240v systems

[LaaLaa1965]

I'd like members' opinions about the following point.....The 240v fire alarm is illegal as it does not provide any battery back up.....also, is there a threat to life if one of these systems is installed?  Conversely, if the system has been maintained and is working satisfactorily, does it need to be changed?

[CivvyFSO]

It is really down to the opinion of the individual fire authority concerned.

Like you say, technically it is illegal but only under signs & signals regulations as the 'signal' needs backup, but many fire authorities do not concern themselves with this too much so long as it is maintained and working. Unless it is a sleeping risk, then it would more than likely be seen as inappropriate if it doesn't have backup power. If it is not a sleeping risk, then a suitable plan with measures to be put in place in the event of a power cut (i.e. Roaming patrols, air horns/radios, tighter controls of hot work... Read: none could be deemed as complying with the fire safety order.

It is down to the good old assessment of the risk. i.e. What are the implications of losing the power, can you still continue to trade/work temporarily with alternative measures in place, or are people still going to put at risk therefore it is time to stop working and wait until it is fixed?

[nearlythere]

Is an electrical fire alarm system necessary for the building?

[Tom Sutton]

Check out http://www.kingfell.com/~forum/index.php?topic=4265.0 maybe relevant to this thread. Also what about Uninterruptable Power Supply technologies ( http://en.wikipedia.org/wiki/Uninterruptible_power_supply ) would they not make it legal.

[CivvyFSO]

I think that it would satisfy any issues under the signs and signals regs.

[Wiz]

Just a small point worth remembering; whilst a UPS might provide the battery back-up to comply with 'Signs and Signals' regs., it is as well to remember that the UPS system is hardly likely to have the self-monitoring and fault warning signals required of the maintained power supply of a BS5839 part 1 system

[AnthonyB]

Even with the back up power issue a 240V AC system will be poorly zoned or not zoned at all (with implications for those investigating an alarm & thus this pulls in the 24V DC equivalents), may have audibility issues if the buliding layout has changed, cannot (easily) take AFD, the cabling and any AFD (usually heat as if you still have smokes on it the HSE will be after you as they are notifiable due to the large radioactive source) will be in poor order and there is no fault monitoring so other than the week you test a particular part of the system you will not know if that part will work at all.

The system will be 35 to 50 years old and really should have been ripped out 15 years ago - there has been plenty of time to do a budget set aside over years to replace the system. Mains only systems and their failure featured in some of the major fires over the years.

No one should be justifying such obsolete equipment any more - you'd have not been able to install such a set up for several decades and adaption to technical progress is needed here.

[LaaLaa1965]

Thanks to you all, the info will be useful

[Tom Sutton]

I agree you should do everything in your power to get them to install an up to date system but what do you do if they refuse. They can make it conform to the signs and signals, you are not required to conform to part 1 and looking at the Manchester experience (http://www.kingfell.com/~forum/index.php?topic=4265.0 reply #5 ) the court didn’t help them. It appears there isn’t much you can do about it other than have the charm and persuasion of somebody like CT.

[John Webb]

An important consideration is the type of wiring in the system. Heat damage to wiring in conduit will bring about a failure of the alarm system quicker with a 240V worked system as the much higher voltage will short through damaged insulation more readily than it would with a 24v system! This was a contributory factor at the 1973 Summerland fire where the building was equipped with a 240V AC system - back up in this case was an IC-driven generator which failed to start......

I'd much rather have a battery-backed system any day!