More on Generators and Emergency Lighting

[Dave_PE]

Working on a new municpal office building, 5 stories, 60,000SF. It will have a generator for selected areas identified to be fully operational, as well as the data center, elevators, etc. I also will be using the generator for emergency lighting throughout the entire building. The building is 277/480V.

With a bunch of different departments, each having several hallways, conference rooms, bathrooms, breakroom, etc. My first choice is have the designated emergency fixtures wired unswitched as nightlights......I have the extra capacity in the generator so load is not a problem....This approach would be sort of wasteful, but for a $100 GTD type device per fixture, there would never be a payback on not operating one or two less lamps. I could also only wire one ballast of a two lamp fixture as a nightlight as a less expensive approach.

I will probably add a central lighting control panel to control the public and hallway lighting, lighitng in the cube farms, bathrooms, breakroom, etc. so I guess I could control it this way. The lighting control panel would sense the generator running and force these lights on. All other individual offices would have occ. sensors.

How do others design\install the lighting control of the emergency lights for multiple rooms.

 

[chris kennedy]

The building is 277/480V.

My first choice is have the designated emergency fixtures wired unswitched as nightlights.This approach would be sort of wasteful, but for a $100 GTD type device per fixture, there would never be a payback on not operating one or two less lamps.

I will probably add a central lighting control panel to control the public and hallway lighting, lighitng in the cube farms, bathrooms, breakroom, etc. so I guess I could control it this way. The lighting control panel would sense the generator running and force these lights on. All other individual offices would have occ. sensors.

I recently did a 25,000SF Dept. of Health and installed about 100 battery back up flour. layins. These fixtures are crap. It was alot of work for a little redundancy since we also installed a 750kva 480/277 gen. set. What is great are the OC installed every where including halls corridors ect. They are made by Sensor Switch and are easy to install and work great. Theres your energy management your honor. As far as the initial cost of these devices I can't tell you now. If you can't find it on line PM me,I have the numbers at the office.

 

[mdshunk]

How do others design\install the lighting control of the emergency lights for multiple rooms.

Go old school and install an emergency lamp in the fixtures you want on during the generator run time.

 

[Dave_PE]

So the EM lamp would be normally off all the time, until the generator runs. Good idea, thanks Marc.

 

[LawnGuyLandSparky]

If the genset has enough capactiy for IT rooms, elevators, boilers, heck - how much is left? Make all the lights "emergency lights."

 

[Dave_PE]

There is about 60kVA of total interior building lighting.....might be a possibility, otherwise I only have about 10kva as designated as emergency.

 

[brian john]

Make all the lights "emergency lights."

The number of data centers I see that have three maybe maybe lights on generator, when there is spare capacity floors me. The lighting load is minimal, when compared to spare capacity.

 

[Mr. Bill]

The GTD's are not installed one per fixture but one per switch. If you have multiple em fixtures controlled by one switch you can use one device. But in smaller rooms like bathrooms with only one em fixture then it would be one device per switch.

If you're going to go old school with an em lamp that's only on when the generator is on make sure you have more than one lamp per room. NEC 700.16.

I had a design where I put every fixture in a room on the em circuit. The AHJ came back and said it was excessive light for means of egress. He wanted the excess light to be fed from a separate transfer switch. There are minimum light levels for egress lighting but I never heard of a maximum. But, that's what he wanted.

 

[spsnyder]

Mr. Bill,

I can't imagine the AHJ could find a max. light level in any code...

What does GTD stand for?

Interesting thread.

 

[bsh]

em lighting

em lighting

Your initial design process is pretty much the way I do it

Also, the emergency lighting you have connected to the generator must provide 1 foot candle of light along the paths of egress. Egress paths include indoors, the exit and outdoor areas past the exit to get the building occupants safely away from the building. If you opt for the emergency lamp in you fixtures be sure that you will have enough light on your egress path. We had an AHJ do an inspection at night with only the egress lighting on and measured the light level.

 

[Mr. Bill]

GTD stands for generator transfer device. It's a product by Bodine. Nine24 also has a device for emergency lighting from a generator called BLTC.

The AHJ wasn't quoting a Code section. He felt that when a room is lit to full brightness then the room is intended for normal use during a power failure. According to him, the minimul amount of light needed to egress falls under Article 700 while lighting a room for normal use would be in the Optional Standby Systems, or Article 702. I just put it all on one circuit to simplify the field wiring.

 

[necnotevenclose]

Are you using any lighting controls? Most lighting control manufactures offer the capability of switching the emergency lights like normal lights. The only difference is they are able to provide a control function so that when emergency power kicks on only the dedicated emergency lights override the local low voltage switch and transfer to emergency power.

 

[Dave_PE]

I never though I'd see and AHJ complain about too much emergency lighting. I guess it would depend on the size of the fuel tank on the generator.....If you have 500 gallons available and the generator could run for two weeks I can see his point.......