BS5839 and the audibility of a fire alarm

[kurnal]

I have ruffled some feathers in a new factory building. The ambient noise including the PA radio runs about 65 dBA. The alarm has been tweeked to just about hit  70dBA in most areas. But it aint clearly audible above the radio in some areas in my opinion even though the meter says it is about reaching the 5dB differential. Seems to depend on the music being played.

So I am asking for an interface to the alarm system to mute the music but not the mic. The argument is who will pay- the client, the alarm engineer ( who is claiming compliance with 5839) or the PA contractor who I say should have taken full account of building safety systems in designing his equipment (The fire alarm was already installed). So my money is on the PA contractor but I would be grateful to hear any other views (if they will turn the B**** radio down!!)

[John Webb]

I'd agree with you - the radio needs to be silenced for audibility of the fire alarm. I had a problem some years ago where my then church in South-East London had dug out the crypt to form a youth club complete with powerful disco equipment. Fortunately we'd specified a 'priority mic' over-ride from the start. When the church was equipped with a fire alarm a couple of years later it was a simple matter to link this over-ride with a relay to the alarm system. One unanticipated benefit was that we only had one false alarm from the youth club - when it cut out the music the person who had done it was put in their place by the other members for being such an idiot and there was never a reoccurance!

[Thebeardedyorkshireman]

This, on the face of it, is a simple case of contract law. You cannot impose contractual conditions post contract. Therefore it sounds like the FA contractor is in the clear UNLESS he was told there was going to be a pa system and he should have made provision under BS 5839 2002 16.2.1d.  The PA contractor is deemed to be a expert in PA, end of. Therefore why should he pay? unless he was specifically told of a requirement to shut down. he could argue that the fire alarm should be audible above the PA or be shut down by the above rule.
The answer is who is responsible for co-ordination of building services? Go for the architect or consultant engineer. They will be on fees so will pass it back to the client or claim on their PI insurance if a mistake has been made and the clanger is big enough.
Somebody needs to read the contract for the construction and fit out of the building. the answer will be in there.
Dave
pa

[Wiz]

Kurnal,
I agree with TBY's viewpoint. I am disappointed that you, my hero, thought the poor old contractors, who will be working to a quoted price and a tight profit, should bear the cost of 'this extra work'!
Sometimes, it is impossible, even with the best will in the world, to ascertain every single variable that might be required on a project at the early planning, design and even quotation stage. Some things only become apparent when systems are 'put to use'. So unless the contractors' quotes specifically said they would do something, or achieve a certain requirement, then it is surely unfair to expect them to pay for something they might have not know anything about. If they had, they could, and would, have allowed for it within their quotes.
At the end of the day, it is the building user that will get the 'benefit' from the extra works that are required, and therefore it is my opinion that it is he who should pay for them, unless he can prove that it was definitely part of the contractural requirements to include them.
p.s. - stop ruffling feathers - they might fall out!

[Big A]

Is turning the radio down an option? or switching to Jazz FM?

=)

[messy]

If the FA engineer knew the radio was being piped through the PA at the design stage, then he should pay as surely the system should be designed to overcome ambient noises.

If not, you've truly opened a can of worms. Surely it is still the responsible person's duty to ensure adequate warning, so ultimately it's down to the RP to pay and then argue about it later(?).

[kurnal]

It certainly is a can of worms. And I am so sorry to dissapoint you wiz by ruffling feathers- after all I normally try so hard to be a pheasant plucker.

The clients specification was clear- fire alarm to BS5839 L1 and PA to whatever the spec is for these systems. The trouble was it was a design and build project so the builder specifies the detail and appoints the contractor. The clients contract is with the builder for the installation and the contractors direct for the maintenance.
The builder handed over the site months ago and is adamant that it is compliant. I dont think it is. But I am only a middle man trying to do a risk assessment and action plan for the client. Meanwhile the contractors have a maintenance agreement in place for their systems so they cant just wash their hands of it and claim to comply with the BS. So ultimately I was trying to get a rational solution believing that all parties had an interest in getting things right. Its only an interface and connection after all. But the client is adamant that he has a right to expect a compliant system.

