Dr. Barbara Lane provides expert evidence on smoke control systems, analyzing PSB's design of the mechanical extract system at Grenfell Tower. Lane criticizes the failure to conduct CFD analysis, inadequate damper specifications, and flawed commissioning processes that failed to demonstrate compliance with Building Regulations.
00:00:20 will you ask dr elaine to come back in please okay
00:00:37 right totally ready to carry on yes thank you yes yes mrs yes thank you yes before we start and just to assist the transcriber this afternoon there were quite a few times where we were speaking over one another and that
00:00:49 were speaking over one another and that makes it incredibly difficult for the transcriber to take a clear transcript so i'm going to try really hard not to do that it's my fault as well but if you could also try to let me finish the question
00:01:01 try to let me finish the question and
00:01:02 and um complete your answer and then hopefully we won't get into difficulty apologies honestly i was doing that thank you so um just to pick up on that point about the size of the vent at the
00:01:15 point about the size of the vent at the head of the stair um i just want to look at something with you if we go to psb's technical submission version six this is it psb five zeros two one four
00:01:26 five zeros two one four yeah
00:01:31 and if we go to page seven within this document
00:01:36 section two point two at the top it says
00:01:41 it says natural air inlet ventilator as the title and you can see in the the text below the stairwell has been provided with a penthouse louvre with a measured free
00:01:52 penthouse louvre with a measured free area of one meter squared and will is permanently open to atmosphere now is it likely that that's where you got your one meter square from yeah i just checked so we i went and
00:02:04 yeah i just checked so we i went and looked at our site measurement appendix so we didn't measure it and it's the free area of one meter squared and that's the number i've put into i think we were talking about
00:02:15 into i think we were talking about leakage calcs weren't we yeah yep yep
00:02:20 yep yep yep and that's a free area so it's different to the yeah yeah okay now given all of the complexities of the design that we've discussed uh is it your opinion that those
00:02:31 uh is it your opinion that those involved with the grenfell tower refurbishment including x over max fordham and psb should have made sure that a cfd analysis a computer fluid dynamics analysis of the proposed system
00:02:42 dynamics analysis of the proposed system was carried out the the three parties is that specific well i've said do you think those involved with the grenfell refurbishment including x over maxwell's psb yeah um i
00:02:56 including x over maxwell's psb yeah um i mean if it's easier to answer those individually rather than as a group yeah no because it's he is yeah so i think i suppose i'm more familiar with the concept of the
00:03:09 more familiar with the concept of the fire engineer doing the cfd for
00:03:14 for a company like psb but i do i am also aware obviously of other companies who do the cfd themselves too okay and not the fire engine i will work on a job
00:03:26 the fire engine i will work on a job where i don't get to do the cfd so i think in my mind um particularly the the fire engineer and then
00:03:36 and then should max fordham have insisted upon it i think that's is that probably more contractual um question rather than a
00:03:47 um question rather than a the truthful answer is someone should have done it but in my mind it it the fire engineer and the mechanical engineer had a duty to make sure it was done yeah and um and i
00:04:01 make sure it was done yeah and um and i would expect psb to have views on when a building is complicated or unusual
00:04:08 unusual or
00:04:09 or outside or the other cfd they've presumably done that they might need to redo it for grenfell tower so to take psb's position yeah
00:04:19 yeah if
00:04:20 if if as was the case when they came into the project no cfd analysis had been done would you have expected uh psb to have advised that such an analysis should be done
00:04:32 should be done i i would expect them to advise it should be done or that they would offer to do it themselves if they have that capability yes um
00:04:39 um now when he gave oral evidence mr mani indicated that the only reason this was not done was that there was no time to do it
00:04:45 do it that was it today one five five page one six four lines 19 to 21. was that a good enough reason not to do a cfd analysis on a project because there's time pressures on the project
00:04:56 there's time pressures on the project and there's simply not time no
00:05:01 mr lay um said yesterday that there was a prevalence of poor practice within the industry at the time in terms of doing these kind of computational fluid dynamics analyses
00:05:13 dynamics analyses but he did accept that it fell below reasonable standards not to have done it do you agree with that yes i do
00:05:22 mr hansen's evidence was in his first witness statement at page 10 was that in practice cfd analysis is more suitable for new buildings where leakages in the structure can be checked and
00:05:34 structure can be checked and accommodated as the building is built
00:05:38 is that right in your opinion that cfd is much more suitable for new buildings than existing legacy buildings suitable
00:05:50 i do you mean it's more i don't know what you mean by suitable so well let's look at his statement at rbk three zeros three three eight nine
00:06:01 rbk three zeros three three eight nine four
00:06:02 four and it's page ten
00:06:08 this is mr hans hanson statement if we look at paragraph 55 he says this in practice the computer modeling process such as cfd is more suitable for new buildings where the
00:06:19 suitable for new buildings where the instance of leakages in the structure can be checked accommodated as the building is built the test in the guide when carried out on site only confirms the extract rate determined by the computer model it does not take into account any leakages in
00:06:31 not take into account any leakages in the existing building structure now do you agree with that well i i'm really sorry but the second the second sentence doesn't even make any sense to me so i think i'll just literally putting that
00:06:42 think i'll just literally putting that aside
00:06:43 aside i think
00:06:44 i think it it
00:06:46 it it it might be it might be easier to numerically model a new building but i don't think um i don't agree that it's more suitable which i think is a
00:06:58 it's more suitable which i think is a different type of word is that okay yes the test and the guide when carried out on site you know i don't know what that i don't know if that means yeah
00:07:08 yeah okay it takes an extra right to turn by the computer model
00:07:14 yeah now in your earlier evidence to the inquiry during phase one you gave evidence about the risks of smoke being drawn out of the fire flat into the
00:07:26 drawn out of the fire flat into the lobby due to the operation of the system and you illustrated that in a diagram um if we could go to that blas 5038
00:07:37 5038 page four
00:07:41 so that was a key diagram that you used to illustrate that point now does that remain a concern of yours regarding the system as designed at
00:07:52 regarding the system as designed at grenfell tower
00:07:55 well any system can pull smoke out of any mechanical system can yeah
00:08:03 yeah so is that a known risk with any form of mechanical system yes
00:08:10 and um is this addressed by any such smoke simply being vented up the extract shafts wouldn't that deal with any uh
00:08:21 uh ingress of smoke that's been sucked from the fire flat
00:08:29 sorry you're so are you asking me that in this system designed to apparently not extract smoke if it will extract smoke when it flows out from one of the flats i think that's
00:08:40 out from one of the flats i think that's the point that's being made is that even if that's a risk isn't that going to be addressed in practice
00:08:47 practice because you you'd have some smoke extraction from both the north and south south
00:08:53 south well it depends on the quantum of the smoke and the quantum of the so-called extract
00:08:58 extract right
00:08:59 right and is it possible to do any kind of qualitative um or quantitative assessment of this risk at this stage he says
00:09:10 he says sorry it's a possible thought well let me put it a different way when mr lay gave evidence yesterday he said yes that's a theoretical possibility but it's theoretical only
00:09:23 possibility but it's theoretical only and it's not a possibility that one would expect a designer to take into account in this kind of system do you agree with that he's saying so he's saying that smoke does leak out
00:09:35 so he's saying that smoke does leak out of the flash or it's only a theoretical possibility would leak out to the flood i think he's saying the latter so it's only theoretically possible smoke leaks out of a flat with the door clown are we
00:09:46 out of a flat with the door clown are we talking about the door being closed or open i think he's saying it's only sorry oh sorry sorry yeah
00:09:53 yeah i think he's saying it's only a theoretical possibility that this type of system is going to be positively pulling smoke from the fire flat into the lobby and he wouldn't
00:10:04 flat into the lobby and he wouldn't expect a system designer to take that into account that was his evidence do you agree with that i don't think so
00:10:15 and is a cfd analysis one way in which you could assess whether that risk was one which was concerning or not on a particular project yeah that's that's my understanding
00:10:31 and in your supplemental report you raise a particular concern about the way the system uh was designed such that it might mean that if um a flat door was open and the stair door
00:10:43 flat door was open and the stair door was shut
00:10:44 was shut the system might carry on operating at high level because the pressure difference between the stair and the lobby would have been lost due to the open flat door as opposed to
00:10:55 due to the open flat door as opposed to the open stair door yeah and you say that that could lead to a phenomenon of smoke being sucked from the flat into the lobby now have we understood that right that that's the concern yeah
00:11:06 right that that's the concern yeah because the fans never turn off they they go to high as the if you want to say the pressure is stabilizing between the stair and the lobby
00:11:15 lobby yes okay yes yeah and then some additional smoke would be might be expected to be drawn out on top of any other smoke already
00:11:26 out on top of any other smoke already leaving the flat of its own yes buoyancy etc yes because but the fans remain on high that was something that seemed to kind of get a bit lost i think when
00:11:37 think when it was being talked about during the summer yeah yes and and and the concern i think is is that the system doesn't know
00:11:45 know whether
00:11:46 whether uh that there's been a loss of pressure because the stair door's open or because the flat doors open does it it doesn't it's not sensitive in that way no because it's it's just measure so if you
00:11:57 because it's it's just measure so if you i suppose another way of looking at it is is
00:11:59 is is if you open the flat door and if there's leakage you know available it's almost like the lobby is extended in the context of in the context of the two
00:12:10 context of in the context of the two little pipes between the the stair and the lobby you know it's no more intelligent than that you know so that it's only it's only taking samples from the stair and at the
00:12:23 taking samples from the stair and at the lobby
00:12:24 lobby it's no cleverer than that yeah the system anyway and do you consider that that is something that should have been expressly considered by psb at the time it did its design
00:12:39 expressly considered what they should know they should know about it yes and should that be documented that they've looked at that risk and evaluated that risk would you expect
00:12:50 evaluated that risk would you expect that to be dealt with somewhere in the design documentation is that what you're saying oh i see what you mean sorry so so the thing about the the handy thing about numerically modeling all these scenarios is you then
00:13:03 scenarios is you then understand um the behavior of the smoke in those scenarios and by death definition then it's documented you'll have reviewed it and you're you've satisfied yourself it's appropriate
00:13:15 yeah yes
00:13:17 yes so it's another reason why you need to numerically model all these systems yeah it's something that the model allows you to understand and interrogate yeah
00:13:29 yeah and just finally on this point is it right that in your opinion mechanical calculations for pressure drop or also to have been carried out when psb was selecting the fan sizes for the new
00:13:40 selecting the fan sizes for the new system
00:13:41 system that is
00:13:43 that is yes yeah
00:13:45 yes yeah and and are you saying that the narrow size of the existing shafts might have caused increased pressure drop in the shafts making it important that the fan sizes were carefully selected to accommodate that
00:13:57 selected to accommodate that amongst lots of other things i mean normally there's a spreadsheet of all the different items that contribute to pressure drop is an aggregate of different things it's not one
00:14:08 different things it's not one it kind of sounds like it's one thing it's an aggregate of all different things so the the size of the shafts is relevant to the calculation and and which professionals would you
00:14:19 and and which professionals would you expect to be involved in that exercise in making sure that the fan size um was correct given the pressure drop to be anticipated is that something for
00:14:30 to be anticipated is that something for the system design or the detailed design or is that something you expect a fire engineer to get involved in no i think i would absolutely be calling the fire sorry excuse me the mechanical engineer
00:14:41 sorry excuse me the mechanical engineer when it came to that level of detail yes
00:14:47 and um just overall in terms of your conclusions about the system um design yeah
00:14:54 yeah um
00:14:55 um you you say if we can go um to your supplemental report blarp25043
00:15:04 at page 36. you say at 3.1.27 at the bottom of that page you say notwithstanding this demonstration of options available to
00:15:16 demonstration of options available to the design team at the time i remain of the view the fundament the fundamentalist fundamental issue is not the system type psb chose it's the quality
00:15:28 the quality of the mechanical extract depressurization system they designed psb failed to provide a smoke ventilation system which complied with the functional requirements of the building regulations now does that
00:15:39 building regulations now does that remain your view yes
00:15:43 yes and has anything that mr lay has said in his evidence yesterday changed your view in any way
00:15:51 no no big no but you know there's lots of things we haven't spoken about yet you know it's not just about where the smoke was flowing so i prefer to say that at the
00:16:02 flowing so i prefer to say that at the you know at the end okay yeah fine i'm gonna move on then to dampers and compartmentation and i want to go within this supplemental report to page 105
00:16:18 and
00:16:20 i want to look at 6.1.1 and following so you say there there are seven published standards under the framework for the testing and classification of dampers and ventilators
00:16:33 dampers and ventilators these range from products called natural smoke and heat exhaust ventilators which require the lowest performance in the event of a fire as they have a very simple function functions to open or remain open to
00:16:45 functions to open or remain open to ventilate smoke directly from a space right up to smoke controlled dampers which rely on the most complex actions and are to provide the highest protection standards in the event of a
00:16:56 protection standards in the event of a fire because they actively direct smoke along a specified route which can then be altered over the course of the fire this range of performance clearly defined in the published standards must
00:17:07 defined in the published standards must be kept in mind when reading this section of my supplemental report and you go on you say mr jones gilbert stated in his oral evidence the inquiry that the gilbert series 54 damper is a
