Expert Evidence - Professor Torero (20 November 2018 Pt 2 of 2)

Full transcript

00:05:13 you

00:06:39 can you please take your seats proceedings will start shortly can I just remind you to say silent and seated until the chair has left the room thank you

00:08:15 all right professor ready to go again yes thank you yes was great yes thank you I just want to return to one aspect of your evidence this morning and then I'll pick up where we left off on

00:08:26 I'll pick up where we left off on vertical so you said that for this type of high-rise building complementation is critical yes yes and do you mean a high-rise building with a stay-put strategy well it will be

00:08:40 with a stay-put strategy well it will be even more critical with the statehood strategy and but but it also applies to buildings with staged egress and and simultaneously equation yeah and you

00:08:51 simultaneously equation yeah and you agreed with me that once complementation is breached evacuation becomes the preferred option yes when vertical compartment 8 yes when the fire starts spreading beyond the floor of origin

00:09:03 spreading beyond the floor of origin would you agree that once compartment ation is breached evacuation is necessary to secure the fire safety of those in the building yes and is it the only viable option at that point yep so

00:09:21 only viable option at that point yep so I just want to return to the importance of the PIR insulation we were just talking about it before the break and just to be clear just to kind of remind

00:09:32 just to be clear just to kind of remind ourselves there was PIR insulation behind the spandrel panels the ACM panels in two layers of 18 millimeters and also a layer a single layer of a

00:09:43 and also a layer a single layer of a hundred millimeters on the columns and also there was some and that was Celotex RS 5000 PIR insulation there was some

00:09:54 RS 5000 PIR insulation there was some kingspan K 15 phenolic foam boards also used on some of the spandrels although that's possibly only about 7% of the total insulation so just to be clear

00:10:06 total insulation so just to be clear what we're talking about here yes as we've discussed PIR has a low thermal inertia inertia and you've agreed that that means a low time to ignition you've also said that the PIR is liable to char

00:10:19 also said that the PIR is liable to char yes

00:10:20 yes can you explain what impact those features of the PIR I lay time to thermal inertia so lay thermal inertia and propensity to char have on flame spread yes the low thermal

00:10:33 have on flame spread yes the low thermal inertia results in very little energy required to ignite the material all the energy gets stuck very close to the surface so with very little energy you

00:10:44 surface so with very little energy you can bring the surface to a temperature of ignition and it starts burning now when a charring material starts degrading and burning it produces a layer of carbon that effectively starts

00:10:57 layer of carbon that effectively starts protecting the material behind so as opposed to a non charring material that will burn completely this material will burn only a fraction and the layer that

00:11:09 burn only a fraction and the layer that is produced prevents the heat from burning any further so you need to have some heat from the outside to help it burn the moment you remove the heat from the outside attempts to extinguish on

00:11:20 the outside attempts to extinguish on its own because effectively no heat can get from the flame to the flow to keep evaporating if you so the charring has one fundamental outcome is that it will

00:11:36 one fundamental outcome is that it will reduce the fraction of the mass of the material that is actually going to burn and leave this big residue of carbon and that big residue of carbon is going to

00:11:47 that big residue of carbon is going to eventually lead to extinguishment of the material itself so it's going to stop burning on its own and you've slain in your report you say that the features of the PIR give rise to the potential to

00:11:59 the PIR give rise to the potential to burn for a much longer time period again first of all what data or other information if you relied upon when you say that the PIR has the potential to

00:12:10 say that the PIR has the potential to burn for longer periods well this is relative and the reason why it's relative is because the duration of burning is a function of the total mass that burns so if if you have a certain

00:12:25 that burns so if if you have a certain thickness of PIR that will give you a certain amount of mass and a certain amount of mass will determine how long it's going to burn now obviously the master you're considering is the fraction that burns

00:12:36 considering is the fraction that burns not the fraction that remains as char so when you compare the amount of mass that you have of PIR compared to other combustible materials like polyethylene or the ADP M the mass of PIR is more

00:12:48 or the ADP M the mass of PIR is more significant and therefore it has a propensity to remain burning for a fairly long period of time relative to the other materials and can you just

00:13:01 the other materials and can you just explain your view about the interaction that we may have got on the building between the ACP panels and the PIR insulation you talk for example about

00:13:12 insulation you talk for example about radiative feedback can you just explain what radiative feedback is yes - as I mentioned the PIR by itself it will self extinguish so effectively the char layer

00:13:25 extinguish so effectively the char layer forms and unless you put an external heat to try to keep the burning going it will just fade out and die so when you have the polyethylene burning in front

00:13:36 have the polyethylene burning in front that polyethylene provides the extra source of heat that's what we call radiative feedback so between the two of them they are supporting each other and so what we see in in the images of the

00:13:50 so what we see in in the images of the burning of the tower it's a it's quite complex in the sense that there's different forms of behavior the certain areas where you have fairly intense burning where that radiative feedback is having both materials burning quite

00:14:02 having both materials burning quite significantly but then later on when you see that the PE has disappeared then you will have self extinction of the PIR and you get residue of unburned PIR left

00:14:15 you get residue of unburned PIR left behind so eventually you get multiple forms of interaction and and the question if it's going to continue burning or not continue burning it's a it's a question of how the two of them

00:14:27 it's a question of how the two of them are interacting in every particular location so how does the PIR affect the rate at which the aluminium composite panels burn that is a very difficult

00:14:39 panels burn that is a very difficult question to answer but I believe that it is

00:14:42 is and it is likely that the PR will have a minor effect on the rate of burning because the polyethylene being thermally thin once it ignites and start spreading

00:14:55 thin once it ignites and start spreading it will spread at a fast much faster rate than the PIR so the the support that the PR can provide to the rate of

00:15:06 that the PR can provide to the rate of spread is probably of secondary importance why does the fact that they're going to burn out at different stages matter in terms of the

00:15:17 stages matter in terms of the development of this fire because one one determines the rate at which it spreads the other determines how long it's going to be burning and so while well the second one is still burning dripping and

00:15:32 second one is still burning dripping and all sorts of other potentially interaction that can happen between the two of them can extend the duration of burning at any localized space so effectively it's that interaction that

00:15:43 effectively it's that interaction that are that one is determining the speed at which is propagating the other one is basically keeping that area burning just

00:15:54 basically keeping that area burning just briefly because we'll get into testing in much more detail at phase two but professor Bisbee has drawn attention to the DC LD tests after Granville which compared PIR with with mineral wool

00:16:07 compared PIR with with mineral wool insulation but using otherwise similar materials to Granville do you agree that a complex but different interaction will also apply to a system incorporating a

00:16:19 also apply to a system incorporating a mineral fiber insulation and a PE called ACM yes there would there would be a it would be a different interaction because the mineral material will not burn by

00:16:33 the mineral material will not burn by itself and but nevertheless he still has the capacity of insulating in other words you can support the continuous burning of the ACM and also you can absorb dripping fuel and it can serve as

00:16:46 absorb dripping fuel and it can serve as a wick you know to keep things burning so there will be other forms of interactions that that the mineral

00:16:57 of interactions that that the mineral wool will have with with the ACM that could potentially lead to no difference or a significant difference depending on the on the characteristics of the assembly and would you say that the

00:17:10 assembly and would you say that the current evidence is inconclusive on the precise role played by the presence of the PIR at Grenville and that further testing would be helpful yes I think that that well what it is clear that

00:17:24 that that well what it is clear that some level of interaction exists it is not really clear exactly what is the level of interaction that is occurring and it's actually even less clear what would have been the outcome in the

00:17:38 would have been the outcome in the absence or of one or or or the other I think the the testing evidence the standard testing evidence that exists right now the particular tests are being

00:17:52 right now the particular tests are being conducted and as VSA 4 1 4 is a tester in many ways doesn't give enough detail to be able to come up to any real

00:18:05 to be able to come up to any real conclusions doesn't have adequate instrumentation and the scenario this is an area that doesn't really honor the complexity of of the system so in terms

00:18:18 complexity of of the system so in terms of those D CLG tests after granville using the mineral wool insulation what significance do you place on those the results of those tests I will say very

00:18:30 results of those tests I will say very little you've said it's very difficult to quantify the impact that the PIR insulation have at this stage in terms of your preliminary view can you give an

00:18:42 of your preliminary view can you give an overall view as to whether you think it had a contribution and if so broadly in what respect well it clearly did have a contribution but I will not be able to say what kind of a contribution it had

00:18:55 say what kind of a contribution it had or if it was very significant or or mildly significant but but clearly there is burning of the PIR and there's evidence that has been contributing to the you know to the energy that is being

00:19:08 the you know to the energy that is being released but quantify that to the extent of being able to say how important that was

00:19:15 was is still not not very clear in terms of the state of the building after the fire would you attach any significance to any areas where despite extensive charring

00:19:28 areas where despite extensive charring of the insulation the ACM remains intact does that tell us anything not not really I mean once again it is it is one

00:19:40 really I mean once again it is it is one of those situations where the complexity of the interactions is such that uh there might have been a convergence of different things that effectively led to

00:19:51 different things that effectively led to an area where the the insulation burned first and then the ACM never caught fire so that there is a possibility of a very

00:20:02 so that there is a possibility of a very good example will be areas that were wetted by the firefighters for example yes I was gonna ask you say for example on level three it's been suggested that there were some areas where there was deep widespread charring to the

00:20:13 deep widespread charring to the installation but where damage to the ACM panels were much more minor insignificant that's level three that does that tell you so so I mean the only

00:20:25 does that tell you so so I mean the only thing that I could probably conclude from that is that there was some element of cooling going on and and that would have in the cooling wouldn't get to the installations of the insulation might have still been burning through the

00:20:36 have still been burning through the cavity while the external part of the ACM was being protected by by the water from the firefighters what about any evidence on the corner columns where there might have been sittin at the

00:20:48 there might have been sittin at the joints of the panels suggesting that the fire was burning behind the panels rather than on the exterior does that have any significance in terms of the contribution of the team

00:21:00 of the contribution of the team materials

00:21:01 materials well it's significant in the sense that it actually does show the the PIR at least to a certain extent can actually burn in the absence of the ACM now the

00:21:13 burn in the absence of the ACM now the real question is I mean you might have sued the position after the fact but there could have just simply be from a very very short period of burning so the

00:21:24 very very short period of burning so the PR could have extinguished very rapidly and we would have not been able to tell them unless you know we did a very systematic analysis of cross-sections to see the charring thickness do you think

00:21:36 see the charring thickness do you think it would be helpful or indeed practicable to do a survey of the insulation to try and work out what remained after the fire versus what remained of the ACM or other components do you think that would be a helpful

00:21:47 do you think that would be a helpful exercise I do believe so because in in in in many ways the interactions between the two materials or the two systems are are relatively unknown and it will be

