal surfaces
02:01:08 cools locally on horizontal surfaces within the building that could be these sort of little shelves that you get at the junctions it could actually be on top of cavity barriers within the system which essentially provide shelves inside
02:01:19 which essentially provide shelves inside the filing system mechanisms of downward fire spread and then you have a locally burning pool fire polyethylene which can heat the material here and these panic assets melt them and then a progression
02:01:31 assets melt them and then a progression further of the polyethylene down the building tonight before we leave that picture you can see some way below where the downward fire spread arrow is pointing there's another bright pinpoint of light do you see it there yes what is
02:01:42 of light do you see it there yes what is that it might be just falling debris right it's hard to say from a still wait we could look at the video now it's moving on then to the next figures 412 113 on page 191 again you could see
02:01:55 113 on page 191 again you could see dripping burning material in both of those pictures falling and landing on window details that's what you say in relation to figure 1 1 2 3 again can you
02:02:09 relation to figure 1 1 2 3 again can you can you point anything specific out from there about how it is that that burning dripping material is actually spreading fire yeah points
02:02:21 fire yeah points receive this inclined front of the flame here it's awesome it's also interesting to point out that after that very bright line passes we see much less flaming we have compartment fires burning within
02:02:33 have compartment fires burning within these fires now but we see dark patches on the cladding yeah which does go to this question of the extent to which the vacuum insulation is still contributing once the polyethylene has burned out of the rainscreen cladding and indicates
02:02:45 the rainscreen cladding and indicates that not so much would be the answer to that question but nonetheless you see we have this this diagonal line here these the bits that we've circled here again if this was in a video what you would
02:02:56 if this was in a video what you would see is material falling down landing on either the window SILS or in cases where the cassettes have disappeared on top of cavity
02:03:07 have disappeared on top of cavity barriers and forming these localized pool fires which then caused generation of energy up and further fuel this diagonal line but the key thing I wanted to mention was if we imagine that this diagonal line sort of stays a diagonal
02:03:19 diagonal line sort of stays a diagonal line which is what we do observe when we watch the progression of these flame fronts or fire fronts across the face of the building if it starts here at the top corner which is where it does start based on the images we looked at a
02:03:30 based on the images we looked at a minute ago we could imagine that diagonal line just moving down like this and the consequence of that would be an apparent lateral yeah because it's a
02:03:41 apparent lateral yeah because it's a diagonal line just moving down right we could also imagine that that line goes like this and it would look just the same so the question is how much of the lateral fire spread is that which is
02:03:53 lateral fire spread is that which is opposed flow along the spandrel panel how much of the lot on the fire spread is that which is dripping burning polyethylene now clearly it's some combination of those two my view is it's
02:04:04 combination of those two my view is it's predominantly this right the dripping and now what enables you from this all the other photographs we'd be looking at to form that view it's a combination of the fact that opposed flow fire spread
02:04:17 the fact that opposed flow fire spread on the spandrel panels would be quite a difficult thing to have happen because these are aluminium coated polyethylene rainscreen panels so they're not they tend not to spread spread fire laterally
02:04:30 tend not to spread spread fire laterally unless there's some other factor at play a post flow fire spread in a in a lateral sense relies on there being fuel
02:04:41 lateral sense relies on there being fuel ahead of the flame front and it relies on there being energy getting to the fuel ahead of the flame front if you have a burning ACM PE cord rainscreen
02:04:52 have a burning ACM PE cord rainscreen panel there's two questions you have to ask the first question is where does the energy go the energy goes mostly out and the second question you have to ask is where does the fuel go and the fuel goes
02:05:04 where does the fuel go and the fuel goes mostly down granted some of the energy goes with it because it's burning so if your energy goes mostly out and you fuel goes mostly down you're not left
02:05:15 fuel goes mostly down you're not left with much it's a cause lateral right right that combined with the fact that when we observe the video in particular the thermal imaging video from the helicopters the EM past videos that were
02:05:27 helicopters the EM past videos that were taken on the night when they switch to a thermal imaging filter in those videos hopefully we'll have a chance to see some of it it is really striking the amount of hot burning debris that is
02:05:39 amount of hot burning debris that is falling down this building which is not visually obvious when you look at an optical view when you look at thermal imaging it's like a waterfall of molten burning material falling off the side of
