Expert Evidence - Smoke Control Systems - Monday 6th June 2022 (2/2)

Full transcript

00:00:26 would you ask us delay to come back in please

00:00:37 right yesterday yes thank you oh my god thank you yes mrs grange yes thank you just one short question and then we'll go back to the topic that we were on um

00:00:46 um should any allowance have been made for um

00:00:50 um the the efficiency of the fan to degrade over time

00:00:54 over time is that something that designers ought to factor into their calculations um i'm not a fan specialist to that level so i really

00:01:03 really couldn't answer that but i yeah no sorry i wouldn't know no i understand i mean regular maintenance sorry just to say your maintenance checks i think that set out the british standard maybe your annual checks might pick that

00:01:14 maybe your annual checks might pick that up because you want to check flow rates and stuff like that so we wouldn't necessarily allow for it i would say you'd have to check it every now and then yeah now before we break off we were talking about leakage rates etcetera and you

00:01:26 about leakage rates etcetera and you asked if you could go to figure seven five at page one six six of dr lane supplemental report so that's a blarp two five zero forty three

00:01:37 two five zero forty three page one six six i think this is where she is analyzing her measurements of window openings yeah do you see that i do

00:01:48 yeah do you see that i do there was a point you wanted to make about this you said so it was something that you said you said that once the door once the window area got bigger than the door area it didn't matter yeah could you bring the equation up again

00:01:59 could you bring the equation up again please

00:02:00 please um

00:02:02 um so

00:02:05 was it the equation where we looked at the the little diagram that i said was quite a nice diagram with the green square so that's paid 160.

00:02:15 160. so i think i probably need to explain something that's a little bit counter-intuitive well that'll do that's is it it's either 160 or possibly 161 is the diagram yes yeah yeah so we zoom

00:02:26 is the diagram yes yeah yeah so we zoom in a bit perhaps just underneath or it says at flat yes you can see that equation there yeah

00:02:34 yeah so so if you had so if we if we take what you said to me which is that dr lanes assumed that because the window was bigger than the door it didn't matter yeah so if we have say

00:02:45 say a window that's

00:02:48 five square meters and a door that's four square meters yeah it doesn't matter the window anymore yeah yeah um but if you have the other way around a door that's five square meters in a window that's four square meters it does

00:02:59 window that's four square meters it does matter yes yes well that's not the case so if you look at that equation so you look at your a1 a2 a3 it's a little bit blurry it doesn't matter what order

00:03:10 it doesn't matter what order your restrictions are in right so this might sound a bit weird but if you had for example two doors of exactly the same area but one in series with the other which

00:03:21 but one in series with the other which is what you're looking at here you still get

00:03:24 get restriction in flow you start to take into account the second door right so once the area you're considering gets big enough you can effectively assume it's

00:03:35 you can effectively assume it's infinitely big yeah and then infinite infinity squared one over infinity square drops to zero and then that term stops having an effect i think that's what dr lane is saying yeah but

00:03:46 that's what dr lane is saying yeah but you need to be substantially bigger than the door for that to work right so if we go back to that diagram now yep

00:03:57 sorry the um the one with the with different window drawings yes sorry so if we go to i think it's seven

00:04:06 seven um

00:04:08 um six on page one six nine

00:04:14 one uh no it's the one that's got the little red area is telling us how the window areas were worked out oh sorry that's 166.

00:04:24 okay so we can't see the full width there but you've got a window which consists of the window frame and the glazed units and then next to it which is a sort of diagonal

00:04:35 diagonal shading is an infill panel isn't it yes yeah so in most cases the infill panels i think at grenfell tower survived

00:04:44 survived um

00:04:45 um when you when you when you think about what the building looks like after the fire a lot of those info panels i think are still there well there are different there are old wingfield panel in window infield panels

00:04:57 wingfield panel in window infield panels behind new window info sure okay yeah but there was something that would have stayed there to restrict the flow right okay um so the biggest area you could have had

00:05:06 have had would have been 1.35 square meters but dr lane says the maximum is so big that you don't have to take it into account as a flow restriction so even if i assumed it was twice that

00:05:17 so even if i assumed it was twice that which is roughly the size of the infill panel plus the window area bearing in mind the window panels didn't disappear and the area below the sill was concrete and didn't disappear you'd end up with

00:05:28 and didn't disappear you'd end up with an area of your external vent um to outside roughly twice the size of the door area yes yeah that's still big enough to influence that equation right and in fact you end

00:05:40 that equation right and in fact you end up with something like about a um i think

00:05:43 think i did a quick calculation in my head and i think it's somewhere between 12 and 15 flow reduction okay which

00:05:50 which when we come back to that diagram you brought up just now which is dr lane's little yeah bar chart i think dr lane calculated that with her maximum area yes which is bigger than the biggest window area which means it's

00:06:03 the biggest window area which means it's including failure of an area that didn't fail in the fire um

00:06:09 um i think she got to a velocity of 1.9 metres on level four like 1.9 meters per second

00:06:15 second so it is quite significant that if you had that bigger by 12 or 15 because it would have pushed it back over the two meters per second that dr lane is critical of i see okay thank you for that well we can we can sorry there's a lot of mass i apologize to this i can

00:06:27 lot of mass i apologize to this i can put that to her tomorrow that's fine um so let's go to figure seven seven of dr lane's supplementary report 173

00:06:39 and what she's done we were just on this before we broke so what she's done in this figure um is to indicate how sensitively sensitive the stair door velocity is to

00:06:50 sensitive the stair door velocity is to the introduction of further leakage pathways

00:06:53 pathways and on the left hand side of this diagram we've got the different floor levels from ground to 23 and then for each floor stair door we've got the air velocity

00:07:05 stair door we've got the air velocity across the stair door in different circumstances in grey that's the open stair door velocity measured during the commissioning process so we can see that in many instances

00:07:16 so we can see that in many instances more than two meters per second was measured during the commissioning yes yes and then in orange we've got the velocity assuming a flat door opening of 1.75 meters squared a kitchen door opening of 1.5 meter squared and a

00:07:28 opening of 1.5 meter squared and a window opening of 0.25 meters squared that's your one of your cases in orange yeah yeah which if i remember rightly when i put those together i had a look at what other modelling had been done in

00:07:39 at what other modelling had been done in this area i think professor torreira used a similar sort of figure for the window breakage when he was looking at the initial fire development in flat 16 it was in the back of one of his reports

00:07:50 it was in the back of one of his reports i can't remember which one sorry i apologize yeah and then in blue the velocity with a smaller flat door opening the same kitchen door opening and a larger window opening of 1.35

00:08:01 and a larger window opening of 1.35 meters squared and then in yellow this is the worst case scenario of dr lane do you see that which is the one we were just discussing flat door opening of one point four meters square kitchen

00:08:12 of one point four meters square kitchen door opening 1.5 meter squared and no window opening assumed yeah so the blue is the maximum window opening size yeah and the yellow presumes there's nothing beyond the kitchen door yeah

00:08:23 nothing beyond the kitchen door yeah okay now

00:08:24 okay now first question should psb have carried out calculations like this um i'm well if you were calculating the system then um you would probably not do this sort

00:08:35 um you would probably not do this sort of calculation you'd probably do a computational model that would do this calculation effectively for you well we've got no evidence that either of those things were done um should one or or other of those have

00:08:46 um should one or or other of those have been done well i think there's there's two things to ask here first of all this diagram's got a big red line for two meters per second on it so it presumes that two meters per second has to be achieved in all these conditions

00:08:58 to be achieved in all these conditions for the system to work well that was psb's performance criteria set out in its technical specification wasn't it it was that it would achieve two meters per second and i think mr marley has said that that was when everything else was

00:09:10 that that was when everything else was closed because they wanted to derive the extract rate from that yes so what i think dr lane's analysis here ignores is that there is also extraction going on

00:09:21 on at the same time and that might produce a lower door velocity requirement so are you saying that

00:09:32 so are you saying that sorry i don't think i understand that okay so

00:09:35 okay so the way these systems work is that they extract some of the smoke yes they induce a flow through the doorway yeah and they dilute the smoke which changes its temperature and it's it's um obscuration as well so

00:09:46 obscuration as well so um

00:09:47 um you don't need necessarily two meters per second at the door

00:09:51 door if you're also extracting some of that smoke you get a combined effect yes i think mr marnie said as long as they were extracting three meters per second at the vent then

00:10:02 then he would be happy with that i think that was the number he used yeah yeah i think that's probably a little bit low and i think they were getting more than that but i i think a slightly bigger number is what i'd normally use but um but yeah as long as you're getting enough

00:10:13 as long as you're getting enough extraction which i think was also mr hanson's point and kept going on about that yes later on in the design but one of the difficulties with that that they never measured that extract rate during

00:10:24 measured that extract rate during commissioning they measured the stair flow rate

00:10:28 flow rate the the line that's that should be the two meters per second yes but if it's no sorry let me finish my question but no readings were taken of the extract rate through the extract fans

00:10:41 the extract fans events themselves yeah but if we go back to discussion we had about leakage pathways if you measure a velocity at the door which is your dominant leakage pathway and you're getting enough flow

00:10:52 pathway and you're getting enough flow through that door to give you the extraction rate that you think you need yeah

00:10:57 yeah then

00:10:58 then you must be getting at least that extraction rate in fact you're probably getting slightly more than that extraction rate because you've got a flow velocity coming through other leakage pathways that you haven't measured

00:11:08 measured so

00:11:09 so if your objective is to get enough extraction rate then just measuring at the door will tend to underestimate the overall extraction rate that you're actually achieving

00:11:19 achieving so it's not illogical to do it that way and it's a very easy thing to measure when you're commissioning particularly in a live building because you don't want to keep knocking on everyone's doors to open their windows and

00:11:30 doors to open their windows and um

00:11:31 um and measure the fly would be very disruptive let me put my question a different way is there any justification for not having performed these calculations given how sensitive the stair door airflow is to an individual flat

00:11:43 door airflow is to an individual flat door being open do you know what i i don't think in all my life of designing a smoke control system i've actually um well i've not for a very long time if i sat down and

00:11:54 for a very long time if i sat down and done this hand calculation because you would typically do it by computer modeling and a lot of people have done a lot of computer modeling of these types of systems and as i think i explained earlier that's tended to lead to some

00:12:07 earlier that's tended to lead to some people considering that there's enough information out there to say that for a given extract rate that's good enough so um can we break it down in stages we don't have any evidence that hang

00:12:18 don't have any evidence that hang calculations were done we've got no documentation showing that we're done have we no we've got no documentation showing that computer modelling was done have we um not for this particular project no so

00:12:30 um not for this particular project no so are you saying that it came down to the designers experience of designing systems like this and making sure there was enough allowance in the system i think that that appears to be

00:12:41 system i think that that appears to be what mr miley did yes and are you saying that that wasn't a reasonably acceptable situation

00:12:47 situation i'm saying i think it has become an acceptable situation i don't think it's the right way of designing these systems but i appreciate that i am one viewpoint

00:12:59 if you'd come in as an advisor on this design and you'd see no hand calculations and no computer modeling would you have been happy to sign off on psb specification um i've faced exactly

00:13:11 psb specification um i've faced exactly that sort of situation numerous times and no i would either insist that i did the modelling work or that somebody did the modeling work and presented it to me now if we look at the commissioning data

00:13:22 now if we look at the commissioning data this is at rbk403784

00:13:32 this is the sorry

00:13:35 sorry rbk

00:13:37 rbk yes so these are the figures that mr partlow um came up with when he did his commissioning for the levels at grenfell tower and we can see we've got the open door meters per second figure

00:13:49 door meters per second figure in the second column after the floor level and then we've got the low grill low speed low grill high speed high grill low speed high grill high speed now a point that i think you make at

00:14:01 now a point that i think you make at paragraph 74 on page 15 of your latest witness statement is that if you went for for example 51 of the level 4 data 51 being i think dr lane's second

00:14:14 51 being i think dr lane's second scenario and how much the maximum window failure scenario yeah um then that would be 4.2 meters per second down to 2.14 meters per second so

00:14:25 meters per second so you make the point that for level four you'd still get more than two meters per second

00:14:31 second through the stair door yeah and i think that's on that the bar chart diagram you had just now yes yeah now but the point i want to put to you is that's fine for level four but it's not fine for lots of the other

00:14:42 but it's not fine for lots of the other levels is it if you take around 50 off this figure you get for example let's pick level 23 it was measuring an open stair door

00:14:53 it was measuring an open stair door velocity of three meters per second so half of that is 1.5 you don't get your two meters per second so um isn't that cherry-picking level four and saying oh well for level four

00:15:04 four and saying oh well for level four where the fire started it would be okay but ignoring the fact it wouldn't be okay for lots of the other levels okay so um i received dr lane's latest report um

00:15:15 lane's latest report um frankly very late i've done what i can to review that report and i wanted to provide something in advance of appearing here just to help set this out now what i didn't want to do is present the panel

00:15:27 didn't want to do is present the panel with 23

00:15:29 with 23 loads of calculations and further analyses i didn't think that would be very helpful in a witness statement i could certainly go through and

00:15:35 and do those calculations and and i will do but i've also included another calculation within my witness statement that makes the point that two meters per second is not necessarily the right criteria to be using

00:15:46 criteria to be using yes i'll come on to that point in a moment in a minute i think you try and justify a one meter per second flow rate through the door i'll come to that point in a minute but just sticking with these figures it's not a complex calculation

00:15:58 figures it's not a complex calculation to do is it you've picked out level four and you've said that half of 4.2 at level four is 2.14

00:16:06 is 2.14 yeah i've chosen level four not because it's the biggest number because it isn't i've chosen it because that was where the fire was on yes but if the fire had started at level 23 or level 17 or a number of other

00:16:17 23 or level 17 or a number of other levels and we take a 50 figure it would fall well below the two meters per second well presuming of course that everything else that happened to lead to that particular flow path happened then you might end up with a flow velocity

00:16:29 you might end up with a flow velocity through the doorway of less than two meters per second yes yes now let's look at what you say in your latest statement that's lay 703 at page 14.