00:22:00 are relatively unknown and it will be very important to be able to establish edom if one can burn without the other one in to what extent that can happen and all those details can only be done

00:22:11 and all those details can only be done with a very detailed and general survey of the remnants of the insulation and is that something you think could be done at Phase two based on the existing evidence well I mean I think if if the

00:22:23 evidence well I mean I think if if the installation was available and properly catalogued yes something that could be done here just going back to the other international fires that we looked at earlier the divided fires in the crossfire in Australia did those other

00:22:36 crossfire in Australia did those other fires involve PE cord ACM panels that's difficult to know I think there are unfortunately the information that is available in most of these fires is is

00:22:49 available in most of these fires is is generally quite inaccurate most of it coming from the media there are reports and all the details on the one that is well investigated is the Docklands fire and there's details of all the materials

00:23:01 and there's details of all the materials in there and and the report is published that's yeah the crossfire yeah so you know I wouldn't be able to say on the top of my head exactly what worked what

00:23:12 top of my head exactly what worked what was the insulation material but uh but we reviewed all those and but it was it was difficult to establish any kind of correlation between them because the one

00:23:23 correlation between them because the one of the terrible things about most of these incidents is that they were very poorly investigated and none of the information was ever made public so so it's very difficult you know to come up

00:23:34 it's very difficult you know to come up with a good correlation of what was in each of this event so do you know whether any of them featured mineral fiber insulation as opposed to for example a PIR type insulation uh I wouldn't know let's move on then I want

00:23:54 wouldn't know let's move on then I want to ask you some questions about the white window infill panels for a moment just again to orientate ourselves as to what we're talking about can we just

00:24:06 what we're talking about can we just look at a figure in your report figure 24 that's JT OS six zeros one that page 62

00:24:16 [Music]

00:24:27 yes and if we can focus on finger 24 at the top that the right hand image sorry

00:24:41 the top that the right hand image sorry the right hand not the left hand

00:24:49 so the the white infill panels we're talking about the ones that we can see down on the bottom right hand side is that right in between the windows in each of the flats and these were

00:25:01 each of the flats and these were extruded polystyrene is that your understanding yes often referred to as XPS extruded polystyrene yes and dr. Lane has estimated in her report these panels made up approximately 13% of the

00:25:14 panels made up approximately 13% of the external surface between levels 4 and 23 again is that consistent with your understanding professor Bisbee has set out the properties of XPS in his report that it

00:25:25 properties of XPS in his report that it has a melting temperature of 230 degrees C compared to eat for example 130 degrees C of PE is that correct yes and

00:25:37 degrees C of PE is that correct yes and there's no figure given for thermal inertia it just says that they melt is that right yes they tend to melt they generally have a very low thermal inertia do you think that these white

00:25:48 inertia do you think that these white window infill panels could have played a role in terms of the vertical flame spread we saw at groennfell town I mean the issue with those those what window infill panels is the cover and so the

00:26:00 infill panels is the cover and so the nature of the cover was slightly different to the rest now clearly because they have an infill of a combustible material they will play a role and and and then if it was a

00:26:14 role and and and then if it was a significant or more or less significant role though that is mostly associated on how they are protected when we talk about when you talk about the cover is

00:26:25 about when you talk about the cover is what you're talking about the fact that there's two skins of aluminium exactly and then the XPS inside just in the aluminium skins I think of at 1.5 millimeters thick yes so you're saying

00:26:39 millimeters thick yes so you're saying that the fact you've got those skins on the outside effect the potential for them to contribute to vertical flame spread yes I mean this is the basic concept of encapsulation so when you

00:26:50 concept of encapsulation so when you have a combustible material that is exposed to the outside is encapsulated and

00:26:57 and and the thickness the characteristics of the encapsulation that you put is going to make it less or more susceptible to engage in in in the planar way now eventually given the size of the nature

00:27:10 eventually given the size of the nature of the fire it is quite clear that they would have participated in in the in the process and how late or how early would

00:27:21 process and how late or how early would have been determined by the capacity of the aluminum layer to protect them from from the flames dr. Lane has got an

00:27:33 from the flames dr. Lane has got an image in her report which she says potentially shows vertical flames rip through those allo glazed panels can we just look at that that's BL a s sorry

00:27:44 just look at that that's BL a s sorry actually before we go to this can I just give a warning that I'm about to go to an image of the tower on fire so if anybody's going to be distressed by that they should leave now

00:27:58 just give it another few seconds

00:28:04 sorry I should have given a warning before that last image of the Bennet yeah so BL a s five zeros 10 and then

00:28:16 yeah so BL a s five zeros 10 and then page 39 figure ten point three seven

00:28:27 yes now in fact the corrected time for this is 1:29 am not 126 although I don't think that matters at all dr. Lena as as

00:28:39 think that matters at all dr. Lena as as highlighted there with little blue dots where the insulating panels were on the building this is on the east face do you think that that potentially shows that

00:28:50 think that that potentially shows that we are seeing some vertical flames spread across those alley glazed panels particularly in the higher levels of the building well we are seeing them burn and and the you if you look at those

00:29:05 and and the you if you look at those those images what you see is that the panels are burning well to the left well we get to the left of the the the burning has reduced so it just by

00:29:19 burning has reduced so it just by looking at the image and I was just looking at that image and I could possibly say that in this particular case the panels were igniting the work contributing to the burning but the

00:29:30 contributing to the burning but the aluminum protection layer actually prevent them from being the ones driving the burning they were just burning a little bit later than everything else and but I think that the same way this

00:29:41 and but I think that the same way this image is there I believe there's others where you will see slightly different processes so it's it's something that I think again the interactions between

00:29:52 think again the interactions between these systems is quite complex so in some cases you will get one side burning faster in other cases you will get another side burning faster is it possible that one of the mechanisms by

00:30:03 possible that one of the mechanisms by which these ignite and then melt is that the you then get a pool of XPS formed at the base of the panel's which could then ignite is that a possible mechanism of failure it could potentially be but but

00:30:16 failure it could potentially be but but generally XPS is a very low density material so when it actually melts it produces very very little liquid fuel so

00:30:27 produces very very little liquid fuel so it's mostly air so in principle the exact density is not very clear what was the exact density of this materials but in principle in as a pool fire

00:30:41 but in principle in as a pool fire probably the contribution will be secondary and do you think that these panels could have contributed to the title heat release rate during the fire on the facade everything would have but

00:30:54 on the facade everything would have but keep in mind that their mass is relatively small compared to everything else or the total amount of energy they can release is actually less these

00:31:09 can release is actually less these window panels are mentioned in three of dr. Lane's potential flame spread routes horizontally across the edges top and bottom vertically along the sides and

00:31:20 bottom vertically along the sides and then this route which is vertically across the the panel's of the length of the tower do you agree that those are

00:31:32 the tower do you agree that those are potential mechanisms by which these panels could have contributed to the flame spread they're all clearly potential mechanisms by kipper given the nature of the protective aluminum plate

00:31:43 nature of the protective aluminum plate I would imagine that anything that is vertical will be a mechanism that we should need to consider for this type of materials horizontal or downward might

00:31:56 materials horizontal or downward might be a very minor mechanism of spread yep can I just ask you briefly then a different material the edpm membrane that's the damp roof membrane yes that's

00:32:08 that's the damp roof membrane yes that's there on the columns between the windows and the columns so after you've got the installation you've got the edpm membrane it's a thin black membrane and then you're into the columns have you

00:32:21 then you're into the columns have you done any work to look at whether that could have contributed to vertical flame spread that would have contributed as all the other components in this particular case is thermally thin so

00:32:32 particular case is thermally thin so this would be a material that would have spread quite rapidly and now it's particularly might not necessarily be as effective for vertical flame spread but

00:32:45 effective for vertical flame spread but nevertheless is a material that will it's density is not low so you have a significant amount of mass and it will contribute to the burning and I want to come on to talk about the role of cavity

00:32:57 come on to talk about the role of cavity barriers in the facade can we just remind ourselves again just to orientate ourselves what these looked like on sight I'm going to show you just some pictures of the open state horizontal cavity barriers if you go to

00:33:09 horizontal cavity barriers if you go to of imaging doctor lanes report B la s6 zeros 8 page 42 figures eight point four five and eight point four six so the

00:33:22 five and eight point four six so the image at the bottom is taken from the manufacturer's literature in terms of these cavity barriers and then at the top we see an example of the installation of one of these in one of

00:33:34 installation of one of these in one of the it's underneath one of the spandrel panels here and can you just explain in general terms what a cavity barrier is I mean when when you have a cavity and

00:33:48 mean when when you have a cavity and particularly if that cavity has combustible materials there is a possibility that a chimney effect can be formed that will actually maintain spread through the cavity the cavity

00:34:01 spread through the cavity the cavity barrier in principle is a mechanism by which you try to stop so you close the barrier in such a way that you prevent the flames from progressing from one place you know to to another and is it

00:34:13 place you know to to another and is it right that this kind of cavity barrier has an intermittent strip that expands with heat to close the gap yeah potentially you know some of the solutions that we apply is when we have

00:34:24 solutions that we apply is when we have intricate geometries and and the cavity barrier can not be cut exactly just with the geometry of the material you will put the strips of intumescent

00:34:35 you will put the strips of intumescent material the intermezzo material with heat will expand and and it will allow the cavity to close now in your report

00:34:46 the cavity to close now in your report you say that no matter how well designed or implemented you do not think that the cavity barriers could have prevented vertical or lateral frames spread at ground fault is that right yes can you just explain

00:34:59 is that right yes can you just explain why that why you're up that view a a cavity barrier is a system that is designed to close a duct when you expect a new propagation is within the duct if

00:35:11 a new propagation is within the duct if you put combustible materials outside the cavity barrier the cavity barrier actually has no meaning because effectively the burning can happen around the cavity very now obviously the cavity barrier will result in in

00:35:24 cavity barrier will result in in potentially slowing what is going on because it will prevent part of the burning but it is not going to stop the spread now unfortunately the cavity varies once they've been overcomed then

00:35:37 varies once they've been overcomed then melting material can actually deposit on the cavity barrier and the cavity where in itself can become a mechanism of spread so in this particular type of scenario the the fundamental principle

00:35:49 scenario the the fundamental principle behind why we put cavity barriers is inappropriate because we have combustibles of both ends so it's it is not blocking any path of propagation so

00:36:04 not blocking any path of propagation so is it right that you think any nonconformity of cavity barriers would not have significantly affected the rate of vertical flame spread that we saw a Gravatar if you look at the photographs up there what you see is that the spaces

00:36:17 up there what you see is that the spaces that are that are left open and let's assume that those are the non-conformities and are generally a small fraction of the overall space now