02:05:50 burning material falling off the side of this building contributing to heating of the cloud and below the flame front so all those two bases whoo I think it's far more likely that the lateral is this diagonal line moving down rather than
02:06:01 diagonal line moving down rather than sideways now you have set out a number of hypotheses for downward fire spread down the vertical fire spread starting
02:06:12 down the vertical fire spread starting on page 197 and you've got essentially three hypotheses D 1 D 2 and D 3
02:06:23 starting with D 1 if I can at the foot of page 197 that is or the top of page 198 that the downward vertical fire spread observed a Grenville tower was primarily to you to the presence of aluminium composite ACM rainscreen
02:06:35 aluminium composite ACM rainscreen cassettes with polyethylene PE filler and your conclusion about that is to be found in the paragraph immediately below at 948 where you say that it's
02:06:48 at 948 where you say that it's considered to be the dominant and decisive factor contributing to downward vertical fire spread and that's clear enough can I just ask you whether you've
02:07:00 enough can I just ask you whether you've formed a view about whether the Allu glaze panels contained in the infill panels and the panels supporting the the vent extract fans contributed as a
02:07:14 vent extract fans contributed as a source of melting and dripping material contributing in turn to down the fire spread
02:07:21 spread I think it's possible but I think that the potential is is in comparative terms quite small right I will base that opinion on two key
02:07:32 I will base that opinion on two key arguments the first would be that as I've already discussed when XPS is exposed to a heat source it tends to shrink away from the flame and then burn in C Chu he's capable of forming a pool
02:07:46 in C Chu he's capable of forming a pool fire under the right conditions but in small quantities he did quite severely I would expect it not to necessarily do that and indeed the presentation the
02:07:57 that and indeed the presentation the PowerPoint presentation that we have from the LF be about the shepherds chord worshipers bushfire they that show some experiments that were done by Bureau Veritas in the wake of that fire to look at panels that have the same at least it
02:08:09 at panels that have the same at least it appears to be the same it's a blue XPS insulation and in that case they actually do set alight some panels and they don't see pooling but they do see shrinking away from the flame so for
02:08:20 shrinking away from the flame so for that reason I would say I'm probably not that substantial and effect the secondary reason is that the XPS is 25 millimeters thick but it has a density
02:08:31 millimeters thick but it has a density that's almost an order of magnitude less than the PE and it's only present as dr. Lane has said over 13% of the exterior of the building as opposed to something more like 70% for the ACM panels so the
02:08:44 more like 70% for the ACM panels so the mass is the mass of material is a fraction of the mass of PE present its heat of combustion is less by about 10 percent than PE so we have we have less
02:08:57 percent than PE so we have we have less of it it has less heat of combustion and it tends not to form pool fires we're not in large quantities so for that basis I would say I mean clearly it's
02:09:08 basis I would say I mean clearly it's going to contribute but I think is it's probably small or negligible now turning to your hypothesis d2 that's on page 199 at paragraphs 9 5 2 and following you
02:09:19 at paragraphs 9 5 2 and following you you say there and I summarized that the exposed edges of the PIR insulation may have contributed indirectly to downward fire spread but you say there's no quotes compelling evidence on quotes
02:09:32 quotes compelling evidence on quotes that it played a role and that's paragraph 9:57 yeah if we just have that up on the screen no compelling evidence but I think you go on to say that it may have played a minor role by insulating
02:09:43 have played a minor role by insulating or heating within the cavity and we've covered that before is that the same mechanisms same idea yes or in Malaysia it's vertical it's keeping heat within
02:09:54 it's vertical it's keeping heat within the system which which has to do something and that would just accelerate the downward yep now the hypothesis d3 at the top of page 200 is the continuous
02:10:05 at the top of page 200 is the continuous vertical channels and extensive internal cavities contributing to downward fire spread and you cover that at paragraphs nine five eight to nine six two there on
02:10:17 nine five eight to nine six two there on that page is your conclusion there that it's likely that downward fire spread
02:10:30 it's likely that downward fire spread would have been somewhat slower as you say at ninety six to have these channels an extensive internal cavities not been present that conclusion is that confirmed by your visual evidence yes it
02:10:42 confirmed by your visual evidence yes it is yeah so but there is there's extensive evidence at rental tower of solidified polyethylene in the locations of those cavities that has dripped down
02:10:54 of those cavities that has dripped down from above to the cooler parts of the building near the base and you have large quantities of polyethylene in the base of the building in those locations which is fairly compelling evidence now I want to turn to horizontal spread and