00:16:44 and i want to look at what you say at paragraph 70 and 71 so you say um in her report dr lame refers to reports produced by colt which relate to the protection of the stairs

00:16:55 relate to the protection of the stairs by a smoke control system similar to the system

00:16:57 system by which i mean they employed extraction from the lobby with inlet via the stair as noted in dr lane's report the

00:17:05 the cult reports were relied upon for smoke control system designs in residential buildings the colt cfd report states that protection to the stair was achieved when the mass flow rate drawn through the door when their smoke

00:17:16 through the door when their smoke control system design was operating was 1.9 kilograms per second which for ambient air through a 1.6 meter square single leaf door opening would equate to a flow velocity of 1 meters per second

00:17:28 a flow velocity of 1 meters per second this matches the velocities shown in the computer modeling images in the report hence

00:17:33 hence either a flow velocity significantly less than two meters per second alone can prevent smoke movement to a stair or a lower flow rate in combination with the other mechanisms extraction and dilution can achieve a

00:17:46 extraction and dilution can achieve a combined effect which results in a lower flow velocity being necessary to protect the stair my experience suggests the latter is the case so

00:17:57 so are you now saying that in fact the key flow velocity across the stair door was one meter per second not two meters per second as shown in psb's design documentation so what i'm saying is what

00:18:09 documentation so what i'm saying is what i've said in my main report which is that there is more to this than simply worrying about the flow velocity that these systems produce the effect they will provide the protection to the staircase through

00:18:20 protection to the staircase through extraction dilution and the flow velocity

00:18:23 velocity okay

00:18:24 okay now

00:18:25 now what i've used there is i thought it might be convenient to use the same reports that dr layne and look at the flow velocities that those reports show and those reports show a flow velocity of one meter per

00:18:36 show a flow velocity of one meter per second or thereabouts through the doorway and that is providing adequate protection to the staircase and those reports have been used to justify residential systems i think for the type of approval for the cult system

00:18:48 the type of approval for the cult system i think that's what dr lane confirms in her report so there are situations four residential buildings using this type of system where one meter per

00:18:59 type of system where one meter per second is considered to be acceptable you say there's more to this than simply the flow velocity through the stair door but that was the only performance

00:19:10 but that was the only performance criterion that was identified by psb and its design documentation wasn't it yes but as i understand it that's because that was what they were testing when they were commissioning and verifying the system

00:19:24 well it wasn't just what they were testing it's what they set out in all the versions of their design documentation from version naught 3 to version 6 including the version provided to

00:19:35 including the version provided to building control it said that the performance criteria would be to achieve a flow through the stair of two meters per second but as dr lane has pointed out they didn't say that was

00:19:46 pointed out they didn't say that was going to be achieved when the flat door was open

00:19:49 was open and as i understand mr miley's evidence that he intended to use that velocity to check that he got adequate extraction yes are you only saying now that one meters per second is acceptable because

00:20:01 meters per second is acceptable because dr lane has shown through her calculations that on many levels the two meters per second would not be met with certain door opening and leakage conditions well i'm responding to dr lane's report which has required me to do some further

00:20:13 which has required me to do some further calculations but the principles that you can have a lower door velocity because you're also extracting smoke are set out in my original report in number of places

00:20:24 of places hasn't dr lane's calculations shown haven't they shown that even if you accept that the sole performance criterion was protection of the stair this system potentially failed to

00:20:36 this system potentially failed to achieve that for foreseeable door opening scenarios no it doesn't because it doesn't consider all the mechanisms that lead to protection of the stair it only considers one of them which is the flow velocity and when you

00:20:48 which is the flow velocity and when you say all the mechanisms you're talking about some extraction of smoke from the lobby which would indirectly protect the stair is that what you're talking so some extraction of smoke which reduces the amount of smoke getting to the staircase there's a

00:21:00 smoke getting to the staircase there's a dilution effect which calls the smoke and reduces the velocity that you need to achieve to stop smoke going into the staircase and there is the opposing flow that's generated

00:21:10 generated i see can i just check that i've understood this i think what you're saying is that if you if you're mr mario or anyone else come to that designing the system

00:21:21 to that designing the system you would design it to criterion to criteria which included two meters a second inflow through the stair door with no other doors open

00:21:33 doors open that that giving you a certain flow rate to to achieve

00:21:39 achieve but you might at the same time be aware that with a flat door open and window open to the outside the flow rate would not be as high as two meters but you would regard that as acceptable

00:21:50 but you would regard that as acceptable i think that's what what you'd have to presume yeah yeah i mean whenever i specify one of these systems that the or systems like this that the number that you actually end up

00:22:01 number that you actually end up specifying to pass on to the the system provider is an extraction rate you will tell them that i would like this extraction rate to be achieved from this space

00:22:11 space and i might make some initial calculations for how big the shafts need to be typically we oversize them and but then

00:22:18 then within my model i might have some more distinct numbers such as a velocity that i'm expecting to achieve through a staircase that's demonstrated that the protection has been provided but the critical number that i would pass on to

00:22:30 critical number that i would pass on to a system a detailed system designer should we call them a supplier is the extraction rate yeah so does it come to this that

00:22:38 this that although one would be designing a system like this to let's say two meters a second in flow across the stair door that does not involve an acceptance

00:22:50 that does not involve an acceptance that two meters a second flow across the stair door is essential to enable the under all circumstances to enable the system to to be effective yeah that's exactly my experience yes

00:23:01 yeah that's exactly my experience yes sir

00:23:02 sir thank you

00:23:05 when and beryl menzies gave her evidence about the smoke control system she was clear that a cold smoke test was an important part of the commissioning and acceptance of

00:23:16 of the commissioning and acceptance of the system by building control and she said that it wouldn't be possible to know whether the system worked including for the different door opening conditions which were foreseeable without such a cold smoke test

00:23:28 without such a cold smoke test now i appreciate what you've said about the design process and the fact you might make some assumptions but doesn't that mean that it's extremely important that you then go on and test whether the assumptions that

00:23:39 and test whether the assumptions that you're making about smoke clearance or whatever in the lobby are correct so if you go back sort of 15 20 years ago when people first started putting in

00:23:50 ago when people first started putting in different mechanical ventilation systems compared to the standard guidance yeah a lot of smoke testing was being done and i think some people still do smoke testing today but personally i wouldn't expect to see smoke testing being done

00:24:01 expect to see smoke testing being done when i was witnessing and commissioning a system because i would take velocity readings and extract readings and i would compare them to my analyses or previous analyses that have been carried out

00:24:11 out i don't really know what a cold smoke test would actually tell you in this instance

00:24:17 instance well let's take it back to the grenfell situation we didn't have calculations and analyses for building control to look at and decide whether or not they were happy with the velocity through the stairs or the extract rate etc

00:24:29 stairs or the extract rate etc so in the absence of such calculations do you agree with miss menzies that it was very important to be carrying out something like a cold smoke test so you could see what the effects were albeit

00:24:41 could see what the effects were albeit in much more limited situations i think if i wanted to convince someone that my system was was absolutely marvelous and was was brilliant at doing what it wanted to do i'd do a cold smoke test because it really underplays the

00:24:53 test because it really underplays the conditions the system's exposed to it's much tougher just to look at the velocities because yeah the velocities are based back on previous analyses and assume hot smoke and and fire so i

00:25:04 smoke and and fire so i honestly i don't think a cold smoke test is critical at all to these sorts of systems

00:25:10 systems so the answer is no you don't agree with no no

00:25:13 no no i've worked with beryl menzies before we've done coal smoke testing together on a project we were looking primarily a dilution effect in that case and we were looking to see how quickly a space cleared of smoke and in that case it can

00:25:24 cleared of smoke and in that case it can be quite useful and quite interesting because you're not modeling something that's dissimilar to the real smoke condition but if you're looking to model or to test and compare against hot smoke emerging from a

00:25:36 against hot smoke emerging from a doorway into a lobby and stopping it going into a staircase a cold smoke test doesn't really that it's not equivalent to that

00:25:43 to that i appreciate it not it's not equivalent but would it not be an important thing to do in the absence of calculations um well no because it's not a relevant test

00:25:54 test i don't think would you agree that a failure to carry out that cold smoke test was compounded by the failure to measure air flow velocity at the dampers themselves um i think

00:26:06 um i think measuring the airflow velocity at the dampers um well the f level c dampers was measured wasn't it you've got that that chart has the airflow velocities at the grills

00:26:18 i think it's measuring the difference between the pressure on one side and the other side no i think it's a velocity measure it's a velocity measurement i think so right okay

00:26:27 so it was measured can you check we'll just check mr marnie's evidence on whether or not yeah we could bring up the table that we had just now that will tell us

00:26:38 tell us um

00:26:39 um yeah it's rbk403784 i think i commented on in my report as well because it's not clear i think uh granville partly was was quite clear

00:26:50 uh granville partly was was quite clear when he did the door velocities and he used an averaging method and took quite an accurate measure of the door velocity but he was less clear about the measurements at the grill velocities at each individual damper

00:27:01 each individual damper which means they're probably not as accurate i suspect as the door velocity measurement but they give you if if you if you measure each one of them but not in quite the right way you still get the balance across them aspect right

00:27:13 get the balance across them aspect right if we look at your report page 278 sorry we've got the um figures on the screen did you want to say anything about them no no i just want to check because my unders my recollection was that these are

00:27:24 recollection was that these are velocities and they are this local speed it's the air velocity can we just look at what you say at page 278 paragraph 4 9 4 2 please of your report

00:27:38 um you say as the system used an atypical arrangement of fans and the damper locations were a legacy of the existing systems design a sensible additional check would have been to measure

00:27:49 check would have been to measure airflow's velocity at the dampers to check that airflow was occurring as intended i think that's one of the things i was thinking of about not having been done what are you referring to there about the sensible additional

00:28:01 to there about the sensible additional check which well i think that measuring the airflow at each of the dampers is a sensible additional check right yeah so not just one airflow measurement at each of the dampers each of the vents

00:28:12 at each of the dampers each of the vents i think what i'm explaining there is that if you're only interested in achieving the extract rate or that's what you're really interested in you only really need to measure the flow through the door because like i said earlier that's likely to underestimate the actual total

00:28:25 likely to underestimate the actual total extract rate that you're achieving so that's a good thing but it's sensible to measure the airflow at the dampers as well um because that tells you um whether the air is going where we're expected to go and that's interested

00:28:36 expected to go and that's interested yeah and just because that would be multiple um measurements at each vent would it if you wanted an accurate measure yeah you have to it's quite difficult to measure um accurately airflow on a relatively

00:28:48 um accurately airflow on a relatively small vent um because of the again i think i explained this in my report there's challenges associated with measuring airflows but again provided you're consistent with

00:28:59 again provided you're consistent with your measuring method at least it tells you what effectively the ratio of of air flow is into the different types of vents right and it doesn't look like that was done does it it doesn't look like airflow at each of the dampers was

00:29:10 like airflow at each of the dampers was measured well that's what the data in the table was that's a measurement to each of the dampers

00:29:16 dampers i see i thought you i thought you were making clear that the vent as a whole was difficult to get a measurement and you needed to get more individual measurements with no no no i don't mean that right okay now dr lane has also

00:29:27 that right okay now dr lane has also expressed some concern that the system as designed by psb might have the effect of drawing smoke from the fire flat into the lobby

00:29:36 the lobby and making conditions for the residents worse in the lobby and in her supplemental report she raises a particular concern that the way the system was designed might have meant that if a flat door was open and the stair door was closed

00:29:49 open and the stair door was closed the system could carry on operating at high level with the fans on high because the pressure difference between the stair and the lobby would have been lost due to the open flat door as

00:30:00 lost due to the open flat door as opposed to the open stair door and that could lead to the phenomenon of smoke being sucked from the flat into the lobby now is that something that you think was potentially enough of a

00:30:11 think was potentially enough of a concern that it ought to have been specifically considered as part of the design so i would say it's a potential scenario but for that scenario to occur you do need your window to have failed you need in this flat configuration you

00:30:23 you need in this flat configuration you need the kitchen door to be open and you would also need the flat door to be open and i think i'm writing saying um whilst we know a lot the flat doors unfortunately failed open

00:30:34 unfortunately failed open i think there was a statement i think it really recently made me mister in dr perce's recent report i think most residents actually closed the kitchen doors behind them particularly those in the the corner flats that evacuated

00:30:45 the the corner flats that evacuated early on um so

00:30:48 so you wouldn't have that flow occurring because you'd have a doorway between or closed door between the fire and the and the extraction system you've also got a situation whereby your internal door to your kitchen tends to open into the

00:30:59 your kitchen tends to open into the kitchen i think they did in the grenfell tower and your front door to your flat opens into the flat so the airflow any airflow you generate is actually going to tend to close those doors

00:31:10 to tend to close those doors so i think what you're saying is that could be a problem but it would depend sorry that would depend on what the door opening conditions might be in the flat itself it's a theoretical scenario but

00:31:21 itself it's a theoretical scenario but it's not one that should occur um so i wouldn't expect a designer to take it into account or even consider it um well that's what take into account me so yeah i wouldn't expect to consider it yeah okay now when mr marney gave all

00:31:34 yeah okay now when mr marney gave all evidence the inquiry he explained that the max fordham proposal for the system which was essentially retaining the original design intent of the system as a push pull one pushing in air from the

00:31:45 a push pull one pushing in air from the south and extracting from the north wouldn't work at grenfell tower and he raised a number of potential problems with that i'm going to summarize he said there'd be excessive pressure drop like he used the analogy of an old quart

00:31:57 like he used the analogy of an old quart into a pint pot he said there could be velocity jets created across the lobby which could push smoke towards the stairs and he says that such a system a push-pull system is much more suitable for a

00:32:08 system is much more suitable for a corridor system where you might get dead ends um and sorry that grenfell you might get dead ends here because of the eye shape

00:32:19 dead ends here because of the eye shape of the lobbies and so push pull is less satisfactory so he gave a number of reasons

00:32:24 reasons why

00:32:25 why he thought a push-pull system as proposed by max fordham wouldn't work do you essentially agree with those concerns or do you think further consideration should have been given to a push-pull system

00:32:37 a push-pull system um i think to get a push-pull system to work you would need bigger extract extraction rates than you would need for the system that was actually put in there i think i explained that in my

00:32:48 there i think i explained that in my report but um yeah i mean we would typically use push-pull systems in long corridor situations you do have to worry about the dead end condition you tend to have

00:32:59 the dead end condition you tend to have to try and get your extraction shafts into those sort of dead-end areas and you have to be very aware of of having a good separation between your shaft and the staircase because you don't want to

00:33:11 because you don't want to um shortcut the the flows that you're achieving etcetera so and i mentioned i think

00:33:16 think one of the paragraphs you showed me earlier talked about the challenges of the building physics with those sorts of systems and the such like so you agree with mr marney do you that push-pull wasn't an adequate solution for grenfell tower well if you could install a

00:33:28 tower well if you could install a push-pull system it might be an adequate system um but i think you would need much bigger extraction rates um so i doubt it would have been an achievable system right now given all the complexities of the design that we've

00:33:40 complexities of the design that we've discussed including that this was a bespoke system do you think that those involved with the refurbishment including x over max fordham and psb should have made sure that a computer

00:33:51 should have made sure that a computer fluid dynamics cfd analysis of the proposed system was carried out my preference i think i've said this about 10 times is yes that sort of analysis should be carried out and did it fall below the standards

00:34:03 and did it fall below the standards reasonably to be expected of those bodies not to ensure that a cfd analysis was carried out again as i said um i wish i could say that it did fall below those standards but unfortunately

00:34:14 below those standards but unfortunately i think that has become the norm

00:34:17 yes something might be the norm but it might still fall below reasonably acceptable standards so you could have a prevalence of poor practice yeah okay so i'll say that thinking

00:34:28 yeah okay so i'll say that thinking about it like that just because it's prevalent doesn't necessarily mean it's acceptable in your view did it fall below reasonable standards not to do a cfd

00:34:39 reasonable standards not to do a cfd analysis here i would say there's a prevalence of poor practice in that area

00:34:46 so i think you're saying yes it did but lots of other people were doing that at the same time yes yeah

00:34:53 yes yeah now you tell us in your report that the psb technical proposal you describe it as light on detail that's paragraph 504 of your report page 161

00:35:06 of your report page 161 and if we go to page 192 power 640

00:35:12 you say that i consider it a deficiency in the technical submissions provided by psb that the specification standard used for their design of the system was not explicitly defined similarly psp did not provide a

00:35:23 similarly psp did not provide a consistent or thorough statement of which standard was applied for each component of the system some of the equipment was stated as needing to meet standards some was not some of the selected components are stated as meeting standards some were not

00:35:36 meeting standards some were not um now would you have signed off on the technical submission prepared by psb for the system at grenfell tower well it's my not my job to sign off anything i'm not building control body but if i was for example a technical

00:35:47 if i was for example a technical reviewer um for a project i would have asked for more detail to be included yeah so can we agree that that technical submission didn't contain the information about the system which you would expect from a reasonably competent

00:35:58 would expect from a reasonably competent designer of such a system i didn't think it did no no

00:36:04 now just in terms of your conclusions if we look at paragraph 22 of your report on page 17 this is your conclusions about the design of the system

00:36:14 system you say at paragraph 22 that there were significant constraints at the tower and then the last three lines you say consequently i consider that the system which focused on protecting the stair by using both shafts for mechanical

00:36:26 using both shafts for mechanical extraction was the most appropriate design response does that remain your evidence

00:36:32 evidence i've not seen anything to change that no yeah

00:36:35 yeah and you say at paragraph 23 i've not been able to identify any appropriate smoke control system designed capable of installation within the constraints of the tower which could have explicitly addressed both the lobbies and the stair

00:36:46 addressed both the lobbies and the stair maintaining tenable conditions in both at the same time again does that remain your evidence yes it does thank you now dampers and compartmentation i want

00:36:57 now dampers and compartmentation i want to turn to that topic now and i want to start by exploring some areas of agreement between you and dr lane in relation to protected shafts and dampers

00:37:07 dampers if we can go to her supplemental report at page 11 so that's blarp 2 5 0 43 page 11.