00:36:29 small fraction of the overall space now given the fact that the cavity is already being cavity barriers already being misused by principle I don't believe that all those non-conformities will have a very significant effect in

00:36:40 will have a very significant effect in altering the outcome you've talked about concerns about these barrage barriers where you've got combustible materials potentially either side and certainly with an ACM panel you've got it on the

00:36:51 with an ACM panel you've got it on the outside and is it relevant that you can get deflection and warping of the alum in panels how does that affect the operation of the barriers well it's the same thing if the if the aluminum panels

00:37:02 same thing if the if the aluminum panels warp deform or fall off then the whole concept of a cavity barrier is he doesn't apply

00:37:12 professor Bisbee has said in his report that horizontal cavity barriers are considered important within range twink rainscreen cladding systems particularly when combustible cladding and insulation

00:37:23 when combustible cladding and insulation products are used would you agree with that statement I think I do agree with the statement you know if they are applied in a way such that they meet

00:37:34 applied in a way such that they meet their objectives so yes of course cavity virus is a mechanism that we have to try to control a fire but we do have to do it in a manner such that effectively

00:37:46 it in a manner such that effectively we're delivering what we want so for example if I have the cavity barrier and I have the cladding sitting on top of it so that the barrier actually crosses and

00:37:57 so that the barrier actually crosses and produces a true barrier that cannot be jumped through then of course then they actually are a very important aspect of the problem I think it is the cavity

00:38:08 the problem I think it is the cavity barrier is is a tool that we have to try to reduce the spread of a fire and and the tool has to be used appropriately so if it's used appropriately and within the bounds of what we want it for then

00:38:21 the bounds of what we want it for then of course it is a it is a good tool that we can put in place so you think there might be circumstances in which it could work but it would all depend on the configuration this is the design and do

00:38:33 configuration this is the design and do you think it can ever work where your combustible material is external to the barrier well then it would not be used as a cavity very will be used simply as a mechanism of try to decelerate a

00:38:45 a mechanism of try to decelerate a process but not necessarily under the principles of a cavity barrier because it is not a cavity barrier anymore if it actually has combustible materials outside

00:38:57 outside do you think at Grenville tower that the cavity barriers wouldn't have been rendered as ineffective if they'd been positioned differently so for example if

00:39:12 positioned differently so for example if they've been put at the base of the panels the spandrel panels rather than part way up do you think that could have affected the situation I think that that a better design would have perfectly be

00:39:24 a better design would have perfectly be possible that would have resulted in a better outcome and and I think is is difficult to say if I did this this is I will get a better outcome I think in

00:39:35 will get a better outcome I think in this particular case we have to be extremely careful because as I said before the cavity barriers by themselves are just a tool you know so they just yes but I do believe that if you use

00:39:48 yes but I do believe that if you use them appropriately and do an appropriate design I do think that that they could improve the way in which the system behaves what about in stabilizing the

00:39:59 behaves what about in stabilizing the panel's themselves is that a role they might be able to perform well I mean you can grant them a structural role but they're not generally designed for that purpose and you could assign them for

00:40:12 purpose and you could assign them for that purpose if that's what you needed and but but it is not the conventional use of a cavity where a Graham for what

00:40:23 use of a cavity where a Graham for what we saw was that the fixing rails for the cassettes that the cassettes were fixed to penetrated the cavity barriers so you have these gaps and do you think that may have played a role in terms of

00:40:35 may have played a role in terms of allowing vertical flame spread look when you start looking into all those details of the cavity barriers what you immediately the conclusion you immediately come up to is the system

00:40:46 immediately come up to is the system that was designed could not be built correctly so effectively you have penetrations complex geometries all sorts of different things that are that by themselves rendered any post possible

00:40:59 by themselves rendered any post possible interpretation of them in reality very very difficult so I mean I think in this case we're talking more about taking a step back and saying

00:41:10 step back and saying this should have been designed better so that it could be implemented appropriately so that the cavity virus could actually deliver its objective and do you think they may have these gaps in

00:41:22 do you think they may have these gaps in these rails could have played a role in terms of either convective or conductive transfer of heat from level to level I mean they would play a role the question once again is to what extent there was a significant role and and that's not

00:41:35 significant role and and that's not clear so everything will play a role but the significance of this elements I think is questionable because again they're these are relatively small gaps compared to the area that is covered so

00:41:48 compared to the area that is covered so how much a flame can actually creep compared to the flames actually burning on the outside would affect the alt the ultimate outcome I I do think that this is probably a secondary role do you

00:42:01 is probably a secondary role do you think that it would be helpful to do some further investigations to better understand the reasons for some different flames spread rates including by reference to cavity barriers is that work that you think would be useful to

00:42:13 work that you think would be useful to do this is one of those cases were I don't believe so I think a system that is poorly designed it is poorly designed by definition so taking a step back and trying to understand it in detail from a

00:42:25 trying to understand it in detail from a forensic perspective might help us design something better but only in in in that sense not necessarily in the sense of trying to establish if it would have affected the rate of the greater

00:42:37 have affected the rate of the greater spread it the system in itself is so complex that that trying to fully understand that system to try to correlate it to flame spread rates it's

00:42:48 correlate it to flame spread rates it's going to be extremely complex almost I would say impossible to achieve nevertheless doing a detailed analysis of the role of a cavity barrier so that we can actually design things better

00:43:00 we can actually design things better might be a very fruitful path to go just pausing there and thinking about the windows we established earlier that there were no cavity barriers around the windows that's something that dr. Lane

00:43:13 windows that's something that dr. Lane and professor Bisbee have both identified do you agree that cavity barriers do play a useful role around window openings to delay both breakout and re-entry well I mean I think that

00:43:25 and re-entry well I mean I think that that is absolutely correct and I think given you know they can't the context in which we are operating but I think you have to keep in mind that we do not protect buildings from fires exiting the

00:43:39 protect buildings from fires exiting the building

00:43:39 building so the concept of protecting the frame requires us understanding that we have a cavity behind that effectively is going to bring the fire back into the building

00:43:50 to bring the fire back into the building so in the context in which we are operating absolutely it is a fundamental problem but in the context of design I think we have to take a step back and first think effectively what are we

00:44:03 first think effectively what are we protecting you know we've never considered the idea of protecting the exit path of a fire we always consider the problem of the re-entry path of a fire so so we have to be very careful

00:44:15 fire so so we have to be very careful when when we state that but I agree given the context is fundamental let's move now then to stage three of your analysis which you say is characterized

00:44:27 analysis which you say is characterized by lateral flame spread and then internal migration of smoke and fire this is between approximately 1:30 and 2:30 a.m. and you've explained that

00:44:40 2:30 a.m. and you've explained that Granville Tower is unusual in that horizontal spread enveloped the entirety of the building in less than three hours is that right yes and you've also said

00:44:52 is that right yes and you've also said that whilst there are multiple pathways for the fire to spread through the facade system laterally none of them really explain the lateral propagation of the fire that we saw is that correct

00:45:04 of the fire that we saw is that correct yes are you still of the view that there is no dominant pathway conclusively established in terms of explaining that lateral fire spread well there's one that appears is very

00:45:15 well there's one that appears is very important which is the propagation through the crown yes and that seems to control through dripping and dropping out burning the breeze it seems to control the rate and which at which it propagates it doesn't necessarily answer

00:45:28 propagates it doesn't necessarily answer the question if it would have propagated in the absence of the crown but it does set the pace at which the propagation is occurring so just to be clear what you're talking about there what you're

00:45:40 you're talking about there what you're suggesting is that the fire propagates laterally around the crown very quickly is that correct yes and then you get burning and dripping PE from the crown

00:45:51 burning and dripping PE from the crown will look at its composition in a moment down on to lower levels which then establish their own fires is that right and then propagate upwards yes and is

00:46:02 and then propagate upwards yes and is that why on some of the faces we see almost a diagonal effect you see it particularly acutely on the west face for example yes and you believe that the the dominant mechanism is that the crown

00:46:13 the dominant mechanism is that the crown melting and dripping and then lower fires making their way up yes I believe that that sets the pace of the propagation so the the crown is the one

00:46:24 propagation so the the crown is the one that defines at what rate is propagating and that mechanism you just described it's exactly the mechanism that I believe is setting the speed at which the lateral spread is happening let's just look at the crown in a bit more

00:46:36 just look at the crown in a bit more detail so this is a parapet of strips of a cm kind of C shaped columns or fin some people describe them as fins vertical fins which were installed right

00:46:48 vertical fins which were installed right at the top of the building to hide the previous concrete parapet is that right yes we can see a useful picture of that in dr. Lane's report this is at BL as50

00:47:00 in dr. Lane's report this is at BL as50 s10 page 69 figure 10 point 7 3 so here we see the crown at the very top and

00:47:11 we see the crown at the very top and what we see are these vertical fins and they are made of aluminium composite ACM panels is that correct yes and they're mounted on c-shaped aluminium channels

00:47:24 mounted on c-shaped aluminium channels that will fit to one another yes in rows and can you explain why you think it was that the fire spread so quickly round the crown I

00:47:37 fire spread so quickly round the crown I I think it's primarily because the as the components of the crown start burning and and the polyethylene starts

00:47:48 burning and and the polyethylene starts melting it pulls underneath and I mean we did a preliminary analysis of of the rate you know showing a bit of this and but I think in in the revised report up

00:48:00 but I think in in the revised report up dr. Bisbee this is analyzed in much more detail and I will concur that that is probably the main mechanism is the pooling of the of the polyethylene in below the elements of the crown that

00:48:13 below the elements of the crown that effectively serves as a as a feedback loop that accelerates the burning all of these elements so you're talking about kind of pool fires at the bottom of these fins yes which then help it

00:48:27 these fins yes which then help it propagate laterally yes and then also are dripping down is that right well then as they're burning and they start dismembering you're gonna have dripping down and pieces falling

00:48:38 have dripping down and pieces falling off and and and that is what effectively starts the fires in in in other locations yeah am i right and understanding that each of these fins

00:48:50 understanding that each of these fins has an exposed core along the edges yes installed they're waiting to propagate from one to the next exactly exactly so I was about to take

00:49:02 exactly exactly so I was about to take that so professor Bisbee has highlighted a number of characteristics which he thinks are important in terms of fire propagation around the crown he refers

00:49:13 propagation around the crown he refers to the fins as semi continuous paths for fire to spread do you agree with that yes and he's highlighted the numerous exposed ACM edges with exposed

00:49:24 exposed ACM edges with exposed polyethylene on the edges yes again do you think that's important yes and he's also drawn attention to the fact that they are effectively C shaped chimneys

00:49:35 they are effectively C shaped chimneys which in themselves would support flame extent

