Emergency Lighting

[websparky]

When a structure is required by the building code to have emergency lighting and exit signs and there is an emergency generator tied into the normal power system, do the emergency fixtures and exit signs need to have a battery back-up?

If so, please provide the code reference and the text that you think makes your answer correct.

Thanks!

 

[iwire]

Re: Emergency Lighting

Originally posted by websparky:
and there is an emergency generator tied into the normal power system,

Dave I am not sure what you mean by that.

Is it installed as Article 700 requires (entirely separate) or is it installed as per Article 702 (mixed)?

IMO if it is 'mixed' than you do not have an emergency system so you must have battery units.

If it is an article 700 system no battery units are required but are a nice supplement.

My code reference would be 700.12(A) through (E)

700.12 requires the source of power to be at least one of the listed supplies Storage Battery, Generator Set, Uninterruptible Power Supplies, Separate Service or Unit Equipment (EBUs).

part of 700.12

The supply system for emergency purposes, in addition to the normal services to the building and meeting the general requirements of this section, shall be one or more of the types of systems described in 700.12(A) through (D). Unit equipment in accordance with 700.12(E) shall satisfy the applicable requirements of this article.

 

[websparky]

Re: Emergency Lighting

Bob,

This would be a "700" system that supplies emergency egress lighting and exit signs in buildings.
What I am trying to determine is if an egress light or an exit sign is required to have a battery back-up even though it is wired to a system that has a generator as a back-up.

Here is the building code:

MEANS OF EGRESS ILLUMINATION
1006.1 Illumination required. The means of egress, including the exit discharge, shall be illuminated at all times the building space served by the means of egress is occupied.

 

[iwire]

Re: Emergency Lighting

I have never seen battery equipment required when the building has an emergency system in place.

I feel that is the reason there is 700.12(B)(5).

700.12(B)(5) Auxiliary Power Supply. Generator sets that require more than 10 seconds to develop power shall be permitted if an auxiliary power supply energizes the emergency system until the generator can pick up the load.

I believe as far as the NEC is concerned we can have the building 'black' for 10 seconds.

But...we have long since established the rules in my area (or how they are applied) are not always in sync with your area.

I do see the issue you bring up with the building code.

shall be illuminated at all times

What happens if we have to work on the circuit?

Would we have to evacuate the space first?

 

[websparky]

Re: Emergency Lighting

Bob,

I believe as far as the NEC is concerned we can have the building 'black' for 10 seconds.

I do see the issue you bring up with the building code.

quote: shall be illuminated at all times

What happens if we have to work on the circuit?

Would we have to evacuate the space first?

Hence, battery back-up lights and signs.

What about a circuit breaker tripping and a room or hallway going dark because the generator is not designed to cover this type of power loss.

 

[iwire]

Re: Emergency Lighting

Originally posted by websparky:
Hence, battery back-up lights and signs.

As I said I have not every seen that as a requirement.

Is it in your area?

By your interpretation installing an emergency generator is a worthless waste of money.

What about a circuit breaker tripping and a room or hallway going dark because the generator is not designed to cover this type of power loss.

Not a concern as far as the NEC.

 

[websparky]

Re: Emergency Lighting

Bob,

Generators do not cover all aspects of emergeny lighting. They are however used in addition to the battery units because a generator will run much longer than the ideal 90 minutes a battery would. Not to mention the generator would also supply emergency power for other loads.

Say normal power is lost to a building and the generator is called on to start and run. The generator will most likely supply power to the emergency lighting within 10 seconds.

Now let's take a different case. Say a feeder trips to a panel that supplies power to an entire floor of the building. This event will not call on the generator to start and run to supply emergency lighting. Now what?

 

[iwire]

Re: Emergency Lighting

Originally posted by websparky:
Now let's take a different case. Say a feeder trips to a panel that supplies power to an entire floor of the building. This event will not call on the generator to start and run to supply emergency lighting. Now what?