00:37:21 if we look at 1.3.27 on that towards the bottom of that page she says mr lay agrees that the smoke shafts and duct work of the smoke ventilation system in grenfell tower

00:37:32 ventilation system in grenfell tower were required to be a protected shaft as described in adb 2013. that's correct yes um yeah i think so yeah and does it follow from this that the extent to which the dampers prevent

00:37:44 extent to which the dampers prevent excessive smoke leakage from the shafts into the lobbies as an is an important compliance and life safety matter um

00:37:54 um yeah

00:37:56 yeah do you also agree that the leakage potential of the system's dampers is important because the damper leakage will reduce the effectiveness of the extract fan

00:38:07 extract fan not necessarily no because if you put all the dampers in and you've run the fan and you've got the extraction rates you want then you must have overcome any leakage that was there

00:38:19 was there i see so provided you've measured the extract and you you're getting the numbers you want if you were sorry if you were designing the system on a piece of paper and handing it to someone and you were

00:38:30 handing it to someone and you were reliant upon that design absolutely working yes you would have to take that leakage into account if however you're specifying a fan and you've allowed sufficient capacity within that fan to overcome what you

00:38:41 within that fan to overcome what you think is likely to be the expected leakage rate then um on your head be it and you better hope it works and that you get the required extraction rates um so you know it it's a difference there

00:38:53 so you know it it's a difference there between someone who's sort of designing in an office and someone who perhaps has a bit more of a feel for what happens on site right yes now if we go to page 12 within dr lane's supplemental report

00:39:05 within dr lane's supplemental report and look at paragraph 1.3.34

00:39:09 she says there we agree there is no evidence that the gilbert series 54 and then in quotation marks smoke evacuation dampers were tested or classified as smoke controlled dampers

00:39:22 classified as smoke controlled dampers in accordance with bsen12101 part 8 bsen 13501 part 4 and bsen 1366 part 10. nor were they tested in full

00:39:34 part 10. nor were they tested in full accordance with the test standard for fire

00:39:36 fire fire and smoke dampers according to bsen part two

00:39:43 part two um

00:39:44 um and that's an area of agreement between you yes um yeah it's it's factually correct yeah yeah and if we look below that at 1.3.35 she says um

00:39:55 she says um we agreed that the gilbert series 54 dampers installed had a leakage rate exceeding the smoke leakage that's the s limit

00:40:04 limit of 200 cubic meters per second per meter square per hour for an es rated fire and smoke damper between norton 9 and after 54 minutes do you see that yes

00:40:18 54 minutes do you see that yes now in this context the designation e and the designation s have particular meanings e means integrity doesn't it it does yeah and s

00:40:29 integrity doesn't it it does yeah and s means smoke leakage is that right correct yeah and you have to have both of those things specified for things like dampers because

00:40:37 because something which maintains integrity like a fire door or for example a fire collar around a pipe or something they can leak smoke

00:40:45 smoke and is it right that you disagree with dr lane's conclusion that the dampers installed at grenfell tower were required to have both an e and an s certification

00:40:56 certification yes i do disagree with that and specifically it's your view that they didn't need to meet the s smoke leakage requirement is that right uh that's correct yes yeah

00:41:07 that's correct yes yeah now just to explore this e and s issue further i want to ask you some questions about different damper types and where those classification requirements come from

00:41:16 from and what they're meant to show in practice now first if we look at approved document b again clg five zeros two two four at page one four four

00:41:27 two two four at page one four four this is within the appendix e definition section of adb it defines a fire damper it's in the top right hand column

00:41:38 column and can you see it says a fire damper is a mechanical or intumescent device within a duct or ventilation opening which is operated automatically and is designed to prevent the passage of fire which is and which is capable of

00:41:50 which is and which is capable of achieving an integrity e classification and or an es classification do you see that yes

00:42:00 and then if we go to dr lane's um main smoke control report at blarp25035

00:42:11 at page 86.

00:42:16 at paragraph 4.8.21 at the bottom of that page we can see that she's got the definition there of a fire damper immediately above and she says this

00:42:27 says this uh in that last paragraph the purpose of a fire damper is to close and remain closed during a fire preventing the passage of fire it is required by adb

00:42:38 passage of fire it is required by adb 2013 to protect openings created by ventilation systems in internal compartmentation do you see that i see that although i disagree with the word required in that paragraph

00:42:51 um okay so subject to uh it being guidance in adb albeit statutory guidance which i don't think that makes any difference sorry but yeah it's still a recommendation but can we agree that the

00:43:03 recommendation but can we agree that the purpose of a fire damper is to close and remain closed during a fire yes

00:43:09 yes so

00:43:10 so fire dampers are not intended to open and close repeatedly as part of a system's normal operation are they um no

00:43:20 then let's go to paragraph 10.15 of adb so back to adb clg50224 at page 88.

00:43:31 and if we look at 10

00:43:38 15 there we have um it's it sets out um something about fire dampers and it says 10.15 fire dampers should be tested to

00:43:49 10.15 fire dampers should be tested to bsen 1366 part 2 1999 and be classified to bsen 13501 part 3 2005. they should have an e classification equal to or greater than

00:44:02 classification equal to or greater than 60 minutes do you see that yes so that's the approved document b definition of fire dampers again or it's telling you what standards fire dampers have to be tested to yeah i think it's

00:44:14 have to be tested to yeah i think it's referred to from a note or a paragraph further up isn't it yeah and um just to see what these e and es classifications mean in more detail if we go to the classification standard

00:44:25 we go to the classification standard itself

00:44:27 itself this is at bsi 50810

00:44:37 this is um a british standard it's en 13501 part 3 2005 and it's headed fire classification of construction products and building elements

00:44:49 and building elements and then if we go to page 9 within this it explains that 5.1.2 what the integrity means and it says integrity e is the ability

00:45:00 and it says integrity e is the ability of a component of a service installation to present prevent the transmission of fire as a result of the passage of significant quantities of flame or hot gases from the fire to the unexposed

00:45:12 gases from the fire to the unexposed side thereby causing ignition either of the non-fire exposed surface or of any material adjacent to that surface so the e the integrity characteristic is

00:45:23 so the e the integrity characteristic is about the transmission of fire and preventing the ignition of whatever is on the unexposed side of the damper for example either due to hot gases or flames is that right yes that's right yeah

00:45:34 yeah and if we turn on to page 10 of this standard we see information about the s the smoke leakage characteristic for fire and smoke dampers and it says there under 5.1.4 s smoke

00:45:47 and it says there under 5.1.4 s smoke leakage smoke leakage s is the ability of the component to resist the passage of gas gases or smoke at ambient temperature

00:45:58 gases or smoke at ambient temperature and during exposure to the standard temperature time test the leakage rate is corrected to 20 degrees c do you see that i do yeah so can we agree that the smoke leakage

00:46:09 can we agree that the smoke leakage measure the s measure is about limiting although not completely preventing the passage of smoke through the damper is that right um it's about restricting it to certain levels if you go back to the previous

00:46:21 levels if you go back to the previous page you had yep part of the integrity only measure at the bottom there is a leakage rate for dampers that's specified at 360 cubic meters per

00:46:32 that's specified at 360 cubic meters per meter square per hour yes so when you add an s classification it changes that figure it makes that figure tighter it makes it a a less leaky damper but so s rather

00:46:44 a a less leaky damper but so s rather than e is the relevant classification if we're looking at whether smoke leakage is excessive for residents evacuating on the other side of a closed damper no i wouldn't necessarily say that right

00:46:56 no i wouldn't necessarily say that right sure where that's come from that's a big jump well um why isn't smoke leakage the relevant thing we should be looking at as to whether or not the leakage is excessive for residents who are

00:47:08 excessive for residents who are evacuating well i mean so for example we have lots of penetrations through walls that don't have any smoke leakage specification provision so i wouldn't necessarily presume that a specific

00:47:20 necessarily presume that a specific smoke leakage requirement for a damper is something that you would necessarily require

00:47:25 require onto an escape route or something like that right you wouldn't would you well i wouldn't i wouldn't i wouldn't necessarily presume it

00:47:33 it just because of what said in this particular standard i would have to work out whether or not a resistance to smoke coming through the wall is is important i mean

00:47:43 i mean lots of things when you test them um allow smoke to pass through them you'd be quite surprised i think most people are quite surprised that you can pass the integrity test with some yeah you can see the furnace through the holes

00:47:54 can see the furnace through the holes but you can still pass the integrity test

00:47:56 test um and things like compartment walls are really tested to that standard there's no smoke leakage expectation for a compartment wall so you could have this weird situation of having a damper that's resistant to

00:48:08 of having a damper that's resistant to smoke leakage in a wall that's not resistant to smoke leakage and then you have the production of smoke from construction products things like wooden fire doors produce quite a lot of smoke when they heat it

00:48:19 quite a lot of smoke when they heat it up and so does things like certain construction materials as well i see so um is what you're saying that because other elements of a building structure might leak smoke

00:48:30 structure might leak smoke that means that you can effectively say that even though your damper is leading directly onto an escape route it doesn't matter how resistant to smoke it is coming through those dampers

00:48:41 coming through those dampers i would put quite that far but i would say that it's a relevant consideration but you have to put it into the context of what's going on around it as well where do you get that from which piece of guidance says that

00:48:54 well i'm sorry i'm i'm trying to meet the functional requirements the regulations not a particular requirement if there's a if there's a piece of guidance that says you must make all your fire dampers um smoke resistant

00:49:05 smoke resistant um onto an escape route which i'm not aware of

00:49:09 aware of um then i would expect it to also say you should be worried about smoke coming through cracks in your construction as well perhaps i don't know it's it's it doesn't necessarily follow one from the other the question is

00:49:20 the other the question is does a certain amount of smoke get onto that escape route matter from a life safety perspective is it does it represent a an unreasonable risk to health and safety of people in the building

00:49:31 the building and and

00:49:33 and and it would be easier and simpler just to say yes it all has to be smoke sealed but that isn't actually what the guidance says it allows you to have variation

00:49:43 variation well we'll keep going with the guidance of what it says but are you saying it's your practice then with a damper that goes on to an escape route that you wouldn't worry about whether it has the s smoke leakage classification i would i

00:49:54 s smoke leakage classification i would i would it would depend on the exposure application that you're looking at so i would prefer and it's far simpler as an engineer quite frankly to define an es type damper

00:50:05 es type damper that's what i would specify or these days because they've now become prevalent i would specify a smoke control damper but if you

00:50:14 if you didn't have access to those for various reasons and you needed to consider a damper with a lesser specification then i would consider the application that dampers being used in so for example

00:50:25 dampers being used in so for example is there a negative pressure in the shaft that that damper is into in which case that would change the what would be an acceptable performance criteria

00:50:34 criteria okay so we looked at the definition of a fire damper just a straightforward fire damper and it only needed an e classification let's go back to adb 2013 again clg

00:50:45 again clg 50224

00:50:46 50224 and look at page 144 and we've now got the definition of a fire and smoke damper below the fire damper again this is in appendix e the definition section

00:50:59 is in appendix e the definition section and it says here fire and smoke damper is a fire damper which when tested in accordance with bsen 1366 part 1999 meets the e s

00:51:10 meets the e s classification requirements defined in en 13501 that's the standard we were just looking at and achieved the same fire resistance in relation to integrity as the element of

00:51:21 relation to integrity as the element of the building construction through which the duct passes intermediate fire dampers may be tested and then there's another standard so um dr lane has summarized the purpose

00:51:32 so um dr lane has summarized the purpose of this type of damper as to to be to close and remain closed during a fire where air handling ducts pass through fire separating elements protecting an

00:51:43 fire separating elements protecting an escape route now do you agree with that that's one of the applications for that type of damper yeah and do you agree that this second type of damper is also intended to close and

00:51:55 of damper is also intended to close and stay closed as with fire dampers but this time it must also have a lower smoke leakage rate hence the s classification so from a sorry if you're using it in that

00:52:06 sorry if you're using it in that application um and for that purpose from a life safety perspective yeah you expect it just to close and stay closed yeah

00:52:14 yeah now can we agree looking at that description that a fire and smoke damper with an es classification has some direct relevance to the grenfell tower situation because first of all the vertical shafts for the

00:52:26 first of all the vertical shafts for the smoke control system pass through the lobbies

00:52:29 lobbies and second the lobbies are part of an escape route from grenfell tower that residents would need to use in the event of a fire so i'd say an es classified damper is one of the options that you could have used yes

00:52:41 could have used yes but can we also agree that at grenfell tower

00:52:44 tower the dampers weren't limited to closing and remaining closed during a fire because the system was designed to allow a manual override during a fire so that

00:52:55 a manual override during a fire so that you could have it closed during part of the fire but then the fire service would activate

00:53:00 activate on another floor and the damper would open where previously it had been closed can we agree that um

00:53:08 um so

00:53:08 so i think the the manual intervention of smoke control systems is not it's not well set out is it it's not something which sorry i'm going to ask you to answer my question at grenfell tower the dampers were not

00:53:20 at grenfell tower the dampers were not limited to closing and remaining closed during a fire because the system was designed to allow a manual override of the system by the fire service can we agree that

00:53:31 fire service can we agree that to allow a manual override of some kind yes

00:53:34 yes well what do you mean of some kind we know that there were fireman's override switches that they could pop their key into

00:53:41 into and activate the system to operate on a different level so if the fire started on level four the fire service might decide that actually they want uh smoke control on level 11 or level 18

00:53:54 uh smoke control on level 11 or level 18 or level 23 and they could manually

00:53:58 manually operate the system so that the dampers then opened on a different floor that's right isn't it well that's what i was going to go on to explain when when you stop me just now so

00:54:07 so i don't know fully what the intention of the manual override function was of the system and i don't think i've seen it fully documented and critically i don't know whether the

00:54:19 and critically i don't know whether the system was intended to be operated during a fire that spread to enable them to move the smoke control to a different floor

00:54:27 floor or whether it was simply intended that there was a capacity to have some smoke clearance after a fire and they're two completely different exposure conditions my understanding um and this is from

00:54:39 my understanding um and this is from discussions i've had on on numerous projects with numerous firefighters approvers mechanical systems designers and the such like

00:54:47 such like is that

00:54:48 is that these days the control systems control systems used to be really difficult and complex to design these days it's all just a programmable logic controller so you can do pretty much anything you want

00:54:59 you can do pretty much anything you want but actually most of the functionality that's available in the smoke control system isn't of interest to the fire service they like to keep it simple and the fire service don't typically expect to move the floor of operation of the

00:55:11 to move the floor of operation of the system

00:55:12 system um apart from perhaps in a when the fire's put out in a smoke clearance capacity so i think there's there's there's some important differentiation there that i also don't know exactly what the intention or what people

00:55:24 what the intention or what people expected the system to be able to do in that case okay if the intention of those little yellow key boxes on each lobby was for the firemen to be able to override during a fire

00:55:36 override during a fire and move the smoke control to a different level to assist them if that's right

00:55:41 right can we agree that those dampers potentially would need to open again when previously they were closed so not just close and stay closed but close and then open well on the basis the system

00:55:53 then open well on the basis the system was designed to operate when there's only a fire on one floor and in one flat at a time i doubt that was the intention but if that was the intention then it would suggest that somebody was expecting the dampers to open and close

00:56:05 expecting the dampers to open and close under

00:56:06 under fire exposure conditions i see

00:56:08 i see let's go to the classification standard again the 13501 part 3 2005 standard and the table shown on page 16 that's bsi 50810 page 16.