00:49:38 extent and flame spread do you agree with that yep and also that there's no cavity barriers around the top of the building no it's beyond that I mean there's not only nothing to stop it but also as it

00:49:50 only nothing to stop it but also as it pulls down you have a mechanism to keep pushing it so any gaps that you might have are being covered by the pool that is being formed underneath and does your

00:50:01 is being formed underneath and does your V remain that the rapid internal penetration of flats above level 20 can be attributed to the presence of the crown and the debris that was falling from it our analysis showed that

00:50:13 from it our analysis showed that effectively the the rate at which the this apartment were being penetrated it effectively was pretty much the same rate as the progression of the fire in the crown so those flats at the top were

00:50:27 the crown so those flats at the top were particularly prone to the effects of the melting the dripping the heating is that correct yes

00:50:38 but just testing the role of the crown do you agree that in any event the fire would be more severe and of longer duration at the higher levels because of

00:50:49 duration at the higher levels because of rising hot gasses and flames ie the flame plumes out towards the top of the building that dirt is so questionable because it really depends on on the time

00:51:01 because it really depends on on the time that is available so like in the case of the tort for example the vertical burning have been so much faster than any lateral spray that the plume never

00:51:14 any lateral spray that the plume never really opened it basically remained very very narrow yes of course it opened a little bit and you can see slightly more damage on the top then you have at the bottom but it's truly almost a vertical plume so in principle it depends a lot

00:51:28 plume so in principle it depends a lot on the capacity of the system to sustain burning to the point that you can use that energy to enhance the spread on the

00:51:40 that energy to enhance the spread on the upper part so do you think that the effect that we saw around the top of the crown could simply be explained by the vertical flame pluming at the top is

00:51:51 vertical flame pluming at the top is that an explanation for it hmm what what do you mean exactly by the effect that what I'm saying is could the could the lateral flame spread the horizontal flame spread that we saw actually be explained by the shape of the flames

00:52:03 explained by the shape of the flames blooming and widening at the top of the building rather than it being about the crown no

00:52:13 I just want to take you to a figure in doctor lanes report that's figure ten point four seven in her report BL as50

00:52:24 point four seven in her report BL as50 Sten at page 48 now this is a diagram of the the crown and just to explain in the

00:52:35 the the crown and just to explain in the bottom part what we're seeing is the top of the building with a Reina bond ACM panel which overlays some insulation

00:52:47 panel which overlays some insulation which wraps around the top of the building do you see that yes and then above that dr. Lane is marked PPC aluminium flashing over the top of the insulation so as I understand it that's

00:52:59 insulation so as I understand it that's polyester powdered coated aluminium flashing which sat on top of the ACM and the insulation at the top of the building and then what we see above that are these fins sitting on top of that

00:53:12 are these fins sitting on top of that does that make sense yes now it's been suggested that the lateral fire spread that we see at the top of the building might have been more to do with the

00:53:23 might have been more to do with the presence of combustible insulation at the top of the building and the rain upon panels rather than the fins would you like to comment on that I mean

00:53:34 you like to comment on that I mean though you have combustible insulation you have the rain among and and you have a platform in which you can actually pull molten polyethylene I do not

00:53:50 pull molten polyethylene I do not believe that there is any conclusive evidence that would show that that this is coming from the insulation and in principle an exposed pool fire it's

00:54:04 principle an exposed pool fire it's clearly a much more severe form of heating than any heating that could come from that insulation that is covered at all ends

00:54:14 it's also said that the aluminium coping that we see over the top there which had projected some of it had not melted that

00:54:26 projected some of it had not melted that it had not melted across the top but it had melted a bit on the face of it again would you attach any significance to that absolutely because if you have melted polyethylene keep in mind that

00:54:37 melted polyethylene keep in mind that the polyethylene is going to melt at a very low temperature so the polyethylene is going to start gasifying at about three hundred and something degrees which is way below the melting temperature of aluminum so will not let

00:54:49 temperature of aluminum so will not let the aluminum heat up beyond that temperature until is fully consumed so effectively the fact that you don't have melting of the aluminum shows that you have something else that is acting as a

00:55:01 have something else that is acting as a heat sink that is taking the energy away and keeping it at a low temperature it's like boiling water you know it will not change above a hundred until you finished boiling all the water it's exactly the same in the case of

00:55:13 exactly the same in the case of polyethylene it will not reach the melting temperatures of aluminum and it's quite telling the fact that the exposed area where you don't have that melt molten material is the one that disappears while all the area that is

00:55:24 disappears while all the area that is covered is one that remains unmelted is it significant that the fins were not backed by any insulation does that change your view about the role of there I think in this particular case is

00:55:36 I think in this particular case is driven by I believe is driven by the pool fire and I think that that clearly needs to be studied in a lot more detail but uh I I do think that under those

00:55:48 but uh I I do think that under those circumstances probably having insulation in the back would have had a very minor impact

00:55:58 so let's come on to lateral flame spread at lower levels of the tower and again we've touched on this so you've said that smoke plumes and heat flings from lower down the building world widen with

00:56:10 lower down the building world widen with height and preheat other sections of the cladding facilitating later ignition and you've highlighted that a key mechanism for lateral flames spread further down the building is that we have burning

00:56:22 the building is that we have burning debris falling from the area's already on fire and then accumulating on horizontal surfaces igniting new localized fires which then spread upwards is that right yes and that's

00:56:34 upwards is that right yes and that's what you were talking about earlier when you said actually you think that is a real candidate to explain why the fire at ground floor towers spread laterally so quickly yes

00:56:53 is is that substantiated by the mapping out of the lateral flame spread that you've done in each direction so in your figure 35 let's just go to that that's

00:57:04 figure 35 let's just go to that that's JT OS six zeros one page 78 you have depicted the lateral spread as I understand it from top to bottom yes for

00:57:18 understand it from top to bottom yes for each face in time is that right yes can you just explain how that supports the analysis that we get this debris falling down and igniting other fires that then

00:57:30 down and igniting other fires that then go up so if you look at the top symbols you will see as they are progressing we're changing the shape and the color of the symbol so basically the bottom

00:57:42 of the symbol so basically the bottom symbols reach the end faster so top symbols reach the end faster than anything else so that will be the the top of the building so that's the progression that

00:57:53 building so that's the progression that is driven by the crowd so then what you will see is once for example if if you take the yellow triangle you will see the fire reaches

00:58:04 triangle you will see the fire reaches the yellow triangle at about a hundred and ten minutes so that that's right in the middle of that top diagram we see the yellow triangle at the top so it's hit the top of the building yes at that

00:58:15 hit the top of the building yes at that point that's West yeah so then debris Falls it ignites the fire in the next one which is the 120 and and very rapidly it progresses up again so you

00:58:27 rapidly it progresses up again so you can see the three triangle so in a period of 10 minutes it's gone down and then all the way come up yeah and then if you look where the next triangles are so you will move all the way down now to about 1:45 and and you can see that a

00:58:41 about 1:45 and and you can see that a piece of debris falls all the way down and then it creeps up so each of those columns represents a piece of debris that landed below and then it spread it up again and once it's gone below and

00:58:54 up again and once it's gone below and landed and then is going up vertically and do you agree with dr. Lane that there's then vertic an umber of vertical weighs three which the fire could then spread across the facade yes I mean you

00:59:06 spread across the facade yes I mean you can see that there's a multiplicity of vertical pathways and it's kind of hard to determine which one is more important on the other she has the columns is the first one and then along window edges

00:59:18 first one and then along window edges and edges of the white infill panels would you agree with that in some parts of the building potentially that's correct in other parts of the building I think there might be other different mechanisms of

00:59:31 might be other different mechanisms of off spread it's not very clear when you look at the progression of the fire when each mechanism dominates and it many times depends to the proximity of the

00:59:42 times depends to the proximity of the column you know where the debris landed you know there's a number of different factors that are going to affect what is the the mechanism that dominates but uh but I think in some areas yes she is

00:59:53 but I think in some areas yes she is correct in terms of the lateral flame spread he talked earlier about opposed flow flame spread and professor Bisbee

01:00:04 flow flame spread and professor Bisbee explained about this in his presentation back in June with reference to the match looking at the match going much slower sideways do you think there's any role

01:00:16 sideways do you think there's any role for opposed flow flame spread in terms of what we see at Grenville I think it's very minor to negligible yeah because you think the primary mechanism is this

01:00:27 you think the primary mechanism is this burning debris down five then going upwards as opposed to it just migrating or actually across the building yeah so if you look at the are the dots for

01:00:39 if you look at the are the dots for example if if you see at 50 minutes you look at the yellow dots you will not see progression to the right so a little bit

01:00:52 progression to the right so a little bit later you will not see another dot appearing the dot has to wait for the debris to come down and and go up nowhere in the diagram you see that you

01:01:03 nowhere in the diagram you see that you have lateral progression there's very few exceptions and there are very rare situations many times when you have debris falling in two places like for example what happens between

01:01:15 like for example what happens between 130 and 140 in the top diagram that the triangles and the squares they seem to burn very close in time so you could actually interpret that that was lateral

01:01:26 actually interpret that that was lateral spread yeah but the reality is that it was actually two pieces of debris dropping almost at the same time falling in places that were very close to each other and then creeping up have you actually tracked that on the

01:01:37 have you actually tracked that on the videos well we've we've tracked in a number of places but it's quite difficult because tracking down where the debris lands generally is from the type of images that we have is not that

01:01:49 type of images that we have is not that precise so we we tried to emphasize in these diagrams as close as possible that process the process became quite evident and and none of the other mechanisms

01:02:02 and and none of the other mechanisms seem to play any significant role so again within the error bars that you can expect in this type of analysis I I don't seem to believe that I found any

01:02:14 don't seem to believe that I found any case where I could unequivocally ascertain that the flame was spreading or posed in the post mode either laterally or downwards in any

01:02:25 laterally or downwards in any significant way do you agree there that there are some pathways laterally that it could have followed albeit slowly for example on

01:02:36 followed albeit slowly for example on the tops and the bottoms of the windows along edges of the ACM cassettes where for example there may have been some exposed edges or indeed along the window infill panels yeah I mean I won once

01:02:48 infill panels yeah I mean I won once again I go back to this this issue that this is these are incredibly complex systems and I would not be surprised that there will be some places in which the frames actually creep under a cavity

01:02:59 the frames actually creep under a cavity there was a that was horizontal that could have possibly happened but it was by no means a dominant mechanism

01:03:12 and what about the potential contribution of the cut edges of the PIR insulation is it possible that that could have played a role either because

01:03:23 could have played a role either because debris was falling down and by that time I was hitting that or because it was burning along the edge well I mean again you go back to the same point this is in

01:03:34 you go back to the same point this is in such level of complexity yes it is possible that he played a role but would that be considered one of the dominant factors for the lateral spread I don't

