Supply To Fire Exit Signs

[wildgoose]

I'm in the process of fitting several fire exit signs into a small industrial unit. These signs will be the standard 3hr maintained versions, with nearby labelled fishtail interupt switches for routine battery backup testing.

My colleague electrician and I have differing opinions about the source of the supply for these lamp units. I say that this emergency lighting supply can be taken from an existing frequently used lighting circuit but my colleague says it must now have its own dedicated 'emergency lighting supply' from the CCU?

To save me trawling through the regs, what am I allowed to do please??

 

[chrish_1977]

I would say go on the lighting, what's the point of having em lighting if it doesn't come on when the lights trip.

 

[Deleted member 26818]

Either, preferably from a lighting circuit.

 

[MDJ]

local lighting circuit as well, it's own circuit is fine if it is linked centrally to local circuits, what a job that will be, your mate is overcomplecating an easy Job IMO. Interestingly though I would like to see your M8s evidence for my own benefit as I fit hundreds myself yearly.

 

[wildgoose]

local lighting circuit as well, it's own circuit is fine if it is linked centrally to local circuits, what a job that will be, your mate is overcomplecating an easy Job IMO. Interestingly though I would like to see your M8s evidence for my own benefit as I fit hundreds myself yearly.

I agree with you. After all, if existing local lighting circuits are good enough for mains smoke detectors, then my reasoning that they must be ok for the signs too!

 

[frank3323]

its in BS5266, you wont find emergency lighting in the regs, i can send u the British standard .pdf if you PM me email address

 

[frank3323]

and EM lighting has to come on when the local lighting circuit goes off, so your exit signs should be wired from whatever circuit is in the same room / same area, through a means of testing (key switch) also, there is no rule on, when tested if the non emergency lighting should stay switched on or go off when the EM lights come on, this is open to interpretation and personally i like to make sure the lights stay on and only the emergency feed is interrupted by the key switch, but other sparks disagree as testing is easier if all the lights go off, and check your EM lights, u need 1 lux at 1 metre on exit routes to please the fire officer, if u think that a standard office lighting is 300 lux this does not take many 8 watt exit signs to achieve.

 

[Adam W]

... check your EM lights, u need 1 lux at 1 metre on exit routes to please the fire officer, if u think that a standard office lighting is 300 lux this does not take many 8 watt exit signs to achieve.

Apparently that's just a theoretical issue at design stage and you can maintain those levels by changing the tubes and cleaning the diffusers every now and again.

 

[tazz]

As frank has stated rule of thumb is local supply feeds local em light. Well worth looking at LED em lights, the Meridian we use are alot brighter than 8w tube types. IMO I like to see em test switches just turn off em lights, alot of older places we service go into darkness when we carry out tests, which i think is asking for court case from joe public on a no win no fee.

 

[wildgoose]

As frank has stated rule of thumb is local supply feeds local em light. Well worth looking at LED em lights, the Meridian we use are alot brighter than 8w tube types. IMO I like to see em test switches just turn off em lights, alot of older places we service go into darkness when we carry out tests, which i think is asking for court case from joe public on a no win no fee.

Good Point - I can see the court case now where some idiot decides to throw themself down the stairs when the lights are off for emergency testing 'Injury Lawyers For You' are just waiting for it to happen

 

[MDJ]

If tazz makes a comment regarding fire alarms I tend to listen, IMO he has real merit in this section.

 

[tazz]

Thanks Mike Its great to be appreciated

 

[Adam W]

As frank has stated rule of thumb is local supply feeds local em light. Well worth looking at LED em lights, the Meridian we use are alot brighter than 8w tube types. IMO I like to see em test switches just turn off em lights, alot of older places we service go into darkness when we carry out tests, which i think is asking for court case from joe public on a no win no fee.

In that situation I agree you'd be better off just switching the EM lights (for the monthly functional test) but I'd feel more comfortable doing the 3 hour test out of hours, otherwise if there was a power cut while you were doing the test there wouldn't be enough light for everyone to get out. Unlikely, but it could happen, which is why we install emergency lights in the first place.

 

[tazz]

In that situation I agree you'd be better off just switching the EM lights (for the monthly functional test) but I'd feel more comfortable doing the 3 hour test out of hours, otherwise if there was a power cut while you were doing the test there wouldn't be enough light for everyone to get out. Unlikely, but it could happen, which is why we install emergency lights in the first place.

I would hope that the emergency lights being tested were still on during the test and the power cut. If the lighting level is no sufficient enough for people to see the way out or to a place of safety, then a redesign is needed. Most of our jobs are care homes so night tested would be suicide.

 

[Adam W]

What I mean is that if there were a power cut towards the end of doing a 3 hour test you might not get 3 hours out of the batteries.
I believe the normal procedure in areas without natural light is to test half of the lights at a time.

 

[tazz]

In this world of testing any thing can happen, must say tho the new led lighting on the market is helping matters 1. no changing tubes every six months, 2. light intensity is far better than an 8w tube, 3. duration period well over 3hrs, this has now become a fit and forget for 5 years.

 

[accordfire]

In this world of testing any thing can happen, must say tho the new led lighting on the market is helping matters 1. no changing tubes every six months, 2. light intensity is far better than an 8w tube, 3. duration period well over 3hrs, this has now become a fit and forget for 5 years.

Totally agree.

We've been fitting LED units for the last six months or so, and we can get them at around the cost of an 8W maintained fitting - they're rated at 4W, and can be used maintained or non-maintained.

As you say, the benefits include far higher light output - measured an increase of around 30% in lux level when replacing tube for LED - first site we did has just had a full discharge test, though rated for three hours, curiosity led me to run them longer - 5.5 hours.

We won't be going back.