BS 9991

[Northern Uproar]

This is in a building in which each flat - and NOT  the communal areas- has its own self contained BS9251 domestic sprinkler installation. How on earth can the maintenance of all these installations in private dwellings be enforced,  controlled and co-ordinated? How many will still be working in 10 or 50 years time? We have enough problems with flat entrance doors and even letter plates for goodness sake.

I mentioned this to the head of fire safety in one brigade and he looked at me like I'd landed from Mars, saw no issues at all.

The issue of lowering the sprinkler requirement from 30m in ADB to 18m may raise a few eyebrows, and did the study into open plan arrangements find that it was OK for all arrangements to be OK with a sprinkler system and additional detectors?

[AnthonyB]

This isn't new and has already happened - I posted about a high rise residential development using exactly this clause a month or two back.

And as you correctly stated Kurnal, the problem of the maintenance of all these installations in the private has already reared it's head after just a few years, with no answer other than someone will eventually end up in one of the courts.

[CivvyFSO]

The issue of lowering the sprinkler requirement from 30m in ADB to 18m may raise a few eyebrows

Where is this? I can see where it states that flats above 30m should be sprinkler protected, but not 18m.

[Northern Uproar]

The issue of lowering the sprinkler requirement from 30m in ADB to 18m may raise a few eyebrows

Where is this? I can see where it states that flats above 30m should be sprinkler protected, but not 18m.

I think I'm reading 29.2, Table 3 wrong? Here it gives the FR requirements for the structure - only gives an Fr rating for unsprinklered buildings for <18m. <30m and >30m have a line thru' it. Table 4 gives vent conditions that seems to allow for 120 mins up to 30 mins, but if they can't be achieved Table 3 should be used, and for that table, the system should be EN 12845, whereas Table 3 states 9251. IIRC, the Resi BS does have a height limit, but ADB says to disregard this.

[CivvyFSO]

I don't know if this is really stating that buildings of such a size cannot be made without following the ventilation recommendations that follow with regards to table 4. i.e. Between 18 and 30m you can build it unsprinklered, but you can't build it unsprinklered AND unvented. Therefore you have to supply the ventilation suggested in table 4.

There are a couple more paragraphs earlier on that state that buildings with flats over 30m should be sprinklered, and there has been comment made that this should not be limited to just 'flats'. The table essentially counters any argument as to whether or not any applicable building over 30m needs sprinklers.

I think that it needs clarification as to what standard of sprinklers is required. It is my opinion that if BS9251 is being used in a tall building, that it should be of the residential standard, as it is not simply the MOE from the flat that is being protected, it is protecting the people who are subject to a stay-put policy. The domestic standard is a fair compromise where open plan layouts are used, as it is the MOE from the bedrooms through the main accommodation that is being protected there.

[colin todd]

Civvy why are fires bigger in higher buildings?

[CivvyFSO]

They are not. If I were to defend the choice of sprinklers being required over 30m then I would suggest that beyond 30m you have almost zero chance of having something turn up at your window that you can escape via.

[colin todd]

So then what is wrong with BS 9251 sprinklers regardless of height.

[CivvyFSO]

I am not talking about BS9251 sprinklers in general, I am talking about the difference between the 'residential' and the 'domestic' requirements.

"It is my opinion that if BS9251 is being used in a tall building, that it should be of the residential standard" i.e. Not just 10 minutes worth of water.

I look at it like this; if you get the correct pressure/flow to enable a suitable amount of water to come out for a suitable amount of time, then where is the problem?

Also, the standard doesn't seem to have the same faith in watermist above 20m.

[colin todd]

ok let me rephrase the question. Why is 10 minutes supply okk for a flat at 29m in height but you need 20 minutes for a flat at 31m.

[CivvyFSO]

30min.

Maybe you need to go read the standard first.

[kurnal]

30 minutes or 10 minutes, 30m or 6m  I feel uncomfortable with relaxing fire precautions in communal areas in lieu of fire precautions in private flats over which no effective control can be exercised.

Its not just a matter of doubling the  permitted travel distance its also doubling the number of flats exposed to the dead end condition so doubling the chance that the escape route wil be exposed to a fire in a flat and the potential consequences should just one of them not maintain their system.

[Davo]

This one requires my H & S head on.

Its like all RAs really, deal with what you have control over (or have more faith in )


davo

sh*t happens, OK

[jokar]

The time limit matters not but I would be interested in the answer to the question set at

ok let me rephrase the question. Why is 10 minutes supply okk for a flat at 29m in height but you need 20 minutes for a flat at 31m.

if any one knows why this is.  What is so magic about 11m etres, 18 metres, 30 metres and 50 metres.  History will do.

[kurnal]

Length of ladders and high rise for the first 3, and hydraulics and gravity for the last.