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Joined: Jul 2002
Posts: 8,443
Likes: 3
Trumpy Offline OP
Even though you fellas come from the other side of the world, could I please pick your brains, if I may?.
There is a bit of a stink brewing over here regarding the use of generators to power E/Lighting, that is used for evacuation purposes.
In the US (and other places for that matter),is it allowed that this be done?.
The problem that a lot of people that are opposed to the change in Regulations, can see, (me included) is the delay in starting of the generator, if it starts at all.
To my way of thinking, if you are in a large building (say a mall, etc) and all the lights go out, you wouldn't be waiting a minute or so, before you panic to get out!.
Another "bone of contention", is the disagreement on a Minimum Lux level for escape lighting, what level do you guys use?.
E/Lighting isn't really something that I've had a lot to do with as an Electrician, but I have as a Fire Officer and it usually involves helping people out of buildings after the E/Lighting system failed to do what it was supposed to.
One thing that the New Zealand Fire Service is going to start doing in the next few weeks is check all these E/Lighting systems and putting some real pressure on the owners of this defective gear, because at the end of the day, it's the Building owner that gives the go-ahead to fit new batteries, etc.
Any other thoughts on this subject you may have, please, by all means, jump in!. [Linked Image]

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Joined: Jan 2003
Posts: 4,391
Good Morning Mike.

Here in the US generators are commonly used for what we would call emergency egress lighting. The generator used for this must start within 10 seconds. To make sure that happens the engines are typically kept warm by a block heaters, and in my area the generators are run once a week long enough to reach full temperature. There is also a service contract with a generator service company to do the maintenance, oil, filters etc.

The NEC wants a on site fuel supply capable of two hours run time with full load. If you go this route it is usually a diesel engine.

In this area (North East US) we also often see natural gas units supplied from the local gas utility.

Here is how the NEC words the exception for on site fuel.

Exception: Where acceptable to the authority having jurisdiction, the use of other than on-site fuels shall be permitted where there is a low probability of a simultaneous failure of both the off-site fuel delivery system and power from the outside electrical utility company.

As I said in my area this is often allowed but in other areas the AHJ says no way.

While we are on the subject we have to keep all wiring for the emergency egress lighting in separate cables, raceways, panels, transfer equipment etc. We can not power someones coffee pot of of the emergency system.

If we want to power both emergency loads and optional loads we need another generator or one generator that has two output breakers one for the emergency and one for the optional. This way a short in the optional equipment will not effect the emergency equipment.

Personally I like the use of both the generator and battery back up units, I am seeing more buildings equipped with battery back up ballasts that will power the individual fixture for 90 minutes.

Many times the emergency circuits power the part of the normal lighting and if the fixture is an HID type that will not restart right away we must provide the fixture with a quartz halogen 're strike' lamp that will provide light until the HID lamp comes on.

Now all that is my point of view, please check this link for some other points of view, [Linked Image]


Bob Badger
Construction & Maintenance Electrician
Joined: May 2001
Posts: 717
Hee hee, nice to be "other point of view".

You know how I feel, and iwire is correct, I don't like using gens as the only source. I'm trained bacwards, forwards, and upside down on gens, and unless very extensive maintenance and testing accompanies the units, I don't feel they should be the only source of emergency power. We did do that testing at the prison I worked at, but have seen it in very few other places.

iwire covered it pretty danged well. Good luck with your "discussion". [Linked Image]

Joined: May 2002
Posts: 1,716
Mike I agree with both Iwire and George

Even though the NEC (as well as NFPA 101 and NFPA 110) requires "Periodic Testing" of article 700 "Emergency Systems" and article 701 "Legally Required Standby Systems", in many cases this is never done after initial testing and commissioning.

In N.C. Hospitals are watched over closely and must adhere to the monthly testing, accredited hospitals ( Joint Commission on Accreditation of Healthcare Organizations ) are visited on regular basis and must present all testing records upon request.

As Bob says, the battery back up fixtures in addition to the generator is the way to go IMO to, and in most Operating Rooms this is the case so the 5 to 10 second delay doesn't leave the staff completely in the dark.


Joined: Jul 2002
Posts: 8,443
Likes: 3
Trumpy Offline OP
Thanks for your comments Guys,
I think that the key is maintenance, where these units are used.
Over here, I'm not entirely sure what the requirements are for maintaining generators, but you can be sure, that it's practically never adhered to here.
I'm all for Battery-Operated systems of either the Sustained or Maintained types, at least then if the Mains do fail, there will still be some light to enable people to escape.
I can see how a continuous source of light would be important in an Operating Theatre.
<shudder> [Linked Image]

Joined: Dec 2003
Posts: 751
Once the building official has blesssed the building and folks have moved in, here in the USA, we have Fire Marshals to ensure that all that maintenance is done. An annual inspection is required to determine if the building owner has been following all the safety rules. Fines are hefty, so that it is cheaper to keep the building safe than to let it go and merely pay the fines.


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