Police Station 911

[tg103]

I was asked to review a possible upgrade of an existing standby natural gas generator at a small police station in Massachusetts. Currently the required life safety lighting and fire alarm system is battery back up and this generator was added some years later. Over the years branch circuits have been added to this generator to serve air conditioning, computers, outlets, and to their 911 call system.

I am not familiar with any codes regarding 911 and was curious if this system should require a separate branch (ATS)from this generator or future upgraded generator. If 911 is considered as a life safety branch would the single source natural gas feed be acceptable or should diesel upgrade be considered as well as MA 2 hr ratings for equipment and feeders.

I appreciate any help.

Thanks.

 

[jghrist]

You should determine if a power outage would also interrupt the natural gas feed.

 

[RonShap]

You need to review NFPA 1221: Standard for the Installation, Maintenance, and Use of Emergency Services Communications Systems.
It is a national standard that is available for guidance.

 

[alehman]

Utility natural gas is generally not recognized as suitable for life safety emergency backup because the chances of a power failure or other disaster interrupting the supply.

 

[powerwagon75]

To add to what alehman said, if you plan to continue using the existing genset, it can be upgraded to operate dual fuel with automatic switchover (natural gas/propane)--if they have a place on site they can store a propane tank.

 

[powerwagon75]

sorry--should have read that more than once! If you are going to upgrade anyway, and the you prefer to go with the gas genset, then it can be spec'ed new with dual fuel capability. Don't know how large of a unit you're looking at, I know Cummins makes a really nice gas engine the is the visual cousin to the C-series diesel. Good, rugged and stable. If a smaller unit, all there gas units are electroniclly governed and dual fuel capable as well

 

[tg103]

Thanks for the helpful answers. I am going to purchase the NFPA 1221 to verify if the 911 system should be considered as a life safety branch.

The existing engine is an Onan 45KW, I would like to upgrade to a 60KW and have it fit the existing foot print in the basement. Cummins can accomodate, but the issue has now surfaced that they no longer provide a city water cooled engine and that a remote outdoor radiator will be required.

I am leaning on moving the entire system outside within an enclosure and make the fuel source diesel.

 

[itsmoked]

Outdoors certainly is safer from a poison exhaust and fire standpoint.