00:17:18 that the gilbert series 54 damper is a smoke evacuation damper which he admits is an industry-defined term to which there is no reference made in a pre-document b or any british standard
00:17:29 or any british standard as stated in their evidence psb considered that the gilbert's damper met the technical specification of section 8.2.5 of the sca guide 2012 such that the gilbert damper damper was an
00:17:42 the gilbert damper damper was an automatic opening vent smoke control damper used for ventilation from corridor or lobby into the smoke shaft or smoke controlled duct and you say the emphasis is yours in
00:17:53 and you say the emphasis is yours in terms of they've said that it was a form of smoke control damper and you say at 6.1.6 mr jones description of the operation of a smoke evacuation damper is consistent with
00:18:05 evacuation damper is consistent with that of a natural heat and smoke exhaust ventilator which as i explained below is the lowest performance possible in terms of functionality but he also refers to the damper having passed the bsen 1366
00:18:18 the damper having passed the bsen 1366 part 2 test requirements and hence having met the requirements in the fca guide for an automatic opening shaft ventilator which is uniquely defined in section 8215 of the sca guide
00:18:31 8215 of the sca guide and then a paragraph if we go within your module 3 report to blarp 2 5 0 36 at page 26
00:18:48 um sorry i think that might be a wrong reference
00:18:51 reference don't worry so you've said in your module 3 report i'll just read it out as a short quote that no damper purchased and installed as part of the primary refurbishment lobby smoke control system
00:19:03 refurbishment lobby smoke control system had been fire tested or classified in accordance with the requirements of the approved document be is that correct yes and does that remain your view
00:19:15 and does that remain your view yes
00:19:17 yes and is it also your view that the dampers that were installed meant that the system could not satisfy the functional requirements of the building regulations that's b1 b3 and b5
00:19:28 regulations that's b1 b3 and b5 yes
00:19:30 yes now i want to ask you some more questions about the need for the s certification for these dampers and in your supplemental report you enter
00:19:42 in your supplemental report you enter you identify an area of disagreement with mr lay about whether or not um the approved document permits a damper with an integrity only test and e only test to be used on escape routes
00:19:56 only test to be used on escape routes now if we can go within approved document b to
00:19:59 to clg 50224
00:20:03 clg 50224 a page 61
00:20:09 this is under the general provisions heading
00:20:14 heading and if we look at 5.48 at the top right hand column
00:20:22 we can see it says that ducks passing through the enclosure of a protected escape route should be far resisting either duct work should be constructed in accordance with method two or method three
00:20:33 three and then there's a note underneath that and it says note fire dampers activated only by fusible links are not suitable for protecting escape routes however an e s
00:20:46 however an e s classified fire and smoke damper which is activated by a suitable fire detection system may be used do you see that yeah now um
00:20:57 um can you just explain what a fusible link is is that the same as a thermal link oh i think so yeah so at a certain temperature it causes the damper to snap shut
00:21:11 it causes the damper to snap shut yeah never talks yeah yeah and what's your understanding of what this guidance is saying about whether an es classified damper should be used to protect an escape route
00:21:29 so we can see it says in the final part of the note however an es classified fire and smoke damper which is activated by a suitable fire detection system may be used yeah that that is my understanding
00:21:42 yeah that that is my understanding and um
00:21:46 but doesn't um isn't this potentially silent about whether a damper which has just satisfied the e-classification but isn't activated only by a feasible
00:21:59 but isn't activated only by a feasible link
00:22:00 link is appropriate on an escape route
00:22:10 so isn't it silent okay so the first sentence is a fire damper and a fire damper has its own definition and by definition it doesn't have s
00:22:22 have s and when it's tested you can there's you have to test the fusible link and then the second sentence
00:22:29 sentence so to me that's a general general recommendation and then the second sentence the author of this you know unusually
00:22:40 unusually worded two sentences says an es classified and therefore in the adb it's called a fire and smoke damper so it's the same thing activated by suitable fire detection
00:22:52 activated by suitable fire detection system may be used and my understanding of that is it's first of all it's doing two things
00:23:00 things it's explaining first of all that the s rating that higher you know the higher performance is needed and they need to be able to close
00:23:11 close quickly rather than wait a fuseable link is it can take some time to close because it depends when the temperature hits it
00:23:18 hits it when the damper is activated or for fire detection system the concept is it's closing very quickly in the fire area yes so that's how i read those two i see together um can we agree though it
00:23:30 i see together um can we agree though it doesn't say an e s classified fire and smoke damper activated by suitable fire detection must be used it says may be used i'm not aware the adb uses the word must anywhere i see yeah i see
00:23:43 must anywhere i see yeah i see and is it right that you would read this together with other appropriate guidance in including bs triple 9 1 2011
00:23:54 2011 which also contains some guidance about dampers on escape routes sorry can you repeat the question is it right that you would as a as a designer or reviewing these systems you'd look at
00:24:06 or reviewing these systems you'd look at the approved document but you'd also have a look at what bs triple nine one said
00:24:11 said about
00:24:12 about um
00:24:13 um dampers on escape routes you could do yes yeah
00:24:20 if we go to bs triple nine one um sorry before we do um do that um
00:24:28 um do you think it's logical that dampers on escape routes need to have the s smoke leakage requirement as well as an e integrity requirement in order to satisfy the functional
00:24:39 in order to satisfy the functional requirements of the building regulation in a high-rise residential building with no sprinklers and a staple policy yes right
00:24:47 right so i think what you're saying is anybody reading this also has got to bear in mind what the functional requirements are that you're trying to meet ultimately like every single other thing
00:24:58 ultimately like every single other thing you do
00:24:59 you do not just what's written in the approved document b yes yeah and would you consider a damper that didn't have the s classification to be capable in a building like enfield tower of satisfying the functional requirements
00:25:11 satisfying the functional requirements if it only had an integrity and not a smoke leakage requirement i don't think that no
00:25:18 now if we go to bs triple nine one twenty eleven it's at bsi five zero six two one
00:25:31 so this is a publication from 2011 fire safety and the design management and use of residential buildings code of practice
00:25:39 practice and if we go to page 117 of this
00:25:45 we can see at 39 at the bottom of that page a heading hvac systems serving the whole building or interconnecting dwellings and other residential units do you see that
00:25:57 residential units do you see that and can you just remind us what hvac stands for heating ventilation and air hopefully air conditioning systems yeah and it says there immediately under the title mechanical hvac systems serving
00:26:10 title mechanical hvac 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 prevents
00:26:21 movement in the system prevents incursion of fire and combustion products on into protected escape routes or allows lines of fire complementation to be breached
00:26:31 breached and then if we go over the page at the top of page 118 it says measures to aid firefighting control should be incorporated including the following and then i want to look at d it says
00:26:43 and then i want to look at d it says there where a ductwork system serves more than one part of a compartmented or fire separated escape route smoke detector operated fire dampers should be
00:26:54 detector operated fire dampers should be provided
00:26:55 provided where the ductwork enters each fire separated or smoke separated section of the escape route and then it goes on where a fire damper is used to protect an escape route it should be tested in
00:27:07 an escape route it should be tested in accordance with bsen 1366 part 2 and an e s
00:27:12 e s classification equal to or greater than 60 minutes in accordance with bsen 13501 part three yeah do you see that yes
00:27:23 now what does this part of bs triple nine one mean for the dampers at grenfell tower in your view is is this a relevant paragraph describing the situation at grenfell tower that we have
00:27:36 situation at grenfell tower that we have fire dampers used to protect an escape route
00:27:39 route yes
00:27:41 yes so is this guidance that um you would expect a reasonably competent designer
00:27:46 designer of a system to take into account in terms of whether or not an es classification of damper ought to be selected yeah so first of all i would expect the fire
00:27:57 so first of all i would expect the fire strategy to very clearly set the standard for the dampers in the lobby absolute first priority and then in an ideal world you know the
00:28:08 and then in an ideal world you know the system designer so psb can read that and understand that that's what's required of them in this particular building okay that's the first thing um
00:28:19 um and then
00:28:20 and then i think
00:28:22 i think but because if and and then to be capable of understanding the differences in the different types of damper
00:28:33 in the different types of damper available on the market when making their decisions about what they're going to do in a particular building
00:28:40 building but but it's a life safety system in itself you might say a re actually a really important part of compartmentation we've talked about that at length
00:28:52 we've talked about that at length to do with grenfell tower and the stay put
00:28:56 put policy and how high-rise residential buildings you know in england are
00:29:03 are you know dealt with and the you know the so-called no plan b um
00:29:08 um so it's such an important part of a fire strategy to make that clear and i see the primary responsibility there to be clear
00:29:19 there to be clear right
00:29:19 right but obviously there's would there's a reasonable expectation that psb or any other company like them would understand the different types of damper and when they're appropriate for use
00:29:31 and when they're appropriate for use i see
00:29:32 i see so i think you're saying the primary responsibility is on the fire engineer to specify the type of damper yeah but you'd also expect a designer of a smoke control system to be
00:29:44 designer of a smoke control system to be aware of the different types of damper and to select appropriately according to its use in a building yeah the building in question or the particular hazard in the building in question
00:29:55 the building in question yeah
00:29:57 yeah yes thank you can we just look at another part of this um bs triple nine one if we go to page 73 in this
00:30:07 in this document
00:30:09 document there's a section um headed mechanical smoke ventilation systems yeah and it says there where a mechanical smoke ventilation system uses a shaft
00:30:20 a shaft it should conform to and then it's got various paragraphs that it has to conform to including 26.2 0.4.2
00:30:30 0.4.2 g is one of them and then if we go to page 72
00:30:39 where we see g it's there towards the bottom of the page third paragraph from the bottom it says here the lobby or corridor vents in the
00:30:51 the lobby or corridor vents in the closed position should have a minimum fire and smoke resistance performance of 30 minutes and a leakage rate no greater than 200 cubic meters per hour per meter
00:31:02 than 200 cubic meters per hour per meter squared when tested in accordance with bsen 13662 now
00:31:09 now this appears to set out a performance standard for a damper which has some similar similarities to an es type damper including maximum smoke leakage rate but it has only a 30
00:31:20 smoke leakage rate but it has only a 30 minute rating and doesn't appear to require an es damper to be provided now do you consider that that part of the british standard was relevant to the dampers installed at grenfell tower
00:31:33 dampers installed at grenfell tower i don't agree that g says an es damper i i so when i read that that is an es damper
00:31:42 damper i think just to be clear okay i see so you interpret that as saying we do need an e s damper i well i don't believe i'm interpreting that's what i read i see okay i understand yeah
00:31:55 what i read i see okay i understand yeah um is another relevant factor potentially that the earlier section we were reading was expressly concerned with protecting escape routes whereas this is not saying anything
00:32:06 whereas this is not saying anything about escape routes it's just talking about mechanical smoke ventilation systems okay so so both sections have the same leakage standards to 200
00:32:17 standards to 200 and then i think what where you might be trying to get to please correct me if i'm wrong is then the the fire resistance is different and i think that's something yesterday
00:32:29 and i think that's something yesterday yeah okay
00:32:30 yeah okay and so the leakage is relevant to an escape route and in picking the the compartmentation needs on your escapers you have to understand the particular building you're in and what
00:32:41 particular building you're in and what the overall rating is etc i hope i haven't uh yeah okay now taking those two pieces of guidance together do you consider that there's any ambiguity as to whether
00:32:52 that there's any ambiguity as to whether a damper protecting an escape route needs to be s rated in a building like grenfell tower i don't think there's ambiguity and would you expect a reasonably competent smoke control designer and a
00:33:05 competent smoke control designer and a reasonably competent fire engineer to be aware of this requirement for the damper protecting an escape route to be s rated yes
00:33:18 and can you just help it sounds maybe an obvious question but i'm going to put it is the distinction in functional performance between an e-only and an e-s damper
00:33:29 damper important to the health and safety of people in a high-rise residential building it's particularly important to the health and safety of people in a high-rise residential building
00:33:40 high-rise residential building for the occupants and for the firefighters
00:33:46 now in terms of the type of damper which should have been specified in your supplemental report uh you referred to mr jones's
00:33:57 uh you referred to mr jones's description he's from gilbert's his description of the series 54 damper that they supplied and he stated in his oral evidence that the gilbert's damper was a smoke evacuation damper which he said was an
00:34:10 evacuation damper which he said was an industry defined term to which there's no reference in either approved document b or any of the british standards have you ever come across the the phrase um smoke evacuation
00:34:21 the the phrase um smoke evacuation dampers before as used by mr jones of gilbert's
00:34:25 gilbert's yeah i think i have on all sorts of other combinations as well which i would struggle to list out sitting here today but there's it's
00:34:36 it's common that there are different phrases used to describe those objects yes
00:34:44 yes now relative to the recognized and certified classifications of dampers such as a smoke control damper a fire and smoke damper or fire dampers where does the
00:34:55 or fire dampers where does the performance of smoke evacuation dampers as tested by gilbert's fall on the spectrum
00:35:05 sorry did you say fire damper fire and smoke damper and smoke control yeah so the the gilbert damper falls underneath the three
00:35:16 underneath the three so it doesn't even satisfy the definition of a fire damper never mind a fire and smoke damper or a smoke control damper is that your evidence that's as i've set it out in my report yeah
00:35:28 i've set it out in my report yeah now if we go to your module 3 report at
00:35:33 blarp25035 and look at page 95.
