Emergency Escape Lighting

[kurnal]

Came across something today I have not encountered before. I wonder what you will make of it?

On a fire risk assessment of a sheltered housing scheme I had come across a non compliant central battery controlled non maintained emergency lighting  system, it was not sensitive to failure of the local lighting sub circuits. It was a 24 volt system based on flourescent fittings - identical in appearance to the normal self contained units but without batteries. I recommended it be reconfigured and or replaced.

The contractors solution was to provide an interface box to the fire alarm system controlling a lighting relay, which in turn brought on the non maintained fittings  on operation of the fire alarm. There is an L2 system installed.

So the lights work on total mains failure to the building or on operation of the fire alarm system. Still not got my head round all the implications though.

[Phoenix]

Hi kurnal,

If there's a fire in the building you haven't got a problem as the lighting will come on through the interface but if there's no fire it could be a disaster!  They could be tripping over themselves, banging their noses and breaking their hips all over the place if the emergency were something as serious as the lighting mcb tripping out.  You'll just have to hope that nothing as serious as this happens and hope that the only incidents they have involve fires.  

Stu

[AnthonyB]

Some of the classic 60's CB systems had a relay from the fire alarm system to illuminate upon alarm as well as total failure.

The system would now operate as escape lighting in a fire situation as even if the fire knocks out a sub circuit only as the fire alarm will put the lighting on (guessing there is AFD).

But the system would not operate as true emergency lighting as you could have a non fire local failure leaving an unsafe situation.

However that could be argued to be a purely H&S issue and that it would provide the necessary escape route illumination in a fire situation so no longer an action for the FRA Action Plan...... if your brief is only fire you could be able to wash your hands of it, but if it's both you still have a problem.

(personally I would prefer it to work for local failure as well without the fire alarm having to have sounded)

[Galeon]

If the building is 3 phase all you have to do is install a phase monitor relay ergo any phase drops out will trigger the CB unit so it don't matter what phase the CB is on. You can then monitor the unit via the fire alarm for dropping out the phase supply and also monitor for fault which is a handy thing to do.

Going back to me PSA GLC works as a young sprog , the local mains failure wasn't taken into account with the CB unit , and to be frankly honest its a better job , I am totally fed up trying to obtain poxy conversions made in Italy that some twat of a designer thinks looks good and two years later he aint the one trying to source a new unit.

You cany beat a standard emergency with nothing to do with a normal light fitting.(where you aint got a CB unit lol)

[Galeon]

Here's a thought why not put in the super-duper Hochiki led self test knows when it goes wrong all singing and my forte dancing and Roberts your uncle , i think young Mr Dave Rooney was on the case the other day , had a quick butchers (look) for all of you not into Easterners looks pretty good to me .

[Wiz]

Prof., surely the problem you have mentioned is nothing to do with the interface that causes the emergency lighting to operate on a fire alarm condition, but all to do with the failure for it to come on during the loss of power to local lighting circuits.

This has always been the problem with CBU systems. They may monitor the incoming power (single or three phase) to the CBU but this provides no emergency lighting output if the power failure is caused on a local lighting circuit elsewhere in the building.

Preferably the emergency lighting CBU should have a maintained output wired to each luminaire but this is held off from illuminating the emergency lighting by the contacts of a relay whose coil is wired to the local normal lighting circuit. Anything else does not really provide protection when losing power to normal lighting.

Alternatively self-contained luminaires will do the same job and in many circumstances much more cheaply.

[AnthonyB]

It's rare to see a new CB system these days even in some of the traditional user groups such as licensed/entertainment premises with self contained/conversion kit units being the norm and a lot of places are ripping them out - I find them in older licensed/entertainment premises and the very rare large 60's office or shopping block that hasn't been refurbished ever.

A lot of newer premises where extended durations are required (often at standby lighting levels) will use a generator and self contained units, the genny providing essential services and standby lighting and if that dies out the self contained batteries in each fitting give a further 3 hours at EL levels in order to pack up and leave.

CB systems seem to be of widely varying efficiency based on a combination of operating voltage and bulb type - some are of little more use than a candle located at various points throughout the building, others you would think the normal lighting was still on.

[kurnal]

Thanks everybody. Have resolved things with a compromise, whilst my brief is only fire we cannot overlook general H&S. As an imperfect but pragmatic compromise the contractor has now agreed to install a number of self contained non maintained units in key high risk areas operating on sub circuit failure to cover non Fire related emergencies. For fire the CB powered units were all configured  to operate on activation of the fire alarm OR failure of the mains. Little fault immunity though. Far from perfect but a big improvement.

[colin todd]

I like CB EL. It is fine if you configure it properly. Remember Big Al, when you were a DO,nearing your 30 years in, and I was just a fresh faced recruit on red watch, they always called it "secondary lighting" because it was, in effect, a complete second lighting system in the premises?

They often used tungsten pygmy lamps, though in the modern fire service they would call them tungsten vertically challenged lamps.

[Galeon]

I like CB EL. It is fine if you configure it properly. Remember Big Al, when you were a DO,nearing your 30 years in, and I was just a fresh faced recruit on red watch, they always called it "secondary lighting" because it was, in effect, a complete second lighting system in the premises?

They often used tungsten pygmy lamps, though in the modern fire service they would call them tungsten vertically challenged lamps.

So much for technology I think we are going backwards not forwards sometimes, mind you can’t beat a good old b&w film on a 42 inch HD colour telly .....................