Emergency Lighting, to change or not to change, that is the question

[baldsparkies]

We have been asked for a second opinion by a company we do a fair bit of work for.
They have had an emergency lighting full duration test conducted and we have now followed up with a second test.
The test related to a large ware house with self contained spot floods fitted around the perimeter and centre RSJ's
Only 2 of the units failed in under 120 minutes, the rest lasted up to 120 to 140 minutes.
The other company suggests replacement of all 22 units because non lasted 180 minutes ??
My issue with this is that the entire installation has generator back up, should mains failure occur.
Also the emergency lighting is to be used for evacuation of the building ??
I explained that my view is that a 1 hour duration should be compliant if supported by a risk assessment.
The generator has a 6 monthly service schedule with load tests and the check its running for an hour on a weekly basis.
Log books for the e/m's are kept on site and all in order.
I said it may be wise for there local fire officer to have some input but that I honestly felt replacement of the fittings wasn't needed.
Some people are just scamming for work, and the price for replacement was astronomical which is why the facilities manager wanted our opinion.
I know there are some bright sparks on this forum and wondered if you guys would feel the same way I did.
Cheers lads :winkiss:

 

[Darkwood]

The consensus is the fitting should be able to hold the lights on for a 3hr duration to comply, you do raise a valid point regarding a risk assessment and would be interesting to see how this thread developes.

What is the service history of the batteries? If I remember they may require replacement every 4 yrs or so (check with maufacturer). I would at least buy 1 battery and see if it rectifies the issue at any given E/M fitting as those twin spot fitting can be expensive.

I find it hard to believe we have a full warehouse of E/M lights that have all failed, more than likely they batteries are all expired.

 

[nickblake]

Im in the process of doing the same testing at a school twin beam emergency lights failed found that some of the lamps have failed so i have replaced then with retrofit led which have improved the light output and hopefully will last longer we change the batteries every 4 years in the fittings and the standard bulkheads we are changing to LED as the cost of the batteries are 3 times the amount of a new led emergency light , as for the risk assessment could be an idea to provide one and submit it with your observations

 

[malcolmsanford]

This 3 hour test is always a bit of a misnomer. The regs say that the fitting must still a "lit" but to what degree must the illuminance be.

Funny enough I have just done this on a new build here and we did the test after charging for 36 hours. The first 1 hour 40 mins was spot on and the light maintained a good level .

Then after this the light deteriorated quite a bit, and by the 3 hours though it was still "lit" it was literally dead. I spoke to a pal in the UK who is much more knowledgeable than I on this and he told me that it would be classed as a pass as long there is still a glimmer, though he would expect them to only lose about 30-50% of the luminescence.

I'm going to do the test again on Friday after draining the battery fully on the last test and giving the unit 72 hour charge.

Strange the Fluorescent power packs stayed illuminated much longer. It was the actual emergency bulkheads that "failed"

 

[Deleted member 72666]

Im in the process of doing the same testing at a school twin beam emergency lights failed found that some of the lamps have failed so i have replaced then with retrofit led which have improved the light output and hopefully will last longer we change the batteries every 4 years in the fittings and the standard bulkheads we are changing to LED as the cost of the batteries are 3 times the amount of a new led emergency light , as for the risk assessment could be an idea to provide one and submit it with your observations

Hi Nick, do you have a link for the retrofit led for the twin spots?

 

[alanl]

As regards the duration, this topic came up a few years ago on the IET forum.
The Designer must design to the Risk Assessment, and specify what the lights are there for.
If for evacuation, then 20 minutes is enough for most locations, there must be a bit of leeway, then add a bit on in case the lighting fails again, and you're going to need a 1 hour rated light fitting.
Now, go and try to buy a 1 hour fitting - there are very few out there, the majority are 3 hours.

So you buy the 3 hour fitting.
Now a year or more later, another Contractor comes along to test the lights. He sees they are 3 hour fittings, so assumes they must last the 3 hours to comply.
He is wrong - he should consult the RA, and original design, if possible.
If not, then a new RA should be done, to show how long the lighting should be illuminated. There would clearly be no point in having 3 hours for evacuation in a single room shop for example (unless LA rules determine that they should), whereas 3 hours may be appropriate in a large department store.
So, consult the RA, if there isnt one, you cannot verify the EM Lighting Installation, as you do not know what duration they should be.

 

[Darkwood]

I think there is a cross over here from product expected operation and actual operation, granted if you only need 1hr and a 3hr product manages 2 then it does its job ...but the issue here is that the function of the fitting is impaired for some reason as it fails to operate to its design criteria, the question left is would said fitting operate correctly on the day... to cover yourself you cannot say it would if it cannit meet its 3hr expected operation.

As has been mentioned, a majority of the time the batteries have expired and should be replaced so I think its a false argument to say it doesn't meet it 3hr design criteria but its long enough to evacuate the premises.

It you had a powercut and one failed and someone tripped in the dark then where would you stand admitting you knew the fitting wasn't meeting its design duration which would indicate something was wrong.

 

[tazz]

Specified areas can be limited to 1 hour, but the problem is the recharge time, No re-entrance would be permitted unless a further 1 hour could be managed by the em fittings. Hence all are manufactured to 3 hours. Work areas require the full 3 hour duration, and if tested or used to this limit....occupation or re-entrance to the building must suspended until the 16hr recharging period has lapsed. Unless the em lighting is wired to the generator in fire proof cable, it cannot be considered as a backup