00:35:39 you say at paragraph 4.8.81
00:35:43 you you say in relation to the dampers at grenfell tower all of these dampers were required to be smoke control dampers as they all needed to function in either the open or closed position depending on the
00:35:55 or closed position depending on the operation mode of the smoke control system now um mr lay yesterday in his oral evidence queried whether the dampers did in fact need to
00:36:08 whether the dampers did in fact need to be able to open and close in the event of a fire
00:36:12 of a fire at grenfell tower because he wasn't clear on what the purpose of the fireman's override switches was and what he said was it might be that the intention of those
00:36:23 it might be that the intention of those was for the fire brigade to use them in a fire by changing the floor of operation
00:36:29 operation of the smoke control system during a fire event but he also said it's possible that the fire brigade might simply use those override switches for smoke
00:36:40 those override switches for smoke clearance after there's been a fire which has been dealt with and therefore he questioned whether in fact these dampers needed to
00:36:51 fact these dampers needed to open and close during a fire rather than just simply close and stay closed now
00:36:58 now what's your response to that um my response to that is the the system as described and offered to the brigade was they could take control of the smoke
00:37:10 was they could take control of the smoke control system and they
00:37:14 and they sometimes i just don't know how to answer these questions i have to say they might like to do that during the fire they might like to do that after the fire
00:37:23 the fire and
00:37:26 so the dampers need to be able to open and close in any of those conditions right yeah and and where do you get that understanding from what's that what's that based upon
00:37:37 that based upon uh when you read what a smoke control damper is in a part quickly eight or ten yeah
00:37:44 yeah yes but in terms of the grenfell system um
00:37:49 um how uh how did you come to understand that the purpose of those yellow keyswitch boxes was that you could use them during a fire or after a fire because i
00:38:01 well i certainly didn't read they have been designed to only work in cold temperature conditions anywhere that might be the easiest answer to give sorry sorry i'm sorry
00:38:13 sorry sorry i'm sorry if that had been the intention of those dampers for use by the fire service that they were only to be used for smoke clearance purposes once the fire was out would you have expected that to have
00:38:24 would you have expected that to have been clearly communicated in the instructions to the system yes that we saw at ground floor level absolutely
00:38:37 now um is it right the adb itself doesn't refer to
00:38:44 to or state any um recommendations about smoke control dampers the highest performance of damper yeah that's correct as i've explained at length in my report yeah now if we go however to the relevant
00:38:57 now if we go however to the relevant british standard which deals with smoke control dampers this is at bsi four zeros one triple seven
00:39:09 this is bsen one three six six part ten 2011 and the dates important from 2011 and it's headed fire resistance tests
00:39:20 and it's headed fire resistance tests for service installations part 10 smoke control
00:39:24 control dampers
00:39:26 dampers and we can see on page 12 of this standard
00:39:30 standard that there's a definition of smoke controlled dampers that are given do you see that at 3.27
00:39:40 and it says it's a 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 within a duct
00:39:54 and um if we go to the introduction to this standard which is on page eight we get some more context on the use of smoke control dampers and i i just want to read those first
00:40:06 and i i just want to read those first two paragraphs under the introduction
00:40:11 it says this when smoke and heat exhaust ventilation are being considered it becomes apparent that a clear path needs to be made between the area where heat and smoke is being generated the fire and the outside of the building to
00:40:23 and the outside of the building to create this path there needs to be ducts and the smoke extract path needs to remain uninterrupted this means that smoke control dampers at the fire and along the path have to be open and
00:40:34 along the path have to be open and remain open smoke control dampers at branches or on the surface of the duct along the path need to be closed and remain closed in fact if the duct crosses a compartment boundary it becomes part of the fire compartment
00:40:47 becomes part of the fire compartment in which the fire started and then the purpose of this european standard is to define test methods to evaluate the abilities of smoke control dampers too
00:40:58 dampers too and then we can see for example at little three it says change state from close to open at elevated temperatures and vice versa yes yes so that's um some useful context to
00:41:11 yes so that's um some useful context to these smoke control dampers in that british standard and you have said in your report i don't think we need to turn it up it's blarp25035 at page 90
00:41:23 blarp25035 at page 90 paragraph 4.8.48 that the primary functional difference when comparing a smoke control damper with the other two types
00:41:30 types that's fire dampers and fire and smoke dampers is that a smoke-controlled damper must be capable of opening and closing in the event of a fire is that right
00:41:39 right yes
00:41:45 based on what you know of other types of dampers or ventilators are there any other types that are also intended to perform that function
00:41:54 i don't understand the question so
00:41:57 so would there be any other type of dampers that would be able to give you that functionality to be able to be capable of opening and closing and vice versa in the event of a fire there's not any other category is
00:42:09 fire there's not any other category is there well well not that i'm aware of but i don't know if it's kind of a yeah okay no
00:42:14 okay no now um
00:42:17 now um we know that psb and um mr lay have drawn attention to certain recommendations in the sca guide about smoke control dampers
00:42:28 about smoke control dampers and um if we can turn up the 2012 sca guide it's at lfb3059241
00:42:42 this is the 2012 version of that sca guide and if we go to page 36
00:42:51 so and under 8.2.5
00:42:56 it says there no formal product standard exists for the use of these products in this application to ensure the necessary product performance is achieved it's recommended
00:43:07 performance is achieved it's recommended that the aov should be regarded as a smoke control damper and the relevant product standards should be considered do you see that now is it right that um
00:43:18 now is it right that um when the in 2012 when the sca guide was produced
00:43:22 produced that there was no formal product standard for these dampers smoke control dampers i put the date in when it was produced to my report i just can't remember it right now i don't have any
00:43:33 remember it right now i don't have any of my reports with me i think what you tell us is that the 2011 british standard that we just looked at was uh published just before this is that right
00:43:44 that right yes so are you out i'm just i prefer because i don't have my reports i can't recall all of these things so there it was my my understanding is by the time this was published and in
00:43:55 the time this was published and in circulation from memory it had the standards had been published by then just when it was being drafted yeah they were not yes yeah and what the sca guide does if we go
00:44:08 and what the sca guide does if we go over the page at page 37 is
00:44:14 is it says in the second line down that there are several applicable smoke controlled damper standards and these are listed below and indeed we get en 1366 part 10
00:44:28 and indeed we get en 1366 part 10 which is the smoke control um
00:44:33 um damper standard there yes listed which is the one it's actually dated 2011. it doesn't say the date there the one that we just looked at so it gives those standards yes but then
00:44:46 so it gives those standards yes but then it goes on to suggest some alternatives and what it says is this below those standards it says any damper tested as fire resisting
00:44:57 any damper tested as fire resisting tests are made using the standard time temperature curve supported by an ad hoc operation test at elevated temperature ed 300 degrees and or 600 degrees c for one hour etc
00:45:09 and or 600 degrees c for one hour etc using a drive open a drive open drive closed actuator could also be acceptable these test standards are listed below and it lists some other test standards
00:45:20 and it lists some other test standards and then it goes on and it says in the final line dampers tested in the closed position to bs 476 part 20 could also be suitable do you see that yes
00:45:33 suitable do you see that yes now to what extent um in your opinion do these recommendations address the need for a damper on an escape route to limit smoke leakage as
00:45:44 escape route to limit smoke leakage as required by bs triple nine one for example as req as in order to meet the functional requirements in a high-rise residential building you mean yes um
00:45:56 residential building you mean yes um reading these three sentences as written you can't see any signal
00:46:02 signal that smoke leakage is relevant
00:46:06 and to what extent do these recommendations address the need for a damper installed in a dual environmental and smoke control system to perform properly
00:46:15 properly after multiple perhaps thousands of open closed cycles is there anything in there that's addressing that no
00:46:26 now picking up on that last sentence of that that guy that dampers testing and the closed position to bs 47620 could also be suitable can we just look at um adb again clg five zeros two two
00:46:40 at um adb again clg five zeros two two four
00:46:42 four page 88.