01:03:45 factors for the lateral spread I don't believe so now finally on this topic you've explained that internationally there are some exceptions in terms of high rise rise fires where the fire did

01:03:56 high rise rise fires where the fire did propagate laterally can we just look at a couple of those examples if we go to figure 25 in your report that's JT OS six zeros one at page 62 so

01:04:10 that's JT OS six zeros one at page 62 so this is the Salafi Tower in Dubai where you say the natural flame spread extended to almost half of the building

01:04:21 extended to almost half of the building is that correct yes and and that's what we see in these images here does it remain the case that there's limited information about the construction details which could have explained that

01:04:33 details which could have explained that in this particular case yes I think this is one of those cases where there's very limited information one thing that appears regularly particularly in media descriptions of

01:04:46 particularly in media descriptions of this case that the wind was quite significant so you can see that the spread in one direction is much more significant than in the others so so

01:04:57 significant than in the others so so there is a possibility that that had an effect but again I mean this is an example where you can see a systematic line of lateral flame spread that is

01:05:08 line of lateral flame spread that is very different you know to what you see in in Greenville when you've also drawn attention to the monte carlo casino and hotel fire in 2008 where the fire spread laterally

01:05:21 2008 where the fire spread laterally across a parapet can we just look at that figure 32 JT OS 6 series 1 page 75

01:05:33 so these are images of the the Monte Carlo Hotel and Casino fire can you explain why you think this has particular parallels with the fire at

01:05:44 particular parallels with the fire at Granville well I mean I think that this particular case the upper part of the building is is a thick layer of combustible material that is rendered

01:05:56 combustible material that is rendered with a non combustible protection the rendering of the non combustible protection performed very poorly so it effectively exposes the the material

01:06:09 effectively exposes the the material quite rapidly so it allows the combustible material to propagate lateral quad rapidly now an interesting aspect of this one and you can see it in

01:06:20 aspect of this one and you can see it in finger D is that this material drips down and and basically deposits in the edges that you can see and those are the that's really the mechanism that continues propagating the fire so what

01:06:33 continues propagating the fire so what you get is molten material depositing in in that ledge and that pool that forms in there is the one that keeps igniting the material forward so in that sense it does show some similarities with with

01:06:47 does show some similarities with with Grenville

01:06:51 I now want to look at re-entry of the fire in stage 3 and then we might take a break in about another 10 minutes after

01:07:03 break in about another 10 minutes after that so you say that your stage 3 is also marked by reentry into flats and the interior migration of smoke and fire you've said that the external fire

01:07:15 you've said that the external fire generates thermal loads as high as 120 kilowatts per meter square we discussed that earlier yes and you've said that that level of heat flux would inevitably cause a failure of and you've said the

01:07:29 cause a failure of and you've said the window glazing the extract fans the UPV CV uPVC windows surrounds allowing flame reentry is that right yes and that flames will then ignite other

01:07:43 and that flames will then ignite other combustible materials inside the compartment causing internal fires yes can we just explore some of the methods of reentry that we have seen in the evidence in Section 7.4 of his report

01:07:56 evidence in Section 7.4 of his report professor Bisbee has drawn attention to a large number of witnesses who comment specifically on the early failure an ignition of the extract found unit and

01:08:07 ignition of the extract found unit and the surrounding XPS panels so you have the extractor fan we looked at the kitchen window earlier extract a fan in the middle it's got a panel surrounding it which is both it's extruded

01:08:19 it which is both it's extruded polystyrene is that correct yes and professor Bisbee has drawn attention to that as a potential route for ingress you've also highlighted that mode of failure in your report now many of these

01:08:33 failure in your report now many of these that Professor Bisbee has drawn attention to in were in the flat sixes on the East face of the tower do you think that this evidence is potentially significant in terms of the route of

01:08:45 significant in terms of the route of fast read back into apartments potentially I think that once again when we think of the design of a window we are designing a window keeping in mind

01:08:57 are designing a window keeping in mind that we don't want our fire spreading from one

01:09:00 from one to another one so we set a certain criteria which is twelve point six kilowatts per meter square has been the criteria that is used for the design of all the window components

01:09:12 the design of all the window components so in principle there is no expectation than any of these components will withstand anything above twelve point six kilowatts per meter squared so in

01:09:24 six kilowatts per meter squared so in principle yes I wouldn't be surprised that one of these elements is weaker than the others we found quite a bit of evidence of exactly the same as we found evidence of other mechanisms and and and

01:09:37 evidence of other mechanisms and and and I would imagine that yes this could be potentially a significant way for the fire to get back in do you think it might have been significant in terms of the timing of the ingress on that face

01:09:48 the timing of the ingress on that face I is it possible that during the early stages of the fire that this was a more predominant ingress path and that had to say you get glazing failures later in the fire there's nothing that makes me

01:10:03 the fire there's nothing that makes me believe that time in this particular case would have been an issue because keep in mind that you're exposing the systems to a heat flux that is an order of magnitude bigger so effectively the

01:10:17 of magnitude bigger so effectively the failure times is are going to be generally quite fast so what difference could it make you know from a time perspective is it's very difficult i I

01:10:28 perspective is it's very difficult i I wouldn't say it would be too significant professor Bisbee's also highlighted some other possible routes of ingress I just want to briefly ask you about some of these gaps in the window framing many

01:10:40 these gaps in the window framing many residents have referred to gaps and drafts around the windows after the refurbishment and some have actually referred to fire directly ingress things through those window surrounds again do

01:10:52 through those window surrounds again do you think that might have that had a role to play she would have had a role I mean clearly if there is a gap in as much as they could be a window open or something like that then there will be

01:11:03 something like that then there will be no barrier so that delay that you will have you know from the moment the flames arrive until the smoke starts getting in and also early on I mean from from from the

01:11:15 early on I mean from from from the perspective of smoke migration it could have been significant because smoke goes up and envelopes the building so you could have areas where effectively you have no heat but you actually have smoke

01:11:28 have no heat but you actually have smoke so the smoke could have easily penetrated through those gaps so from the perspective of smoke migration I think it might have a significant role but from the perspective of re-entry of

01:11:39 but from the perspective of re-entry of flames that's probably not a significant just to be clear I was going to come on to open windows in a moment I was talking here about we know the windows were pushed out during a fisherman and there were gaps down the side that were

01:11:50 there were gaps down the side that were filled with insulation and residents have talked about drafts around those gaps or some have just to be clear do you think that's a potential path of

01:12:02 you think that's a potential path of fire or smoke spreads back in any gap is a potential path for smoke any gap in any potential path for spread requires a

01:12:13 any potential path for spread requires a condition of failure and that condition either is the ignition of the insulation a heat flux sufficient to break it heat flux sufficient to melt something so so then because you require a condition for

01:12:25 then because you require a condition for failure and your heat insult is so much higher than it was designed for then I think that's what makes the difference minor because of those heat fluxes

01:12:36 minor because of those heat fluxes everything will fail there rapidly we've also heard instances of the softening and the melting of the uPVC and then entry I mean that's a similar route you agree that that says yes yep you've

01:12:48 agree that that says yes yep you've talked about firmly induced breakage of window glazing and then open windows do you think they may have played a role in terms of windows is a hot night windows

01:12:59 terms of windows is a hot night windows being open flame spread going up is that I think more again more than flame spread I think the role of windows is probably more significant in regards to smoke migration it had

01:13:14 smoke migration it had it's been suggested that double-glazed units are resistant to fire attack and that it's by no means certain that they will failed you during a fire would you agree with that no spray-foam professor

01:13:27 agree with that no spray-foam professor Bisbee has identified the use of spray foam to seal gaps around the windows to provide a final airtight seal and he has considered this to be potentially significant in terms of the ingress of

01:13:39 significant in terms of the ingress of fire and smoke around the windows do you think that the presence of spray foam could have exacerbated the ingress I mean it would have like everything else but I do think again that this falls in

01:13:53 but I do think again that this falls in that category were I will not be able to establish a ranking between all of this because they will all fail and in a very short period of time what about whether any of the internal

01:14:06 what about whether any of the internal compartment fires themselves on the night once they're burning could have contributed to the external flame spread the extent of or the severity of the

01:14:17 the extent of or the severity of the external flames but is that a possibility not that that is actually a true fact you know clearly if you have a fire that starts in a compartment the compartment has a fuel load so it has a significant amount of energy that is

01:14:29 significant amount of energy that is being released and that energy is going to partially spill out particularly if doors are closed so it's going to spill out and it is going to contribute to the

01:14:40 out and it is going to contribute to the energy that is being released now clearly again the interplay between how fast is it's spreading and how fast you reach conditions in which this internal

01:14:53 reach conditions in which this internal fire start contributing is what really matters but effectively once you start releasing that energy that energy has to go somewhere and part of it is going to go out and it's going to contribute to the process do you think there are any

01:15:05 the process do you think there are any times in the fire or particular aspects of the burning we see on any of the facades where you think that's happening there's nothing in particular I mean I think there's obviously certain areas

01:15:17 think there's obviously certain areas like the

01:15:18 like the as explained by dr. lane and professor Bisbee in the areas around the 12th floor where you have particularly unusual burning were potentially what is

01:15:30 unusual burning were potentially what is happening inside is having more effect on the rest but but those seem to happen generally after the fire has passed and and if they are contributing they're

01:15:42 and if they are contributing they're contributing to the heat that is in the plume and those contributing to what is happening much much further I'm now

01:15:53 happening much much further I'm now going to move to a separate topic so this might be a good moment for a good time yes that's right we'll have a break enough tension oops I think in the end I'm talking about for evidence please

01:16:04 I'm talking about for evidence please and feedback at 20 fast

01:16:12 [Music] 21st Street please

01:27:22 ready to go on yes good it's just one question relating to that last topic about ingress through windows we were talking about the fact that it may not

01:27:34 talking about the fact that it may not have made much difference given you've got 120 kilowatt per meter square fire going up vertically that weaknesses in the window arrangement may not have made much difference in terms of ingress

01:27:46 much difference in terms of ingress giving you get glazing failure anyway what about downward flame spread so the primary mechanism you were talking about earlier of melting and dripping debris

01:27:58 earlier of melting and dripping debris which then accumulates on ledges or window ledges and then them itself creates smaller fires which go up is it possible in that situation the

01:28:10 possible in that situation the weaknesses in Windows whether it's the extract fan unit or other weaknesses around the sides could have could have then played a role or more significant role yes I think that if if you have to

01:28:23 role yes I think that if if you have to breathe and obviously you have much less insult from the fire on the external part and and weaknesses in the window design would have had a more significant impact on potential ingress of the

01:28:35 impact on potential ingress of the flames so I now want to move to consider the internal migration of smoke and fire and at this point and it's important to draw attention to your addendum to your phase one report where you've