02:11:05 I want to turn to horizontal spread and the crown if I can and I'm going to show you a little bit of video again I should repeat the trigger warning this is yeah very much this building very much on fire and a lot of people might find that
02:11:17 fire and a lot of people might find that distressing there is also some audio that goes with it again people might find that distressing so that if they if they don't feel they're up to seeing it then they should either leave this room or remove themselves from the livestream and I get it asked 559 yeah right this
02:11:33 and I get it asked 559 yeah right this is video for all I'm going to ask you to pause if there's anything you think we should be looking at this is in the context of horizontal spread and particularly the crown contributing to
02:11:44 particularly the crown contributing to fire spread and we can start at 529 or 535 minutes and 30 seconds we can start mr. Chanin hey we should start now yes
02:12:15 [Music]
02:12:29 I'm you can stop it there so yeah this is just a video showing that still that we looked at a few minutes ago where you can see the you can clearly see the the material the burning material dropping
02:12:40 material the burning material dropping down the right-hand side of that corner column this being the northwest corner you can see the formation of these bands of light of the junctions between the columns and hopefully this is one part
02:12:51 columns and hopefully this is one part of the video where we actually observe that progression but I couldn't say if it is for sure
02:13:09 [Music]
02:13:33 yeah so this this is the NPAC this is some impasse yes for the pre-emptive stop Paul so yeah this is some of the impasse image where it appears they're
02:13:44 impasse image where it appears they're using some kind of thermal filter or thermal imaging filter here night vision and it's just instructive I think to look as this video progresses obviously
02:13:55 look as this video progresses obviously the regions that are burning appear to have saturated the filter because they're so hot but you can see the amount of hot debris that's falling from the tower which really I think supports this idea of the downward mechanism you
02:14:10 this idea of the downward mechanism you want him to continue yes because I mean I well I guess the other comment I would make here you can it's not so clear here but you can see that the farthest extent of progression of this fire is along the crown on the west face so the the the
02:14:23 crown on the west face so the the the farthest horizontal progression as we move around the building as the fire progresses in all five of the videos that I've produced demonstrates that the the fire progression around the building
02:14:35 the fire progression around the building both clockwise and anti-clockwise if you're looking from above is at the crown and that the rate of that spread is actually reasonably consistent throughout the duration of the fire so it's almost like a linear fuse moving
02:14:47 it's almost like a linear fuse moving around the top of the building so H we continue and see if we can see much could anyone tell me if he's all under control or caulk
02:15:10 they need that one at all can we then go 2 and 7/8 well up the 707 just move on
02:15:21 2 and 7/8 well up the 707 just move on to the net use the next sequence sequence for and just tell us if this anything
02:15:41 anytime here yeah yeah here you get a nice close-up view at the level of the crown it's hard to see do you see the set of vertical lines these are the
02:15:52 set of vertical lines these are the vertical elements of the crown you can see that the crown itself is burning and beneath the crown you have what appears to be to my eye a pool of polyethylene
02:16:05 to be to my eye a pool of polyethylene which is melting on the coping element that sits directly beneath the crown is that the leading edge of the flame front on that face at that point we continue
02:16:17 on that face at that point we continue to see how
02:17:05 I think we'd probably come to the end of what may be useful for you to comment on but if there's anything else in these sequences that you think assists illustrating horizontal spread
02:17:16 illustrating horizontal spread particularly the crown no I mean I think what I commented on previously says it all that the the hypothesized mechanism at the crown is probably worth restating that those crown elements a burn and
02:17:27 that those crown elements a burn and spread fired preferentially yes and create what is essentially a fuse around the top of the building the mechanism is they burn they drift polyethylene onto the coping directly below the formation
02:17:38 the coping directly below the formation of a localized pool fire which progresses laterally ignites the next crown elements and it progresses yeah I'm around the building yep thank you
02:17:48 now the other thing to pick up here is that you say in your your report at page two three eight moving ahead significantly in it to the the BM end
02:18:08 significantly in it to the the BM end well to the beginning of horizontal fire spread hypotheses which and you have a number of hypotheses under E at paragraph one one four you say it's
02:18:21 paragraph one one four you say it's worth noting that under normal conditions upward spreading fires and fire plumes tend to spread outward as they travel upward that's because the heat and smoke was travel upward from afar from an inverted cone that widens