00:56:25 here we've got a table which

00:56:28 which provides some more information about the different performance criteria for fire resisting dampers table two and we can see that for the first classification in the table e the integrity we can see

00:56:40 the integrity we can see the

00:56:43 uh 360

00:56:43 meters cubed per hour per meter squared leakage limit for integrity do you see that yes and then the next row down shows that for es for integrity and smoke

00:56:57 for es for integrity and smoke that the

00:56:58 that the maximum leakage limit is 200 meters cubed per hour per meter squared do you see that yes ambient temperature yes yeah

00:57:08 yes yeah and we can see from the columns um showing the leakage limits at ambient temperature and and during the fire test i think that it's both it's 200 for both

00:57:19 i think that it's both it's 200 for both do you see that leakage limit at ambient temperature is 200 max

00:57:24 200 max and the leakage limit during the fire test it says 200. that's for so that's for an eis

00:57:33 no for es

00:57:36 for es under the max oh sorry for the max one sorry i was looking at the wrong table yes yeah

00:57:41 yes yeah and then if we go to the british standard which is dealing with fire resistance tests which is

00:57:47 which is bsen 1366 part 10 2011. this is at bsi zeros one triple seven

00:58:02 this is fire resistance test for service installations part 10 smoke control dampers if we go to page 12 and look at clause 3.27 and there's a definition here of a smoke

00:58:14 and there's a definition here of a smoke controlled damper and it says smoke control damper device automatically or manually activated which can be open or closed in its operational position to control the flow of smoke and hot gases into from or

00:58:27 of smoke and hot gases into from or within a duct do you see that i do see that although there's a different definition of a smoke control damper in

00:58:34 in bsen13501 part four if i remember rightly

00:58:38 rightly right well we can have a look at that if necessary um let's go to paragraph um to back to dr lane's report now

00:58:48 blarp25035 at page 90.

00:58:58 the reason i mentioned that is because the term smoke control damper it has a plain english meaning that it had for i think a number a long time and then it was put into a standard when the

00:59:09 then it was put into a standard when the standard came along the standards sort of overwrote the plain english meaning but there are still versions within the bfi canon that refer to it as a smoke control damper so pretty much any damper

00:59:20 control damper so pretty much any damper that's involved in a ventilation system could be classed as a smoke control damper it's a terrible piece by 2011 we've got this particular definition within bsen 1366 part 10 2011 haven't we we have yes

00:59:34 1366 part 10 2011 haven't we we have yes yeah yeah

00:59:36 yeah yeah and um

00:59:38 and um paragraph

00:59:40 paragraph 4.8.48 of dr lane's report sorry i think it might be a page earlier

00:59:48 she says the primary functional difference when comparing a smoke control damper with the other two types so that's a fire damper and a fire smoke damper

00:59:56 damper is that a smoke control damper must be capable of opening and closing in the event of a fire now do you agree with that

01:00:03 that looking at the definition as it applies to that 2011 british standard using the definition from um that particular standard yes yeah

01:00:16 and the difference is because this particular type of smoke controlled dampers need to be able to open or close depending on the location of a fire in a building

01:00:26 building yes yeah

01:00:32 and can we agree that a smoke control damper is subject to the same es requirements particularly in respect of maximum permitted smoke leakage as a fire and smoke damper i think i'm writing saying a smoke control damper

01:00:44 writing saying a smoke control damper can have an s classification or not as well

01:00:48 well right now do you agree that the features of smoke control dampers namely one being able to open and close during a fire and two being able to limit the amount of smoke passing through it to a

01:00:59 amount of smoke passing through it to a specified maximum match what the dampers at grenfell tower were meant to do

01:01:06 i can't really say that because i don't know if they were intended to open and close in the manner that a smoke control damper isn't anticipated to be used so a smoke control damper is anticipated to be opened and closed at elevated

01:01:19 to be opened and closed at elevated temperatures whereas if the intention of the opening and closing at grenfell tower was for smoke clearance purposes you wouldn't expect that to be at an elevated temperature so i can't say that that definitely lines up right

01:01:31 that definitely lines up right now do you agree that the dampers specified by psb were gilbert's dampers which were not tested for closing and opening during a fire and didn't have an s smoke leakage

01:01:42 and didn't have an s smoke leakage classification they didn't have a i don't think they were tested for smoke leakage classification formally so they didn't have a formal classification for smoke leakage correct yeah i don't think

01:01:53 smoke leakage correct yeah i don't think they had any formal classification to any standard did they uh no they didn't no they'd been tested to a test standard but they'd modified the standard yeah yes or sorry modified the test procedure yes we're going to come to that in a

01:02:04 yes we're going to come to that in a moment

01:02:05 moment now in terms of the need for the s classification if we come back to the question of whether these s certified dampers were required at grenfell tower let's go back to adb

01:02:16 grenfell tower let's go back to adb at

01:02:17 at clg50224 and i want to look at page 61. um

01:02:23 um so 61 this time and we look at paragraph 5.48

01:02:29 at the top of that page and that says this ducts passing through the enclosure of a protected escape route should be fire resisting

01:02:40 resisting i.e the duct work should be constructed in accordance with method two or method three see paragraph 10.9 below and then there's a note below that it says fire dampers activated only by

01:02:52 says fire dampers activated only by fusible links are not suitable for protecting escape routes however an es classified fire and smoke damper which is activated by a suitable fire

01:03:03 is activated by a suitable fire detection system may be used see paragraph 10.15 do you see that i do see that now can you help us first this reference that there to a feasible link

01:03:14 reference that there to a feasible link what is a fusible link so a fusible link is a

01:03:20 is a typically a sort of a piece of solder or something like that which fails at a given temperature um so it fails once so once it gets hot so at

01:03:29 so at a fire damper activated by a fusible link would typically have some kind of hold open mechanism so it might be a um a pneumatic hold open or a spring loaded hold open and a bit like a uh

01:03:42 hold open and a bit like a uh an old-fashioned sort of game keeper's trap

01:03:44 trap um there's a trigger which allows that to slam shut and the trigger is activated by heat so typically the melting of a of a small linkage so is a fusible link sometimes described

01:03:55 so is a fusible link sometimes described as a thermal link um

01:04:00 um yeah i think that might be this i suspect possibly a thermal link might be a slightly more expansive term because it perhaps might include electrical sensing devices that detect

01:04:11 electrical sensing devices that detect the temperature and then signal it whereas a fusible link is just like a fuse wire it fails definitely once but to be honest i couldn't be 100 sure on that right now just help us with this what's your interpretation of what this

01:04:23 what's your interpretation of what this note part um says about whether an es classified damper should be used if following this guidance to protect an escape route i don't think it says it should be used

01:04:34 i don't think it says it should be used as it may be used so it's offering an es classified fire smoke damper as an option

01:04:40 option for protecting escape routes and what it's saying is definitely not an option is a fire damper with just a fusible link right can we agree then that this guidance

01:04:51 can we agree then that this guidance seems to be silent at best on whether a fire damper without a fusible link is acceptable so do you mean a fire damper that's actuated for example by a um a smoke detector yes um

01:05:03 detector yes um i think it i think you could interpret that paragraph and i think it's a very similar paragraph um around about paragraph 1015 which

01:05:12 which so i think you could interpret that to say that you can just have a fire damper so an e-classified damper with smoke detection

01:05:19 detection and and is that something that you would recommend in in a system which is protecting an escape route that you could just have a fire damper so only protecting integrity not smoke leakage

01:05:32 protecting integrity not smoke leakage so in on on an escape route sorry so in most circumstances um your e and your es rated dampers are quite similar in terms of scale and size

01:05:43 quite similar in terms of scale and size so if i had carp launch i would simply specify an es damper um but i have sorry can i would you be comfortable specifying

01:05:54 would you be comfortable specifying simply a fire damper so i've had to look at exactly that situation recently on some legacy buildings where they only had fire dampers that had been put in that were activated by smoke detection um so we

01:06:07 activated by smoke detection um so we did some analyses and and it was on a ventilation system to work out whether that was acceptable so it may be acceptable in certain circumstances but you have to do your analyses to work out whether that's okay

01:06:19 whether that's okay and would it be acceptable at grenfell tower we know that the lobby escape route was an important escape route for residents to get to the stair how could one logically conclude that

01:06:30 how could one logically conclude that you don't need the s part of the classification the smoke leakage part and that you only need integrity how is that logical so one of the problems with the approved document is it doesn't give us a specific

01:06:43 us a specific specification for dampers that are used on mechanical smoke extract systems in fact it doesn't deal with mechanical smoke extract systems at all really it just references it out to other standards so if i went to um

01:06:57 other standards so if i went to um let's say i went to part 6 which is referenced from the approved document b that says i can use a modified smoke control damper which is not a classified damper and if

01:07:10 which is not a classified damper and if i went somewhere else like bs triple nine one that would say that on a mechanical smoke extract system i could use a damper that had um a different smoke leakage characteristic to an es damper so there must be something

01:07:22 damper so there must be something special about mechanical extract systems that people think enables you to have a different smoke leakage characteristic for the dampers and what what is that so

01:07:33 so i anticipate that the purpose behind that is that um because you're if you're extracting then you're typically putting your shaft into a negative pressure so if you do have any leakage any

01:07:44 if you do have any leakage any additional leakage um your leakage will tend to be towards the shaft and not back out onto another floor plate yes and we'll come to see in a moment whether that was the case or not at grenfell tower

01:07:55 grenfell tower um

01:07:57 but it if es fire smoke dampers or better were not according to this guidance required to be installed on escape routes where would they need to be installed

01:08:09 where would they need to be installed i mean where else would you put your es fire and smoke dampers if you're not on an escape route sorry i don't think the approved document nor the british standards tell us where you should or you shouldn't use something they're saying it's an option that you could use

01:08:21 saying it's an option that you could use in these circumstances so i wouldn't expect to interpret that paragraph to tell me where i have to use an es standard damper it's an option that you could use to overcome the concern which is because an es

01:08:33 concern which is because an es classified damper for example cannot be operated just by a fusible link yes well let's have a look at bs and triple nine one now um we've looked at this before in a different context bsi five zero six two

01:08:46 different context bsi five zero six two one

01:08:49 just to be clear the s damper in that application can't be this by fusible link sorry

01:08:57 um this is fire safety in the design management and use of residential buildings code of practice go to page 117 of this and at the bottom of the page at 39

01:09:08 and at the bottom of the page at 39 there's a as heading hvac systems serving the whole building or interconnecting dwellings and other residential units do you see that i do yeah and it says mechanical hvac system

01:09:20 yeah and it says mechanical hvac system so hvac stands for heating ventilation and air conditioning i think yeah so

01:09:26 so such systems serving the whole building should be designed to prevent the spread of fire and smoke from the room of fire origin throughout the building in particular measures should be taken to ensure that air movement in the system

01:09:37 ensure that air movement in the system prevents incursion of fire and combustion products into protected escape routes or allows lines of fire complementation to be breached and then if we go to the next paragraph

01:09:49 and then if we go to the next paragraph at the top of the next page page 118

01:09:54 there's a heading measures to aid firefighting control should be incorporated incorporated including the following and then d

01:10:02 then d where a ductwork system serves more than one part of a compartmented or fire separated escape route smoke detector operated fire dampers should be provided where the ductwork

01:10:13 should be provided where the ductwork enters each fire separated or smoke separated section of the escape route and then this where a fire damper is used to protect an escape route it should be tested in accordance with bsen

01:10:24 should be tested in accordance with bsen 1366 part 2 and an es classification equal to or greater than 60 minutes in accordance with bsen 13501 part 3.