01:28:48 phase one report where you've essentially highlighted that there's a need to do a lot of further work at phase two specifically say to correlate the firefighter activity and the smoke spread during both stages two and three

01:28:59 spread during both stages two and three of the fire is that correct yes can we just go to what you've said in your addendum so if we bring that up that's JT OS six zeros too at page one and I

01:29:12 JT OS six zeros too at page one and I just want to highlight a couple of paragraphs here in the second main paragraph you've said because you have done a 999 call analysis of a new of

01:29:23 done a 999 call analysis of a new of people reporting smoke in certain areas and you've said there are multiple 999 calls during stage two that 105 to 130 reporting smoke in the

01:29:35 105 to 130 reporting smoke in the lobbies as the fire spread vertically up the building from flat 16 on level 4 to the roof above level 23 most of these calls center around the middle of the building with smoke in lobbies reported

01:29:46 building with smoke in lobbies reported by callers on levels 10 11 12 and 14 time between 125 and 128 of these reports any level 14 is clearly reported as having a significant amount of smoke

01:29:57 as having a significant amount of smoke prior to this there's also a report of a smoke-filled Lobby higher up the building on level 22 at 1:21 this latter report is likely to be due to the internal spread of smoke as the fire had

01:30:08 internal spread of smoke as the fire had not reached level 22 by this stage so there is it right that you're mainly highlighting what the pattern of the 999 calls was showing yes in terms of the spread of smoke and and then you say

01:30:22 spread of smoke and and then you say this in your third paragraph you say from the onset of stage 3 that's 1:30 to 2:00 a.m. 999 call is consistently reports thick black smoke considered

01:30:33 reports thick black smoke considered unpassable by residents in the lobbies these include the 12 14 16 18 and 21st to 23rd level lobbies within the period 130 and 140 alone and then you say

01:30:46 130 and 140 alone and then you say further 999 calls for the rest of stage 3 report a similar situation on the 10th 11th 19th and 20th levels some of these also report smoking the stairwell itself it's clear that from the onset of stage

01:30:57 it's clear that from the onset of stage 3 internal smoke spread is fairly ubiquitous above level 10 is that correct yes now you've noticed the levels there in terms of smoke spread do

01:31:08 levels there in terms of smoke spread do you think there's any significance in terms of where smokes being reported at that point in the building can you extend a bit what do you mean well you've you've you've highlighted certain parts of the building 12 14 16 18 20

01:31:22 parts of the building 12 14 16 18 20 first to 23rd effectively the middle of the building and then the top of the building do you think that's significant in terms of the pattern of what we're seeing well it is significant in the sense that is somehow unusual that you

01:31:34 sense that is somehow unusual that you have concentrated calls in certain areas of the building which clearly show you that there was some unusual that was happening in there and and we have not been able to gather the

01:31:47 and we have not been able to gather the complete amount of information to be able to establish exactly what qualities yes

01:31:52 yes now you've highlighted some examples in your report from the available footage that we have of the tower of smoke emerging from flats on the opposite side

01:32:03 emerging from flats on the opposite side of the tower to the fire front the flame front on the east side can we just have a look at these images but before we do I probably ought to issue a trigger another trigger warning so we're going

01:32:15 another trigger warning so we're going to be looking at images of the tower we're just looking at smoke spread to be the tower it's not the tower on fire but some people may find these images upsetting or distressing and in which case they should have done leave now so

01:32:32 case they should have done leave now so those images of figures 48 to 52 that's Jay TOS six zeros one starting on page 88 we can bring that up

01:32:49 [Music]

01:32:53 so these are images my understanding is on the west face of the facade yes and we see as early as [Music]

01:33:03 [Music] 157 158 that there is smoke emerging just explain to the top image where is the smoke emerging from on that image where's your fairing - you can see a

01:33:16 where's your fairing - you can see a darker color often pointed out to us so these are the types of images that you can see you can see it very clearly on

01:33:27 can see you can see it very clearly on that bottom image and your top entrance it's hard to tell but yeah somewhere in there okay so this is West face it's 157 2 a.m. you say that the significance of

01:33:43 2 a.m. you say that the significance of this is that that's movement of smoke would only be possible if complementation is breached for two units is that right so it's got through one flat into the lobby through the

01:33:56 one flat into the lobby through the lobby and into another flat is that correct and and why did you think it was so important to highlight that because the conditions are such that the doors

01:34:10 the conditions are such that the doors themselves would have not failed the flats on the western facade were not on fire yet so that clearly tells you that

01:34:22 fire yet so that clearly tells you that the doors had to be open as opposed to the doors having failed because of an event because what you're saying is there's no flame front there yes on the west face to cause a flame induced

01:34:33 west face to cause a flame induced failure of the doors so you're deducing from that that it must have been smoke spreading through an open door yes that

01:34:44 spreading through an open door yes that was left open by a fleeing occupant well that could potentially be the case it could potentially be firefighting intervention it these are the kinds of

01:34:56 intervention it these are the kinds of things that I think before any conclusions are drawn we have to be very very careful that all the available information is correlated there's also some factual evidence that

01:35:09 there's also some factual evidence that firefighters found considerable smoke in certain lobbies very early on in the fire for example firefighter a bairn who goes up and finds smoke in the lobbies as early as 120 in some areas you're

01:35:21 as early as 120 in some areas you're aware of that yes in the light of that and your analysis of the 999 calls that you've done and I realize this is only a preliminary analysis do you agree that the lobbies appear to have been

01:35:32 the lobbies appear to have been compromised on a number of floors very early in the fire for example by 120 and certainly by 125 126 yes I mean there is sufficient evidence to say that there

01:35:45 sufficient evidence to say that there was a level of compromising of the lobbies quite early on I think it's really really not 100% certain to me the exact timings because it's not always we

01:35:57 exact timings because it's not always we don't always have exactly the times for example when the firefighters were in different places that was a result of we've called the flat sixes being

01:36:09 we've called the flat sixes being exposed to fire and therefore smoke and then people leaving the flat sixes and yes absolutely that would compromise no

01:36:20 yes absolutely that would compromise no absolutely I mean I think that that is a possibility and that will imply that the self-closing mechanisms were not working and and so and that people didn't close the doors so I think that that clearly

01:36:35 the doors so I think that that clearly that is a possibility that needs to be evaluated very carefully and is that is that the kind of detailed work you'd want to do at phase 2 which is to try and look very specifically about

01:36:46 and look very specifically about occupant egress door condition firefighter activity floor by floor flat by flats yes to turn piece it together so you can make a correlation to gain certainty on all the timings and in

01:36:59 certainty on all the timings and in particular of the level at which they have been compromised by smoke now given that you have said you want to do much more detailed work at phase 2 at this

01:37:10 more detailed work at phase 2 at this stage what I'm proposing to do is just explore some of the broad themes that you have identified a new report which are potentially important in terms of internal smoke spread but just before we get to that

01:37:22 spread but just before we get to that it's right to notice in it that you've emphasized again the importance of maintaining these internal compartment ation lines of Defense yes and you've said the internal smoke spread

01:37:33 said the internal smoke spread particularly into the lobbies and stairwells correlates strongly with past fire events that do result in a high number of casualties is that right yes so in contrast some very large

01:37:47 so in contrast some very large international fires with comparable internal fire spread have not resulted in penetration of smoke and flames into the lobby or stairs was that right yes and I know it's very difficult in

01:37:58 and I know it's very difficult in general terms but can you give us an indication of why and those events it didn't penetrate into the lobby in the stairs what was it about those buildings that were potentially different to what we saw at Granville well I mean I think

01:38:10 we saw at Granville well I mean I think in in in many of these cases it was the layout of the building and in for example the case of the address one of the main structural walls that of the

01:38:23 the main structural walls that of the building basically separates the apartments from the corridor so you have a very significant compartmentalization

01:38:34 a very significant compartmentalization barrier in in there clearly a big issue is is obviously the the doors and not in the sense of the doors withstanding the

01:38:45 the sense of the doors withstanding the event but more in the case of the doors being left open or closed so the quality of the maintenance of the building is is clearly appropriate some of this fires happen in buildings that were fairly new

01:38:56 happen in buildings that were fairly new so they had they had not been damaged so things like self closes were probably all working appropriately so in general conceptually is very simple in the sense

01:39:07 conceptually is very simple in the sense that it is about keeping the barrier in place and that's the quality of the barrier in itself and the quality of the doors and their capability of self closing and it is it therefore right to

01:39:20 closing and it is it therefore right to assume that the compartment ation separating each flats from the neighboring flats to be capable of resisting any significant passage of smoke heat and fire from one flat to another yes and

01:39:33 fire from one flat to another yes and that's the case even in the event of a very significant external facade fire eventually you might end up having a a problem but the compartmentalization in

01:39:45 problem but the compartmentalization in principle should be designed to a level in which it withstands the fire for a very significant period of time and compartmentalization as I said is design on the basis of a post flashover fire so

01:39:57 on the basis of a post flashover fire so you already have the time that it takes for the fire to enter the time that it takes for the fire to transition to flashover and then the time of the that you have for the failure of the

01:40:08 you have for the failure of the compartmentalization under those conditions so you have all these significant delays that in principle should allow people to migrate to the lobby and then from the lobby to the

01:40:19 lobby and then from the lobby to the stair so you have already two layers of compartmentalization that you have to breach so in principle compartmentalization is a very robust way of giving a very significant amount

01:40:31 way of giving a very significant amount of time for people to enter the stairs and be safe in the stair for an even longer period now moving to some themes that we can pick up and I just want to

01:40:42 that we can pick up and I just want to discuss door failure by fire for a moment will come to penetration of smoke in a moment but concentrating on door failure by fire you've noted that the

01:40:53 failure by fire you've noted that the flat doors that were removed from the building when tested or one of those exemplar after that doors was tested demonstrated 15 minutes integrity when it was tested by the BRE on behalf of

01:41:05 it was tested by the BRE on behalf of the Metropolitan Police that's right isn't it and is it right to note that that's a test with a seven hundred and forty degrees C failure temperature yes that right which is above flashover

01:41:16 that right which is above flashover temperature is that right so flashover temperature is about 500-600 degrees yes that correct so does it remain your view that the failure of the doors by fire is most likely to occur in cases where

01:41:28 most likely to occur in cases where flashover is reached yes and where flashover is not reached it's unlikely the doors going to fail due to turn or fire yes you've highlighted in

01:41:40 turn or fire yes you've highlighted in your report that despite major damage in many of the flats a significant number did not attain flashover you also say in your addendum report that fire induced or failure could be a contributing