02:18:32 afar from an inverted cone that widens as it rises due to entrainment of fresh air into the fire plume and they said that resident results in a characteristic V pattern it is the spread at the crown that simply an example of that V pattern or is it is it
02:18:46 example of that V pattern or is it is it different no I mean I believe that that what is driving the spread at the crown is the lateral progression of the pool
02:18:57 is the lateral progression of the pool fire beneath it yes and not the not the inverted cone effect from the vertical spread no if if that were the case then
02:19:09 spread no if if that were the case then I would have expected the way we observe fire
02:19:12 fire progress around the building to be to be different than it is you know I would have expected vertical fire spread up an East face to be more of a cone in the first place right yeah now turning to your hypotheses I think I could take
02:19:24 your hypotheses I think I could take these quite quickly e1 para 1 1 1 5 page 2 3 8 is it right that your hypotheses are not as well developed in relation to
02:19:36 are not as well developed in relation to horizontal fire spread as they are in relation to vertical and downward upward and downward spread the hypotheses are not as well developed I mean I think we have I think we have more of them because there were more things we wanted
02:19:47 because there were more things we wanted to just make sure yeah or rather I was many many ideas were popping in as to what could be causing this lateral I mean it's it's worth noting that I think
02:19:58 mean it's it's worth noting that I think as Professor torero said yesterday with the Grateful Tara fire is quite unusual in the context of lateral or horizontal fire spread in that when we've seen other fires in buildings that have similar rain screen materials we tend
02:20:09 similar rain screen materials we tend not to see the entire building engulfed so the question is why has that happened at Greenville tower the distinguishing feature appears to be the ground but I
02:20:20 feature appears to be the ground but I wanted to make sure that that I looked at every possible option so that's why we have a large number I'm not sure I would agree that they're less develops I mean I think that it's such an unusual mechanism that I'm proposing or
02:20:33 mechanism that I'm proposing or hypothesizing in that it's not something we see every day you know upward fire spread dong combustible material is pretty straight forward downward fire spread by burning dripping thermoplastics is pretty straightforward
02:20:45 thermoplastics is pretty straightforward this lateral mechanism is if you like a unique situation which is a consequence of the architectural features of grab for tower so it's it's the fire spread mechanism for which I certainly want to
02:20:57 mechanism for which I certainly want to do a lot more work at phase 2 to make sure that we interrogate that and test that hypothesis to show whether or not that is the dominant mechanism as I believe it is now I think your initial
02:21:08 believe it is now I think your initial assessment at least at this stage perhaps subject to further work is that the dominant cause it's your your phrase of horizontal spread was a combination of pooling of melting or melted and
02:21:20 of pooling of melting or melted and dripping polyethylene and also the tendency of fire flumes to widen as they move up
02:21:25 move up it's a combination of those two are you able to give us any kind of quantification as to which is the dominant of those two well in the absence of the melting dripping and pooling the upwards wouldn't matter so
02:21:37 pooling the upwards wouldn't matter so you know the upwards spreading is almost a consequence of the downward spreading now dr. Lane says that the horizontal spread would also have occurred across the exposed edges of polyethylene on the spandrel panels do you agree with that
02:21:51 spandrel panels do you agree with that again that would be an opposed flow fire spread mechanism on a fuel in a horizontal direction as I discussed earlier yes the important question there
02:22:02 earlier yes the important question there is where does the energy go where does the fuel go and on the basis of my answer you've probably got a sense that I don't think that's a particularly important mechanism in this case right as to hypothesis e2 which is paragraph 1
02:22:16 as to hypothesis e2 which is paragraph 1 1 to 6 at page 239 I think your your conclusion is that in theory PIR could contribute to the spread of flame but
02:22:28 contribute to the spread of flame but you can't quantify the extent of that contribution is that a fair way of summarizing your your view of that hypothesis I think it's it's possible but I've no evidence to suggest that it right are you able to express any of you
02:22:41 right are you able to express any of you now on the extent to which the presence of PIR contributed to the horizontal spread of fire not in any quantified way no right doctor Lane's view is that at least at an early stage the presence of
02:22:53 least at an early stage the presence of cut and exposed PIR edges in the cladding structure may have support along the spandrel panels may have supported horizontal flame spread can you agree with that or I think it's
02:23:05 you agree with that or I think it's possible the thing it's important to recognize about that is that in order for flame to spread in an opposed flow mode horizontally even on PIR Celotex
