700.16 Emergency Illumination (2011 NEC)

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construct

construct

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The second sentence states, "Emergency lighting systems shall be designed and installed so that the failure of any individual lighting element, such as the burning out of a lamp, cannot leave in total darkness any space that requires emergency illumination."

My scenario is a 4-story college campus building with classrooms and commons area. There is a standby generator that will start and restore lighting and selected loads if the entire building loses it's normal supply. If normal egress lighting branch circuit(s) fail on one floor or a portion of a floor, the standby system will not not come on, thereby leaving that area dark.

The architect says he has complied with 700.12. The first sentence states, "Current supply shall be such that, in the event of failure of the normal supply to, or within, the building........................."
I don't see that the within part has been complied with.

Your opinions or take on this would be appreciated. :?
 
construct said:
The second sentence states, "Emergency lighting systems shall be designed and installed so that the failure of any individual lighting element, such as the burning out of a lamp, cannot leave in total darkness any space that requires emergency illumination."

My scenario is a 4-story college campus building with classrooms and commons area. There is a standby generator that will start and restore lighting and selected loads if the entire building loses it's normal supply. If normal egress lighting branch circuit(s) fail on one floor or a portion of a floor, the standby system will not not come on, thereby leaving that area dark.

The architect says he has complied with 700.12. The first sentence states, "Current supply shall be such that, in the event of failure of the normal supply to, or within, the building........................."
I don't see that the within part has been complied with.

Your opinions or take on this would be appreciated. :?
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I'm not sure I completely understand the question, but when a generator is used for backup power, most areas usually have two sources of lighting:

1. The normal lighting system that includes most lights, and is only connected to the utility supply.
2. The emergency lighting system that only includes the required emergency egress lights, and is connected to both the generator and utility system.

The two act as backups to each other. If you have both these systems in the egress path, it probably complies with the section you posted.

And you must have more than one lighting element (lamp, tube, LED) on the emergency side in each area. That's why emergency fixtures normally have two heads.

But a circuit breaker is not a "lighting element", so you don't have to consider what happens if a circuit breaker trips during a power outage. There is no requirement to have the emergency lighting served by multiple circuit breakers.

I do believe many engineers like to install fuses on generator supplied emergency fixtures, just to make sure something like a shorted ballast doesn't take out the entire branch circuit, but its not a requirement.
 
steve66 said:
I'm not sure I completely understand the question, but when a generator is used for backup power, most areas usually have two sources of lighting:

1. The normal lighting system that includes most lights, and is only connected to the utility supply.
2. The emergency lighting system that only includes the required emergency egress lights, and is connected to both the generator and utility system.

The two act as backups to each other. If you have both these systems in the egress path, it probably complies with the section you posted.
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On each floor, there are emergency egress lights connected to both the utility system and the generator; there is also normal lighting supplied by the utility system. If something fails with the utility system supply through the distribution panel on one floor, the generator system will not come on.
 
It's a little confusing the way you're presenting the information. Let's leave the generator out of the issue for a moment.

If a branch circuit which serves lighting loads trips or is shut off, will emergency lighting come on?
 
Take it one step further if I may. In any given area, is there any lighting connected other than the branch circuits on the utility (only) circuit.

(We often have buildings that any any given area there is switched lighting of the "normal" branch circuit but in addition there is a unswitced lighting circuit that is 24/7 and on the generator circuit)
 
The requirement is more clearly stated in NFPA 101. The 2012 version states in paragraph 7.9.2.3,

"The emergency lighting system shall be arranged to provide the required illumination automatically in the event of any
interruption of normal lighting due to any of the following:
(1) Failure of a public utility or other outside electrical power supply
(2) Opening of a circuit breaker or fuse
(3) Manual act(s), including accidental opening of a switch controlling normal lighting facilities"
 
mgookin said:
It's a little confusing the way you're presenting the information. Let's leave the generator out of the issue for a moment.

If a branch circuit which serves lighting loads trips or is shut off, will emergency lighting come on?
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construct said:
No.
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But won't the emergency lights still be on and running off the utility power, even though the generator doesn't start?