00:46:52 yeah so i want to look at paragraph 10.15
00:46:57 10.15 and it's note one that i want to look at it says their fire dampers testing using tested using ad hoc procedures based on bs476 may only be appropriate for fan
00:47:08 bs476 may only be appropriate for fan off
00:47:08 off situations in all cases fire dampers should be installed as tested now in your opinion is that relevant to whether or not um
00:47:19 um ad hoc testing to bs 476 can be appropriate in a system like grenfell tower so there's a warning here
00:47:30 so there's a warning here and it's not replicated in the sca guide maybe
00:47:35 maybe a good way to explain that is it right that bs 476 part 20 is a historical test standard from 1987 relating to testing fire resistance of elements of construction rather than
00:47:47 elements of construction rather than damper specifically and it had been superseded many years before that sca guide came out
00:48:01 i'm being really yeah i'm going to say yes bs 476 actually on its own doesn't mean anything but anyway but yes i know what you're trying to ask me yeah well it was um so in the sa
00:48:13 ask me yeah well it was um so in the sa guide it was bs 476 part 20 yeah that was being cited yeah um is that a what i'm saying is is that a pretty out of date standard to be referencing in
00:48:24 of date standard to be referencing in the sca guide well part 20 she said frantically trying to remember i think that's where this oh it's just a description it's not a test for a damper for example yeah it's not a
00:48:36 for a damper for example yeah it's not a damper test standard let's put it that way does that contain any smoke leakage measurements we can't see that it does no no no what no we wouldn't do yeah
00:48:51 and um what is your view about the appropriateness of the sca guide recommending or permitting the use of a damper
00:48:59 damper tested to that standard bs 476 part 20 as a potential route for a smoke control damper i think it's not appropriate
00:49:14 now by making recommendations about the appropriate use of dampers without reference to the s maximum smoke leakage requirement did the 2012 and 2015
00:49:27 did the 2012 and 2015 versions of the sca guide in your opinion reflect the functional requirements in the building regulations including b1 and b5 enough for high-rise residential buildings no
00:49:38 residential buildings no if a designer was designing a system of a type that was referred to in the sca guide would it be reasonable simply to use that guidance on the specification of such components
00:49:54 my opinion on any industry guidance not just the sca guidance is it has to be read in the round so that means understanding
00:50:06 that means understanding other
00:50:08 other say statutory guidance documents and non-statutory guidance documents and that you need that level i suppose i'm going to have to say knowledge and competency before you interpret an industry
00:50:21 before you interpret an industry stat an industry set standard and i don't have that view solely about the sea guide i just want to be fair about that i think it applies to any industry guidance document
00:50:33 industry guidance document okay
00:50:36 yes so is it your evidence that a reasonably competent designer specifying components for a system wouldn't just take the sca guide at face value but would ask the question
00:50:47 question is this going to meet the functional requirements in the building that i'm designing for i think you have a duty to do that under both well anyway i don't know if you need me to say i think you have a due to do that under both cdm and
00:50:59 have a due to do that under both cdm and the building regulations myself yeah yeah
00:51:03 yeah and
00:51:04 and now following on from mr lay's evidence yesterday it appears to be agreed that the gilbert's dampers didn't even meet those lower sca guide recommendations because the testing method which had
00:51:16 because the testing method which had been done was from the closed position and was not compliant with 1366 part 2. and as mr jones in his evidence made
00:51:27 and as mr jones in his evidence made clear the dampers were were also not fire fire and smoke or smoke control dampers
00:51:34 dampers now
00:51:35 now in your view was that something which a reasonably competent designer in receipt of the test data from gilbert's could have been expected to identify and pick up
00:51:54 i think that um
00:51:58 um the the gilbert's information they sent to the design team at the time informed the design team i can't remember the words off by heart but it did tell them
00:52:10 but it did tell them the damper do you want to put it up because i i can't
00:52:15 can't i haven't got the reference here just to paraphrase the detail in my report which is more important than this paraphrasing i'm going to do now there there was a warning in the
00:52:28 there there was a warning in the document
00:52:29 document that it hadn't been tested to
00:52:32 to the
00:52:33 the the required standard okay
00:52:37 okay but i suppose having done what i've had to do in the last two years to drop to try and decipher this problem i i think i probably have some sympathy that it's
00:52:49 probably have some sympathy that it's quite a difficult thing to derive all on your own on on a job and i have found it incredibly difficult when doing it for the inquiry okay
00:53:01 when doing it for the inquiry okay um but in this particular case there there was a slight there was some warning okay but then you needed to get into the detail of the test and what that meant
00:53:13 detail of the test and what that meant and what you were trying to do okay
00:53:19 sorry sorry miss grange i think that anyone who's taking responsibility for a product as we've spoken about again at length for the last few years about the clutching everything else dampers are
00:53:30 clutching everything else dampers are not different um
00:53:32 um the designer has to be able to understand the background testing and its relevance to the application the designer
00:53:44 the designer you know is solely responsible for placing that product in it's the same for clouding as it is for dampers
00:53:54 okay so just to be absolutely clear are you critical of psb for not picking up that the damper hadn't been tested in full compliance with the sen-1366 part two
00:54:07 sen-1366 part two or not oh well i am of psb yes because they are a member of the smoke control association or certain individuals there were and they understand the sca guide very well and i trust
00:54:18 the sca guide very well and i trust therefore they understood how to interrogate the damper standards
00:54:27 and would you have expected them to then communicate that these dampers didn't have any classification or formal certified status to others on the the refurbishment
00:54:39 to others on the the refurbishment project should that have been communicated to others yes it should and who are the others that it should have been communicated to so i think building control needed to know
00:54:48 know um the fire service will have wanted to know and then the responsible person needed to know um
00:54:56 um i should say again though if the proper standard if the proper performance needed for grenfell tower have been written down in the first place and people were assessing products off
00:55:07 and people were assessing products off those standards that might also have helped
00:55:11 helped okay
00:55:16 yes i see so i think what you're saying is had the fire strategy contained the performance standards for the dampers and people were then referring back to that and checking
00:55:28 referring back to that and checking whether that standard was met that would have helped everybody yeah exactly because on most good job jobs the contractor in the end will kind of go through a list if they said this have i got that have i checked
00:55:39 got that have i checked have i you know have i checked my test certificate so if it isn't written down you run the risk of of more error but
00:55:47 but in this particular case um there was no performance set by anyone
00:55:54 anyone and despite gilbert's communicating it wasn't a certified damper it was accepted willingly
00:56:03 now can we look back to your supplemental report blarp25043 at page one two eight
00:56:14 and at section 6.7 you've got a heading development and revision of damper guidance in the sca guide yeah and i just want to read out the two paragraphs setting out the purpose of this section
00:56:25 setting out the purpose of this section so what you've said at 672 is as i've set out in section 6.6 when compared with the provisions in adb the sca guide 2012 and 2015 introduced a
00:56:37 the sca guide 2012 and 2015 introduced a set of unique and substantially lower performance standards for dampers in smoke shaft systems when you go on at 673 the purpose of this section is to show evidence of how
00:56:50 this section is to show evidence of how the alternative standards were originally developed for the sca guide 2010
00:56:55 2010 as a stop gap measure but were instead retained until their removal from the sca guide
00:57:01 sca guide 2020
00:57:02 2020 after the grenfell tower fire now without going through all the emails that you quote in this section of your report is it a fair summary of your view to say
00:57:13 to say that the sca guides alternative options for appropriate dampers appeared from these emails to be originally intended as a temporary course of action pending the publication of standards for
00:57:25 pending the publication of standards for smoke control dampers which we saw was done in 2011. yes and
00:57:32 and um is it right that even though we then had a standard published in 2011 for formal smoke control dampers the alternative routes in the sca guide
00:57:44 the alternative routes in the sca guide were not removed after the standards publication and you say that that was a substantial or if people followed that guidance there was then a substantial reduction
00:57:55 there was then a substantial reduction in performance requirements in the sca guide which was out of line with other guidance including british standard guidance is that correct yes
00:58:08 thank you um
00:58:14 now mr lay in his evidence in his report and his evidence yesterday he acknowledged that the gilbert's dampers weren't certified to certain formal standards nor did they meet the sca
00:58:25 standards nor did they meet the sca guide recommendations um
00:58:28 um as they were contingent on a compliant test from an open position and if we can go to paragraph um sorry page 199 in mr la's report lay 701 at
00:58:41 page 199 in mr la's report lay 701 at page 199
00:58:42 page 199 he deals with certification at 663
00:58:48 and he says this based on the information in the wf 309 850 report so that's the the test report that was obtained for the damper the damper may
00:58:59 obtained for the damper the damper may be able to achieve an e 60 classification an integrity 60 classification however it cannot do so on the basis of the report itself as the test was not
00:59:10 the report itself as the test was not conducted fully in accordance with the procedure of bs en 1366 part 2 in that the damper was closed at the start of the test
00:59:20 the test it is credible that based on the information in that report the damper could have been classified as a 60-minute fire damper using bs 476 part 20 methodology but i have not seen a
00:59:33 20 methodology but i have not seen a classification of the damper to this standard
00:59:37 standard and if we can also go to page 203 of his report
00:59:41 report and paragraph 678 he says at the top after considering the dampers he said based on the above i consider that the dampers had performance characteristics
00:59:52 performance characteristics that could allow them to perform adequately within the system despite the issues with certification now in your view is it open to a reasonably competent designer
01:00:03 reasonably competent designer to specify a component which not has not actually been tested in respect to particular performance characteristics but which is believed could or may pass
01:00:14 but which is believed could or may pass that test if done no
01:00:18 no so is such hypothetical testing ever an acceptable substitute to actual testing is hypothetic what a hypothetical test sorry well saying to yourself we haven't
01:00:29 sorry well saying to yourself we haven't done the test in the way that it it sets out
01:00:34 sets out but
01:00:34 but knowing what i know about this damper i think it might well pass that test and then behind the ground hopefully it'll be grand i think so when i think about these dampers i actually find mr jones as evidence the
01:00:47 actually find mr jones as evidence the most important um and he explained why um what on the surface might appear like a minor point you know the damper needs to go from the close to the open position he explained really carefully
01:00:59 position he explained really carefully and i listened to him very carefully about
01:01:05 why that's a very difficult um
01:01:09 um motion
01:01:10 motion in heat for something made of metal to go through and i interpreted from what he said you probably have to make your damper a little bit more robust in all sorts of
01:01:21 little bit more robust in all sorts of different little ways i couldn't possibly speculate and so i think that's why this test and doing the test is so important
01:01:32 important so you can see its behavior in a standardized way and compared the products side by side as a designer so i'm not into hypothetical testing or hoping
01:01:46 hypothetical testing or hoping an untested product might be grand i consider that very unprofessional actually
01:01:54 now um some questions about cumulative versus a constant leakage rate if we go to your module 3 report it's at blarp 2 5 0 35 at page 228.
01:02:09 yeah you included a graph of the volume flow rate during the test of the gilbert's damper
01:02:18 damper and if we just look at this graph i'm going to read out what you say about um the leakage on the preceding pages what you say is it's interesting to note that as a result of dropping below the smoke
01:02:29 as a result of dropping below the smoke leakage limit of 200 cubic meters per meter squared per hour from nine minutes to 53 minutes the cumulative
01:02:40 minutes to 53 minutes the cumulative leakage of this damper was in fact lower than that of a damper with a constant leakage of 200 cubic meters per meter square per hour which would have complied with adb 2013.
01:02:53 complied with adb 2013. now mr lay has referred to this observation in his report when considering um how leaky the gilbert's dampers were now are you able to help us as to why
01:03:04 now are you able to help us as to why the the maximum leakage requirements in the relevant standards are not expressed as a
01:03:10 as a accumulative rather than a constant figure so
01:03:14 figure so why they require you to stay under the 200 figure at all given points in the test rather than being expressed as a cumulative average across the test
01:03:26 cumulative average across the test period yeah so first of all i put this graph in my report i think it's important to understand why because my original plan when i started out on this journey was i
01:03:37 when i started out on this journey was i was going to try and quantify leakage because i you know i was asked to look at leakage to see if it was concern the night of the fire and i was going to try and quantify the
01:03:48 and i was going to try and quantify the leakage and in the end i wasn't able to do that satisfactorily and this graph has remained it doesn't say anywhere as i'm aware as to why it isn't you know an aggregate or
01:04:00 to why it isn't you know an aggregate or cumulative quantum and instead it's in the moment but i can only guess it's because the damper has to perform in the moment on the night of the fire but that is a
01:04:11 the night of the fire but that is a guess because it's not written down and then i think you asked me something else as well
01:04:16 as well no no
01:04:17 no no that's fine yeah i mean taking a step back and thinking about a real world application and bearing in mind life safety
01:04:27 when assessing whether an escape route is safe for a resident to go through during a given minute is the instant leakage rate more important than an average rate over a much longer time period
01:04:37 period so first of all remember this isn't the damper that was installed in grenfell tower this is the gilbert damper that was tested okay so the damper and ground full tower was
01:04:48 so the damper and ground full tower was smaller
01:04:49 smaller and the
01:04:51 and the leakage standards say the smaller the damper the higher the leakage in the same test so this isn't representative this was the problem i had in the end it's not actually representative of the installation and grenfell
01:05:04 installation and grenfell um
01:05:05 um why is damper in the moment um sorry can you just say the question again rather than cumulative on the night of the fire i would imagine it's both
01:05:15 both right
01:05:16 right what i was asking is is it does the standard require it to be the instant leakage rate because um
01:05:24 um a resident could be escaping at any point along this time curve and the to the residents from the residents perspective it's not really relevant whether there's an average that's underneath what's relevant is whether
01:05:35 underneath what's relevant is whether they're getting a an unhealthy dose of smoke
01:05:38 smoke as they're escaping is that the reason why it's an instant leakage rate yeah so i i don't know that for a fact so i prefer not to speculate if you don't mind i i just you know i don't know and
01:05:49 mind i i just you know i don't know and i haven't thought haven't thought about it
01:05:51 it you know in in that context okay is that okay so i prefer yeah i i don't know the answer to that okay
