System protection area limitations

[ERR07]

Good day.

Does the NFPA system protection area limitation is equal to the required by FM Standards. I'm working in a FM fire protection system and I haven't found in which Data Sheet is this information. By NFPA I have extra hazard (one riser per every 40000ft2) and by FM Standard the project is HC-3.

In advance thanks for your time and help.

 

[cdafd]

Check the latest fm data sheet 2-0
Maybe 2.4.1.6


One example of a situation where the FM standards are no longer as stringent as NFPA 13 is in the maximum size of a "system". NFPA 13 limits the size of a system to 52,000 sq ft (4,800 m2) per floor for light and ordinary hazard systems and 40,000 sq ft (3,700 m2) per floor for extra hazard and high-piled storage. But FM Global Data Sheet 2-0, "Installation Guidelines for Automatic Sprinklers",8 allows much more area per system. FM originally published their standards in March 2010 without any limitation to the size of a system. Then they changed their standard in January 2011 to a maximum system size of 60,000 sq ft (5,600 m2) (total, not per floor). It is possible that this requirement will change again in the future.

http://m.magazine.sfpe.org/sprinklers/challenges-fire-sprinkler-industry

 

[cdafd]

http://www.eng-tips.com/viewthread.cfm?qid=301937

 

[Sdpaddler50]

CDA, that 2011 thread is a good one. Thanks for posting it. I always recommend staying with the NFPA area limits (40K for high pile) when doing these. It keeps the ahj happy. Also, as noted in that old 2011 thread, having these massive systems can be problematic when dealing with hydraulic calcs, inspector test acivation, etc. Lastly, when these are drained down for repairs, a huge system would take forever. its not fair to the sprinkler tech who wants to start work and not sit there forever watching water pour out of a 2in drain.

 

[Sdpaddler50]

One last thought. From an environmental standpoint = water wastage when draining.

 

[ERR07]

Thank you both for you observations. I will check the latest FM 2-0 DS, I'm working with one dated Jan-2010.

Knowing this I will size my systems by NFPA because the local fire code is based on it and have to meet both requirements.

Thanks again.

 

[TravisMack]

I just downloaded the latest FM 02-00 and it still states the system size is only limited by hydraulic calculations.

2.4.1.6 Sprinkler System Maximum Area of Coverage
The maximum area of coverage for a sprinkler system is limited only by (1) the hydraulic requirements of
the sprinkler system’s design and (2) the waterflow alarm requirements outlined in Section 2.6.4.
Note: If the local authority having jurisdiction (AHJ) limits a sprinkler system’s area of coverage based on
a local code, follow the local code.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com