ScottyUK: Like our own Prime Minister, I don't trust May any further than I could toss her... I thought the idea of the scope being vetted first was a good one. They seem to be missing 'who approved what, when, and why'.
I agree with those questions, and perhaps the questions need to start even further back, like "How did our regulations become so weak that this design was ever proposed, let alone constructed?" which is definitely in a lot of peoples minds.
In my opinion UK codes - or more specifically the adopted European Norms in the guise of BS EN standards - seem to have become less prescriptive over time compared to the older British Standards and now leave a lot of room for judgement and (mis)interpretation because they are full of increasingly complex methods of describing things in a way which is difficult to apply to the real world. By contrast the handful of US codes I've worked with - mainly power generation, with US manufacturers selling into the Middle East where my employer was the Owner's Engineer - are a lot more prescriptive than the equivalent EN codes. Generally the US codes are easier to follow than ours because they are fairly explicit in their requirements.
The issue of prescriptive vs interpretative codes is a thorny one. If you want to promote innovation, design / building Codes need to allow for a degree of subjective assessment and interpretation, and this will require "experts" to ensure the intent is satisfied. If you stick with prescriptive codes, then all designs will use the same "tried and tested" materials and methods of construction, and end up pretty much looking the same.
It's early days in the investigation, and I hope the Inquiries will determine the real root cause, but it seems to me that the core problem at Grenfell was a joint failure by the designers, specifiers, suppliers and installers: they all seem to have forgotten the underlying principles of preventing spread of fire and smoke, and they introduced a new path of fire attack (from the outside in). This is the biggest mystery to me: how can a building cladding system be designed and installed where none of the parties apparently had a fundamental understanding of the principles of fire engineering?
I doubt that a composite zinc cladding would have given a better result than the composite aluminum actually used. And the insulation was as specified, I think.
Don't know, but the zinc coated steel would have a much higher melting point... the aluminum would melt at 700C or so... The heat would have quickly destroyed this and allowed the insulation to melt and/or burn, contributing to the consumables.
"Cladding fitted to Grenfell Tower during its refurbishment was changed to a cheaper version, documents obtained by the BBC suggest.
Documents show the zinc cladding originally proposed was replaced with an aluminium type, which was less fire resistant, saving nearly £300,000."
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
I agree with your observations re. prescriptive vs interpretative codes. My work is largely process plant / power plant rather than buildings, so the prescriptive codes possibly suit these risk-averse industries with established technologies better than the interpretive ones.
The problems with regulatory oversight go back much much further than the current government, but it happened on their watch so they will likely take whatever blame is apportioned. The cynic in me says that they're terrified that a damning report might be the final nail in their electoral coffin given the fragile grip they have on power.
As an Brit who has spent the last 40 years working in North America, and presently visiting the old country , perhaps my observations will Add something to this discussion. Anyone based in australia or north america probably has no comprehension of how badly things have deteriorated in the UK in the last decades. I am absolutely amazed about how normal project management skills have not been applied in this case. The normal engineering ethics basic of " protect the public" seems to be totally missing here. Everything seems to have been based on cost reduction. Field inspections have dropped dramatically, lower cost materials approved without being examined by knowledgeable personnel , installation of sprinklers examined but dropped from further consideration because they would not contribute to the visual appearance of the buildings exterior. The whole thing is now being driven by the politics of a**e covering and responsibility avoidance. The so called investigation shows all signs of being a whitewash.
The fact of the matter is the occupants of this tower were very low income persons with a high percentage being immigrants from third world countries who had previously expressed severe reservations about their living areas , whose complaints were ignored by those responsible. Does anyone here really think justice will prevail??
"This is the biggest mystery to me: how can a building cladding system be designed and installed where none of the parties apparently had a fundamental understanding of the principles of fire engineering?"