01:06:00 okay now when addressing the cumulative leakage issue if we could go to your supplemental report blarp25043
01:06:10 um i want to look at page 140 where you've got figure 6.4 this is a figure that um i took mr lay to yesterday
01:06:21 to yesterday and if we blow that up figure 6.5 it's the bsen 1366 part 10 2011 so that's the standard that dealt with smoke control dampers
01:06:32 dampers and and you are trying to explain the test conditions for this smoke control damper in this figure is that correct yeah well it was because i was fascinated by what
01:06:44 it was because i was fascinated by what mr jones said and i was trying to work out
01:06:50 how you know i could understand that using
01:06:55 using characteristics of metal under heat yes and in box b you've drawn attention to certain properties that the metal would have under heating including expansion and loss of stress
01:07:07 including expansion and loss of stress strength and stiffness is that correct yeah
01:07:09 yeah um and mr jones of gilbert's he said during his evidence this is day 157 page 73 line
01:07:17 73 line 17-23
01:07:19 17-23 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
01:07:30 blade could 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 based on what you know about the properties of the the metal um
01:07:41 um does that sound right that it's likely to be much more onerous to start the damper from the open position heat it and then see whether it can close yeah and what the leakage requirement is than if you've started only in the closed
01:07:53 if you've started only in the closed position
01:07:54 position exactly and then presumably when you've done enough tests you're able to work out then the kind of strengthening or other things you need to do so that the final product you know can
01:08:05 so that the final product you know can get through this the prop the standard test i thought that i actually found that really interesting yes yeah but um is it right that without actually carrying out the test it it's not going
01:08:16 carrying out the test it it's not going to be possible to say what the difference might have been for any particular damper exactly
01:08:29 now the size of damper which was tested by
01:08:32 by gilbert was different it exceeded the size of damper that was installed at grenfell tower is that right yes and
01:08:40 and does that mean then that compar comparing the cumulative leakage of the gilbert's damper to that of um
01:08:48 of um the damper installed at grenfell tower is not going to be comparing like with like that's correct and that's why i had to give up in the end and i decided to quantify the whole thing now in terms of durability of
01:09:00 now in terms of durability of operational reliability of the gilbert stampers
01:09:04 stampers i just want to look at that aspect of damper performance yes if we go within your module 3 report to blarp 25035 at page 92
01:09:16 and if you look at paragraph 4.8.7 t at the bottom
01:09:22 you you tell us what the key differences are for the test method for evaluating integrity and smoke leakage performance for smoke control dampers and you say the key differences are as follows and
01:09:33 the key differences are as follows and if we go over the page
01:09:37 the first difference is that the smoke controlled damper is subjected to a greater number of open closed cycles prior to testing this is termed the durability of operational reliability a smoke control damper intended for a
01:09:49 smoke control damper intended for a combined smoke and environmental system is subjected to 10 200 open closed cycles prior to fire testing a fire damper and fire and smoke damper is subject to just 50 open closed cycles
01:10:01 subject to just 50 open closed cycles and then you also point out in b the point we were just discussing that the ability of a smoke control damper to change from open to closed or vice versa elevated temperatures is tested in that
01:10:12 elevated temperatures is tested in that particular more onerous standard now um as for the open and closed cycles requirement as the dampers were part of an environmental ventilation system at grenfell tower is it right that they
01:10:24 grenfell tower is it right that they were reasonably expected to open and close many times this week each week yes they were programmed to cycle open and closed all day well as a function of temperature
01:10:35 well as a function of temperature yeah
01:10:37 yeah and no such testing to anything like 10 000 cycles um occurred for the gilbert's dampers did it nothing i'm aware of
01:10:48 absent testing data on their durability following long-term use is there any um available evidence about how they might have performed in a fire
01:10:59 they might have performed in a fire scenario after many months of use in an environmental system is that something that could just be uh
01:11:05 uh assessed in general i don't think i don't know i
01:11:11 i i don't know
01:11:14 mr lay yesterday his response to that point was well you could expect your maintenance of the system to pick that up so if they've
01:11:25 if they've that they're having problems because their durability simply isn't good enough
01:11:31 enough then you would expect your regular maintenance visits to pick that up is that in your view an acceptable substitute for having tested the durability of dampers in a dual environmental and smoke
01:11:43 in a dual environmental and smoke control situation i i think it's it's an additional thing it's not in lieu of
01:11:50 lieu of i i pre again i'm only presuming the you know a product that can get through that number of cycles and be exposed to heat looks slightly different to one
01:12:02 heat looks slightly different to one that doesn't so that's the first point and then again as covered at length in module three i think it is or well anyway the rro module
01:12:13 anyway the rro module um
01:12:14 um yes maintenance was needed anyway and we know that that didn't really occur so in my mind it's two separate things not one or the other yes
01:12:25 not one or the other yes now mr jones and mr lay both refer to the relevance of the shafts being depressurized when assessing the risk of smoke leaking out of the damper
01:12:37 of the damper now can we agree that just as a matter of basic physics if the shafts have negative pressure relative to the lobbies
01:12:43 lobbies smoke shouldn't leak into the lobbies correct
01:12:47 correct now is it your view that a smoke-controlled system designer is entitled to assume when designing the system and specifying the dampers that the shafts will remain depressurized during a fire through correct operation
01:12:59 during a fire through correct operation of the fans no that's that they're trying to make that happen that that's the whole point of your fan selection all the different things that have to be accommodated
01:13:10 things that have to be accommodated um
01:13:11 um into your final fan rating that's what you're trying to do so anything you forget to incorporate at the time it may mean
01:13:19 mean the fan in the event of a fire you know can't cause the necessary negative pressure okay and and would you ever allow for fan failure when you're picking your dampers
01:13:32 failure when you're picking your dampers would you ever say to yourself well i can't assume that the fans would always start and that there will be negative pressure in the shaft so i need to make sure that my dampers would be capable
01:13:44 would be capable of dealing with excessive leakage in the event that the shafts aren't depressurized yeah understood so my my understanding of
01:13:55 understanding of um
01:13:56 um oh how do i know this the idea of having you know restricted leakage and a damper is that it can i i understand that
01:14:08 is that it can i i understand that it's not meant to provide the level of let's call a compartmentation only when the fan is on no that is not my understanding i think that's what you're asking yes it's meant to be able to provide the compartmentation aspect
01:14:22 provide the compartmentation aspect as a compartmentation device okay does that make sense so it can't only provide compartmentation if the fan happens to go on too that's as i understand things yes yeah
01:14:35 that's as i understand things yes yeah so take the south shaft for example yeah um and we'll see some figures for this in a moment assume at low at low level fan speed
01:14:47 assume at low at low level fan speed yeah but actually that fan wasn't being very effective yes and assume that you've got some smoke venting up the south shaft as a result yeah i think what you're saying is that you've got to
01:14:59 what you're saying is that you've got to assume in your design and your damper selection that your dampers up up and down that south shaft underneath the north shaft could hold
01:15:10 underneath the north shaft could hold back excessive smoke leakage so we have to be careful have to be careful about this now um
01:15:21 so as let's call it a certified damper has let's call it a minimum acceptable leakage
01:15:32 and that that's all that's possible it's not taught about anything beyond that before the grandfather based on my experience does that make sense so
01:15:44 experience does that make sense so the a certified damper if the fan goes off or is off or something happens we'll have a minimum leakage potential
01:15:55 we'll have a minimum leakage potential only okay if they're we can't
01:16:00 we can't yeah
01:16:03 can't stress straight beyond that i understand yeah let's look at your supplemental report blarp25043
01:16:13 and i want to look at page 143
01:16:18 you've extracted here the table of airflow speeds across the north and south shaft dampers which mr partlow of psb measured during commissioning
01:16:29 commissioning and you've highlighted some of the figures
01:16:33 figures with coloured boxes so figures in red show a negative figure which means that the pressure in the shaft
01:16:44 shaft was in fact higher than in the lobby and then you've highlighted some in yellow where there was just simply no pressure differential between the shaft
01:16:56 pressure differential between the shaft and the lobby now can you just explain the significance of this and why you've included it in your report in your supplemental report yeah i thought it was interesting and it's
01:17:08 was interesting and it's um
01:17:10 um i don't know how what conditions the measurements were taken in first of all so
01:17:16 so it
01:17:17 it actually and mr lay ex explained this very clearly yesterday that this doesn't represent the shaft in its entirety in that moment it's a number from one you know from one
01:17:31 it's a number from one you know from one lobby at a time so that so can't be seen any other way um
01:17:36 um and it's showing there it's showing probably
01:17:42 probably that
01:17:43 that if the two fans were on at the same time i don't know if they were but i'm assuming they were that potentially the
01:17:50 the north shaft you know is basically pulling on the side shaft that might be one way of interpreting it yes yeah we know in other words there isn't you know it's not demonstrating it you know would
01:18:02 it's not demonstrating it you know would suck up the shaft basically yes yeah we know the two fans were rated differently weren't they yes the south chef fan i think was pulling out extracting um two
01:18:13 think was pulling out extracting um two cubic meters per second and the north fan 3.6 they were meant to be yes yes so the northbound was meant to be stronger than yes it was mentally um
01:18:23 um mr lay said yesterday in his oral evidence well um hang on a minute in fairness to this system it wasn't really intended to be extracting
01:18:35 really intended to be extracting smoke on low mode from the south shaft so he's not concerned about these figures
01:18:42 figures and i think in his his written statement he said well actually what this shows is it might be pushing some air out into the lobby and you get some dispersal so it could be a positive thing
01:18:54 it could be a positive thing now to what extent would these figures have concerned you on commissioning to get these figures showing that the south shaft wasn't performing in the way the system
01:19:06 wasn't performing in the way the system appears to have been designed to operate
01:19:13 so there's about eight points sorry i'm sorry yeah it's probably too much there's a lot of points there i think all i'm prepared to say is
01:19:24 is i i don't know the conditions each number was measured in so it's really hard for me to speculate okay
01:19:35 okay um
01:19:36 um and
01:19:39 it it and also this is cold temp these are cold temperature conditions as well i mean i could go on i've tried to explain that you know i don't know that
01:19:50 explain that you know i don't know that like there's no big flourishing conclusion here about this data okay okay is mr lay right though according to your understanding that the system wasn't
01:20:01 understanding that the system wasn't really intended to extract smoke south when it was on low mode is that your understanding of how the system was designed well apparently the system doesn't extract smoke at all
01:20:14 so i think that's mr lay's opinion i don't have anything to add to that yeah okay mr chairman i think that's a good moment for our afternoon break yes
01:20:25 good moment for our afternoon break yes i've almost finished this topic uh but right well we'll take a break there anyway we'll um stop there we'll come back at 25 to 4 please thank you unusual restrictions apply thank you
01:20:41 thank you 25 to 4 please
01:37:45 would you ask dr lane to come back in please
01:37:59 all right dr lane ready to carry on yeah yes thank you yes it's strange yes thank you yes just finally on dampers i want to look at um psb's justification for
01:38:10 to look at um psb's justification for not specifying es smoke control dampers and so what we know was that it was just the gilbert series 450 series 54 damper that was selected
01:38:22 series 54 damper that was selected no no particular performance standard was specified it was just that damper selected
01:38:27 selected mr marnie's evidence was that smoke-controlled dampers weren't used because first of all none were available on the market at the time and second secondly he said the dimensions and the size simply wouldn't
01:38:39 dimensions and the size simply wouldn't work with the size and position of the shaft at grenfell tower now if we can bring up your addenda and errata
01:38:47 errata document please at blarp2504
01:38:53 at page three
01:38:58 and in section 1.1.1 you set out your methodology in relation to a search for smoke control dampers and fire and smoke dampers
01:39:09 dampers and fire and smoke dampers from 2015 that are available on the market in june 2015. so you tell us at 1.1.2 that you carried out a limited and ultimately time constrained search of dampers available on the market in june
01:39:21 dampers available on the market in june 2015
01:39:23 2015 and you tell us at 1.1.11 two up from the bottom of the page from this limited activity have found that two smoke control dampers and two fire and smoke dampers were available in june 2015
01:39:36 dampers were available in june 2015 and you summarized your criteria for the search of products that you did at paragraph
01:39:41 paragraph um on page four of this over the page at 1.1.19 so your criteria you were looking for was these are if the product achieved at least the required fire and smoke
01:39:53 least the required fire and smoke performance of es60 was stated as suitable for use in a concrete and masonry wall and was available in dimensions that would fit the existing openings of the north and south
01:40:04 south shafts
01:40:06 shafts now
01:40:07 now um
01:40:09 um in this document you've emphasized that you carried out a limited search only in particular focusing on the loss prevention and certification board red brook scheme although there were other
01:40:20 although there were other third party certifiers at the time is that correct yes
01:40:26 and then on paragraph 1.1.3 on this page further up um
01:40:32 um you say this i've it's not a matter for me to carry out any further work on this subject i've had no access to project specific mechanical engineering or construction detailing and thus make no attempt to
01:40:43 detailing and thus make no attempt to conclude on this matter beyond stating there appears to have been in 2015 some suitable products worth considering and with the relevant performance requirements for the grenfell tower
01:40:54 requirements for the grenfell tower primary refurbishment work now um the results of your search are then summarized in table 1.1 on page 5 of this document
01:41:07 so there we've got the products that you identified so two smoke-controlled dampers and two
01:41:16 and two fire and smoke dampers that were identified and satisfied the criteria that you were looking for is that correct
01:41:25 correct yes that's correct
01:41:29 and would you have expected a reasonably competent system designer to have searched for and specified one of these dampers all of which have at least an es certification yeah so in my quick search
01:41:45 i found these four i looked at area of opening only also and these are the four that i found and yes i would expect a reasonably competent person to carry out a more
01:41:57 competent person to carry out a more extensive search yes
01:42:00 yes now mr lay has said and and he made clear in fairness to him that he hasn't had very long to look at this which he hasn't
01:42:08 hasn't that um in his view at least some of these dampers would potentially stick out too far into the lobby they would protrude into the lobby now what what is your response to that point
01:42:19 what what is your response to that point yeah so the two fire so i checked the depth last night the two fire and smoke dampers are the same or smaller depth and