02:23:18 mode horizontally even on PIR Celotex specifically that isn't protected with a foil facing ie at a cut edge you need a significant external heat flux that is sustained and so in the absence of a significant external heat flux causing
02:23:30 significant external heat flux causing it to continue progressing which means you kind of already need a fire there yeah you're not gonna see that these these the lateral fire spread on PIR in the absence of an external heat flux will stop Kevlar generally right okay
02:23:44 stop Kevlar generally right okay hypothesis III page 240 para 11:35 that hypothesis is the continuous vertical channels and extensive eternal cavities present in the structure contributor to
02:23:56 present in the structure contributor to the rate of horizontal fire spread your your opinion is that I think this is 11:35 that it was not likely I mean not
02:24:07 11:35 that it was not likely I mean not directly although obviously indirectly as a consequence of having influenced both the vertical upward and downward yeah it is there any evidence that cavity barriers were at all effective in
02:24:19 cavity barriers were at all effective in initially preventing horizontal fire spread not prior to the point at which the fire reached the crown not that I'm aware of no and indeed as I as I've mentioned I think there is evidence that
02:24:32 mentioned I think there is evidence that after the fire fronts had passed a particular level on a building that whatever polyethylene was remaining tended to form pools and burn locally on
02:24:44 tended to form pools and burn locally on top of the cavity barriers potentially making matters a bit worse yes and we could see hypotheses e4 and e5 and your
02:24:55 could see hypotheses e4 and e5 and your conclusions about that efore you reject and E 5 is about the the architectural crown and you've explained you up the role and ready that you plan relations that you say it played in relation to to that there's
02:25:08 played in relation to to that there's also a hypothesis e6 which is the contribution made of any by the aluminium and XPS composite window infill panels and I think your conclusion there is that they played a
02:25:19 conclusion there is that they played a role but you can't quantify it I'm summarizing perhaps inaccurately but but is that is that a fair description of your view about that this is with reference to the infill panels
02:25:30 is with reference to the infill panels yes yes I mean the infill panels as we've discussed they they have fuel in them that is bustable and can burn so in a fire that's progressing laterally I would expect that fuel to become involved
02:25:41 expect that fuel to become involved somehow and contribute but yes quantifying it I couldn't do that okay now dr. Lane says and again for reference purposes its page 31 of part 10 of her report at paragraph ten point
02:25:52 10 of her report at paragraph ten point five point nine that this is her pathway see she says the these panels can connect to the other combustible materials at the head and the sill of
02:26:03 materials at the head and the sill of the window and therefore provided a route above and below for horizontal fire spread in reaching your own conclusion on hypothesis e6 did you take that view into account yes but again it
02:26:17 that view into account yes but again it seems to me that that would require what is effectively again an opposed flow lateral fire spread mechanism for the same reasons that I think it's unlikely on the ACM panel which is a combustible material with two aluminium skins I
02:26:29 material with two aluminium skins I think it's unlikely to occur on an infill panel and given them given the way that you already described XPS behaving which is in a different way with a higher emission point I think
02:26:42 with a higher emission point I think than the polyethylene would that also mean that that also means that you think it's unlikely that that would have been on a root for horizontal fire spread I mean I think to call it a root for
02:26:54 mean I think to call it a root for horizontal fire spread it's not something that I make an alternate least eight I think when when the infill panels get hot the foam inside them will potentially pyrolyze that will release
02:27:05 potentially pyrolyze that will release flammable combustible pyrolysis products those products will burn if there's a fire around what the consequences of that are for a lateral fire spread
02:27:18 that are for a lateral fire spread mechanism I couldn't say I would expect them to have some influence undoubtedly but I wouldn't be able to quantify it and I wouldn't suggest that it's a significant one very much very good and
02:27:29 significant one very much very good and can I finally turn to the last topic which is spread back into the building just one or two questions about that you've covered that that part seven of your report at page 253 under Section
02:27:42 your report at page 253 under Section 7.3 possible routes of ingress and you've identified from paragraphs 1167 to 11725 possible routes
02:27:55 paragraphs 1167 to 11725 possible routes for ingress of smoke and fire back into the building my question is are these set out in any order of likelihood the five routes yes in its page 253 1168
02:28:12 five routes yes in its page 253 1168 open windows 1169 extract fan units 1170 pre-existing gaps no they're not set they're not set out in any order of