01:10:35 part 3. do you see that i do see it although when i read it when you read it back to me there i'm quite confused as to why they needed two sentences there i don't know why they didn't just say and it should be tested in accordance with bsen 1366-2

01:10:48 in accordance with bsen 1366-2 and an es classification but why why they said where a fire damper is used to protect an escape route well i'm curious actually why they've done it yeah i can't help you but are we

01:10:59 done it yeah i can't help you but are we sorry can we be clear that it's where it's saying there in that second part where a fire damper is used to protect an escape route which is the case at grenfell tower this piece of guidance is saying it

01:11:10 this piece of guidance is saying it should be tested in accordance with that standard and an es classification equal to or greater than 60 minutes should be achieved yes you're saying that yeah yeah

01:11:21 yes you're saying that yeah yeah now

01:11:22 now with the benefit of this wording in this british standard and thinking back to the wording we looked at 5.48 of adb do you agree that an es classification

01:11:33 do you agree that an es classification ought to have been provided for a damper on an escape route well again i don't think that answers the question for us for a system like grenfell tower because in this particular configuration you'd

01:11:44 in this particular configuration you'd expect an hvac system to shut down and not be able to create the negative pressure that i think a mechanical system provides there is a separate specific reference to mechanical

01:11:55 specific reference to mechanical ventilation systems in bs triple nine one if i'm if i recall correctly which um gives a different interpretation particularly in the later version so are you saying that because

01:12:07 version so are you saying that because it's a mechanical system and you would expect negative pressure in the in the in the ducts in the vents that

01:12:15 that uh potentially that was a justification for not having es classification dampers that appears to be an interpretation that's been applied both in

01:12:25 both in later versions of this standard and other guidance like the sca guide and i can understand the logic behind that because we have different smoke protection requirements

01:12:37 different smoke protection requirements for the openings into protected shafts depending on the different exposure conditions so i think there's there's definitely scope to be able to to have a different standard um quite why it was felt

01:12:49 standard um quite why it was felt necessary to do that i i can't explain i presume it's to do with testing standards availability of equipment all these sorts of questions yeah but but somebody wrote a standard and it was suitably authorized um that

01:13:03 and it was suitably authorized um that says these things let's assume for the moment that es classification dampers possibly even smoke control dampers themselves but certainly es fire and smoke dampers were available for grenfell tower

01:13:16 available for grenfell tower why would you not specify them for use on an escape route given the importance of the lobby at grenfell tower um i think if they were available um and you could

01:13:26 could overcome all the constraints at grenfell tower then i expect you would do it yeah yeah um i mean one of the things that you you notice i mean there's lots of problems with well there's issues of

01:13:38 issues of you have availability you have different sizes you have questions such as i know dr lane's gone into this and i've mentioned this you have problems with things like actuators and how they interface with your dampers

01:13:50 and how they interface with your dampers but also when you have things like es dampers you have to worry a lot more about the installation of them because it's not just a damper itself that might leak it could leak around the damper so you often see extra things like patches

01:14:02 you often see extra things like patches and such like around the dampers which would be very difficult to achieve at grenfell tower because you'd have to work inside a very small shaft to try and install

01:14:13 and install extra sealant effectively okay so the application so saying it's available doesn't just mean so you can buy one off the shelf you have to be able to fit it yes and maintain it i understand

01:14:24 maintain it i understand um let's look at your report again now lay 701 at page 199 and i want to look at paragraph 664 first

01:14:35 first you say this you say um and we were talking here about the sca guide at the time and this was the sca guide 2012. you say whilst the sca guide includes a general suggestion that dampers should

01:14:46 general suggestion that dampers should be smoke control dampers it does not suggest that they need to be s classified smoke control dampers and provides alternative specification options which differ from the specific requirements for smoke control dampers

01:14:59 requirements for smoke control dampers tested to en 12101 part 8 and en1366 part 10. to satisfy the sca guide specification criteria for dampers used in a smoke control system the design would only

01:15:11 control system the design would only need to meet the least onerous of the possible criteria set out in section 8.2.5 of the sca guide and then over the page in some cases

01:15:22 and then over the page in some cases this may only require the dampers to be fire dampers tested to bs 476 part 20. as noted in the previous paragraph the gilbert series 54 dampers appear to be

01:15:33 gilbert series 54 dampers appear to be capable of meeting the bs 476 part 20 criteria but are not certified as so doing

01:15:41 doing now just to be clear your opinion is that the gilbert's dampers

01:15:46 dampers did not actually meet any of the sca recommendations because they were not tested in accordance with any of the test procedures specified in the sca guide that's right isn't it

01:15:57 guide that's right isn't it um if we're going to treat the wording in the sea guide as prescriptive

01:16:04 it's a little bit tricky because they were tested to a standard 1366 part two but they modified the protocol of that standard so you couldn't be classified under that

01:16:16 couldn't be classified under that standard yes they did measure smoke leakage during that test and they did check for integrity and the the ability to resist spread of fire

01:16:29 the the ability to resist spread of fire it's a bit of a weird one really so there was a test it wasn't fully to the correct standard there is protocols within classification that allows you to still offer a classification under certain circumstances but

01:16:41 certain circumstances but i don't think you could say in the strictness of the wording that it was actually tested to that standard because there was a variation no

01:16:48 no i think that's a long way of saying that you agree

01:16:52 you agree that these dampers were not tested to any of the standards identified in the smoke control association guidance were they correct yeah yeah

01:17:03 yeah yeah i'm sorry sorry i'm sorry that was long-winded but i wanted to to be clear um about the fact that you you test things you sometimes modify those tests because of the application you're going to use something in and

01:17:15 you're going to use something in and there's no point i mean it'd be very easy to test something say i've got a certification i can use it in this application but what if it's a slightly different application the test wasn't applicable to you might meet something that comes from

01:17:27 you might meet something that comes from statutory guidance that's intended for a different building type or a different building situation but it doesn't mean to say that you've actually achieved what you should be achieving so that's

01:17:38 what you should be achieving so that's why after that clarification yes i see let's just have a quick look at the sca guide lfb3059241

01:17:46 and i want to start page 36

01:17:57 so it begins this is automatic opening vent smoke control damper used for ventilation from corridor or lobby into smoke shaft or smoke control duct and it says no formal product standard

01:18:08 and it says no formal product standard exists for the use of these products in this application to ensure the necessary product performance is achieved it is recommended that the aov should be regarded as a smoke control damper and the relevant product standards should be

01:18:20 the relevant product standards should be considered

01:18:23 but then it goes on and if we go over the page

01:18:27 the page at 37

01:18:29 at 37 it says if we pick it up second line down it says there are several applicable smoke control damper standards and these are listed below so those are the some of the smoke control damper standards we've looked at and

01:18:40 damper standards we've looked at and then below that it says this any dumper tested as far resisting tests are made during the standard using the standard time temperature curve supported by an ad hoc operation test at

01:18:51 supported by an ad hoc operation test at elevated temperature using a drive open drive close actuator could also be acceptable and these tan standards are listed below and then right at the bottom it says dampers tested in the closed position to

01:19:03 dampers tested in the closed position to bs 476 part 20 could also be suitable

01:19:10 so um

01:19:12 um can we just look now at adb again

01:19:17 adb again um clg

01:19:19 um clg 50224 page 88.

01:19:24 if we go back to paragraph 10.15 and note 1 in 10.15 we can see says this fire dampers tested using

01:19:37 says this fire dampers tested using ad-hoc procedures based on bs-476 may only be appropriate for fan-off situations in all cases fire dampers should be installed as tested do you see that i do see that yeah now d-fan

01:19:49 that i do see that yeah now d-fan fan-off situations refer to systems not involving a fan operating as part of the system

01:19:55 system um

01:19:56 um my understanding of why that's there is because you could have two situations for the type of ductwork and scenario ventilation ducts etcetera that's being discussed here you can have a situation

01:20:07 discussed here you can have a situation where you are extracting or a situation where you are pressurizing and blowing into a duct in one of those situations you wouldn't want to use a 476 damper because you

01:20:18 want to use a 476 damper because you could be blowing smoke out of a leaky damper

01:20:20 damper whether that would be the same for an extraction solution i could understand why you might somebody might make a case to say actually no it's fine but the adb has gone for a blanket ban on that because in most ventilation systems in

01:20:32 because in most ventilation systems in some cases you're pushing in some cases you're pulling so i suspect that's probably what it's reflecting right can we agree that bs 476 part 20 is a historical test standard from 1987

01:20:43 historical test standard from 1987 relating to testing fire resistance of elements of construction rather than dampers specifically and it was superseded many years ago yes it was yeah and it didn't contain any smoke leakage

01:20:55 and it didn't contain any smoke leakage requirements as opposed to restricting hot gases to prevent ignition yes yes it had effectively just an integrity requirement in this regard so um can you explain how the sca guide has managed to

01:21:07 explain how the sca guide has managed to recommend or permit the use of a damper tested to this very old standard as acceptable for a smoke control damper

01:21:18 as acceptable for a smoke control damper situation well i imagine it's for the same reason the approved document in 2013 had bs476 in it it was a legacy standard that lots of products have been tested to

01:21:30 but it wasn't actually tested fully to that standard was it no it wasn't no no but the the test conditions it was exposed to um if you'd

01:21:41 if you'd um i'll be careful here because i'm not a testing engineer and i've i've witnessed lots of tests i've got some knowledge of this but i think i'm right in saying that if you basically change the wording on the front from um bsen 1366 part 2 and wrote 476 across

01:21:56 um bsen 1366 part 2 and wrote 476 across the top of it you'd basically completed exactly the same test now um

01:22:02 now um i just want to summarize uh what's in dr lane's supplemental report are we going to a new topic um no it's it's linked to this if i could just finish this subtopic i would be really grateful i

01:22:14 subtopic i would be really grateful i know this is a very technical drawing subject

01:22:16 subject i apologize it's terrific isn't it dampers i'm sorry in dr lane's supplemental report page 128 and following what she has done is exhibited a number

01:22:27 what she has done is exhibited a number of emails

01:22:29 of emails that were exchanged around the time that the sca guide was being drafted in 2010 which shows that these alternative options for dampers in a smoke control

01:22:42 options for dampers in a smoke control situation were merely intended as a temporary course of action pending the formal publication of standards for smoke control dampers which then occurred in 2011 with the

01:22:54 which then occurred in 2011 with the publication of bsen 1366 part 10 and in 2011. however these alternative routes were not then removed after the standards publication

01:23:07 standards publication resulting in dr lane's view in a substantial reduction in the performance requirements shown in the sca guide now first of all is it right that the sca guide 2020 has now removed all of

01:23:19 sca guide 2020 has now removed all of those alternative routes recommending only smoke-controlled dampers compliant with

01:23:26 with bsen12101 part 8 2011. i think it did yes

01:23:31 yes do you have a any view did you know that that was the backdrop to the sca guide recommending those alternative options as a stop gap while the the formal british standard

01:23:42 while the the formal british standard was being developed um yeah i mean i i i presume that's the case i've worked on numerous projects with various remote control systems where people have complained they could not get hold of

01:23:53 complained they could not get hold of smoke control dampers which would suit their application typically due to the size of the damper or a particular duct or opening they've got to fit it into and that's right up until

01:24:05 and that's right up until well the last one i can remember was about four or three or four years ago so i know there was definitely a supply problem and there's often a lag between someone that's reducing a standard and then suppliers being able to book tests

01:24:17 then suppliers being able to book tests to be able to test those products and then get them to market and make sure all the maintenance and spare parts are available so you could be facing i imagine from a standard being introduced to

01:24:27 to products being available on the market could be a good 18 months and then dampers come in lots of different sizes so you know but did you know that those alternative provisions in the sca guide were intended as a stop gap a short-term

01:24:38 were intended as a stop gap a short-term stop gap in 2010 pending the publication in 2011 of formal smoke control damper standards i didn't know that specifically no i've only um understood that from the summary of that

01:24:49 that from the summary of that information that dr lane's presented i've not i'll be honest there was thousands of pages of documents dropped in

01:24:55 in tr 245 i think it was i've not had a chance to look at those they only arrived very recently do you consider that in the light of that the sca guide contained appropriate guidance on the

01:25:07 contained appropriate guidance on the standard of design for dampers used on escape routes um i think it included a it included a bare minimum option it's not it's not the standard i would

01:25:19 it's not it's not the standard i would like to use but i can appreciate why they perhaps did it

01:25:23 did it because there's probably no standards before that i think prior to that people were basically just taking it back to being equivalent to a smoke-filled fire door which is one of the options in in a previous version of

01:25:35 the options in in a previous version of the sca guide and they wanted to move it forward and i guess these things have to move forward in steps you you can't go from

01:25:41 from nothing to to the full-on system to the to the full-on damper specification i presume that's why it is but i i don't know the full background too but they're bare minimum standards and those standards weren't met by these dampers

01:25:52 standards weren't met by these dampers were they

01:25:53 were they um

01:25:56 not specifically no no thank you mr i think that's a good moment for our break it is it all right thank you very much well

01:26:04 well it's time we had a break i think uh yesterday and we'll stop there we'll resume please at 24 and uh again please don't talk to anyone about your evidence while you're asked the room all right thank you very much

01:26:25 thank you very much krusty four please

01:45:40 would you ask us delay to come back in please

01:45:53 right mr lay here we go yes onward right yes yes thank you a few more questions on dampers i'm afraid um

01:46:01 um can we go to page 387 of your report um lay 701 page 387 at paragraph one two one seven

01:46:11 one seven here you you say whilst the dampers could not be classified as s-type dampers they did have data on their leakage at a pressure differential of 300 pascals

01:46:22 300 pascals in her report for phase two of the inquiry at figure 6.43 dr lane evaluated the leakage from the gilbert series 4 50 54 dampers and at 6.5.76 concluded that the cumulative leakage of that damper

01:46:34 the cumulative leakage of that damper type would be less than a damper classified as type s which could have a constant leakage of 200 meters cubed per hour per meter squared i also note that it was 74 minutes into

01:46:45 i also note that it was 74 minutes into the test that the damper leakage exceeded 360 meters cubed per hour per meter squared the maximum leakage rate permitted for the basic specification of a smoke control damper from en 13501 part four

01:46:58 control damper from en 13501 part four now

01:46:59 now in other words i think what you're saying is the gilbert's damper leaked at different rates at different points in the test but the averaged leakage rate over the test period was under 200 cubic

01:47:11 over the test period was under 200 cubic meters per hour per square meter is that right yes yeah yeah and

01:47:17 and 200 cubic meters per hour per square meter is the maximum leakage permitted for an s-certified damper at any given point in the test period is that correct uh yeah yeah

01:47:30 that correct uh yeah yeah now can we agree that the maximum smoke leakage requirement for an s-certified damper is not expressed as some kind of cumulative or average number over the test period but is

01:47:42 number over the test period but is about whether at any given point in the test period the 200 cubic meters per hour is exceeded i would say for a classification of type s that's correct yes yes and taking a step back and thinking about a real

01:47:53 step back and thinking about a real world application of this and bearing in mind live safety we're concerned with a damper on a vertical shaft being used for a smoke control system which exit onto an escape route when assessing whether that escape

01:48:06 route when assessing whether that escape route would be safe for a resident to go through during any given minute isn't the instant leakage rate more important than an average rate over a much longer period not necessarily it depends on the

01:48:18 not necessarily it depends on the exposure condition um because you've got um fans running et cetera and and stuff like that as well so i'm not entirely sure the leakage rate is as critical as being suggested but you know

01:48:30 critical as being suggested but you know you you are well i suppose also the fire grows so i don't think i can answer that question it's a bit more complicated than that well what i'm putting to you is that in other words if the damper leaked so much during a particular period of peak

01:48:42 during a particular period of peak leakage that a particular resident can't safely get through the lobby the fact that it may have leaked much less before or after is of scant comfort from the resident do you agree with that um i suppose so yeah although

01:48:55 um i suppose so yeah although a little word of caution about that i'm not entirely 100 sure about the test procedure that they used and whether or not the um the leakage rate that they determined is a function of the test procedure

01:49:08 a function of the test procedure or whether it's a function of the actual damper itself because it was an ad hoc test procedure i don't know whether the the process they used might be responsible for getting a different value because it's quite a it

01:49:19 different value because it's quite a it is a very sudden and sharp drop-off yeah when you look at the graph it is a very sudden change so i do wonder whether it's actually a product of the test procedure perhaps rather than the dampers characteristics okay

01:49:31 than the dampers characteristics okay let's turn to the test methodology behind that cumulative leakage rate for these gilbert's dampers if we go and look at page 197 of your report at paragraph 658

01:49:43 at paragraph 658 and i want to pick it up four lines down you say in this test the damper was in a closed position at the start of the test this is not commensurate with the

01:49:55 this is not commensurate with the procedure set out in the test standard this is not this does not appear to have been a test intended to achieve an s classification as no check on the leakage of the damper

01:50:06 as no check on the leakage of the damper at ambient temperature prior to the fire test was carried out now

01:50:11 now starting the damper from a closed position in the test would affect the reliability of the smoke leakage measured during the test can we agree that it could do yes yeah

01:50:23 can we agree that it could do yes yeah and if we look at dr lane's supplemental report if we go to