01:42:30 and the smoke control dampers are deeper than the products installed on grenfell tower yeah right yeah so does that i mean he seemed to think that that would have been an impediment to using them
01:42:41 have been an impediment to using them because they'd stick out from the wall the smart control dampers yeah but did you agree with that so this is exactly why i didn't want to do any retrospective design work on on my own
01:42:53 retrospective design work on on my own so i found these four products and then i would want to sit down with various people and work out what could be installed appropriately in grenfell tower and i'd go off and find some others as well
01:43:04 others as well so on the surface of it yes one one of the smoke control dampers particularly would substantially stick out of the wall if it wasn't stalled the same way
01:43:14 same way and might that preclude its selection it's very well might in the end yeah but that didn't happen at grandfather
01:43:26 and how much of a problem would it be to have dampers sticking out into the lobby is that not an ideal situation to have or have you ever had a situation where you you would take the plain line of say
01:43:38 you you would take the plain line of say a damper out to ensure that you've got a better performance specification out of plane dampers are very common but i think this this isn't really an out-of-plane damper situation
01:43:49 out-of-plane damper situation it
01:43:50 it um so out of plane dampers are very common and then again this is pure speculation because i wasn't on the design team for grenfell tower you'd have to think then about
01:44:03 have to think then about if that could be incorporated into the into the lobby shape somehow with without removing you know say comfort and access but just really be i'm just pure speculation now yes but an out-of-plane
01:44:16 speculation now yes but an out-of-plane damper is commonly used in buildings i'm not implying off to the extent of graham this one might have been in grenfell tower right okay but i think what you're saying is at
01:44:27 but i think what you're saying is at least two of these wouldn't have been significantly out of plane the fire and smoke dampers which would have a substantially better performance than the smoke ventilator
01:44:38 the smoke ventilator are so are of a similar depth okay and that's all i've got to say this was a quick check looking at some products and this is a list i produced
01:44:49 products and this is a list i produced and when you say there are of a similar depth do you mean they're of a similar debt to the gilbert's ones that were installed at grenfell tower exactly yes these smoke control dampers are are
01:45:01 these smoke control dampers are are deeper
01:45:03 deeper than the installation of grandfather yeah
01:45:06 yeah now in the event that a designer couldn't source an appropriately certified damper would you expect a reasonably competent designer to record and communicate any such restrictions or limitations
01:45:18 such restrictions or limitations in the context of this fire safety equipment yes
01:45:28 and in the event that mr mani was unable to identify a suitable damper to perform the required duties at grenfell tower what would you have expected a reasonably competent smoke ventilation system designer to
01:45:40 smoke ventilation system designer to have done
01:45:54 i think we're you know we're back to the same themes again so that there was a performance standard written down in the first place so the reasonably competent what you say
01:46:06 so the reasonably competent what you say smoke ventilation system designers that we said weren't operating on their own yes yes
01:46:15 yes yes and i i've no evidence that one there was an attempt to source in the first place which is more important to my mind but if there have been an attempt to source one and there was problems with
01:46:28 source one and there was problems with its installation and impacting the lobby i would expect that to be a design team consideration and some kind of final conclusion reached i don't think the smoke ventilation system designer
01:46:41 ventilation system designer would contractually be allowed to make that decision on their own on a job where it was interfering with a public you know a public area okay okay i'm not really prepared to go
01:46:53 okay okay i'm not really prepared to go any further than that so i think what you're saying is that it would need other
01:46:57 other members of the design team to
01:47:01 to be content with the situation if they couldn't put in the dampers that they felt were necessary so either they were prepared to have some kind of obstruction in the lobby unlikely or
01:47:12 lobby unlikely or um you know we're we're back to then i would if the smoke control dampers you know
01:47:18 know there again we're back to the same situation where that impacts the compartmentation not just the smoke ventilation system and there's a performance issue
01:47:29 and there's a performance issue around the functional requirements i think that's a very difficult thing to do on your own as a smoke ventilation system designer i think was the phrase you used okay
01:47:42 think was the phrase you used okay now just briefly thinking about other system components the fans in your
01:47:49 in your module 3 report for the transcript this is at page 15 paragraph 10 8 10 blarp 2 5 0 36 you say that the extract fans for the
01:48:01 you say that the extract fans for the system were not correctly specified and you say that the systems extract fans should have been rated to a temperature of a thousand degrees c when tested and classified in accordance with the relevant standards
01:48:14 now
01:48:17 the depressurization systems that are referred to in the standards you quote are all extracting directly from a fire zone
01:48:25 zone does that change your view is it relevant that the british standards you refer to are talking about extracting directly from a fire zone does that mean that the uh fan perhaps
01:48:38 does that mean that the uh fan perhaps didn't need to be rated so highly at grenfell tower in terms of temperature okay so that's and so i've updated the temperature expectation for a fan and a non-sprinkler building since then
01:48:52 and a non-sprinkler building since then um
01:48:53 um what's the ques what did you say so because the fan isn't extracting smoke directly directly from the fire does that affect uh the extent of performance of the fan that's required
01:49:06 performance of the fan that's required it could it could be a consideration yes the guidance in in the sca guidance at section 8.2.6 in the 2012 sca guide on page 37 states that a typical fan
01:49:19 page 37 states that a typical fan specification for a mechanical extract smoke system will be for 300 degrees c for 60 minutes do you consider that to be an adequate standard that's the standard typically
01:49:31 standard that's the standard typically um specified in a sprinklered building i see so you're saying if it's not a sprinklered building you potentially have to allow for higher temperatures
01:49:42 have to allow for higher temperatures typically you try you raise the temperature standard for your fan i see yeah can we look at mr lay's report briefly on this it's lay 701 at page one six
01:49:59 and a page seven three six two seven three eight he says this he says fans are often specified with a temperature rating below the fire temperatures expected in compartment fires which can exceed a thousand
01:50:11 fires which can exceed a thousand degrees c
01:50:12 degrees c this is in part a practical measure as fans that could tolerate extreme temperatures are not practically available for the general building market now just pausing there is that your understanding as well in an
01:50:24 your understanding as well in an unsprinklered building yes the temperatures can be extremely high and i know you know that that's yeah yes i agree with that concept yeah yeah but i think the point he's making
01:50:35 yeah but i think the point he's making is that
01:50:37 is that fans that could tolerate extreme temperatures are not practically available
01:50:41 available yes i i under i understand that i understand the rating of fans that one can buy yes yeah you really agree with that i do yes he says also the movement of air over fans will typically ensure
01:50:52 of air over fans will typically ensure that they're exposed to a lower temperature than a compartment fire and where fans are remote from the fire compartment significant cooling of the smoke will take place before it reaches the fan again do you agree with that that's a relevant consideration when
01:51:04 that's a relevant consideration when you're specifying your fan temperature yes that is a good consideration when one is thinking about a fan and then he says at the next paragraph the sca guide includes data from the bre
01:51:15 the sca guide includes data from the bre study and then he gives the name of the study which provides information on expected fire sizes in unsprinkled dwellings and characteristics of flow leaving the fire flap by the entrance
01:51:26 leaving the fire flap by the entrance door and has included this information and if we go over the page
01:51:38 he says there the fans were in line with the expected standard set out in the sca guide sorry i just want to see if there's paragraph 7.38 back on the previous page
01:51:51 sorry if we go back up so he's got a table of data from that um study
01:51:58 study thank you and he says from the data in figure 215 it can be established that with an extraction rate of over 5 cubic meters per second the temperature of smoke at the door of 690 degrees c is reduced down to
01:52:09 of 690 degrees c is reduced down to below 300 c when it's mixed with ambient air entering from the inlet pathway this has been confirmed in modelling such as that used by colt for the type of approval of the cold shaft systems
01:52:20 approval of the cold shaft systems whilst care should be taken in applying results from one system to another the significant reduction in smoke temperature by the the time smoke reaches the fan is well established and the 300 degrees c recommended by the fca
01:52:32 the 300 degrees c recommended by the fca guide for relevant parts of a smoke control system is expected to be adequate
01:52:37 adequate now again do you agree that based on some of the information including from the cult modeling that's been done
01:52:44 been done the the sca guide's recommendation of the 300 degrees c is adequate is adequate i think the co you know we the we've been through the code modeling
01:52:56 we've been through the code modeling it's for a specific
01:53:01 type of lobby and fire size and ultimately the
01:53:09 the i think
01:53:10 i think i don't agree that in an unsprinklered building
01:53:14 building um a fan at a rating of 300 300 degrees celsius can automatically be considered adequate now right and what what
01:53:25 what so we we would typically recommend something at 600 degrees and they are
01:53:34 they are purchasable and practicable on the market okay thank you
01:53:39 thank you and
01:53:40 and just before i come to your overall concerns about the design of the system because you've helpfully summarized those in your supplemental report and i'll quickly take you to that um
01:53:49 um do you agree that these systems can be quite temperamental these smoke control systems
01:53:55 systems and difficult to get to work in practice is that something that's recognized within the industry known about is that your experience yeah i don't think they're temperamental but i think that
01:54:08 they're temperamental but i think that there you know all the different parameters that we've discussed today and in mr lay's report and my report and in in all the evidence um i think they're very complicated
01:54:19 um i think they're very complicated systems sometimes with competing parameters they tend to be very delicately designed to put it that way and so they are
01:54:31 and so they are they they can be susceptible to reacting to small changes in states and
01:54:39 and my experience particularly when i've been in the unfortunate position of trying to commission one and i think miss menzies raised this as well it can be very difficult
01:54:51 well it can be very difficult for quite some period of time until you get all the i call it balancing right okay
01:54:56 okay so there you could call it a highly engineered system that's susceptible to small changes in state yes that is my experience thank you yeah and if we go to your supplements sorry before we do go
01:55:08 supplements sorry before we do go somewhere else could i just go back to paragraph 738 i just want to check on one thing yeah um what mr lay is saying in paragraph 738 is that you uh
01:55:20 is that you uh you can expect to get some mixing with ambient air yeah as the smoke um
01:55:27 um leaves the flat and enters the inlet pathway so the temperature he says will have come down fairly significantly by that point you've then got the smoke rising
01:55:39 you've then got the smoke rising up the shaft yeah and um mixing with other air at that point yeah where which i think he would say yeah gives you a figure of well below 300 degrees centigrade by the time it
01:55:51 degrees centigrade by the time it reaches the extractor fan yeah you do you disagree with that well so it depends where the fire is the size of the fire and how close it is to the fan well you're assuming that there's a single flyer fire in a single flat i
01:56:04 single flyer fire in a single flat i think yeah up at level 23 all right up at level 23 and um that the smoke comes out of the door um for whatever reason for whatever reason there's some some
01:56:17 reason there's some some some temperature again i i don't like speculating i don't like speculating like this so i understand on a lower floor
01:56:23 floor so the phenomenon phenomena as described i understand and agree with it it's not wrong right okay um
01:56:32 um but as a designer it you've to you've to make a choice about how you know how how fine you're going to go in terms of a reasonable scenario and
01:56:44 in terms of a reasonable scenario and all i've got to say is that we we choose in an unsprinklered building with this type of system and residential we try not to
01:56:57 and residential we try not to go uh recommend 300 degrees you fan yes other people do well my question sure mr you know mr day can explain help there yeah well my next question was going to be
01:57:08 be in your view is it unreasonable to choose a 300 degree rated fan i i i think where you have considered it and
01:57:20 where you have considered it and explained it and you satisfied yourself that the range of scenarios relevant to to your building and you can justify it i would rarely have a problem with that right okay so i think but i don't see
01:57:32 right okay so i think but i don't see any of that you know it's always back to the same thing and grandfather i'm not in that position to tell you that that's what happened well i understand what you say about not having the um the workings so to speak
01:57:43 having the um the workings so to speak yeah yeah but i don't understand you to be saying that uh no reasonable designer could have opted for a 300 degree rated fan no reasonable designer
01:57:54 reasonable designer i'm sure a designer could reasonably come to their conclusion that a 300 degree c fan was appropriate for grantful terror yeah that's what i would want it to be if they if they if
01:58:05 would want it to be if they if they if they can satisfy themselves that 738 is applicable in all reasonable scenarios
01:58:11 scenarios all right is that okay yes that's helpful thank you very much yes thank you thank you mr chairman um let's go then to your overall conclusions just briefly look at those blarp25043
01:58:24 at page 89. what object are we on again sorry got a big this is where you've set out your overall conclusions about the design oh yeah okay yeah and at 4.6.7
01:58:40 you say these documents therefore contain the information needed to avoid the serious issues with psp's approach to the performance standard they expressly designed into their system for grenfell tower
01:58:51 grenfell tower um
01:58:52 um and and i think you're talking about various um the sca guides bs triple nine one etcetera and and then you say these are failure to consider performance objectives and
01:59:04 to consider performance objectives and the associated relevant leakage paths incising the components relied upon in the system design failure to comply with the performance recommendations of individual components such as lobby dampers
01:59:15 such as lobby dampers failure to comply with the functional requirements needed from the system as as a protected staff in an unsprinted high-rise residential building with a staple strategy fairly to consider the hazard posed by extended travel distance in the lobby
01:59:27 extended travel distance in the lobby and methods to mitigate it in the absence of mitigation from the system design
01:59:32 design failure to consider the performance of other passive and active measures easy fire doors self-closers and dampers when considering the hazard of smoke leakage to lobbies and failure to consider all the above in the context of interlinking of the
01:59:44 the context of interlinking of the functional requirements b1 b3 and b5 in an unsprinkled high-rise residential building now does that remain an accurate summary of your views about the flaws in the design process for grenfell towers yes
01:59:57 design process for grenfell towers yes yep
02:00:00 now briefly commissioning and approval now in your module 3 report for the transcript this was at 10.13.6
02:00:11 you said at page 25 blarp25036
02:00:17 that the commissioning process even in the context of the limited performance criteria set by psb did not demonstrate compliance with regulation 7 of the building regulations 2010.