02:28:23 they're not set out in any order of likelihood but throughout the following section and in particular on the basis of evidence from the bereaved survivors and residents I what I conclusion that I
02:28:37 and residents I what I conclusion that I get to on this incidentally that evidence is very helpful in this regard is that it would appear that the routes of ingress depends on the nature of the fire spreads that is adjacent to the
02:28:49 fire spreads that is adjacent to the flat so early on in vertical upward fire spread where the fire is still quite small then the ingress routes are related to the extract fan and the window construction and we have comments
02:29:02 window construction and we have comments in the witness statements and to that effect in particular associated with the extract fan nearly failures are the extract fans as the fire grows and becomes large as professor Tamara said yesterday glazing is actually not that resistant to high heat fluxes and we
02:29:15 resistant to high heat fluxes and we have comments from certainly in the flat sixes as we move up the building as the fire is growing people refer to their windows exploding inwards quite suddenly and with very little warning I'm prior to failure of the extract fan
02:29:26 I'm prior to failure of the extract fan so the ingress routes depends on the mechanism of upward as the fire is larger the mechanism changes and whilst I haven't looked at the witness statements as as regards the ingress
02:29:38 statements as as regards the ingress during downward or lateral fire spread yet my expectation would be again as as Professor torero commented yesterday that the construction around the window and the inflow
02:29:49 and the inflow the extract fans would be more important because the downward spread mechanism is locally a smaller fire with lower heat fluxes than the very large heat fluxes you get in the vertical up front with a
02:30:00 you get in the vertical up front with a big fire plate yes thank you very much and I think you summarized that effectively under Section 7.5 as a section summary at paragraphs 204 sorry
02:30:11 section summary at paragraphs 204 sorry 1,200 and forth to the end of that section yes professor you'll be glad
02:30:23 section yes professor you'll be glad today that I've come to the end of my questions with two minutes to go before 4:30 I'm going to do what we customarily do which is to ask the Chairman to rise
02:30:34 do which is to ask the Chairman to rise for a few minutes to see whether there are any questions that I have not asked this afternoon which I should be asking say if I could do that yes well if you don't mind you're gonna keep a little
02:30:45 don't mind you're gonna keep a little bit longer well no problem have a five-minute break to let Council take stock okay from there any more questions all right so we're trying to give her the option though keep this as short as
02:30:56 the option though keep this as short as we can yes we have an alarm
02:31:04 well I can save five minutes mr. minify sooner if you can yes - thanks
02:39:12 I think there'll be a few more questions but before we continue can I just remind everybody that there will be a routine fire alarm test at a quarter to five the
02:39:24 fire alarm test at a quarter to five the announcement will tell you not to take a action and that's quite right so just be aware that's going to happen but just ignore it
02:39:32 ignore it yes mr. chairman Thank You professor just one or two further questions first and I want to ask you about the failure of the aluminium window frames when you
02:39:45 of the aluminium window frames when you were doing your work leading to this report did you consider whether there wasn't evidence which showed that aluminium frames had failed not in the early stages of the fire as would be
02:39:57 early stages of the fire as would be relevant to the fire spread right let me show you something time please ask the witness to have our m et triple zero one zero eight six seven which is the
02:40:08 zero eight six seven which is the witness statement provided to the police by Daniel Brown firefighter Brown M et triple zero one zero eight six seven and
02:40:20 triple zero one zero eight six seven and I'd like you to be shown please page ten of that
02:40:37 let's trip triple zero m ET triple zero that's it one zero eight six seven page ten
02:40:57 they're now in the second from the last paragraph this is Daniel Brown statement and he was one of thee was one of the
02:41:08 and he was one of thee was one of the first pairs he was in the first pair into flat 16 he says I realized that where I'd seen the kirpan of flame is in fact where the window had been the window and frame were no longer there
02:41:20 window and frame were no longer there and it had completely dropped out leaving a hole in the wall I carried on following the line on the ceiling to above the fridge and then notice in the corner
02:41:27 corner an orange ember falling outside the window area so I looked out the window to investigate what this was now hema he gives evidence that the
02:41:38 now hema he gives evidence that the frame had dropped out and does that tell you anything does that affect your view of the means of egress of this fire from flat 16 I mean I'm reasonably certain
02:41:52 flat 16 I mean I'm reasonably certain the frame hadn't dropped out he says he did reasonably certain that it's still there after the fire so we should have photos to confirm that right I'm
