L1 System compensatory for cavity barriers?

[stayedon43]

I am dealing with a consultation with an A.I. who is proposing the installation of an L1 system as a compensatory feature for the ommission of cavity barriers within a factory producing chilled and frozen foods. This does not lie well with me as although persons within the factory should have early warning of fire, missing cavity barriers, i believe, could lead to fire spread and early structural failure. Would building insurers be happy with this compensatory feature?. Any advice will be much appreciated

[Clevelandfire]

for life safety this isnt a big problem and I wouldnt be worried, but for a building protection measure then no - soeak to insurers im sure theyll have something to say for this

[stayedon43]

Thank you. You have confirmed my thoughts, perhaps a suggestion to inform the insurers would be appropriate.

[messy]

Would there be detection in the cavities?? - Otherwise I can't see the advantage of L1

[Chris Houston]

What about the safety of the fire fighters.  One need for cavity barriers is to prevent fire spread over their heads.

[jokar]

Firefighters role now is saveable life and saveable  property.  In this instance whilst it is not a good solution providing the firefighters were aware that the cavity barriers were absent and that the L1 system ( fitted in all cavities) works and allows the staff to evacuate it could fit as a compensatory feature.  Again would the insurers actually insure it as it would probably end up as a car park.

[kurnal]

There are a lot of questions I am afraid.

How big and how deep are the voids?
Where are they - above false ceilings?
Will there be detection in the voids?
Apart from the cavity barriers to be omitted  will there be any other compartmentation issues involved?
As its a food plant will there be any insulated sandwich panels involved above or below the voids?
If the AI is recommending the L1 as a compensatory feature has he identified that he has considered firefighter safety in this decision?

[Chris Houston]

Firefighters role now is saveable life and saveable  property.  In this instance whilst it is not a good solution providing the firefighters were aware that the cavity barriers were absent and that the L1 system ( fitted in all cavities) works and allows the staff to evacuate it could fit as a compensatory feature.  Again would the insurers actually insure it as it would probably end up as a car park.

What if it is someone other than the local fire fighters who have to put out the fire (the army for example), what is someone is trapped inside?  I think the need for cavity barriers is there for a reason and fire detection is not enough to compensate for this.

[stayedon43]

Clearly a good topic to debate. I hope you can understand why I posted the thread. I need to be comfortable with my reply, as indicated it may well be safe for the persons inside but what about the firefighters who may have to attend the incident. I believe LISP is involved as it is in the other 2 units. Would it be appropriate to alert the AI to the fact Im not happy with the exclusion of cavity barriers ?
Thanks again

[kurnal]

Yes - in fact the udivided ccavities may be an insignificant hazard compared to the potential hazards presented by LISPs - depending on their insulation, support, installation standards and fire stopping. I would get the LISPS right first then consider the cavities.

[Clevelandfire]

Firefighters role now is saveable life and saveable  property.  In this instance whilst it is not a good solution providing the firefighters were aware that the cavity barriers were absent and that the L1 system ( fitted in all cavities) works and allows the staff to evacuate it could fit as a compensatory feature.  Again would the insurers actually insure it as it would probably end up as a car park.

What if it is someone other than the local fire fighters who have to put out the fire (the army for example), what is someone is trapped inside?  I think the need for cavity barriers is there for a reason and fire detection is not enough to compensate for this.

There is alot of misinformation about the subject of protection for firefighters.

This argument doesn't hold true for say premises where a fire appliance wouldnt reach them for  20 minutes

In which case by the time crews got their equipment off, and did  dynamic risk assessment was done you could be talking 30 minutes. And by then the cavity is probably breached anyway,

Its another bit of government  guff really. How are you going to make operational crews aware that there is no cavity protection? if they knew and persons were trapped do you think that would stop them going in.

Im not having a go Chris Im just stating fact - its another " well thought" government initiative that means diddly squat in the real world.

Fireifghetrs are paid to deal with fire emergencies

Fire is dynamic and whilst to a point predictable sometimes things go belly up. SO theres no real point!

[kurnal]

But on the other hand Cleveland BS476 tests are not real fires. So the effect of structural protection, thouh we class it as half hour, one hour etc , just sets a benchmark that little insignificant or single storey buildings can fall down quickly as a result of a fire because people should be able to escape easily and fire fighing can hit all parts by spraying water on the outside.

But more complicated buildings need to stand up a little longer becoause they are larger, higher, have a greater popullation increasing the chance of someone needing rescue, and areas of the building that cannot be hit using a jet through a window outside, so firefighters have to enter and penetrate for effective firefighting. So these buildings have to be safe for a little longer.

And once we start putting in LISPS and the like we need to start being particularly careful that such a fire cannot spread over and around firefighters cutting off their means of escape- and more important delaminate and drop on them.

For firefigher safety an L1 alarm cannot be of any use as it will long since have been silenced if they are working in the building. And even if it hasnt been silenced  BS5839  only requires cables of limited fire resistance.

So for half hour, one hour, two hour fire resistance read an increasing standard of resistance to the effects of fire commensurate with the size, nature and value of a building provided for the safaty of all relevant persons inside and outside the building, firefighters and for the protection of business continuity and the national economy.

[Mr. P]

What aout the use of FR curtains?  I have recently asked for that in a new build.  Could have insisted they rebuild, but achieved the same compartmentation.  A very large section between offices and workshops were made up, plus additional dets in voids.

[Davo]

stayedon43
Didn't a frozen food factory burn down in Grimsby a few years ago?
I believe it was the same scenario as the Prof was talking about.
Question I always ask myself is what would the FRS require to certify it?
(yes I know we have moved on but lets face it its a good start for someone of my level of knowledge)

davo

[Midland Retty]

stayedon43
Didn't a frozen food factory burn down in Grimsby a few years ago?
I believe it was the same scenario as the Prof was talking about.
Question I always ask myself is what would the FRS require to certify it?
(yes I know we have moved on but lets face it its a good start for someone of my level of knowledge)

davo

It would depend Davo...I'll try and be brief on this one as I do tend to ramble!.

It would have been inspected in some way shape or form, but as always the Inspector will partially be reliant on any information to hand about the construction of the building.

Remember too that Building Control would have been responsible for the fire safety aspects of the factory when first built.

Also the fire service had a statutory bar placed on it under the Fire Precautions Act - so if the building was subject top be certified and there were some elements that the fire authority didnt like at the building control consultancy stage, Building Control were not duty bound to act on those concerns. And the fire service couldnt go in afterwards to ask the factory owners to make upgrades.

Consequently I have come across some thjing which have been passed by Building Control which wouldn't be to our liking, and we have made comment at the consultancy stage which were ignored.

If the building has had several owners and has been standing for some years with the odd alteration here, an extension there the ammount of information slowly dwindles or becomes distorted and unfortunately that can mean stuff gets missed. There is of course the situation where some building practices and materials which were deemed to be acceptable in the past have now been found to be actually quite dangerous, or at the very least "not up to modern day standards".

Inspectors are not always able to poke their heads above ceilings to establish if lines of FR are carried up to true ceiling height and the like.

Hence the need to be vigillant and as the Prof mentions you shouldnt be complacent when it comes to large buildings which need to maintain structural integrity and give protection for firefighters.