01:50:29 blarp25043 at page 139

01:50:37 and we look at the top of the page in figure six four here what she's done is um help as to what the

01:50:46 the relevant test conditions are in the two minute period that the damper is required to change position from open to closed if you're following the test methodology properly

01:50:58 properly and if you look at box b we can see that she's got the text there elevated temperature material effects on damper ability to close tightly the gilbert's tested smoke evacuation

01:51:11 gilbert's tested smoke evacuation damper ventilator was comprised of first of all a frame of 1.5 millimeter galvanized mild steel and damper blades one millimeter galvanized mild steel

01:51:24 one millimeter galvanized mild steel and she explains at temperatures up to 445 degrees c the strength of mars still reduces up to minus 10 percent the stiffness of it

01:51:35 minus 10 percent the stiffness of it reduces up to minus 35 and it expands by 0.5 percent for the

01:51:42 for the 0.91 meter long blades tested by gilbert's this is equivalent to an expansion of minus five millimeters do you see that i think it might be approximately five millimeters um but i

01:51:53 approximately five millimeters um but i can see that yeah but do you agree with those observations about what's likely to happen to the galvanized mild steel in the damper during the time in the test where

01:52:04 during the time in the test where normally it's required to move from open to closed under elevated temperatures so first of all i'm not a metallogist so i can't tell you if those numbers are right and

01:52:14 right and but

01:52:15 but you know dampers are intended to um well sometimes i guess some cases they might be more leaky ambient some cases there might be less leaky ambient depends on the damper has been designed

01:52:26 depends on the damper has been designed but certainly a damper that's made of steel i would expect the damper manufacturer to be aware of the fact that

01:52:32 that it will heat up and that could change the

01:52:36 the interaction of the different blades but exactly what that means for a particular damper it could go either way i think well can we agree that any distorting of the damper blades due to

01:52:47 distorting of the damper blades due to increased temperatures before the pressure of the system is then applied to the blades is likely to weaken their resistance and make it more likely to leak smoke well i don't think the strength reduction is particularly

01:52:59 strength reduction is particularly relevant here i i honestly don't think i couldn't answer that there's so much complex

01:53:05 complex um

01:53:08 factors and features happening there you know i'd expect the manufacturers designed it to take that sort of thing into account um but i don't think you can do one number and say yep that would definitely

01:53:19 number and say yep that would definitely be okay or not okay when i've watched a lot of fire resistance tests and one of the hardest things to do is to predict what's going to happen with metal elements

01:53:27 elements in a fire resistance test you often think that more robust things will sail through a fire resistance test but actually

01:53:34 actually because they're fixed and they can strain all the forces they buckle and they and they fail but dampers are typically designed with that sort of thing in mind so i wouldn't i well i'm not a sufficient

01:53:46 i wouldn't i well i'm not a sufficient expert in fire resistance testing or metallurgy to make a claim that that has an effect yes but one of the problems is we don't know do we because the gilbert's damper was uh started in the

01:53:57 gilbert's damper was uh started in the closed position so it never underwent this bit of the test did it i mean it'd be more relevant if we had a figure for its leakage ambient that's the probably more interesting number that would be useful to have i just want to read out to you what mr

01:54:09 i just want to read out to you what mr jones of gilbert said when he gave all evidence for the transcript this is day 157 page 73 lines 17-23 when asked about the impact of starting from the closed rather than the open position he said it

01:54:22 rather than the open position he said it would have been more onerous to start it from the open position because of expansion of materials if the damper was open for a period of time then what would happen is the damper blade could swell the frame could swell etc and then

01:54:34 swell the frame could swell etc and then we'd have to watch out for more adjustments if you will of the damper product itself so that that was the evidence of um mr jones of gilbert's that that suggests

01:54:45 mr jones of gilbert's that that suggests doesn't it that actually the leakage is likely to be more if these dampers undergo the test procedure properly as it was intended to rather than starting from the closed position i i wouldn't

01:54:57 from the closed position i i wouldn't like to infer exactly how the leakage would change it could mean that the mechanisms might jam or something like that that may be what he was referring to but i honestly think it would be a mistake without

01:55:08 think it would be a mistake without doing a proper analysis and maybe having one tested to draw that sort of inference because it is a very complicated matter there's lots of little bits of metal here or moving in different ways and i think it would be

01:55:19 different ways and i think it would be an error to to infer that but mr i mean mr mr joseph and gilbert it's his dampers he's seen them tested maybe he knows that for a fact i don't know let's look at another aspect of

01:55:30 let's look at another aspect of determining the damper's likely performance namely operational reliability and durability now dr lane has explained in her report that the method for testing smoke control dampers is different to that

01:55:41 control dampers is different to that from fire dampers and fire and smoke dampers

01:55:44 dampers and the key differences are that the number of open and closed cycles either durability of operational reliability requires 10 200 cycles for a smoke control damper

01:55:56 200 cycles for a smoke control damper prior to fire testing versus just 50 open closed cycles for fire dampers and fire and smoke dampers and as we've seen the testing um

01:56:07 and as we've seen the testing um of the ability to the dampers to change from open to the closed position and vice versa is tested at elevated temperatures in the tests now as for these open closed cycles

01:56:18 now as for these open closed cycles requirement since the dampers were part of an environmental ventilation system at grenfell tower can we agree that they were reasonably expected to open and close potentially many times in a week

01:56:30 close potentially many times in a week yes

01:56:31 yes and can we agree that being tested for over 10 000 cycles smoke-controlled dampers are therefore shown to be effective after a much longer operational lifetime and as part of a multi-component system

01:56:42 multi-component system um i don't know if it's tested for a longer operational lifetime and i don't know whether they there's a suggestion of perhaps changing the service interval or the inspection interval because of that presumed more resilient

01:56:56 that presumed more resilient but i'm not sure it necessarily tells you anything if you're regularly inspecting and maintaining your dampers i'm not sure it matters that much

01:57:06 so you don't think it matters that much to test them for over ten thousand opening closed cycles as per the smoke control i'm not an expert on damper testing to that level of that

01:57:17 damper testing to that level of that degree to be able to say why they put that into the standard there must be a reason why they put it into the standard mustn't there well i presume there's a reason for it but i wouldn't be able to say what that reason is i didn't write the standard i see

01:57:29 the standard i see now um

01:57:30 now um is it your view that the smoke control system designer is entitled to assume when designing the system and specifying the dampers that the shafts will remain depressurized during a fire through the

01:57:41 depressurized during a fire through the correct operation of the fans i think that is a presumption that's made yes right and you also refer to the stack effect present potentially compensating for any

01:57:53 present potentially compensating for any failure of a fan to start and you say that in your report this is paragraph four nine four page one five four that uh that could possibly be as much as seventy percent of the overall system

01:58:04 seventy percent of the overall system effect could be from the stack effect so in fact in some system types yes i think i'm referring there to different system types aren't i um and i'm talking about um

01:58:16 um and i'm talking about um the different uh

01:58:18 uh yeah there's different types of system um but certainly in systems that use shafts and mechanical shafts a significant effect can be from the natural sac effect yes do you agree that these systems are notoriously prone to

01:58:31 these systems are notoriously prone to fault and quite often don't work as expected when when tested i would say that uh mechanical certain types of mechanical smoke

01:58:42 certain types of mechanical smoke control system um have a different reliability to others but i would say that there is a potential for a reliability issue if you don't maintain them properly right should the immediate consequence of fan

01:58:54 should the immediate consequence of fan failure in those circumstances have been specifically considered when selecting the damper so not to assume that the vents would always be depressurized because the fans are working but perhaps

01:59:06 because the fans are working but perhaps to assume that there could be a fan failure for whatever reason and thereby take that into account when selecting the dampers um i think that would be best practice um i don't think

01:59:17 would be best practice um i don't think it's necessarily standard that everybody does that

01:59:21 does that and

01:59:22 and it's very difficult to do that because the computational modeling methods that are used um it's quite tricky to model things like damper leakage it's only really a very recent thing that you've been able to do that so at the time i don't think it's something

01:59:34 at the time i don't think it's something i would have expected someone to do right but i would say things have moved on and we might well do that sort of thing now

01:59:41 thing now even if you're using a smoke control damper dr lane as has pointed out that some of the british standards including bsen12101 part 8 2011 on smoke and heat control systems specifically

01:59:54 control systems specifically warn about the risks of fans not extracting enough air leading to smoke leaking back through excessively through the dampers do you agree that that's a risk that designers ought to be aware of

02:00:07 designers ought to be aware of um i'm not sure it's well i'll be perfectly honest i can't recall whether that's a standard that's relevant to this type of system particularly um the en 12101 covers a wide range of different remote

02:00:18 covers a wide range of different remote control system types um i'd have to look at the standard and read it to give you an honest answer sorry okay um

02:00:25 um let's look at the table of airflow speeds um that were taken by mr partlow and sent to mr hansen of building control as part of the commissioning of the grenfell system this is rbk403784

02:00:49 sorry actually that that's the that's the original version of them let's look at dr lane's annotations on this it's at

02:00:57 it's at page 143 of dr lane's supplemental report

02:01:04 blarp25043 yes so there's that table in the middle of the page and what dr layne has done is put some borders around certain numbers

02:01:15 borders around certain numbers now this is a low grill so it's south grill low speed we can see that the numbers in red indicate a negative airflow i.e the airflow was going from

02:01:26 airflow i.e the airflow was going from the shaft into the lobby and those in orange indicate no airflow in either direction they're naught now

02:01:35 now in her report dr lane notes that the negative airflow was recorded across 12 floors and zero readings on four floors at this low grill when the flam was at low speed

02:01:47 low speed now

02:01:48 now do you agree with that interpretation of the data for the south shaft well it's just a statement of fact that's that's the data it's presented yeah yeah and do you agree that this might mean

02:02:00 and do you agree that this might mean that the system wasn't in fact depressurizing the south shaft and that in fact there was positive pressure going from the shaft back into the lobby well it's in the low speed mode so it's

02:02:11 well it's in the low speed mode so it's not trying to depressurize the shaft in that particular mode but it shouldn't be there shouldn't be a positive pressure from the shaft back in there because the fan is at low speed surely yeah but the

02:02:23 fan is at low speed surely yeah but the fan is also pulling against the stack effect of the building so these commissioning data was taken in what sort of march february march time so the air outside would have been cold and the air inside the building would

02:02:34 and the air inside the building would have been warm so you would have had the maximum stack effect pulling against it which would have been very different compared to something that happens in in june or something like that so

02:02:45 june or something like that so i don't think it's necessarily a particular concern what it doesn't tell me

02:02:50 me is what's happening on other floors when for example so we look at floor 12 when they tested floor 12 in low speed

02:03:01 when they tested floor 12 in low speed mode they saw some flow out of the south shaft in low speed mode that doesn't tell me that there would also be a flow out of the shaft on level 20

02:03:11 20 when you operate the system on level 12 these are individual data for individual flaws

02:03:17 flaws so i think dr lane suggests that you can infer

02:03:21 infer data for the whole building from each of these within her report and i think that's wrong but if it's not overcoming the stack effect for the south shaft even at low speed

02:03:33 speed that's the system not operating as it was intended to is it

02:03:39 um i'm not sure what the system was intended to do at low speed apart from um create a little bit of background ventilation i infer that a little bit of background clearance and to not um make

02:03:51 background clearance and to not um make the doors the pressure at the doors and the force at the door so you can open the doors it didn't have a particular defined functional role at low speed

02:04:03 unless i'm missing something did i see i mean you say in your latest statement that this might mean that the system was acting in a smoke clearance capacity i pushing out um the smoke um

02:04:15 the smoke um but but how is that acceptable given that that was not how it was designed to work

02:04:20 work well i mean it's it's it it's not it's designed for condition which is to try to deal with the the larger flows when the door is open but so if you take um let's look at level 12 again for example

02:04:32 let's look at level 12 again for example that says in low speed we are seeing 2.1 meters per second flowing into the north shaft and 0.9 meters per second flowing out of the south shaft so that suggests

02:04:43 out of the south shaft so that suggests that even with everything else closed you're actually getting a little flow through the shaft strip all through the lobby which would be beneficial that's a good thing yes i i realize you're

02:04:54 good thing yes i i realize you're trying to put some positive um well i'm quoting the data sorry i'm not trying to put a positive spin on anything i'm telling you what this data that dr lane is relying upon says well with respect mr lay if this

02:05:06 says well with respect mr lay if this system had been working as intended we shouldn't see negative figures there should we i don't know because i don't know what the intention in the south shaft was

02:05:18 i'm sorry i didn't mean to interrupt you had you finished yes sorry yes um i'm a little puzzled because um

02:05:26 um i'd understood the system to be designed in such a way that unless and until the stair door was opened

02:05:34 opened the fans would be running at fairly low speeds

02:05:38 speeds is that right that's correct yes so um is the

02:05:43 is the are are these figures for the airflow at low speeds indicative of what would be happening if the stair door were closed

02:05:55 if the stair door were closed i think they are yes yes so at that point the south shaft which ought to be sucking smoke out of the lobby is not doing its job

02:06:06 doing its job so when the door when the stair door is closed the south shaft and the north shaft are running at a low speed but they're both designed to remove smoke aren't they they are but they're designed to remove smoke when they're running at high speed

02:06:19 smoke when they're running at high speed so what i think we're seeing here you you mentioned the paragraph just now where i talk about the fact that there's a um a natural stack effect in these systems yeah i think what you're seeing here i suspect is actually that natural

02:06:31 here i suspect is actually that natural stack effect occurring right so what's happening is that if you turn the fans off completely so you turned it back into something more akin to the original system

02:06:42 system you would have effectively a chimney attached to an inlet and if the air is warm inside the building and the air is cold outside then you will naturally get a flow pulling up that shaft and that flow can

02:06:54 pulling up that shaft and that flow can be quite strong what i suspect is happening is that in low speed mode the fan isn't strong enough in the south shaft to pull against

02:07:02 against that stack effect and therefore air is flowing through the lobby still and going out through the north shaft you notice on the lower floors the velocity coming out

02:07:14 coming out it becomes a velocity flow back into the shaft and that's because those floors of course are situated in a different way compared to where the fans are and i think that probably has a has an effect so that's

02:07:26 probably has a has an effect so that's that's

02:07:27 that's you know just pulling two and two together and using my my experience in the fluid dynamics that i think is what you're seeing here but it wasn't a stated design condition apart from

02:07:38 stated design condition apart from to avoid having too much flow out of the lobby

02:07:42 lobby so that you stop the door from being opened

02:07:46 opened all right thank you very much yes thank you

02:07:50 you now um

02:07:51 now um just rounding off on on the topic of dampers um it's right isn't it that none of the revisions of psv's technical submissions uh prescribed a leakage performance to be achieved by the

02:08:02 performance to be achieved by the dampers installed in their in in the system did they no not them away off no they just specified a product namely the gilbert

02:08:09 gilbert gilbert series 54 dampers yes yeah

02:08:14 um dr lane's uh supplemental report refers to these types of dampers as ventilators and they had the lowest performance

02:08:25 and they had the lowest performance standard in the event of a fire and she contrasts them with a certified smoke control damper which is on the other end of the scale in terms of onerousness of requirements and complexity of function

02:08:36 requirements and complexity of function do you agree that with that summary of the spectrum of what we see here i'll be honest i got quite lost reading that part of dr lane's report i'm not quite sure