Now what?

The area that emergency feeder supplies is in the dark.

The problem that you describe I believe is the driving force in keeping the emergency system as limited as possible and not mixing it with the normal systems.

All I can go by is what I have seen and to be honest I have seen and worked on many large buildings that use only generator back up.

I am confident in this area (New England) that battery units are not required in buildings with another type of emergency system in place.

Give me some credit Dave I understand the shortcomings of generator supplied emergency systems. I work on them frequently in January I will be installing a 500 KVA emergency / standby generator in an existing facility.

The most common problem is the generator not starting when needed. This was very much brought to the forefront when the last big black out happened in the North East. Many places where left in the dark.

But battery units are also junk if they are not properly maintained.

I personally like to see EBUs backed up by generator but I feel that is a design choice and not a code requirement.

[ December 24, 2005, 07:08 PM: Message edited by: iwire ]

 

[pierre]

Re: Emergency Lighting

I took a look at 7.9 Emergency Lighting of NFPA 101, and there are no requirements to have additional means of backup if you already have a generator. The NEC does not require it either. I believe that the mixup of "at all times" might have slipped through the cracks, or the "up to 10 sec" delay is acceptable with generators.

 

[websparky]

Re: Emergency Lighting

Here is what I have found:

NFPA 101 Life Safety Code 2000
7.9.2.2*
The emergency lighting system shall be arranged to provide the required illumination automatically in the event of any of the following:
(1) Interruption of normal lighting such as any 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

7.9.2.5
The emergency lighting system shall be either continuously in operation or shall be capable of repeated automatic operation without manual intervention.

The * above referes you to the Appendix for further explanation.

A.7.9.2.2
Where approved by the authority having jurisdiction, this requirement is permitted to be met by means such as the following.
(a) Two separate electric lighting systems with independent wiring, each adequate alone to provide the specified lighting. One such system is permitted to be supplied from an outside source such as a public utility service and the other from an electric generator on the premises driven by an independent source of power. Both sources of illumination should be in regular simultaneous operation whenever the building is occupied during periods of darkness.
(b) An electric circuit or circuits used only for means of egress illumination, with two independent electric sources arranged so that, on the failure of one, the other will automatically and immediately operate. One such source is permitted to be a connection from a public utility or similar outside power source and the other an approved storage battery with suitable provision to keep it automatically charged. Such a battery should be provided with automatic controls that, after operation of the battery due to failure of the primary power source or to turn-off the primary electric source for the lights, the battery will be shut off after its specified period of operation and will be automatically recharged and ready for further service when the primary current source is turned on again.
(c) Electric battery-operated emergency lighting systems complying with the provisions of 7.9.2.2 and operating on a separate circuit and at a voltage different from that of the primary light can be used where permitted. (See NFPA 70, National Electrical Code ?.)
These requirements are not intended to prohibit the connection of a feeder serving exit lighting and similar emergency functions ahead of the service disconnecting means, but such provision does not constitute an acceptable alternate source of power. Such a connection furnishes only supplementary protection for emergency electrical functions, particularly where intended to allow the fire department to open the main disconnect without hampering exit activities. Provision should be made to alert the fire department that certain power and lighting is fed by an emergency generator and will continue operation after the service disconnect is opened.
Where emergency lighting is provided by automatic transfer between normal power service and an emergency generator, it is the intent to prohibit the installation, for any reason, of a single switch that can interrupt both energy sources.

 

[sceepe]

Re: Emergency Lighting

For a generator only system, If you have two separate feeds to each emergency fixture. One feed is from the normal power distribution system and the second is from the emergency panel. In order for the area to go dark, you need to have a two simultaneous failures which is just not very likely.

IMO battery units are never maintained and the odds of them working 5 years down the road is pretty small.

 

[iwire]

Re: Emergency Lighting

Dave

A.7.9.2.2
Where approved by the authority having jurisdiction, this requirement is permitted to be met by means such as the following.