02:42:03 photos to confirm that right I'm reasonably certain that the wind the aluminium window frames of flat 16 are still are still there so the entire frame has not dropped out on the hypothesis let's assume for the moment
02:42:14 hypothesis let's assume for the moment that the Chairman were to find that it did as a matter of fact how would that affect your view if at all how would it affect my view of the means of fire egress from the compartment does he say
02:42:30 egress from the compartment does he say at what time this is well this would be after 120 should be after 120 80 then it wouldn't affect my view right then it may not help that I asked this next question but I'll ask it anyway now you say in paragraph 3 86 that I
02:42:44 now you say in paragraph 3 86 that I won't take you back to it that the windows used in grenfell are constructed from an extruded aluminium profile with a polyamide thermal break built into the frames is that is that material
02:42:58 frames is that is that material something which melts at a much lower temperature than aluminium I haven't looked recently the specific properties of polyamide but it tends to be
02:43:09 of polyamide but it tends to be polymer that has better than typical thermal performance one of the reasons they probably in fact I believe their product sheet states that the reason they use polyamide is so that they can
02:43:21 they use polyamide is so that they can have a thermal break prior to coating which involves the elevated temperature processing so but I think certainly that temperatures below
02:43:33 think certainly that temperatures below the 600 660 that we would expect for aluminium yes yeah so if it has a polymer in it and it it melts do you consider that the window frame would fail at a temperature lower than the
02:43:46 fail at a temperature lower than the normal temperature for aluminium which is six hundred and sixty degrees centigrade also it depends what we mean by fail so it depends what role the polyamide thermal break is playing from mechanical mechanical perspective within
02:43:57 mechanical mechanical perspective within the window frame I wouldn't be familiar enough with the system at this stage to say if loss of that thermal break would cause a mechanical failure of the window frame it's possible but again I'm
02:44:10 frame it's possible but again I'm speculating there's certainly something that I'll look out on the basis of that question yes
02:44:31 and can I please ask you to be shown the clipping or your first clip and go to 112 this is a question which I've been asked to ask you about jets and the
02:44:43 asked to ask you about jets and the reason I've been asked to ask you this is that in your evidence in July you've said that there was evidence of water being applied by jet at 112 I just want to look at the video to see just to be precise with you exactly what you were
02:44:54 precise with you exactly what you were and maybe still are I think talking about at 112 at 112 I think what I hope what I said is that there's evidence of water on the ground at 112 a warning
02:45:07 water on the ground at 112 a warning trigger warning rifle trigger warning possible possibly seeing fire on the building although this clip isn't supposed to can i just stamp wait for 10
02:45:18 supposed to can i just stamp wait for 10 seconds and then ask the question can we please be shown the clip at 112 start at 112 not and not seconds please for
02:45:28 [Music]
02:45:42 did you see any evidence though of the application of water at 112 no I mean I think what you're referring to is there is there does appear to be water on the ground below flat 16 at 112 yes there's
02:45:57 ground below flat 16 at 112 yes there's two in my mind this is something that I've considered it at some length in looking at the issues we discussed really previously with respect to the potential jet at 111 one explanation is
02:46:10 potential jet at 111 one explanation is it's my understanding that when a hose is charged it's not uncommon for a firefighter to just give it a quick spray to test that everything is fine as
02:46:22 spray to test that everything is fine as it should be before they start their deployment so it could be that that is the reason for their water being on the ground
02:46:27 ground at that time the other possibility is that there is I believe evidence of burning debris on the ground prior to 112 and it's conceivable that the
02:46:38 112 and it's conceivable that the firefighters who were on site there decided to put that burning debris out as we no longer see it burning here at 112 and that is the reason for the water on the ground at 112 so yes considered it at some length and
02:46:49 so yes considered it at some length and those are the two explanations I can come up with professor thank you very much those are the extra questions I have for you it remains for me to say thank you very much to you for coming along today to assist us with our
02:47:00 along today to assist us with our investigations and give your evidence we're extremely grateful thank you thanks for those that mr. Millard we're really grateful to you for putting your expertise with our disposal you've produced some very substantial reports
02:47:12 produced some very substantial reports and you've explained them all very fully and I for one have found it very interesting and helpful - thank you sir thank you very much indeed right
02:47:35 mr. chairman just before 4:45 that is the business for the day yes thank you very much may I have your attention please
02:47:41 please ten o'clock tomorrow to use the fire alarm system is about to be tested