BS9251 currently up for review

[kurnal]

Please can someone explain why if I install a domestic smoke alarm in my new house ADB recommends a grade D LD2 or LD3 - ie mains powered with battery backup. The battery back up is necessary so that I maintain protection during a power cut.

But if I wish to install domestic sprinklers National guidance such as BS9991 allows me to make a range of trade offs in lieu of the benefits of sprinkler protection. That's great.... but for a pumped water supply  BS9251  does not require any back up to the power supply to the pump- so I lose the protection in a power cut. (para 5.3.4 page 16).

People say that there is little likelihood of a coincidence of a fire occurring at the time of a power cut ...but in a power cut out come the candles and lpg heaters and up goes the fire risk........

Is it time BS9251 was brought up to a proper life safety standard for the supply to the pump? Or if not why not?

[wee brian]

Because you cant do it with a 50p battery.

As for ADB and snoke alarms. I seem to remember that one issue was that having two types of alarm was more expensive for manufacturers than having one.

[kurnal]

Thanks Wee B. Clearly a case of political expediency in order to stimulate and encourage the installation of systems. I see the original logic and motivation  but 9 years on, as the standard is currently under review,  I suggest its time to move things on to a more resilient footing. I am going to suggest a halfway house.

Where  a system is installed in an otherwise ADB compliant dwelling then the status quo remains. But where the system is part of the protection to communal areas or where trade offs are agreed then the resilience should be enhanced such that the system is not compromised by a simple power cut  or by the failure of an individual tenant to maintain their installation. Is this realistic?

[colin todd]

Kurnal, I thought that this was my idea, when I put it to a little group you sat on.  Not that it matters who gets the brownie points.  Wee B it is expensive, but, unless you are the sprinkler trade trying to prove how cheap sprinklers are, it makes no sense to have  a means of escape that is reliant on a sprinkler system which is disabled every time there is a power cut. We first specified the use of a UPS under these circumstances years ago, and drew the issue to the attention of the BSI committee years ago.  Costs a lot.

[kurnal]

Brownie points? I am on the naughty chair in some quarters for daring to suggest it. You are welcome to take my place in the stocks for a while if you wish.  

I wonder if some of the excellent points contained in the BAFSA Technical Guidance Note No 1 will be incorporated into BS9251?

In a tall building with a firefighting lift the duplicate power supplies should not be a problem.