Who knows their way round Building Regs? (fire)

[Newboy]

"12.5 The external envelope of a building should not provide a medium for fire spread if it is likely to be a risk to health or safety. The use of combustible materials in the cladding system and extensive cavities may present such a risk in tall buildings.

Externall walls should either meet the guidance given in paragraphs 12.6 to 12.9 or meet the performance criteria given in the BRE Report Fire performance of external thermal insulation for walls of multi storey buildings (BR 135) for cladding systems using full scale test data from BS 8414-1:2002 or BS 8414-2:2005.

The total amount of combustible material may also be limited in practice by the provisions for space separation in Section 13 (see paragraph 13.7 onwards)."

 

[JohnD]

what's that extracted from? Some document that is legally enforceable? What's the stated penalty for non-compliance?

Does "should" mean "must?"*






*no, it doesn't

 

[Newboy]

what's that extracted from?

Approved Document B (Fire safety) – Volume 2 - Buildings other than dwellinghouses (2006 Edition incorporating the 2013 and 2013 amendments)

Part B / Vol. 2 / Section 12 Construction of external walls

What's the stated penalty for non-compliance?

https://www.planningportal.co.uk/info/200128/building_control/38/building_regulations/3

Does "should" mean "must?"*

I guess that's where lawyers earn their money - interpretation?

But if something "should not" and in fact it "does" then that would suggest it has failed to meet the requirement.

Also applicable (as already pointed out)

http://www.legislation.gov.uk/uksi/2005/1541/contents/made

and possibly:

http://www.cps.gov.uk/legal/a_to_c/corporate_manslaughter/

 

[JohnD]

thanks

I was looking at BR part B4, except I was looking at the 2010 edition

 

[^woody^]

"12.5 The external envelope of a building should not provide a medium for fire spread if it is likely to be a risk to health or safety. The use of combustible materials in the cladding system and extensive cavities may present such a risk in tall buildings.

Externall walls should either meet the guidance given in paragraphs 12.6 to 12.9 or meet the performance criteria given in the BRE Report Fire performance of external thermal insulation for walls of multi storey buildings (BR 135) for cladding systems using full scale test data from BS 8414-1:2002 or BS 8414-2:2005.

The total amount of combustible material may also be limited in practice by the provisions for space separation in Section 13 (see paragraph 13.7 onwards)."

That text if from the Approved Document B, which is not the Building Regulation for this. The text in the green boxes in the AD is the actual requirement which must be met and would be used in any investigation/prosecution.

But the reference to BR135 and the BS documents would be a valid requirement as there are probably no other authorities for assessing performance of the cladding.

 

[Newboy]

Thanks for clarification - apologies I got my docs mixed.

 

[wessex101]

Putting aside the sheer tragedy of recent events and just focusing on trying to identify the potential system failure that allowed it to happen. I have not had to look too closely at regulation B4 for non-residential for quite some time but I was always under the impression that the main thrust of the regulation was to prevent fire spreading between adjacent buildings, a throw back to the earliest building regulations and the great fire of London. So assuming the building had enough distance separation between adjacent buildings and the structural elements had the required fire resistance so the building did not collapse then any external cladding could potentially be combustible. Having said that I was involved in some high rise external cladding in the 90's and everything was totally non-combustible. It would never have arisen that I would have even considered a potentially combustible cladding panel, what were they thinking when they specified that polyethylene crap.

I fear it is a case of yet another national tragedy before the authorities take action to protect the public. The Herald of Free Enterprise for example, everyone would have been horrified if they new it was standard practice for a ship to sail out of port with the bow doors open, but until it went horribly wrong the authorities turned a blind eye. The Bradford City stadium fire, a timber football stand with years of accumulated rubbish piled underneath and people smoking above, it seems crazy that that was permitted but it took the deaths of 56 people before the authorities took steps to ban timber football stands. The list goes on and on, Kings Cross underground fire, the Manchester Woolworths fire etc.

I have worked on numerous large public buildings where the lack of appropriate fire precautions are scandalous but those in authority choose to ignore all advice on the grounds of cost or just inconvenience. I do not think sprinklers are necessarily the answer except as a back up where the structural fire precautions cannot be achieved. Why cant we build buildings without combustible materials, and ensure fire compartmentation is correctly installed and maintained, something as simple as fire doors that are correctly installed and regularly inspected and maintained, it isn't rocket science.

 

[John D v2.0]

Strangely enough timber is actually considered better then steel for fire performance for escape. The timber will char but a thick log will last long enough to get out, a steel beam will bend under the heat. Hence having to box in steel with plasterboard.

 

[wessex101]

Strangely enough timber is actually considered better then steel for fire performance for escape. The timber will char but a thick log will last long enough to get out, a steel beam will bend under the heat. Hence having to box in steel with plasterboard.

Don't confuse the structural integrity with spread of flame. A hardwood beam may well char slowing down the eventual collapse but it adds to the total fire load and could well facilitate the spread of the fire throughout the building. Grenfell Tower fulfilled its structural integrity in that it did not collapse probably due to the concrete structure but everyone was still killed in the terrible fire that spread through the building via the flammable cladding and no doubt all the flammable furnishings and fixtures and fittings.

I cannot remember the details but there was a lightweight timber panel block of flats under construction a few years ago, about 4 storeys high from memory that caught fire before the external brick cladding was in place. It completely burnt to the ground in something like 8 minutes just leaving a pile of ash and twisted scaffolding.

 

[John D v2.0]

Interesting, just goes to show how complicated designing buildings for fire safety is.
And as building get bigger, everything scales up extremely unfavourably.

 

[Newboy]

I cannot remember the details but there was a lightweight timber panel block of flats under construction a few years ago, about 4 storeys high from memory that caught fire before the external brick cladding was in place. It completely burnt to the ground in something like 8 minutes just leaving a pile of ash and twisted scaffolding.

http://www.bbc.co.uk/news/uk-england-hampshire-11268241

 

[JohnD]

wooden buildings during construction must be terrible, before they have (hopefully fire-resistant) external cladding, and internal plastering added.

There is a hotel near me that is timber framed and pre-fab panelled. They added a brick skin after it was built

 

[tony1851]

Most of the deaths at Grenfell would have been through toxic smoke inhalation.
It begs the question: were fire doors to the flats and the staircase lobbies perhaps useless because of being propped open?
If the staircase enclosure had been used/maintained as designed, there seems no reason why occupants could not have escaped, even from the upper floors. The staircase enclosure would of course be structurally sound for a long period (1 hour? [not sure]).

 

[wessex101]

Actually it wasn't that one in Basingstoke, it was in a more built up area. I did a bit of Googling and it turns out there have been several, one in Colindale in North London, Newcastle, Manchester, Canterbury.

Its not looking good for timber framed blocks of flats.

 

[JohnD]

Most of the deaths at Grenfell would have been through toxic smoke inhalation.

Although if the building hadn't been wrapped in flammable foam that generates toxic smoke, the question of blaming the residents for their death wouldn't come up.