The Law regarding Fire Alarm Systems.

[kurnal]

Mike answered the point for me. Yes he is absolutely right that the purpose of the fire alarm in these situations is to alert all those who need to be alerted. Once that is done the noise prevents good communications and causes distress to those who are totally dependent on others to assist them to escape. When I produce an emergency plan for a care home I usually  suggest that once all staff and visitors and anyone else who is intended to leave under their own steam is accounted for, then the alarm should be silenced but not re-set. This gives the staff chance to communicate and minimises distress for those in their rooms who are awaiting assistance and who may well be waiting a long time if they are at the opposite end of the building to the fire. Hospitals likewise have their own HTM codes for fire safety including special provisions in the design of the fire alarm system. You can download  or obtain these here:

http://www.dh.gov.uk/en/Publicationsandstatistics/Lettersandcirculars/Firecode/index.htm

[Wiz]

I stand by everything I mentioned in my previous post including all the facts and figures that I mentioned.

I am certainly not trying to mislead anybody and resent the implication.

I am certainly not going to allow contentious claims to go unchallenged on Firenet, otherwise the unwary may take them at face value

Obviously, it is up to the readers to decide who or what they want to believe and I feel that my point has been made in adding another viewpoint to the claims being made.

Furthermore, I also won't be drawn in to a childish slanging match with someone who admits that he has been ignored by all the authorities and banned for life from forums peopled by just those who should know all about the subject!

[kurnal]

Thanks Wiz. Your postings are always well informed and well argued. Moderating a forum can be challenging, as a member of other forums I have seen the damage that can be caused when people deliberately post incorrect material or make outrageous or offensive claims or comments. It is easy for the regulars to become disillusioned and to turn away from a forum when this starts to happen and hope this does not happen with firenet.

By the same token I always try to give people the benefit of the doubt and welcome the chance to share knowledge and experience amongst ourselves and with new posters. However whilst it is good to challenge existing practice and standards this should be argued from a certain foundation of knowledge, the role of the forum in educating people I think is more to point people to the sources of information and then discuss, rather than to try and educate people from the base level.

I think as other forums are specifically set up to discuss electrical safety we should draw a line under that particular discussion and leave the arguments on equipotential bonding to them. I know it was I who asked David to expand on this but in hindsight it was clearly taking us outside the scope of firenet. I hope you both agree.

[Midland Retty]

Hi Mike/Kurnal,
I don't actually disagree, some NHS staff hate fire alarm systems going of all of the time, but it shouldn't of taken me to go around and warn everybody, should it?
I have another first hand example that I remembered over the weekend: It was at a furniture store in Canterbury that had two entrances, the main entrance was at the rear where the car park was therefore the CIE and single bell were located there, but before the Fire Brigade arrived two students stopped for a chat outside the front door which delayed their entry, as they were chating the plate glass window next to the front door exploded on to the street in front of them!
Could have been nasty.

I posed a question on the Electricians Forum yesterday concerning why the 17th Edition of BS 7671 fails to comply with EAWR 1989 and I have now been banned for life from the Forum.
Now thats' what I call freedom of speech!
Would anybody care to ask them "why they are still using a fusing factor so many years after we all stopped using fuses?" on my behalf.

David Im confused.

Are you saying that at this particular hospital there was a fire alarm activation and all the sounders failed?

Or were the alarms deliberately silenced by staff?

If it was the latter then I could quite understand that (as per Mike Buckley's excellent summary above)

If it was the former I'd find that very difficult to believe.

[Graeme]

is this a wind up?  

shoot me now

[Wiz]

is this a wind up?  

shoot me now

It's not you who needs shooting, Graeme.

[David Rooney]

is this a wind up?  

shoot me now

It's not you who needs shooting, Graeme.

We can't all be on drugs...... this really is happening..!!

[Wiz]

For those that have seen the film Inception, this could be a dream within a dream within a dream.

[Midland Retty]

Hi David

Im not suggesting you are telling fibs, but it is difficult to believe that this actually happened for several reasons.

Even with my limited knowledge of fire alarm systems, I simply can't accept that all of the sounders failed.

[Meerkat]

So let me get this right...  The fire is severe enough to MELT the sounder(s) but has not in this time allowed smoke to spread out of the compartment where it started and activated another detector?  This is of course assuming that the compartment was small enough in the first place to only have one detector.  Don't you think you might be stretching the credibility of the scenario just a little bit?

[Meerkat]

So it's a real scenario?  What happened next then?

[Wiz]

In a two zone overlapping bell system each zone is supposed to be able to provide an adequate decibel level on its' own, just in case the other zone is in down time........

The above isn't a requirement of BS5839-1. Providing such a system seems like a good idea but the extra expense obviously isn't considered worthwhile by BS.

[AnthonyB]

Early total sounder failure did occur at Hendersons, Woolworths & the Rose and Crown however this was purely down to one of two factors:
a) 240V AC only supply, with mains failure leading to non function
b) The use of non fire resistant cabling on sounder circuits

That is why fire alarm systems are now 24V DC providing at least 30 minutes of alarm after 24 hours mains failure and that for years protected cable had to be used on sounder circuits (& now all circuits).

This seems to do the job and in most well managed buildings 5-10 minutes of alarm should be enough to ensure evacuation (some larger & public buildings and those with a more complex evacuation strategy excepted). Sure eventually any system would fail due to fire damage, but I would be worried as to why anyone would still be inside at this time.

I've encountered system failure, but this is often in buildings with pre BS5839 systems or due to a massive panel failure, but on the latter daily visual panel inspection & weekly tests picked these up promptly and contingencies put in place.

So it seems we are trying to over engineer things a little here!

[Midland Retty]

Anthony B. Those were my thoughts exactly.

[BLEVE]

Me too, guess great minds do indeed think alike