01:41:51 or failure could be a contributing factor in the latter part of stage three yes is that correct but you don't think it's going to be a significant contributing factor during stage two or earlier is that right yes does that remain your view the remains

01:42:03 does that remain your view the remains may be let's turn then to penetration of frack doors by smoke we know from dr. lanes report that there are a number of difficulties with many of the flat doors

01:42:14 difficulties with many of the flat doors including that they don't comply with relevant cold smoke leakage requirements and an absence of test evidence which correlates with those doors is it your

01:42:25 correlates with those doors is it your view based on what you've seen in the general themes emerging that the doors fail to maintain compartment Asian in terms of smoke spread yes as possible

01:42:36 terms of smoke spread yes as possible you have noted yourself in your report reports of smoke coming through flat doors for example at 125 and 126 just based on the 999 calls yes what do you

01:42:47 based on the 999 calls yes what do you think is the significance of that in that early stage again it goes back to the problem of multiple breaches of compartmentalization so so if if if

01:43:01 compartmentalization so so if if if there's a call that indicates that smoke is coming into that flat through the door that basically means that the flat is not on fire and the smoke is coming

01:43:13 is not on fire and the smoke is coming through the lobby and that must have come through from another another apartment so effectively you have again this path where you have multiple levels of failure before it starts entering the

01:43:26 of failure before it starts entering the apartment so I think this needs to be explored in very significant detail because are given the long period of time that people spend in those spaces

01:43:37 time that people spend in those spaces it is fundamental to try to understand what were those breaches yeah I was just going to draw attention to that it obviously it's right isn't it any door will fail after a certain amount of time

01:43:49 will fail after a certain amount of time or may fail after a certain amount of time but here it may have been very significant for those that were trapped in in flats that there was smoke spread coming through the doors in terms of

01:44:00 coming through the doors in terms of their ability to survive in those flats and then or potentially be rescued is that your age that's correct it's fair to mention there are some instances of doors apparently performing slightly

01:44:11 doors apparently performing slightly better on the night so take Antonia Runkle Otto who's there until 6:00 in the morning potentially Natasha Alcock another example some examples of it performing more

01:44:22 examples of it performing more effectively what what do you think is the potential significance of that in terms of the overall pattern that we're seeing was it too early to say well I think it is actually very difficult you

01:44:34 think it is actually very difficult you know to attend because clearly we in theory should be operating under the assumption that the doors are all my genius and therefore every flat should

01:44:45 genius and therefore every flat should have been designed in fairly similar manner and it should have been maintained and kept and that generally is not the case and and what we get is significant variance in the level of

01:44:58 significant variance in the level of maintenance in the care that these things are given even the way in which they are designed or or built so so variations are expected both in the use

01:45:09 variations are expected both in the use and they and in the construction so I believe that that's that is probably one of the main reasons why you find some differences in what people observe I'll

01:45:25 differences in what people observe I'll keep an egress you also have discussed and you've already mentioned it a number of times the effect of occupant egress on complementation does it remain your view that that would have a negligible

01:45:36 view that that would have a negligible effect unless the doors are not closed behind people when they leave is that right yes so you think just the the opening and closing of a flat door onto a lobby is unlikely to affect the

01:45:50 a lobby is unlikely to affect the overall pattern of smoke spread significantly valiums yes I think that if you if you think of the process of egress if people are evacuating that basically means that this is that the smoke that they are

01:46:02 this is that the smoke that they are exposed to within their apartment is still not the type of smoke that will threaten their lives so whatever is coming into the lobby of people evacuating their own apartments will be

01:46:15 very far from tenability and so I would not expect that that would have a significant impact on the lobby itself now if the door is left open then there

01:46:28 now if the door is left open then there will be a significant delay under which conditions can actually change and then you can actually have a different kind of smoke entering the lobby area yeah so

01:46:39 of smoke entering the lobby area yeah so if those door closers are ineffective or not installed is it your position that the contribution to the spread of smoke is going to be greater much more significant yes and is it also going to

01:46:51 significant yes and is it also going to be significant in terms of the oxygen potentially getting into those flats and the fires you have in those flats yes although I will believe that that in a scenario like this one will be a secondary effect

01:47:02 secondary effect I mean clearly when you have a post flashover fire is is considered to be an under ventilated fire so the more oxygen you put in the more intense it burns but

01:47:13 you put in the more intense it burns but in this particular case given that the fires coming from the outside and you have window breakage and so forth probably the impact will be secondary but yes of course it will had some more air into the part well imagine you are

01:47:25 air into the part well imagine you are fleeing a flat 6 and you've seen your kitchen window on fire potentially your kitchen starting to burn you flee out the door and the closer doesn't shut behind you is that that compartment

01:47:38 behind you is that that compartment likely to come to flashover quicker because you've left the door open oh no no actually it will be the opposite I'm not yes because you're gonna be losing smoke so effectively that will delay the

01:47:51 smoke so effectively that will delay the transition to flashover but there will be an easy transmission of smoke from the flat into the lobby and then once the flood transitions to flashover you have a

01:48:02 have a better ventilation on the flat so the fire will be more intense so both dr. Lane and professor Bisbee have emphasized a significant body of

01:48:14 emphasized a significant body of evidence which suggests that many of the door closes were not effective on the night and professor Bisbee has emphasized a number of flat sixes on the space where this may have been the case

01:48:25 space where this may have been the case have you formed any views at this stage as to how significant you think that might have been in terms of the overall compromise of the lobby's wid snake I mean that is a very difficult question

01:48:37 mean that is a very difficult question to answer because I think obviously if the door doesn't close the effect on compromising the lobby's is very very significant now the m4 unfortunately

01:48:48 significant now the m4 unfortunately self closing mechanisms are not necessarily the most reliable you know of systems just to give you a very simple example the door between the witness room and the coffee room

01:48:59 witness room and the coffee room somebody has removed the self closing mechanism and and this is done regularly and because effectively it creates a

01:49:11 and because effectively it creates a self closing mechanisms tend to disturb our usual way of using living environments so I think having an enormous reliance of self closing mechanisms is probably asking too much

01:49:25 mechanisms is probably asking too much of a system that is a very secondary means of protection in principle if the fire would have not emerged from the compartment of origin it would have

01:49:37 compartment of origin it would have remained compartmentalized then all this secondary elements are just extra redundancies that we're putting in place that are not truly significant to the fire safety strategy now the problem is

01:49:49 fire safety strategy now the problem is when everything else fails then these are the only things that can pick up the pieces and then they acquire a significance of they were never intended to have

01:50:00 I mean are there other options too door closes ah no no we should have them and under the expectation that there will be a very significant rate of failure

01:50:12 a very significant rate of failure that's why it becomes you know sort of an ultimate redundancy and not a primary means of protection the door is the the one as it were weak link in the whole

01:50:23 one as it were weak link in the whole competition design isn't it because in a building like rain falls again Italian rest is concrete yes so I would have

01:50:34 rest is concrete yes so I would have thought that the trying to have effective self closes on the doors was pretty much critical to the concept of compartment ocean it it is you know in a

01:50:46 compartment ocean it it is you know in a certain sense okay so if of Lee if the compartment fails okay and people evacuate and leave the door you would have compromised the lobby but then you

01:50:58 have compromised the lobby but then you have from the lobby to the door of the stair you have another fire resistant door so you you're putting multiple layers of protection to try to make sure that one picks it up now if if the fire

01:51:11 that one picks it up now if if the fire remains within within the unit and it compromises the lobby then you have a new smoke extraction system that will try to clear that out but the people that are staying in the other flats will

01:51:22 that are staying in the other flats will be protected by their own compartmentalization so in principle yes you're putting all this elements and because we recognize that the door is the weakest link in compartmentalization this is what we put

01:51:33 compartmentalization this is what we put the self closing mechanisms but we have to also recognize that these are not systems are generally maintained at a level that we have an absolute guarantee that they're going to work yes follow

01:51:45 that they're going to work yes follow them actually the stair door is of really fundamental critical importance absolutely in terms of protecting your egress room yes and you would imagine that them

01:51:57 yes and you would imagine that them being the stair door a public space of the building the maintenance level of those self closing mechanisms will be of a much higher quality than what you would expect could happen in oh yeah and because it's a firefighting

01:52:10 oh yeah and because it's a firefighting shaft it has to have a higher rate of that we're gonna explore all of that with with dr. Lane yep another topic is firefighter activity you've highlighted this

01:52:21 activity you've highlighted this including running hoses through stairwell stairwell doors or breaking down flat doors for example the breaking down of the the flat 16 door and in

01:52:34 down of the the flat 16 door and in terms of the significance of this what you say is that it this is arguably less significant if you're just fighting a one fire floor it's kind of what you just said yes but that becomes really problematic once you've got multiple

01:52:45 problematic once you've got multiple fire floors on fire if you have doors held open particularly to the stairs is that correct absolutely because effectively if the fire remains was in the compartment the stay-put strategy

01:52:57 the compartment the stay-put strategy stands and therefore people are not required to evacuate the building so the stair in a way will not be used until the firefighters establish a team

01:53:08 until the firefighters establish a team that does their can be used again and so during their operations the possibility of filling the stair with smoke is real and and it is part of the concept of a

01:53:20 and and it is part of the concept of a stateful strategy so so in that sense it is not as a very significant problem but if you have multiple floor fires then you have to evacuate people while they are operating there's a convergence of

01:53:31 are operating there's a convergence of timescales and and then their operations become in conflict you know with the actions of the occupants of the building so I think you also make this point it is it prevents a change of strategy from

01:53:43 is it prevents a change of strategy from stay-put to evacuation if you've already compromised your evacuation route exactly makes it much more difficult to take the decision of moving from one strategy to another and have you formed

01:53:55 strategy to another and have you formed any preliminary piece about how significant that the holding open of doors or the battering down of doors might have been in explaining the early egress of smoke onto lobbies or compromise of egress routes then from

01:54:09 compromise of egress routes then from the preliminary information that we have it seems that the evolution of the issues of the stairs and in some cases a lobbyist is very dynamic so I think that this opening and closing of doors and so

01:54:20 this opening and closing of doors and so forth seems to be a very significant aspect of the problem missing or damaged fire stopping here you've relied on the assessment by dr. Lane and does it

01:54:32 assessment by dr. Lane and does it remain of your view that there are only minor weaknesses in for example the staring closure in terms of compartment ation have you seen anything that would suggest that there were any penetrations

01:54:43 suggest that there were any penetrations that were causing issue with complementation I think that's correct yes

01:54:52 Ingres as a result of this smoke control system and the vents onto the lobbies have you had a chance to consider appendix J of dr. lanes yes report and her concerns based on

01:55:05 yes report and her concerns based on some of the factual evidence that we've heard about the possible passage of smoke via the vents the dampers in the smoke control system between lobbies and do you have any views about the