Unfortunately, I don't think there is a lack of understanding of the fundamental principles of fire engineering, I think there is a culture throughout the process and it includes the local councils, curtainwall construction sector/consultants. contractor & project management firms. The email from KCTMO’s project manager sent to Artelia, its cost consultant, about cladding prices. It said said: “We need good costs for Cllr Feilding-Mellen and the planner tomorrow at 8.45am!” Rock Feilding-Mellen is chairman of Kensington and Chelsea’s housing committee. Artelia replied with three options including that “fully cassette-fixed cladding” would save £293,368. On July 1st 2014, IGI Taylor the town planner for RBKC prepared a submittal to the RBKC Planning Dept. for approval. It seems the RBKC Council waited until the 11th hour to ask for "incentives" to award Rydon Construction the contract. The contract was awarded to Rydon the day after the submittal, on 2 July, 2014. It is RBKC that chose which of the 3 cladding options to go with. That said EXOVA WarringtonFire was a consultant to KCTMO for the greater Lancaster Estate redevelopment project; which included the Sports Center & School.
Even though a D-Notice has not been issued, there is in some aspect, the equivalent. Those involved in the first response & aftermath of the Grenfell Tower Fire are under Coroner's Restrictions and then the site itself is restricted and being walled off with solid metal sheet fencing.
Given the estimate, that recovery will not be complete until the end of 2017 and coroner's investigation, longer still, it might as well be a D-Notice.
There is a general description of the Fire Fighting response on Firehouse.com Forum. Link
Epoxy bot ,I accept your D notice analogy ( altho many here will not know what that is) but it seems to me that it is ScottyUK who is making the most pertinent observations. Where is the engineer or architect who stood up to state " this is dangerous, I wont sign off on this" . In my career in underground mining , I have only very rarely constructed to codes and standards. On things like fire protection , explosives , etc , somehow we pass the necessary knowledge to the next generation. Certainly the local mines act provides the absolute minimum standard ( and that can vary geographically) but we aspire to "best achievable practice" and constantly challenge ourselves and each other as to "is there a better way to do this?" and cost is very much secondary. In my opinion todays focus on meeting standards , without critical thought , goes a long way to explaining many of society's woes these days.
I guess we will have to wait & see just how many other structures have the same combination of Celotex RS5000 & Reynobond PE. With two large companies like Arconic/Alcoa & Celotex; there are surely to be more. If an architect or engineer were presented with a list of 20 other buildings where the two materials has been used in a similar applications, they would have to be quite knowledgeable on the subject to not feel somewhat compelled to accept such a submittal. Finding themselves in a defensive position. Something has gone terribly wrong with the concept of Unconscionable in the UK Building Design community. Worse, the powers that be in government, don't have the good sense to realize they are completely out of their depth at making determinations about building safety and should stick to choosing colors they like.
Having just read up on how fires are dealt with, one of the primary concerns for the crew at the point of attack, is reducing the volume of smoke and heat in the affected area. Venting the fire, as close to the fire as possible is a standard tactic. Yet, it can be argued that, the use of Polyethylene ACM cladding, completely changes the manner in which firefighters can extinguish a fire in a dwelling. Not being able to vent a fire for fear it will set the exterior on fire, greatly increases the danger for the firefighter and the ability to contain the fire to one unit in a multi-family dwelling. It is entirely possible the London Fire Brigade vented the Grenfell Tower fire and the flames set the bottom edge of the 4th floor ACM cassette on fire. On the whole there is comparatively little exterior damage to Flat 16 where the fire originated.
dik,
I don't know what kind of panel Greg was considering, but the architect's drawings did show "zinc composite panels". Apparently, some of these are made with zinc on one side, aluminum on the other, with other stuff in the middle.
Hokie66... I don't know what zinc coated composite panels are (unlikely pure zinc; you can get zinc panelling, but it is 3 to 5 times the price of prefinished HDG panelling, but I assume they are pre-finished HDG steel cladding... different terms used are a bit of a problem. The difference in what was spec'd and what was used may have introduced a bit of a delay, but, may not likely have stopped the fire. The real problem is the large air gap (chimney) and the 6" (150mm) flammable and toxic polyiso insulation attached to the original concrete precast panels. This was a terrible choice of materials and the people that have signed off on this have killed 80 people.
"Worse, the powers that be in government, don't have the good sense to realize they are completely out of their depth at making determinations about building safety and should stick to choosing colors they like."
The powers that be, may have been acting in good faith...
As I noted in my posting above to miningman,
"Combustible cladding has been permitted based on reports arguing fires involving combustible aluminium panels would behave similarly to ones with non-combustible ceramic tiles.
Developers use them to persuade inspectors to sign off buildings.
Exova, the company that produced the reports, refused to comment.
The company, also known as Exova Warringtonfire, is a fire testing and engineering company."