02:00:29 building regulations 2010. now having heard the evidence of those involved with the commissioning and now also mr lay's views on the commissioning yesterday
02:00:37 yesterday does it remain your view that the commissioning process did demonstrate compliance with the building regulations yes it does
02:00:46 and um in terms of mr partley's evidence about the process of commissioning to what extent have the concerns you raised in your report been addressed by his further evidence about the steps he
02:00:58 his further evidence about the steps he took to commission the system even though all those steps weren't documented um
02:01:08 so
02:01:10 what did you say how much have they been delayed
02:01:14 delayed i mean what i'm really asking is um
02:01:17 um is it acceptable when you're commissioning the system um not to document all the steps in the commissioning process there are two questions here i'm sorry
02:01:28 there are two questions here i'm sorry to interrupt you but one is whether it's acceptable not to document the steps yes okay the other is if the panel were satisfied that what mr partly said
02:01:39 partly said was
02:01:40 was correct in other words of the truth of what he'd said how does that affect the witnesses i'm happy to put it in that way exactly so first of all is it acceptable not to
02:01:52 so first of all is it acceptable not to document all the steps that were taken as part of the commissioning process so the the documentation is not just about the steps it's about the data so you know we've been obsessing about the
02:02:04 know we've been obsessing about the airflow measurements and you know moving the lines up and down the whole point of documenting and recording the final state data
02:02:15 state data is to be able to have these conversations knowing that's what the final state is okay i i
02:02:21 i i so that's the one thing i listened to everything very carefully and i've re re-read mr partner's extensive evidence it
02:02:32 it i i there's a few specific things i still
02:02:36 still don't get as such so i don't understand how when i look at the say the latter logic behind the control panel i don't understand how there's a different
02:02:48 don't understand how there's a different fan speed in high and low at every floor for example there's a big long list to think there's a list of things that i still don't understand and i i didn't get comfort at the end
02:03:01 comfort at the end that the the dampers have been visually inspected because remember they're open in environmental mode so the visual inspection of the dampers and the very final air flow rates when the system and
02:03:14 final air flow rates when the system and all the cause and effect testing was finished i just can't see that i have that still so i i am uneasy about changing my mind about the commissioning based on my own experience
02:03:26 commissioning based on my own experience also of commissioning and witnessing others commissioning yes okay and to pick up the point about the dampers and his oral evidence mr partlow explained that when checking the dampers
02:03:38 explained that when checking the dampers he would use his laptop that's correct to monitor whether the dampers on any other floors had opened or whether they were closed yeah is what you're saying is it would be very important to for
02:03:50 is it would be very important to for that also to be a visual check yeah because that's like the let's say that's about the signaling coming from the control system and that actually in all the scenarios we've run you know that
02:04:01 the scenarios we've run you know that that that is robust okay
02:04:05 okay but the signal and then what the item at the end of the signal does are two different things and that's why it's so important yes the signals have to be accurate first
02:04:16 signals have to be accurate first and then it is that product whatever it is
02:04:20 is responding appropriately to the signal so doing nothing closing opening and when you've done this a few times and mr partner was very clear on this you see that it's not so
02:04:32 clear on this you see that it's not so simple
02:04:33 simple to get all of those things to work until the very end and that's why recording that end state is so important to prove
02:04:42 to prove that all the different products could do the right thing at the right time okay and i just can't find that surety from my perspective and does that mean that commissioning a
02:04:54 and does that mean that commissioning a system like this is quite a labor-intensive process you might need lots of people assisting with the commissioning to ensure that you've got visual inspections of other dampers when you're
02:05:07 inspections of other dampers when you're testing on different floors not lots of people but more than one i i think it was two people wasn't i think you would definitely need more than one person right
02:05:17 right i suppose you're going to ask me now how many people would i bring i haven't told you about that so it's not lots of people we don't need to over you know don't need to kind of over egg the situation yes i see
02:05:29 situation yes i see um
02:05:30 um so
02:05:31 so having considered mr partly as evidence do you consider that overall and setting aside your concerns about recording results
02:05:40 results do you think the process taken was sufficient to demonstrate this the system was performing as intended i don't think so no again can i just ask you yeah is that because you don't accept what mr partly says in its
02:05:52 accept what mr partly says in its entirety or no that's not no because i think mr partlow gave very thorough evidence so it's not that i'm you know i've decided it should be dismissed
02:06:03 it should be dismissed um
02:06:06 it's a whole series of things actually i should have written this down so it's the issue of not visually inspecting the dampers i i we still don't know what the fan speeds were in high and low and he
02:06:18 fan speeds were in high and low and he explained in his oral evidence that he had different settings on every floor i just don't understand that at all because there's one high signal one low signal in the control panel so i don't know how he said he had a different
02:06:29 know how he said he had a different number per floor and just a few things he said
02:06:33 he said didn't reassure me okay but
02:06:37 but i
02:06:38 i it might be more robust if i was to set that out properly rather than try and answer it off the hoof here um i do think that he was very expansive and helpful in what he said here
02:06:52 and helpful in what he said here i mean i raised the question because and i understand how you you forming a view which depends to some extent on your assessment of various bits of the evidence including
02:07:03 various bits of the evidence including what mr parkland says and including the the data that you've got or in some cases don't have we may or may not find it necessary to make decisions about some of the detail okay okay um
02:07:15 some of the detail okay okay um but if we do need to grapple with it i think we yeah and we need to understand why you don't think okay some some of the evidence is reliable yeah so
02:07:26 the evidence is reliable yeah so [Music]
02:07:29 [Music] it seems to me that everything happened very quickly at the end and i know what that is like from my own experience i think that i i know i know myself that
02:07:42 i think that i i know i know myself that when
02:07:43 when members of my team or other teams want to do the damper checks electronically rather than physically i i always say no because it's sad's law you you will miss one or there's
02:07:55 you you will miss one or there's something wrong i don't understand the fan speeds i don't understand uh
02:08:04 i don't understand this judgment on the door and the pressure switch and
02:08:09 and i suppose in in my mind there was a level of judgment for each system which taken all together demonstrates some lack of rigor i think is probably
02:08:21 some lack of rigor i think is probably the best way to say and in a complex system like this that would make me feel less confident in it than more confident that what had been done on site was to the right
02:08:34 been done on site was to the right standard and i am drawing in my own experiences in the past of similar activities
02:08:45 um cold smoke testing now um in her supplementary report on smoke control miss menzies says um and for the transcript this is paragraph 291 bmer five zeros
02:08:57 paragraph 291 bmer five zeros sorry 607 at 68. she says in my experience systems are generally demonstrated on-site using a cold smoke test to illustrate the directional flow of smoke the speed of dispersal and
02:09:08 of smoke the speed of dispersal and level of visibility whilst this will not fully replicate an actual fire situation it will be indicative as far as i can ascertain this was not suggested or undertaken
02:09:19 undertaken and when she gave oral evidence she was clear that a cold smoke test was an important part of commissioning and accepting the system by building control now
02:09:28 now do you agree with what miss menzies says in that respect yes i do do you agree that in the absence of a cold smoke test it would not be possible to know whether the system worked
02:09:39 to know whether the system worked including for the different door opening conditions which were foreseeable so ms menzies said that the the doing a cold smoke test would assist in working out what would happen with
02:09:52 in working out what would happen with the system when you did have more door opening conditions yeah yes i'm happy to agree with the word assist it's not the oh you know it's not the only thing that should be done
02:10:03 should be done but it will assist along with all the other data measurements from the devices mr lay said in his evidence yesterday that well that might have been done 15 or 20 years ago before this type of
02:10:16 or 20 years ago before this type of system became much more accepted he said he had done a cold smoke test once with miss menzies but it was not a representative test it didn't involve hot smoke and therefore he wouldn't have
02:10:28 hot smoke and therefore he wouldn't have seen it as a test which uh needed to be done on this system do you agree with that no i don't we we have
02:10:35 have in the end we actually bought our own [Music]
02:10:39 [Music] smoke machine so we could arrive on site and use it and i find it to be most helpful indeed so whenever you're commissioning a system like this would you always do a cold smoke test we always try to because
02:10:51 cold smoke test we always try to because we're
02:10:52 we're we we always try to depending on what position you're in you know and isn't it a good way of exposing what you might not have worked out yet or you might not know about the system but if i
02:11:04 might not know about the system but if i if i had to push you on this and say would it be would it fall below the standards of a reasonably competent commissioning person not to do a cold smoke test what would you say well what i would say is
02:11:16 would you say well what i would say is you know it's it's a really easy so it's a really easy thing to do it's not expensive
02:11:22 expensive and i can't imagine why you wouldn't do one especially when it comes to the approving authorities on a system like this
02:11:29 this quite frankly they absolutely love to see it working and it gives people reassurance that's my experience um i i i think it would be pretty unfair
02:11:40 um i i i think it would be pretty unfair for me to say that you know it's this thing it's the same the documentation only for the cold smoke test i wouldn't have any problem with the system but i think
02:11:50 think you know it's an easy thing to do particularly in an existing building and with the system with all these different parameters i think that's about the fairest i can be so you
02:12:02 about the fairest i can be so you wouldn't want to venture on what other people do because i ask because it sounds like it's not mr lay's experience that this is done as a matter of routine yeah but he's never come commissioning with me it is exactly in your case it is
02:12:15 with me it is exactly in your case it is routine yeah what about the rest of the world the world are you
02:12:22 yes she says in my experience they are generally demonstrated well that's that's miss men's evidence i'm not inviting you so are you going to give us her evidence i i think that there i think that
02:12:34 i i think that there i think that there's a lot of there are people out there who who love a nice cold smoke test and i think it's reasonably common i can't comment on mr lay's experiences
02:12:45 experiences but certainly um for projects i do with arab and with other consultants because we we do both um i think my experience is more common
02:12:57 um i think my experience is more common than not that you would do a cold smoke test particularly when you have a i would say that you know a really interested approving authority and they want to know exactly what's going on okay right thank you is that okay yeah
02:13:09 okay right thank you is that okay yeah can i just follow up on that yeah in the situation we had at grenfell tower where we know
02:13:15 we know we had a system which didn't have detailed design documentation behind it didn't have performance objectives specified etc would that mean that not doing a cold
02:13:27 would that mean that not doing a cold smoke test in that situation would fall below the standards reasonably to be expected because you hadn't done the calculations in the first place yeah i fully agree with miss menzies on
02:13:39 yeah i fully agree with miss menzies on this and it should be not only should it have been offered it should have been asked for by building control
02:13:55 thank you the night of the fire now i just have some brief questions on that um just to be clear this is going to be primarily a factual matter for the panel
02:14:06 primarily a factual matter for the panel uh and the chairman to decide in fact what happened on the night did the system work did it not what is the evidence and most of that is factual evidence
02:14:16 evidence and just to be clear um you're in the same position as mr leon you're not a forensic fire investigator absolutely not and i haven't carried out a forensic fire investigation
02:14:27 a forensic fire investigation um in my section 12 and section 13 of my report that's not purpose yeah so is it fair to say that all you can do again like mr lay is draw certain factual matters to the
02:14:39 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 using your experience of these systems
02:14:49 systems correct yep yep now
02:14:53 now i've just got a few questions on this the level 11 north dampers and the potential breach of compartmentation uh involved with that um
02:15:03 um in your supplemental report this is at page 17 for the transcript paragon one paragraph
02:15:10 paragraph 1.4.53 yeah you say that you and mr lay disagree about whether there was a likely breach of compartmentation by the north shaft level 11 dampers on the night of the fire
02:15:22 night of the fire um now can we just go to your storyboard um
02:15:26 um in your module 3 report it's at blarp25038
02:15:32 page 29 and it's storyboard 12.