If so, I'd say it complies. If not, I'd say it doesn't comply.
 
augie47 said:
Take it one step further if I may. In any given area, is there any lighting connected other than the branch circuits on the utility (only) circuit.
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There is only one branch circuit for all lighting in each area supplied by the utility. The few emergency fixtures are also connected to the generator in addition to being connected to the same utility supplied branch circuit.
 
After talking to the MEP Engineer, they are going to supply the normal lighting from one utility source branch circuit panel. And supply the emergency/normal lighting from a utility source branch circuit originating in a different panel and also connected to the generator. I believe this makes it compliant with 700.17.

Thank you all for the input. :thumbsup:
 
steve66 said:
But won't the emergency lights still be on and running off the utility power, even though the generator doesn't start?

If so, I'd say it complies. If not, I'd say it doesn't comply.
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That was the issue, since both normal and emergency were served by one circuit. If the circuit opened, then the generator would not start and supply the emergency lights.
 
steve66 said:
But won't the emergency lights still be on and running off the utility power, even though the generator doesn't start?

If so, I'd say it complies. If not, I'd say it doesn't comply.
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If there's a fire in that part of the building and the circuit breaker feeding the lighting in that area trips, the emergency lights have to come on.
 
construct said:
That was the issue, since both normal and emergency were served by one circuit. If the circuit opened, then the generator would not start and supply the emergency lights.
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That's different. There is usually one branch circuit from a normal panel for the normal lights, and another branch circuit from the emergency panel for the emergency lights.

mgookin said:
If there's a fire in that part of the building and the circuit breaker feeding the lighting in that area trips, the emergency lights have to come on.
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But with a generator, the emergency lights are normally on anyway. I'm picturing a typical corridor with every third light connected to the emergency panel, and the other 2/3'rds of the lights on a normal panel, with all the lights normally on. So 2 breakers would have to trip to leave the corridor dark.
 
construct said:
The second sentence states, "Emergency lighting systems shall be designed and installed so that the failure of any individual lighting element, such as the burning out of a lamp, cannot leave in total darkness any space that requires emergency illumination."
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I would understand the sentence to mean that you cannot just have one lamp for example in an exit sign. or a corridor or a section of a corridor that upon one lamp burning out their would not be any emergency lighting in that area.

I am not aware of the normal lighting source being a consideration in this requirement. That is why unit equipment typically had two remote heads on the unit. To me all this means you have to have at least two lamps supplying emergency illumination in any given area requiring emergency illumination.
 
construct said:
That was the issue, since both normal and emergency were served by one circuit. If the circuit opened, then the generator would not start and supply the emergency lights.
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It is not uncommon to have a corridor supplied by a N/E panel where loss of the utility transfers the panel to the emergency generator. I am not aware that each branch circuit needs to be monitored by the emergency gen system. If you lose a branch circuit in an area requiring lighting the area would be in the dark and someone is going to trouble shoot the problem and correct the reason the branch circuit breaker is opening


edit: The required egress lighting would not be on a local switch assessable to the public.
 
steve66 said:
That's different. There is usually one branch circuit from a normal panel for the normal lights, and another branch circuit from the emergency panel for the emergency lights.



But with a generator, the emergency lights are normally on anyway. I'm picturing a typical corridor with every third light connected to the emergency panel, and the other 2/3'rds of the lights on a normal panel, with all the lights normally on. So 2 breakers would have to trip to leave the corridor dark.
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You would need to make sure that these emergency lights have battery backup ballasts in them. That way, no matter what fails, the lights will still come on.
 
gadfly56 said:
You would need to make sure that these emergency lights have battery backup ballasts in them. That way, no matter what fails, the lights will still come on.
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I am only aware of a few section in the code that would require unit equipment when there is an emergency generator system.

one example would be in hospital operating rooms
 
construct said:
There is only one branch circuit for all lighting in each area supplied by the utility. The few emergency fixtures are also connected to the generator in addition to being connected to the same utility supplied branch circuit.
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are you sure what you describe as a few emergency fixtures are not on a night light circuit served by an N/E panel?
 
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