02:08:46 sure she appears to be hanging a lot on the fact that one of the witnesses used the term ventilator although he used the term shaft ventilator she says that it doesn't apply to the

02:08:57 she says that it doesn't apply to the approved document b but the approved document b if you look up automatic opening vents at the back of the index it it that's how it refers to these things i i found honestly found it very confusing i'm not quite sure

02:09:08 quite sure i could say i agree or disagree with dr lane in that section because i'm not quite sure what the intention of it was mr mani's evidence was that smoke control dampers weren't used because none were available on the market at the

02:09:20 none were available on the market at the time

02:09:21 time and because the dimensions and size wouldn't work with the size and position of the shaft now um

02:09:28 now um in dr lane in her addenda and errata dated the 30th of may 2022 if we could go to that blarp2504

02:09:39 if we could go to that on page three in section 1.1.1

02:09:51 page three

02:10:00 yes sorry um if we go to 1.1.11 here on this page

02:10:05 this page basically what she's done is she's done a search of the internet to see what products were available at the time this the dampers were being specified by psb

02:10:16 psb and what she says at 1.1.11 is from this limited activity i found that two smoke control dampers and two fire and smoke dampers were available in june 2015. and she summarizes the criteria

02:10:30 2015. and she summarizes the criteria for her search of products on the following page at 1.1.19 on page four

02:10:39 she says there the the criteria that she used to conclude they were suitable at grenfell tower were that if the product achieved at least a fire and smoke performance of es60 it was stated as suitable for use

02:10:52 es60 it was stated as suitable for use in a concrete or masonry wall and was available in the dimensions that would fit the existing openings of the north and south chats now and then the results of dr lane's limited search are summarized on page

02:11:04 limited search are summarized on page five table one one and there we can see that she's identified two smoke control dampers

02:11:15 dampers and two fire and smoke dampers she's given the product specifications and references to the archive product data sheets

02:11:23 sheets now

02:11:24 now um have you had an opportunity to review those product sheets no i haven't um i i very briefly looked at this it came in very very late

02:11:36 very very late i'm sorry but uh there's a huge amount of information that would have to go through to determine whether this was was relevant did you do your own search to check whether mr marney uh was right that there weren't smoke

02:11:48 uh was right that there weren't smoke control dampers or fire and smoke dampers available and suitable for grenfell tower at the time did you do your own equivalent search well i'm not sufficiently experienced in the final

02:11:59 sufficiently experienced in the final selection of mechanical components to decide first of all what is or isn't appropriate because you have to worry about lots of things not just the dimension of the whole but um no i didn't i i've

02:12:10 um no i didn't i i've so my experience i think i mentioned this earlier is that there certainly are issues with getting the right dampers in the marketplace and have been for some time so

02:12:21 some time so what he said in his statement did accord with with my personal experience and what i've heard from many other mechanical engineers and i think dr lane herself for her previous report did a search for

02:12:33 previous report did a search for equipment and spoke to her colleagues and

02:12:36 and hadn't managed to find something at the time um it's only really last week that she managed to find something okay yeah and i don't know whether these were take this any further well i mean i had a brief look at them

02:12:48 well i mean i had a brief look at them um all of the smoke control dampers um just from the pitches on the front of the brochures they've all got very large surrounds so fitting those into those holes would have made the size of the

02:13:01 holes would have made the size of the opening very very small they've all got large boxes on the outside of them that have the actuator in them so you'd have to have them sticking out of the wall

02:13:12 sticking out of the wall and to reference dr lane's preferred standard the approved document be it 10.11 fire dampers are supposed to be installed within the fire existing element not sticking out of the wall so you know setting aside the fact that i'm

02:13:24 you know setting aside the fact that i'm pretty sure the residents at grenfell tower would have been rather upset if they'd had dampers sticking out at roughly head height right in front of their front doors and i don't think it was practical insulation so i think mr marley made

02:13:37 insulation so i think mr marley made that point so i just had a brief look to see whether it matched his evidence and i think it does and i did notice but you haven't done a detailed analysis of the measurements and the measurements at grenfell tower to check whether or not she's right that

02:13:48 to check whether or not she's right that you could have installed these dampers in the wall there no no but i don't think um from what i could see there are other issues um for example i think was the bsb damper or the action air one of those needed installation from

02:14:00 those needed installation from effectively both sides of the wall which you wouldn't have been able to do at grenfell tower because you can only access from the lobbies so that would have been a very significant consideration i suspect in selecting dampers

02:14:12 dampers i see and could you not have um taken the plane of the dampers outwards if necessary sorry i think i've just mentioned that i don't think you could um so

02:14:22 um so the approved document b says you're supposed to fit dampers in the fire existing element it's in 10.11 it's on the same page as 10.15 that we were looking at earlier

02:14:33 looking at earlier and i'm not sure whether you have it sticking out of the wall whether that's an actual tested condition so you'd be using a damper outside it's certified applications so that would be a breach of

02:14:42 of another part of the approved document b and also the standards and it these dampers i mean the mandic ones are probably these things tend to be 600 800 millimeter deep

02:14:53 be 600 800 millimeter deep which means it would have been sticking out of the wall right in front of residents and they would have had to negotiate those and the ones at low level you would have created a bit of a labyrinth for people to get to their right their flats i

02:15:05 to get to their right their flats i think you know i guess you could have considered that but by the time you've boxed it all in to make it look nice and not look like a warehouse um you're lost even more i doubt that's something that residents would have

02:15:16 something that residents would have would have wanted well we had boxing in of gas pipe work all the way through the lobbies didn't we yeah we did but it's not as obstructive um and wouldn't be in a local wasn't in a location that i don't think that was would have been obstructive like these dampers were i

02:15:28 obstructive like these dampers were i think

02:15:29 think um commissioning and approval very briefly now because we're running out of time sure um you say in your report this is paragraph 38 at page 20 that the commissioning and handover documentation

02:15:40 commissioning and handover documentation was not to the standard that you would like to see however this does not mean that the commissioning was in itself inadequate or that a proper handover did not take place

02:15:49 place now in your opinion did the commissioning and handover of the system uh satisfy the standards reasonably to be expected of competent system designers and commissioners as far as i can tell from mr parker's statement yes

02:16:02 can tell from mr parker's statement yes so even though we know the cause and effect matrix was deficient i think you've agreed with that

02:16:08 that and that many of the tests that ought to have been carried out simply weren't documented and all we have is mr partlow's oral evidence suggesting he did carry out those tests so i think sorry you're suggesting that that

02:16:20 sorry you're suggesting that that satisfied uh reasonable standards are you sorry just go back through those points again um so the cause and effect concern is the fact that the environmental mode wasn't fully represented on the cause and effect well

02:16:33 represented on the cause and effect well i think there were other cause and effect uh

02:16:36 effect uh items that should have been there like the operation of the fireman's override switches um although they were cited within the commissioning test on that so we we know it was carried out because

02:16:47 we we know it was carried out because this commissioning certificate says they were all checked and mr parker says they were all checked and he also i think described that that was how he sometimes operated the system on different floors so

02:16:58 so yeah i totally agree the documentation documentation to me is more like a sign-off sheet than a full commissioning pack um

02:17:06 pack um but admittedly my standards for commissioning documentation come from a nuclear power plant so they're slightly different to to this okay so even though the documentation falls below the standard you would like to see

02:17:18 standard you would like to see you you don't think that overall the commissioning process did i i don't have any evidence that says it it wasn't adequate yeah now i'm going to turn briefly now to just a few questions about uh what

02:17:29 just a few questions about uh what happened on the night of the fire and before i get to that i want to make it clear that since this is primarily a factual matter did the system work on the night what's the evidence to suggest

02:17:40 the night what's the evidence to suggest it did or didn't work that it's ultimately going to be a question for the chairman and the panel to decide that

02:17:45 that and you're not a forensic fire investigator are you i'm not i did do a forensic fire course but it was some time ago so is it fair to say that all you can do in your evidence and the same would apply to dr lane is draw certain

02:17:58 would apply to dr lane is draw certain factual matters to the attention of the panel and provide a non-expert opinion about what that might tell the panel about what occurred on the night um

02:18:07 um yes yeah and using my understanding of smoke control systems and fluid dynamics as part of that yes yes

02:18:14 yes now um

02:18:16 now um there's a disagreement between you and dr lane about the

02:18:22 the time period during which you would expect

02:18:25 expect this system to have operated is that correct

02:18:28 correct there appears to be yes yes so if we look at uh dr lane's supplemental report blarp25043

02:18:37 and we look at page 13

02:18:41 at paragraph 1.3.44 so dr layne has summarized the extent of agreement and disagreement at the top of that page and she says we

02:18:52 the top of that page and she says we agree that the design condition for a smoke ventilation system in a high-rise residential building is a single-story single flat fire with smoke production causing smoke ingress in a single lobby

02:19:03 causing smoke ingress in a single lobby we are not in agreement as to when this single lobby condition is exceeded mr lay does not agree it is when smoke enters a second lobby preferring instead

02:19:14 enters a second lobby preferring instead there being a fire in another flat so

02:19:18 so is it fair to say that that you determine the end of that um

02:19:26 um of that period to be uh when the fire hit level five and we have fires in in flats at level five but dr lane has determined that the end of

02:19:38 dr lane has determined that the end of that period is instead when there is actually smoke in a second lobby say at lobby number five so i i disagree with what dr lane's written there i don't say that

02:19:50 i don't say that the

02:19:52 the end of the design for condition is when fire spread between levels um but i'd also disagree with the opening sentence of dr layne's statement there as well because there's nothing in any standard or guidance that says the

02:20:04 standard or guidance that says the design condition is breached when smoke propagation causes smoke ingress in a single lobby the design condition is a single fire in a flat that's expected to be

02:20:15 in a flat that's expected to be contained to that flat or in the immediate vicinity of that flat i think is probably the the correct wording of it when you put all that together

02:20:23 together i think dr lane has extended that into smoke production i don't necessarily agree disagree with dr lane that it's appropriate to extend that and

02:20:33 and but what i was more concerned about when i did my analysis is first of all what's the minimum time you could have used and that's when you do have fire spread between floors and that appears to occur

02:20:45 between floors and that appears to occur at zero one zero seven or thereabouts um much earlier than dr lane has put into her report which is is a matter for for the panel to decide what the evidence says on that

02:20:56 decide what the evidence says on that but i used the figures from from the chairman's phase one report for that i then considered what factors might influence the action of the smoke control system and the primary thing

02:21:08 control system and the primary thing that might change that was the action of firefighters and certainly i felt that by zero 120 the firefighting condition had changed the firefighters had been deployed to multiple floors they were laying hoses

02:21:20 multiple floors they were laying hoses they were opening doors on multiple floors

02:21:23 floors from zero 120 onwards and that fundamentally changes it whether smoke got into different levels or not um well it was by the way during those firefighting operations

02:21:34 during those firefighting operations it's reported by firefighters and residents that there were smoke in other lobbies but they were certainly opening the doors

02:21:41 the doors and that could have changed the operation of the system or what it was expected to do i see that's helpful thank you

02:21:47 thank you now the level 11 north dampers i want to ask you briefly about this now at page 17 of this report dr lane identifies another area of disagreement with you

02:21:59 with you and she says at one if we go to page 17

02:22:06 at 1.4.5

02:22:09 she says um we disagree that there was likely a breach of compartmentation by the north shaft level 11 dampers on the night of the fire

02:22:19 fire and then um if we look at your report if we could go to page 401 of your report paragraph 1270

02:22:33 you say this you say at the north shaft on level 11 the bre found no visible evidence of dampers being closed during part of the fire this is not evidence that the dampers

02:22:45 this is not evidence that the dampers were not closed at the start of the fire simply that the visual evidence of closure is absent as noted above the level of contamination that could occur at dampers will vary the bre noted

02:22:57 the bre noted that the evidence for the south dampers being closed was limited and variations in surface coloration were as the north dampers would generally be within a region of greater smoke contamination than the south dampers

02:23:10 contamination than the south dampers as the north dampers were located high at high level within the lobby then if evidence on the south dampers was slight it may not be surprising that evidence on the north dampers would be further limited so that's what you say about

02:23:22 limited so that's what you say about this

02:23:23 this and can we just look at what the bre report said about it if we go to met three zeros three nine eight zero seven

02:23:33 and i want to look at page

02:23:36 page 112 of this so this is the bre's grenfell tower fire investigation on-site investigation report and if we look at paragraphs one five

02:23:47 and if we look at paragraphs one five three downwards here they're dealing with level eleven they say at one five three inspection of the low level dampers found that the metal surface on the edge of the blade tips where the blades normally contact

02:24:00 tips where the blades normally contact each other when in the closed position was noticeably cleaner and had less smoke soot residue than the rest of the blade surface the transition between this area and the rest of the blade surface was also

02:24:12 rest of the blade surface was also marked by a very clearly visible line in bre's opinion a likely explanation from this was that both of the lower dampers were closed during part of the fire so that's the south dampers they're

02:24:23 fire so that's the south dampers they're saying there's this noticeably cleaner and less

02:24:27 and less soot

02:24:29 soot residue on the blade tips yes which might suggest that they were closed during part of the fire and then opened that's the south side dampers

02:24:40 that's the south side dampers and then still dealing with the south side dampers they say examination of the inside edge of the damper frame see figure 107 showed a slight variation in surface coloration but it was not

02:24:51 surface coloration but it was not sufficiently clear to indicate whether the dampers might have been closed during part of the fire so looking at the inside edge of the damper frame

02:24:59 frame there was a slight variation in surface coloration but that wasn't sufficiently clear on the south dampers yes yes yeah then if you go to the north dampers it's at 155 below they say inspection of the

02:25:10 at 155 below they say inspection of the high level dampers showed that the contact points on the damper blade tips were uniformly coated in smoke smoke and soot therefore unlike the low level dampers there was no visual evidence for

02:25:22 dampers there was no visual evidence for the high level dampers being closed during part of the fire so the bre have distinguished in the soot markings that they can see as between the south dampers and the north

02:25:34 between the south dampers and the north dampers yes yes and that might suggest based on that evidence alone that the north dampers were open because there was uniform coating in soot and smoke

02:25:46 was uniform coating in soot and smoke whereas the south dampers have got this distinct line on the edges of them and might suggest they were closed yes it would suggest that well and sorry the south the south dampers were found closed

02:25:56 closed so we so what you just said there is and the north dampers were found open so um

02:26:02 so um what i'm trying to express in that paragraph that i wrote a little bit clumsily i suppose is that

02:26:08 is that obviously when the south damper closed you would expect there to have been some sort of delineation between the um the area that's covered by the closed

02:26:19 the area that's covered by the closed dampen area that isn't covered and that was quite slight so that suggests there must have been a fair amount of smoke contamination happening in that area then when you look at the north damper

02:26:30 then when you look at the north damper there is no differentiation and that damper was found open i believe at the end of the fire was it found out in the fire well just check i think that both um the dampers were found open at level

02:26:41 um the dampers were found open at level 11.