(a) Two separate electric lighting systems with independent wiring, each adequate alone to provide the specified lighting. One such system is permitted to be supplied from an outside source such as a public utility service and the other from an electric generator on the premises driven by an independent source of power. Both sources of illumination should be in regular simultaneous operation whenever the

I think that backs up my opinion that battery units are not required when a generator supplied lighting system is in place.


What do think it says?

By the way is NFPA 101 adopted in your area?

The NFPA has dozens of codes none of which mean much unless adopted.

 

[don_resqcapt19]

Re: Emergency Lighting

Dave,
Take a look at 7.9.1.3.
This section specifically permits a 10 second delay. Also look at 7.9.1.2. It limits where the emergency lighting is required.
Don

 

[websparky]

Re: Emergency Lighting

NFPA 101 Life Safety Code 2000
7.9.2.2*
The emergency lighting system shall be arranged to provide the required illumination automatically in the event of any of the following:
(1) Interruption of normal lighting such as any 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

Don,
How does a generator provide for (2)above?

Bob,
The rest of what you quoted is below.

Both sources of illumination should be in regular simultaneous operation whenever the building is occupied during periods of darkness.

I have never seen an emergency generator running "in regular simultaneous operation". The word simultaneous means "at the same time". Do the generators in Mass. run 24/7?

 

[iwire]

Re: Emergency Lighting

Originally posted by websparky:
Bob,
The rest of what you quoted is below.

Both sources of illumination should be in regular simultaneous operation whenever the building is occupied during periods of darkness.

I have never seen an emergency generator running "in regular simultaneous operation". The word simultaneous means "at the same time". Do the generators in Mass. run 24/7?

No the generator does not run 24/7, the rest of the emergency system does.

The feeders, the OCPDs, the branch circuits, the fixtures.

Dave how is it done in buildings you inspect?

Do your EBUs operate continuously or are they dark until the power goes out?

 

[don_resqcapt19]

Re: Emergency Lighting

Dave,
I guess you can't use unit equipment either, as I have never seen one without an internal fuse.
Don

 

[websparky]

Re: Emergency Lighting

Don,

Unit equipment with battery backup does not have a fuse.

 

[don_resqcapt19]

Re: Emergency Lighting

Dave,
Every one that I have ever installed had a fuse on the control board...most were not designed to be replaced as they were soldered in place. Look at this manual for one type of unit equipment. Some of the models have a fuse in the battery lead.
Don

added link

[ December 26, 2005, 10:24 PM: Message edited by: don_resqcapt19 ]

 

[iwire]

Re: Emergency Lighting

Both sources of illumination should be in regular simultaneous operation whenever the building is occupied during periods of darkness.

What is interesting to note is that this requires both sources of illumination to be run simultaneously not both sources of power.

Typically unit equipment does not provide illumination until a power failure.

As far as the fuse in unit equipment I do not think you will find any unit equipment that does not have a fused DC output. Running wiring directly from a storage battery without OCP would be a fire hazard.

 

[ron]

Re: Emergency Lighting

I've been missing the action here
I've struggled with

7.9.2.2 The emergency lighting system shall be arranged to provide the required illumination automatically in the event of any of the following:
(2) Opening of a circuit breaker or fuse

and couldn't come up with a solution.
The buildings I design have multiple generators paralleled on a common bus, and by the time we consider reliability of where to create an Article 700 or 701 source bus, it is easier to establish a battery system for the emergency lighting. Still, it doesn't account for a local lighting circuit to fail, just the circuit that serves the inverter for the emergency/egress lights.
So, I don't have a solution either. When I specify fixture mounted battery ballasts, which is often, I've been trying to specify the self testing type ballasts such as http://www.bodine.com/products/selftest.html to reduce the NFPA 101 required testing that gets ignored.

[ December 27, 2005, 08:37 AM: Message edited by: ron ]