Power Source for Fire Pump vs. Emergency Power source.

[jkim780]

Just out of curiosity, per NEC(2002)695.3(A), a fire pump is allowed to be supplied by a single source, where reliable. In my area, electric utility service is considered reliable and allowed to feed fire pump. If that's the case, why do I still need a generator where the emergency power system is required, for instance, atrium application. If you consider your electric utility service is reliable, then why do you need an alternative electric power?
The generator will only go online, when their is power failure at utility service or fault at service equipment. It is unlikely you have both of them at the same time when their is a fire.

Any thoughts?

 

[gene]

Re: Power Source for Fire Pump vs. Emergency Power source.

Yes, the utlity service is considered reliable, that is the reason you must feed the fire pump from the line side. If you should lose your main sevice to a fault on the load side you're still protected for fire service from the line side.

 

[hurk27]

Re: Power Source for Fire Pump vs. Emergency Power source.

And what would be the odd's of having a power failure (utility failure) at the time you have a fire? But if you have critical power requirements you can still have a power failure so a EMG generator is still required for critical loads IE: a hospital. These are two separate requirements that require separate method's to comply.

 

[jkim780]

Re: Power Source for Fire Pump vs. Emergency Power source.

Wayne,

From NEC handbook(2002)

emergency systems are designed and installed to maintain a specific degree of illumination or provide power for essential equipment if normal power supply fails. Examples of essential equipment include fire pumps and operating room and life-support equipment in hospitals.

I guess what I am trying to say is that Fire pump is also essential eqipment but why it is allowed to take chances with utility service while others are not. I am working on this project that has a fire pump and the smoke control system for atrium. Code requires a secondary back-up power for the smoke control system. So, I going to need a generator for that. So, my point was that if your utility source is reliable and you are allowed to supply the fire pump why not the somke control system?

I think I heard or read somewhere that the sprinker system is for property protection (I am not sure if this is correct or not. Please someboby help me on this) and fire alarm system is for life protection. Is this something to do with this?

 

[nvcape]

Re: Power Source for Fire Pump vs. Emergency Power source.

My understanding is that where there is no written requirement for a generator the reliability utility power falls back to the fire marshall to make a determination. If you don't have a hospital, large assembly area, or high rise where people could not exit in time with a power failure, the AHJ would probably not require it. If you have an area with overhead lines that are close to the buildings where they could get damaged, you likely will be required to have a generator. Beyond this, the insurance carrier might have a concern and requirements.