01:55:17 do you have any views about the potential significance of that at this stage or is that something you'd like to do further work on well as dr. Elena indicates at the beginning of appendix J the system was designed for a one floor

01:55:30 the system was designed for a one floor fart so while there's a number of non-compliances that she highlights in the appendix it is clear to me that a system that was designed for a one for

01:55:41 system that was designed for a one for fire in particular we were talking about vertical shafts fans and dampers it is very clear that his performance is completely unreliable so whether it was properly design or improperly designed I

01:55:54 properly design or improperly designed I would have absolutely no we would not surprise me at all that the system didn't perform at all but does it concern you that we have factual evidence where people are reporting

01:56:06 evidence where people are reporting smoke coming through those vents and straight into the lobbies well the evidence is that the system is performing poorly because it's bringing smoke into the lobbies now that could

01:56:18 smoke into the lobbies now that could have been because of the non-compliances but it could also have been because the system was designed to take basically deal with one floor one of the things that is not clear yet from Appendix A

01:56:32 that is not clear yet from Appendix A and I think it should be explored a bit more in detail was the way in which the dampers were activated because effectively the detection of smoke within a lobby will activate the dampers

01:56:44 within a lobby will activate the dampers for that specific floor but what was the algorithm not supposed to do if you had smoke in ten different floors so the way in which the system is operating smoke

01:56:55 in which the system is operating smoke management systems are very precise balance of pressures where you effectively have to push this in one direction so that you clear

01:57:07 in one direction so that you clear another space without necessarily altering what is happening in in in in a fire so many times when when you change the equilibrium of the system's smoke

01:57:18 the equilibrium of the system's smoke might end up going in all the wrong directions so I think that there is there is a reason for concern and and and there is a reason to look into the space but I think we have to keep in

01:57:30 space but I think we have to keep in mind that it was a system that was designed for a one floor fire and that is a fundamental weakness of the system not necessarily the non-compliances in

01:57:41 not necessarily the non-compliances in general at this stage before we move to your untenable stage for in general do you have any more developed views about smoke migration in the light of the phase 1 evidence or is that something you want to go away and and look at in

01:57:53 you want to go away and and look at in more detail yeah I think I'd rather not comment any further because I do think that that requires a bit more detail analysis so you'll stage 4 you described

01:58:06 analysis so you'll stage 4 you described as the untenable stage and you say this is from 2:30 a.m. until extinction of the fire and this marks significantly untenable conditions in the fire can you

01:58:19 untenable conditions in the fire can you just be clear what you mean by untenable here and unten abilities is a very complex concept to define because it is partially perception and partially reality an individual that walks into

01:58:34 reality an individual that walks into smoke might encounter conditions will not allow him to survive for her to survive so in principle that is the definition of inten ability so is when

01:58:46 definition of inten ability so is when the concentrations of carbon monoxide of toxics or even visibility are such that it disables the individual and eventually leads you know to its death

01:58:57 eventually leads you know to its death and but there's another concept as an ability which is purely the perception or the individual sometimes the the conditions might not be such that they

01:59:10 conditions might not be such that they threaten the life to the person but the fact that they see then smoke bellowing from some

01:59:15 from some door is sufficient to deter somebody from crossing a stair or crossing the lobby and and they will return back and turn around so that could also be perceived as a condition of tenability

01:59:27 perceived as a condition of tenability so in this particular case I think you know at this stage when I refer to the nobility I refer to both because effectively there is a number of instances where people will see the

01:59:39 instances where people will see the smoke and decide that they couldn't go through without really recognizing that they could have potentially go through and and other people that might have chosen to go through they might have actually managed to get out so there's a

01:59:51 actually managed to get out so there's a little bit of variability in there that then is is highlighted by total person's report afterwards but I think that the that's what I refer to as the nobility

02:00:03 that's what I refer to as the nobility is basically both conditions that are actually harmful to the individual but also concede conditions that the individual perceives as harmful and therefore changes his actions because of them to that and can you explain the

02:00:19 them to that and can you explain the capacity of some residents to succeed in self evacuations and after 3:00 a.m. and when we've got numerous examples of people who were able to get out after

02:00:31 people who were able to get out after 3:00 a.m.

02:00:32 3:00 a.m. down those stairs yep I think I think it's a it's a combination of both is people that actually made a better choice in the sense that despite

02:00:46 choice in the sense that despite perceiving that the conditions were dangerous they probably just simply took the decision of moving through but also there is a component and it's quite clear from the 99 calls

02:00:59 clear from the 99 calls the system is very dynamic so there are moments where effectively the stairs seem to clear up more than other moments so I think they might just simply got the right window so I think it's a

02:01:12 the right window so I think it's a combination of both very difficult to ascertain but I think if we can manage to pinpoint the way in which smoke is migrating then we will be able to at

02:01:23 migrating then we will be able to at least establish which are the conditions that were acceptable which ones were not so that then you know we can ascertain more or less what was the

02:01:34 can ascertain more or less what was the interaction of the people with you know with the smoke so just to be clear you think on the evidence you've seen at the moment that there probably was real variability in the conditions of the

02:01:46 variability in the conditions of the stairs over time yes in this phase yes clearly and and in terms of the the hot spot or hot zone that dr. Lane identified in her report

02:01:58 that dr. Lane identified in her report teen levels thirteen sixteen where we saw for example the stair lights had really completely melted in contrast to other lights further up higher up the

02:02:09 other lights further up higher up the tower where they were still intact she suggested in her most recent report that this may have been due most likely to firefighter activity possibly because of the holding open of doors at or near

02:02:22 the holding open of doors at or near these levels and the migration of very hot smokin gases into the stair at those at that point is that consistent with with your reading of the evidence so far

02:02:35 with your reading of the evidence so far in terms of what it what might explain these is hot zone yes that's perfectly possible and I do think that you know a little bit more detail is necessary in ascertaining the timing of the

02:02:47 ascertaining the timing of the firefighting actions particularly the timing but but I do think that that form of behavior is not conventional behavior in a stair having a hot zone requires

02:03:01 in a stair having a hot zone requires having hot gases entering but at the same time exiting because the heat doesn't carry over it just stops I have after a certain region so so it does

02:03:12 after a certain region so so it does require a quite an unusual pattern of behavior that needs to be really carefully looked at and it could potentially be associated to firefighter activity mmm could it be to do with multiple doors being held open at

02:03:24 multiple doors being held open at different levels and thereby allowing the passage of smoke and then an exiting of the positives me it is more most likely necessary that we'll be multiple doors open at the same time yeah just finally in terms of there

02:03:43 time yeah just finally in terms of there was a refuse sheet door off the lobby's with it with a refuge sheet down with doors onto it and those refuge sheets is it right that were relatively undamaged

02:03:54 it right that were relatively undamaged yes do you think those could have been some kind of refuge in this farm my attitude towards this type of thing is

02:04:06 attitude towards this type of thing is that if you design a place to be a refuge then that place shall be treated as such in this particular case we designed the stair to be such and the

02:04:18 designed the stair to be such and the stair failed and so there is no guarantee that any of the spaces could have been an appropriate refuge for four people mr. it said that's the end of my

02:04:32 people mr. it said that's the end of my questions that the convention is now that we just pause and have a short break to see if there are any more questions that I need to absorb okay we would normally have five list you want a

02:04:44 would normally have five list you want a bit longer it may be I mean we've got the time we have right we'll have a

02:04:55 the time we have right we'll have a break ten minutes to give the action please

02:05:06 right tempis for them please

02:13:10 I think a few questions still just to press G topics really first the stare doors and then the roof so on the stair

02:13:21 doors and then the roof so on the stair doors I take it you're aware of doctor lanes more detailed investigation into the stair doors and the fact that they may have actually has been as low as 20 minutes integrity fire resistance is

02:13:32 minutes integrity fire resistance is that correct yes do you agree with dr. lane that the stair doors being held open or being jammed open for example by firefighter equipment or other objects

02:13:44 firefighter equipment or other objects appears to be the primary reason for the failure to maintain complementation as between the lobby and the stairs well that will be whatever the reason

02:13:56 well that will be whatever the reason was why they were left open if the doors were open that would have been the primary mechanism by which the stairs would have been compromised as opposed to any issue about the integrity of

02:14:07 to any issue about the integrity of those doors the as I explained for the doors of the flats the temperature at 20 minutes would have been of the order of eight hundred and something degrees so

02:14:18 eight hundred and something degrees so the lobby would have already had to be at about 800 degrees and for the doors to fail so if if the doors were mmm not

02:14:31 to fail so if if the doors were mmm not the best other other capabilities who would have still taken a lot you know to make them fail so I think opening of the doors is clearly a much more viable

02:14:43 doors is clearly a much more viable mechanism do you think any issues about the integrity of those doors are insignificant or do you think that they still have a role

02:14:57 when we're talking about compartment ation and again you know we we've discussed this issue that it is how you gain robustness to the system and the moment the doors are not out there of

02:15:09 moment the doors are not out there of the desired quality clearly you're losing robustness to your system and the problem with having poor quality doors is that their modes or failure not necessarily only because of heat they

02:15:21 necessarily only because of heat they might sometimes not be placed appropriately and so they might introduce leaks there's numerous are the mechanisms by which the doors you know a poor quality door can actually affect

02:15:33 poor quality door can actually affect the performance of the compartment Asian things yeah and just finally one question about the roof based on what you know had people being able to access

02:15:44 you know had people being able to access the roof do you think that could provide have provided a kind of safe space a safe refuge there is no evidence that our Eva equations through the roof or

02:15:57 our Eva equations through the roof or the roof as I said heaven can actually be appropriate I think there's been numerous incidents and there's been many people thinking of

02:16:08 and there's been many people thinking of ways by which you can gain the benefit of being outside but uh but but it is is something that should not be promoted because there is no evidence that the

02:16:21 because there is no evidence that the roof represents a safe space for people my questions I just like to say thank you very much professor I know you have put a huge

02:16:32 professor I know you have put a huge amount of work into your Faison report and I'm sure a huge amount of work is going to go into your phase-two report as well and we are extremely grateful for your time and your commitment to this inquiry thank you thank you yeah

02:16:44 this inquiry thank you thank you yeah and I'd like to endorse that we're really grateful to you for putting your undying expertise at the dispersal of the inquiry you produce a very full and comprehensive report for us already for

02:16:56 comprehensive report for us already for which we're very grateful and now you've explained certain aspects of it today so it's been extremely useful and may I say very interesting thank you thank you very much indeed

02:17:17 so it's um professor Bisbee tomorrow at 10:00 and mr. millet will be taking him right thank you very much well that's it for today we'll break at this point we

02:17:28 for today we'll break at this point we resume tomorrow at 10 o'clock thank you all very much