02:15:36 12. yep so this is where you analyze the performance of the north shaft as a protected shaft and the diagram is divided into early middle and late stages of the fire yes
02:15:48 middle and late stages of the fire yes and
02:15:49 and if we look at the text box pointing at l11 in each diagram pointing at level 11 you've got for each diagram you've got a
02:16:01 you've got for each diagram you've got a label
02:16:03 label identified as box number three which says likely that level 11 north shaft dampers were open for the duration of the fire do you see that yes
02:16:14 the fire do you see that yes and in respect to the early stage only you say below that in box 4 on the left hand side spread of heat and smoke possible between level 4 and level 11
02:16:25 possible between level 4 and level 11 lobbies due to open north shaft dampers now can you just briefly summarize what evidence you relied on when concluding that it was likely that the level 11
02:16:37 that it was likely that the level 11 north shaft dampers were open for the duration of the fire the vre forensic analysis of the dampers so we looked at that with mr lay yesterday
02:16:48 yesterday you're saying you relied on the bre's post fire investigation report is that right yes
02:16:55 right yes and the fact that um they indicated that there was a some visual evidence of a cleaner um
02:17:04 um line along the blades of the north shaft dampers which might indicate um sorry
02:17:11 um sorry i'll start again yeah it indicated that for the south shaft dampers on level 11 there was a line indicating a difference between the smoke at the blades
02:17:22 smoke at the blades and there was an absence of that for the north shaft dampers which were more uniformly coated in smoke and soot is that right yeah so in in my mind
02:17:33 yeah so in in my mind one shows movement and the other doesn't that's how i saw it in my mind and i accepted what bre observe let's just look at that it's at met
02:17:44 met 3039807
02:17:47 3039807 page 112.
02:17:53 and it's um paragraph well it's they deal with one 153 and 154 what they found on the um low level dampers the metal surface on the edge of the
02:18:05 the metal surface on the edge of the blade tips where the blades normally contact each other was noticeably cleaner and had less smoke and soot residue than the rest of the blade surface
02:18:14 surface and then if we go down to paragraph 155 they contrast that with the high level dampers it says inspection of the high level dampers showed that the contact points on the damper blade tips
02:18:25 points on the damper blade tips were uniformly coated in smoke and soot therefore unlike the low-level dampers there was no visual evidence for the high-level dampers being closed during part of the fire do you see that there
02:18:38 part of the fire do you see that there so is it that part of the bre report that you were relying on when concluding that it was likely that the north shaft dampers were open during the fire
02:18:50 during the fire so did you say i concluded yeah so you said in your text box that it was likely they were open throughout the fire likely yeah that's correct and that's based on the the bre text you shown here
02:19:04 based on the the bre text you shown here and similar text for all the other dampers no i know this isn't your text and i understand i think the principle that if the if the 11th floor north dampers were uniformly
02:19:16 11th floor north dampers were uniformly coated with soot
02:19:19 soot that's evidence that they open for a considerable period of time does it tell you anything in your expert view about when they opened
02:19:31 view about when they opened so or for how long they were open i'm not an expert in sort of deposition on on any level and i'm not a friend you know i'm not a forensic fire engineer um
02:19:43 um the
02:19:44 the i hope you know
02:19:47 i can't tell timing i hope i made that very clear um
02:19:54 that it's not possible for me to confirm a time anything happened i actually said that at the very start of all of this analysis i asked the question because your
02:20:04 your diagram should yes had a label saying open throughout the fire so i i oh sorry so it says likely lightly open throughout the fire well it
02:20:16 lightly open throughout the fire well it was just throughout the fire that i oh yeah
02:20:19 yeah that was based on the bre text only and no other
02:20:25 no other right no no other i didn't draw anything else in
02:20:30 else in thank you
02:20:33 thank you i mean both you and mr lay then go on to analyze some of the factual evidence about the movements of residents on level 11.
02:20:41 level 11. um i'm not going to take you through all of that now um we've got it set out in detail in mr lay's report in your report and
02:20:50 and uh we also now have professor purse's report who's also considered the timings of movement um but i think that the point he makes is there may well have been a flat door open
02:21:01 open from quite early in the fire uh due to movements of the jafari family and the point you make is when you look at the timings um i think you're trying you're saying
02:21:13 um i think you're trying you're saying that that doesn't necessarily follow given the timings and that there may have been another source of smoke on level 11.
02:21:20 level 11. is that a fair summary of the difference between you difference between myself i haven't read mr purser's report are you talking about mr i was talking about you okay so just we need to be very
02:21:31 you okay so just we need to be very careful so i i looked at level 11 and level 18 to try and see if if
02:21:42 if if there was information that could allow me to say with some surety or not that the events that caused the dampers to open at level 11
02:21:53 to open at level 11 happened before level 8 level 18. the level 18 damper was the end state didn't want to assume one thing or the other so that's why i did that analysis the
02:22:04 so that's why i did that analysis the second thing then i i was trying to see if you could definitively state it was damper leakage or flat entrance
02:22:15 it was damper leakage or flat entrance doors being open and in
02:22:20 and in at level 11 and level at 18 also because then i was going on to try and work out when this extreme event at that lobby may have occurred to trigger the
02:22:31 may have occurred to trigger the scenario that rena said
02:22:34 said causes the dampers to operate in in an unexpected way that's what i was trying to do
02:22:40 to do thank you
02:22:42 thank you yeah and it can't be taken out of that context so i was trying to work out when extreme event extreme fire was possible and thus the arena
02:22:52 arena triggering of the dampers and then
02:22:55 and then if level 11 was likely to have occurred before
02:22:59 before level 18
02:23:01 level 18 and everywhere i have likely and options because i i don't find that it's possible
02:23:09 possible as myself to say one thing definitely happened
02:23:14 happened and i hope i haven't given that impression at all that's helpful yeah and just help us with this if the panel were to find if that there was a damper open at level 11 throughout the fire
02:23:26 open at level 11 throughout the fire level 11 north shaft yes if that was the conclusion yes um just what is your opinion about what the effect would be on the operation of the
02:23:38 effect would be on the operation of the system because mr lay's evidence is essentially well that would make no difference because there's negative pressure in the shaft and you might get a little bit of turbulence of smoke but no more
02:23:50 no more now do you agree with that that if there's a damper open higher than the floor in which it's operating on so suppose this make control systems operating at level four where the fire is but you've got
02:24:02 is but you've got a rogue damper that's open at level 11 say
02:24:07 say do you do you say that that would have had an effect on the performance of the system well my understanding of that is so when the if this happened
02:24:18 if this happened at when the fire started on level four and if the damper was open at level 11 when the next when the dampers opened appropriately at level four the fan from
02:24:29 appropriately at level four the fan from the get-go is extracting off two two open floors and
02:24:36 and in the event that hadn't been incorporated in the design and it's highly likely that it wasn't it it does impact the resulting air flow potential at level four
02:24:50 why does it have an impact if the shaft is
02:24:53 is depressurized because of the operation of the fan are you talking about i think you might be talking about leakage upstairs now it's another leakage path it's another
02:25:10 well they put it in layman's terms found that the head of the shaft is drawing from two places yeah not one yeah no exactly i mean i i i would i was going to say it's split in two but a thousand
02:25:21 to say it's split in two but a thousand people were writing in explaining that it's not that linear and i understand that but in really really really crude terms that that's what you're doing if that damper was open okay yeah thank you
02:25:32 okay yeah thank you now um another topic that you've dealt with um
02:25:36 with um in response to mr lay's report is he has highlighted some firefighter evidence uh including evidence from firefighter moore who gave evidence at phase one that suggests that smoke may have been
02:25:48 that suggests that smoke may have been venting from the south extract point at about 3 30 a.m on the night of the fire that's mr lay's in this delays report and you've responded to that in your
02:26:01 and you've responded to that in your supplemental report and in your report you make reference to your own site visit observations and you comment on the evidence of firefighter more yeah and you say this you say i had
02:26:12 more yeah and you say this you say i had the benefit of visiting the site post fire unlike firefighter moore i was able to observe the south elevation from firefighter moore's location under the external concrete
02:26:23 location under the external concrete mezzanine walkway in my opinion the sole photograph that firefighter moore was shown this was during his evidence gave insufficient information for him to confirm which bent of the five vents potentially was
02:26:35 bent of the five vents potentially was visible to him on the night that he was able to observe i'm in no way criticizing firefighter moore and i note the proximity of the external walkway to grenfell tower and the relatively confined space between it
02:26:46 the relatively confined space between it and the tower into which large and small debris burning debris and human remains fell throughout the night and you produced a photograph in your
02:26:57 and you produced a photograph in your report
02:26:58 report if we could go to that in your supplemental report blarp25043 at page 187
02:27:08 now that's the photograph that you had in your report
02:27:14 report um
02:27:14 um so can you explain what this photograph shows
02:27:18 shows it shows the canopy and the vents underneath the canopy
02:27:25 canopy and are those the vents that went to the south shaft remote control system so the vents that are immediately above grant the grenfell tower label yes those aren't the smoke control vents no
02:27:36 aren't the smoke control vents no they're not no they're at level two they're higher up is that much higher up yeah let's go to inq3015
02:27:46 this is a screenshot showing a database of photographs from getty images perhaps we could blow them up
02:27:54 and it was made available to the inquiry by the metropolitan police service yeah and here we can see um
02:28:02 um some different photographs yeah there's three there of the entrance way yes to grenfell tower um
02:28:10 um now
02:28:13 now does either of those photographs the the ones that are further out show the level two vent
02:28:19 two vent no so the the one where you can see say three
02:28:23 three three panes of glass above the green canopy yes the one at the bottom yeah the vents are not there
02:28:31 right sorry the level two events excuse me obviously the vent underneath the canopy can be seen right and um
02:28:40 and um was there a particular reason why you chose the photograph that you used for figure eight one which was a much closer image of the tower was there a particular reason why you chose that photograph no
02:28:52 chose that photograph no um now with reference to these photos um is it right that you think that firefighter more could have been mistaken in the evidence he gave about seeing smoke coming out of the level two
02:29:03 seeing smoke coming out of the level two smoke control vents so he so
02:29:07 so he so firefighter morse saw what firefighter moore saw
02:29:11 moore saw but he was asked a question about a specific vent as i've said in my report i i
02:29:17 i i decided to go down and try and see what i could see in under the walkway at the edge of the walkway or further out past the walkway and unless you step out into fresh air
02:29:28 and unless you step out into fresh air um you you can't see the smoke vents up at that height that's all i observed i see so if you're standing underneath to go right out you have you have to step out and stand
02:29:40 have you have to step out and stand there
02:29:41 there and that made me think that in when he was asked the question he was asked completely out of context it was very difficult for him to
02:29:52 it was very difficult for him to understand that there were there was another vent the one shown in these photos here and at different times in the night there was smoke in the lobby
02:30:03 there was smoke in the lobby and there was also smoke from other sources in that area and i consider all of that sufficiently you know there's multiple different options and what i've just said there
02:30:15 options and what i've just said there i couldn't say that
02:30:19 say that he saw one thing you know the one thing only okay and it's not meant to mean anything more than that and it's absolutely not a criticism of firefighter more in in any shape or form
02:30:30 firefighter more in in any shape or form okay thank you mr chairman i've come to the end of my pre-prepared questions right so we better have the usual break and haven't we the usual break lane i don't need to explain to you why we have a break at this stage um
02:30:42 we have a break at this stage um 10 minutes ought to be enough wouldn't 10 minutes yes i think it should well if it's too long you can send the usher to come and collect us as soon as you're ready
02:30:53 ready we'll have a break for 10 minutes unless we're called back in 20 to 5 please thank you
02:31:04 thank you very much 225 unless you call us back soon
02:40:44 i think would you let uh ask dr lane to come back in please thank you
02:40:56 all right well let's ask any more questions shall we yes ms grange there are no further questions for dr lane uh i just want to thank her very much for all the assistance that she's given us um on this topic so thank you very
02:41:09 us um on this topic so thank you very much yes well quite right and i haven't had
02:41:12 had my thanks and the thanks of the other members of the panel thank you for all the work you've done on this yeah inquiry it's been enormous and uh thank you again for coming back i think for the third time now isn't it it's the tenth time no no not given
02:41:26 tenth time no no not given it
02:41:27 it but you've certainly given evidence on three occasions yeah we are very grateful to you it's the tenth day yeah the tenth day yes my tenth day answering questions here right well i hope the
02:41:38 questions here right well i hope the experience hasn't been it's been horrendous but worthwhile and as mr leigh said yesterday it's been an honor of course so well thank you it's right that we said thank you we are as i say very grateful yeah
02:41:50 you we are as i say very grateful yeah thank you and now you're free to go yeah thank you thank you very much
02:41:59 thank you ms grange well that's it for the day
02:42:03 the day i should repeat my thanks of yesterday to those who are sitting here keeping us going and
02:42:07 going and also to those out in the back room who are keeping us going but we we finished there and we resume with a different witness at 10 o'clock tomorrow yes good thank you very much
02:42:41 you