02:26:42 11. i can't recall to be honest yeah yeah but i'm not sure it's right to say that the south dampers were found closed but what i'm saying is that there was obviously a lot of smoke contamination happening um to these dampers and i

02:26:54 happening um to these dampers and i expect there would probably be slightly more smoke contamination happening to the to the north dampers um and depending on how long they were both open or closed for but what i'm concerned about is that

02:27:07 but what i'm concerned about is that just because there's a lot of smoke contamination on an open damper that's found open at the end of the fire doesn't really tell me exactly when it opened

02:27:15 opened in the fire history and you know this fire lasted for an extraordinary long period of time and there could have been a very long exposure condition here so i can't really say from that whether

02:27:28 so i can't really say from that whether it was open at the start of the fire or not because that evidence could have easily been obliterated by a long duration of exposure yeah but it's right isn't it that for all the dampers found open by the bre after the

02:27:40 dampers found open by the bre after the fire including some open at level 18 the bre concluded that the damper was probably closed during part of the fire based on soot deposits lighter deposits on the blade tips and the frames but the

02:27:52 on the blade tips and the frames but the only exception to that that's drawn in the bre report is the north shaft level 11 dampers where they've referred to a different smoke such pattern that's right isn't it yeah because it's factually different yes so they have

02:28:04 factually different yes so they have drawn attention to it yeah if we look at dr lane's supplemental report blarp25043

02:28:12 page 192.

02:28:16 at figure um 8.3 she's provided a post-fire photograph of the level 11 lobby in figure 8.3 below we can make that as big

02:28:27 figure 8.3 below we can make that as big as possible and you can see she's marked up the low the low level south shafts in blue and the high level shafts in orange dr lane

02:28:39 the high level shafts in orange dr lane makes the point that this seems to show soot staining from ceiling to ground level throughout and no evidence of this region of greater smoke contamination

02:28:50 region of greater smoke contamination that might affect the north shaft dampers more than the south shaft dampers

02:28:55 dampers can you just help us where have you got that from that there's this level of greater smoke contamination that's likely to have affected the higher dampers than the the lower ones so we know on some of the levels we saw that

02:29:06 know on some of the levels we saw that the north dampers were more heavily contaminated than the south dampers on other levels we definitely saw that and are you saying that was the case for level 11. sorry i'll just complete what i'm saying um what i'm saying here is what just

02:29:18 what i'm saying here is what just because i can't see now a differentiation doesn't mean say differentiation didn't occur during the fire

02:29:24 fire if there was a hot flowing layer and there was a lot of turbulence i'd expect everything to be coated but during the fire it could well have been a hotter flowing layer at the top there's just not enough information to in this

02:29:36 not enough information to in this photograph to say it definitely didn't happen or it definitely did happen all we're seeing here is a photograph after a very long sustained and extreme fire exposure right so i'd expect the whole thing to

02:29:48 right so i'd expect the whole thing to be covered but it doesn't tell me what happened during that fire exposure now the other evidence that you draw attention to in your report about what happened on level 11 is the movements of

02:29:59 happened on level 11 is the movements of the jafari family and other witnesses in terms of

02:30:03 terms of the conclusions you draw about uh whether there were whether there's evidence to suggest that these north dampers might have been open earlier in the fire

02:30:12 the fire now can i just clarify one factual point it will be a matter of um matter for the panel to decide as a matter of fact whether um your version of the facts is is the

02:30:25 um your version of the facts is is the version that they prefer um

02:30:28 um or indeed whether the panel wants to go this far at all but i just want to clarify one thing that we're slightly puzzled by in your report um if we go to your errata sheet this is

02:30:39 um if we go to your errata sheet this is a lay

02:30:42 a lay 702 at page three

02:30:51 no that's yeah seven zeros two at page three

02:30:56 three yep here you've corrected what you've said about the jafari family's movements and you've corrected the corrected paragraph is at the bottom of this page

02:31:08 paragraph is at the bottom of this page and

02:31:09 and i just want to ask you about a line in this

02:31:13 this in that you say um

02:31:18 you say i've considered in more detail the likely timeline of events at level 11 to determine if there's any evidence that the north dampers might have been open early in the fire which may have been evidenced by significant smoke

02:31:29 been evidenced by significant smoke leakage to that level as far as can be ascertained maria and fatima jafari exited flat 86 on level 11 at 0 19.

02:31:40 exited flat 86 on level 11 at 0 19. as they exited the building at 0-122 having called the lift and then after a brief wait used the lift to descend directly to ground maria left her sister and father in the

02:31:51 maria left her sister and father in the flat expecting them to follow and according to nadia jafari the flat door would stay open if it was not locked then you say this maria jafari and mr jafari had a more complex journey which

02:32:03 jafari had a more complex journey which sadly resulted in mr jafari losing his life now we think there's an error there in that you're you're referring to maria jafari but you should be referring to nadia jafari and mr jafari had a more

02:32:15 nadia jafari and mr jafari had a more complex journey i i agree yes yes sorry that's my mistake yeah that's fine and the other thing we wanted to clarify with you is on what basis do you say that maria jafari is likely to have left the door

02:32:27 jafari is likely to have left the door open

02:32:29 open because we've we've checked the witness statement of maria jafar and we can't see that she says that she left the door open when she and her mother left

02:32:38 left nadia jafari does say that the door may have been open but not maria jafari and we wonder we want you to clarify where you got that from so i i took it from

02:32:49 you got that from so i i took it from nadia jafari saying that but also my understanding of putting it all together and trying to be succinct without missing out any details for the family was

02:33:01 for the family was that

02:33:02 that maria and

02:33:04 maria and her mother they left early but there was an expectation that their father and nadia were going to come as well and they knew that the only way of closing their door i believe was to lock it

02:33:15 it and i seem to recall either nadi i think nadia went back to get mr jafari's keys um at one point so i put that together and thought well

02:33:26 so i put that together and thought well if

02:33:27 if my

02:33:29 my if i've left behind my elderly father and my sister who've had an operation would i lock them into the flat to close the door or not and i think i surmised that i probably wouldn't have done that

02:33:41 wouldn't have done that and i put that together with nadia jafari's evidence that she that she thought the flat door may have been left open as well right so it's an assumption you've made that maria jafari may not have closed the door behind her

02:33:53 may not have closed the door behind her yeah but based upon the fact that i believe i can't remember things one of the systems says you had to lock the door to be able to properly close it so yeah okay

02:34:03 yeah okay now um

02:34:05 now um if the north dampers on level 11 had been open

02:34:10 been open just assume that for the moment factually if they'd been open what

02:34:15 what difference would that have made to the system's performance on the night in your view um

02:34:22 um difficult to know because you'd need to have a flow path um from so so if if it tried to draw air from the um north dampers on level 11

02:34:33 on level 11 it would come against resistance from the doors that are closed um interior doors that were closed i think particularly nudgy jafari is quite clear that when she saw the fire in the kitchen she closed the door so don't

02:34:44 kitchen she closed the door so don't there's any evidence there's any doorways that were open to the

02:34:48 to the lobby so you would have come up against the resistance pathways that are quite significant so it may not have made a huge amount of difference to the extraction at level four that was that was quite significant extraction

02:35:00 that was quite significant extraction difficult to know i'd have to do the calculations um but you'd have to make quite a lot of presumptions to do that sort of calculation okay

02:35:07 okay but i mean if it was open and we're worried about damper leakage then you would expect to see smoke coming out of it i think that's dr lane's presumption is that smoke did

02:35:18 lane's presumption is that smoke did come out of the level 11 dampers and it came out of those dampers before anybody could have left the door open and i don't think the timeline suggests that even the corrected timeline that dr

02:35:29 that even the corrected timeline that dr lane has issued doesn't seem to suggest that right okay now in terms of i'm sorry before we go on just just um help me understand the mechanics of this um if if um

02:35:41 um if if um dampers are open on a higher floor and the fans are running uh isn't the airflow going to be from the lobby into the shaft um there would be some airflow from the

02:35:52 um there would be some airflow from the lobby into the shaft but exactly how much

02:35:55 much can be achieved will depend on the flow resistance pathway and if all the doors on that lobby are shut that will be quite a high resistance pathway um compared to if it's for example if the

02:36:06 compared to if it's for example if the fire if the door is open to the staircase on level four for example then i understand it's just the mechanics of how the smoke leaks back into the lobby from the shaft where it ought to be drawn up the shaft

02:36:18 where it ought to be drawn up the shaft yeah it shouldn't so the fans are running um i guess if you've got um a big opening i suppose a damper might be big enough opening then as air is sort of flowing

02:36:29 opening then as air is sort of flowing past the damper you'll get a bit of turbulence and that could spill a little bit of smoke in because whenever you've got sort of smoke going past and and clean air next to it you will get a little bit of mixing um so i guess you

02:36:41 little bit of mixing um so i guess you could have had a small amount there but not to the level that dr lane suggests i think was

02:36:45 think was what witnesses that she was relying upon so yeah yeah i mean that might explain for example a smell or a very light quantity of smoke all right yes thank you okay thank you

02:36:57 all right yes thank you okay thank you chairman i'm conscious of the time and i'm i'm looking at my questions and trying to pair them right back i think i'm going to need to be another five minutes if that's okay well five minutes i'm sure would be all

02:37:08 well five minutes i'm sure would be all right we take all the support staff for granted rather when we do this but um actually that's all right okay thank you and another topic you you deal with in your report is whether there were

02:37:19 your report is whether there were breaches of compartmentation and damper leakage

02:37:22 leakage uh

02:37:23 uh shown by the evidence and you discussed the evidence of farhad neder on level 23 who gave evidence phase one of this inquiry about having seen smoke leaking

02:37:34 smoke leaking into level 23 from the north and the south shafts and you essentially say i can't really reconcile that evidence with how the system was supposed to work is that fair yes that's fair yes yeah

02:37:45 is that fair yes that's fair yes yeah now again let's assume mr neder was right i know you've pointed out that there might have been other pathways for smoke to enter that lobby but let's assume he was right and he could clearly see

02:37:56 see smoke entering the lobby at level 23 from the north and the south shafts and filling up as he described what does that tell us about the system performance in terms of its

02:38:07 performance in terms of its compartmentation at level 23 at that point in the fire so it would be just before 1 30. so um i mean i anticipate the dampers

02:38:19 so um i mean i anticipate the dampers might have been on the south shaft expect them to be cold bit warmer on the north side perhaps so that would affect the leakage rates you'd have to expect the fan would have to be off

02:38:29 to be off um to see that kind of effect both fans

02:38:36 so you'd only expect to see that if the fan was off yes yeah what about for example if the south fan was undersized and simply wasn't counter balancing the

02:38:47 and simply wasn't counter balancing the stack effect what about the fact that there could have been smoke accumulating in that south shaft is that not a possibility um well the smoke has got to so if it's coming from level four which it would

02:38:58 coming from level four which it would have been at that point in time um it's got to be at low level in level four and then get into that shaft and then come up the building and and fill it up um

02:39:09 it up um the impression i get from i think the bre evidence about the staining at level four of the dampers um is that there wasn't a huge amount of smoke exposure onto those dampers now there's lots of things to take into

02:39:21 now there's lots of things to take into account there like firefighting water and the such light that could have changed that evidence as well so if that shaft had been able to fill with smoke and because you have dampers and all

02:39:32 and because you have dampers and all dampers leak then i guess stack effect could have meant that you could have seen some smoke coming out from the south shaft yeah it's possible and what about the north side well you definitely need the fans to be

02:39:44 well you definitely need the fans to be off i think on the north side for that to happen yeah because you're very close to the fans at that point yeah so you would expect the draw to be strongest at level 23. uh you would expect it to be strongest at level 23 that's right yeah yeah

02:39:56 yeah and then um you've also addressed at some length in your report and in your statement the conclusions you draw about evidence of some firefighters including firefighter more about what was seen outside the tower during the fire and

02:40:09 outside the tower during the fire and you've drawn attention to firefighter moore's evidence that he may have seen smoke being extracted from the second floor vents at around 3 30 in the morning yes yes now again it's going to be a matter for

02:40:20 now again it's going to be a matter for the chairman and the panel to determine what conclusions they draw from that evidence but can you just help us with this have you attended the tower and looked for yourself at what view firefighter moore would have had of the

02:40:32 firefighter moore would have had of the second floor vents given the position he said he was standing in um i don't know the precise position he was standing in i think he said he was standing just under the shelter of the walkway i think he was acting as the safety officer if i

02:40:43 he was acting as the safety officer if i remember rightly so he had to make sure he had a good view i don't think he's given us on a plan exactly where he was where he was stood but

02:40:52 but um i think standing under the walkway looking up i'm pretty sure you can see most of the tower and i think in dr lane's recent um tranche of evidence that arrived on

02:41:03 um tranche of evidence that arrived on the 30th of may there was a video that was taken from someone stood on the edge of the walkway because the part of the video is obscured by the walkway above and that shows a clear view up the side

02:41:14 and that shows a clear view up the side of the tower um but i think yeah the walkway was quite high wasn't it it was it wasn't just a shallow walkway it was quite high up and i think anyone stood under the walkway would have a pretty clear view quite a long way up the tower

02:41:26 clear view quite a long way up the tower right okay yeah thank you

02:41:29 thank you and in terms of your conclusions about what you've drawn on the night is it fair to say that you remain of the view that the system there's evidence to suggest that the system did operate on the night

02:41:40 the night uh in the way it was intended to for the short period that you would expect it to work for yes thank you

02:41:47 thank you mr chairman um i've got no further questions right well actually i had lots more questions but i've really paired back to the essentials

02:41:58 um i'm happy to stop there and take up further questions that are suggested so perhaps if we could have until five two um that's okay yes

02:42:09 yes you think you need well if you don't need as long as that will you ask the actually to come in of course yeah mr lee just said you understand how we work these things and when council gets the end of her questions we have to have a short break partly to enable her to

02:42:21 a short break partly to enable her to take stock but mainly to enable others who

02:42:24 who are following the proceeding some elsewhere to suggest questions that perhaps we ought to put to you so we'll stop now we'll um

02:42:32 um we'll resume at five to five and then at that point we'll see if there's any more questions that we need to ask you no problem for me thank you well if you gave the asher now that'll be good

02:42:51 right we'll say five to five unless you send for sooner thank you thank you

02:55:07 would you ask mr lay to come back in please

02:55:18 all right mr lee well let's see if any more questions for you yes it's grange uh no mr chairman there are no further questions

02:55:25 questions um so um just to say thank you to mr lay for coming and assisting us with our enquiries today thank you well we certainly are very grateful to you mr lei it's when we have to deal with quite complex and difficult questions it's

02:55:37 complex and difficult questions it's very often helpful to have more than one expression of opinion and view on the subject because we get a better chance of seeing things in the round and maybe understanding them well as a result so

02:55:48 understanding them well as a result so thank you very much for coming in it's been very helpful to hear you very interesting and uh now you're free to go thank you very much it's it's been my honor to be here thank you thank you

02:56:07 well thank you very much mr grange that must be it for today yes it is before we leave i'm just going to say a word of thanks publicly to those who are helping us to run these

02:56:18 us to run these uh proceedings and stenographer of course whose fingers we always cause to ache by the end of a long day i'm sorry about that but thank you very much for putting up with us and and for the documents manager and those behind

02:56:29 the documents manager and those behind the scenes who are still operating the live stream so thank you all very much so we shall resume with the new witness tomorrow morning yes we have dr lane tomorrow morning you and we should do that at 10 o'clock yes please 10 o'clock

02:56:41 that at 10 o'clock yes please 10 o'clock tomorrow thank you very much