The alarm was installed but not commissioned before the PA went in messy. So I think the PA contractor had a duty of care under HASAWA and the signs and signals regs to ensure his installation does not adversely affect a safety system. Then on commissioning of the alarm the alarm contractor should have identified the high ambient noise level and made a recommendation to provide an additional interface.

I think Dave has it about right, and the bottom line is that the client will end up paying and then chasing the builder for redress. It will then be the builders job to examine his spec and consider a counter claim against the contractors. Only the solicitors will benefit though.

[Thebeardedyorkshireman]

Kurnal
If this was one of my jobs (maybe it is!!) and I had a maintenance agreement for the site I would fit a  mains interface free of charge on the loop at the next service visit. Use this to operate a boxed relay switching a socket and plug the amp into this. If the job is L1 it can't need much cable. Simple fix, costs buttons and generates lots of good will with the client. Lean on the MD of the fire company and appeal to his common sense but don't go contractual or he will dig his heels in!! If it is one of mine, I await yor call!!
Dave

[Wiz]

...... I would fit a  mains interface free of charge on the loop at the next service visit. Use this to operate a boxed relay switching a socket and plug the amp into this. ....
Dave

TBY, Kurnal said there is a microphone, I'm guessing available for use for evacuation message purposes, on this system. Killing the mains supply to the amp. would also disable this. (No, this is not one of my jobs!) Obviously, the type of interface you suggested should be able to isolate the music only. however, I wonder if this is the real problem why no-one wants to say ' Don't worry, I'll sort it out'; maybe the amp. would also need replacing  with one where there is the facility to mute the music but not the mic. and this is making the overall requirement more than just a bit of cable and some interfaces.

[Thebeardedyorkshireman]

Wiz
This type of requirement is part of a PA/VA system which is a whole new ball game. Anything involving an evacuation message (even if you only announce its a false alarm) Must comply with the VA requirements eg Fire resisting cables, dual path signals, monitored everything etc etc. If the job has been done correctly, the VA amp will have an input to kill the music whilst leaving the mike active. How will you hear the mike message if the fire alarm sounders are sounding to evacuate the building? You cannot silence and then give a message by anything other than true Certified VA
Can and worms may be the order of the day! Send Lucky in to sort it out with matron in the black stockings (matron not Lucky- Hopefully)
Dave

[kurnal]

Thanks for your help on this. And you put a whole new slant on things Dave. Blimey the pheasant has eaten the worms and all thats left is the can now.

Its not really a voice evacuation system. (at least I hope not because the PA is bog standard). I use it in the strategy for two main reasons. If we have a fire alarm and the sounders operate, but one of the fire wardens finds the cause immediately - last time it was Mrs Mop with her brush handle- we will receive that message in the evacuation control room  and silence (but not reset)  the alarm immediately. And then put out a message over the PA to tell persons to cancel the evacuation and return to the building, minimising the down time for the business.

The second reason is if we receive a pre alarm we will get a local alarm sounder near the panel and we will use the PA to put the  wardens on standby just in case.

In the absence of a microphone the system will fail safe - everybody will be tipped out. But we do need to mute the music so we know the alarm can be clearly heard.

[Thebeardedyorkshireman]

Kurnal
Try the line relay i suggested earlier, but programme the output as 'silenceable' only. Thus when you have a full alarm the pa will shut down because the output will be active, but when you silence the alarm it will become deactivated and you can use the mike again before you reset the panel. Robert marries your Aunty Mary. Usual disclaimer applies.
Dave

[kurnal]

But Dave thats not legal. He is already my Mothers Brother. I would advise you not to get involved with the lonely hearts forum if thats the best you can do.

Thanks for the advice on the fire alarm. That seems a pragmatic way forward.