Article 700, Batteries or Generator?

[iwire]

As long as I have been in this trade I have been of the opinion that the correct way to provide emergency lighting was with a generator and that use of emergency battery units was a cheap way out pushed by the bean counters.

In the past couple of years this view of mine has been changing.

I am interested in how others feel about this issue, remember I am talking about emergency loads not data centers or anything that falls outside of article 700.

Something that really started this change of opinion was 9/11, obviously that is not an regular emergency but shows to me having all your emergency power from one source can really backfire.
A single event on one floor may cut off all emergency service to the floors below or above depending on the generator location.

Many of the buildings we do use a combination of self contained exit signs, stand alone emergency battery units and ballasts with battery back up. With today's battery technology it seems like the way to go.

Forgetting the upfront costs of generators and all their separate distribution gear and branch circuits you still have the cost of a service contract to maintain the genset, this would easily off set the costs of replacing the batteries once in a while.

Also there is a new fluorescent lamp product out, it is a fluorescent tube that works like normal but glows for hours after power is removed, it can be removed from the fixture and used like a flash light and if hits the ground and shatters it still produces light for hours.

So how about it, what are the engineers feelings on this or the feelings of other installers like myself, should we steer clear of generators?

Any opinions on this will be more then welcome.

Bob

 

[pierre]

Re: Article 700, Batteries or Generator?

Bob

I totally agree, and from an economic standpoint also.
Some or all of the unit emergency lights will not have to be on the emergency system/generator, so the generator can be sized smaller. The wiring involved would be reduced, not necessarily a good thing for electricians, but the scope of the job may change with additional installation of products they may not have considered before the reduction of the cost of the emergency system.
With all of the new technology headed our way, this may be the way of the future.

Pierre

 

[bennie]

Re: Article 700, Batteries or Generator?

Something interesting is to punch in keyword "Batteries" and examine the variety of design and purpose.

My camcorder takes a lithium-ion, 7.2 volt, 2500 mAh rechargeable battery, cost $100.00 each. This battery will last for approx one hour of recording.

 

[ron]

Re: Article 700, Batteries or Generator?

Very often, if the generator is for life safety loads only, the owner is not likely to test it as required, unless the AHJ is on his game. So even when I spec a generator for life safety loads, I spec battery backed up exit and egress lighting anyway.
Almost nobody notices the increased cost within the big picture of the rest of the project. Sometimes the contractor gives the battery backed up units for free if they didn't notice the requirement during bidding.

 

[lazorko]

Re: Article 700, Batteries or Generator?

Any centralized system can fail! Depending entirely on a generator and emergency power distribution system can mean that a failure would leave no life safety protection. While a battery unit can fail, most large installations would have a number of units along the exit paths - chances are better that some of them will operate.

 

[Guest]

Re: Article 700, Batteries or Generator?

For EXIT lights a battery powered Light-Panel is a good way to go:

Lightpanel Technologies

 

[lightpanel]

Re: Article 700, Batteries or Generator?

What's nice about the LightPanel is that it gets twice as bright on emergency battery power--a nice trick just when you need it most.

Originally posted by awwt:
For EXIT lights a battery powered Light-Panel is a good way to go:

Lightpanel Technologies

 

[brian john]

Re: Article 700, Batteries or Generator?

The firm I work for is involved in the maintenance and testing of generators and batteries systems (UPS and lighting). In my/our expierence in both UPS and lighting systems the battery is the weakest link.

Sealed batteries are normally good for 3 to 5 years depending on temperature, quality of charger, and number of discharges. Additionally most lighting inverters we see utilize the cheaper of the available batteries on the market and the chargers are not the best.

Flooded batteries while better (IMO) than sealed batteries they require more maintenance and in lighting inverters seldom get this maintenance. The number of DRY wet cells we see in lighting systems is equal to the number of lighting systems we have seen with wet cells.

Lighting systems usally are designed to provide 90 minutes of lighting after that your in the dark. I won't mention that if there is no power one probably should not be in the building.

As for point of use battery systems, these are a cheap stop gaps to avoid adequate emergency lighting. Most building engineers I know hate these and most lighting battery packs we test do not work for the required time frame.

Generators while having their own problems can supply lighting, elevators and fire pumps. Central distribution permits easier maintenance and generators can support the loads for longer periods of time.

IMO the best system is a combination of the two, selective battery placement of battery packs and a generator. One finds that 10 seconds is a LOOOOOOOONG time to wait for a generator to start and transfer. Having immediate lighting minimizes accident in the dark. Additionally the battery packs or batteries are only utilized for ten seconds (or close to 10 seconds) extending the battery life. BUT maintenance or regular replacement of all batteries is necessary.

 

[greensky]

Re: Article 700, Batteries or Generator?

For the tragedy of 9/11 both the generator and battery have no used.Now a days there are luminous tape place in emergency exit, those are chargeable by lights and it can be used quite long time approximately 2 hours depending on illumination charge.I am only talking for emergency situation where electrical power is not usable.The luminous tape I am talking is widely used in new vessel of international route and there is no maintenance here except that the charging light which is ordinary flourescent or incandescent lamp place in exit areas are always lit.There is an instrument here to determine the illumination requirement for charge.This flourescent tape give better guidance during total black-out in emergency exit like in the buildings.
Generators,batteries and inverter are only good as a tempory ways of giving power but in some cases like 9/11 this flourescent tape is much better, it will lead the escapee to the right direction in the even total power failure.

 

[brian john]

Re: Article 700, Batteries or Generator?

"Generators,batteries and inverter are only good as a tempory ways of giving power but in some cases like 9/11 this flourescent tape is much better, it will lead the escapee to the right direction in the even total power failure."

While the above is a true statement, basing our emergency needs on the tradgey of 9/11 is short sited. Most building emergencies do not involve something as terrrible as 9/11. There are random blackouts, localized fires ect. The addition of flourscent tape is a plus but gen sets and lighting inverters are still necessary.

Generators if properly maintained can and do operate as more than a temporary power.