Wet-pipe or Dry-pipe system?

[madvb]

1) What is the proper way to determine whether a dry-pipe or wet-pipe system should be used? I have looked at design winter dry bulb temperatures, and it seems that most cities in California have a winter dry bulb temperature at or below 32°F and record low temperatures even lower.

Winter design temperature for one of my projects is 30°F with record low at 20°F. A dry-pipe sprinkler system is specified, but our State Fire Marshal stated they will not approve a dry-pipe system for this location. Is there a calculation that needs to be done that will tell me if a wet-pipe system is adequate?

2) Does NFPA require all portions of the piping containing water in a fire sprinkler system (wet or dry) be maintained above 40°F? If so, can pipe insulation be used to accomplish this?

Thanks.

 

[cdafd]

Did they say why a dry pipe would not be allowed??? High piled stock application ???

If the design meets 13 seems like it is up to you/ owner which type of system they want to put in

Would say if the pipe cannot be maintained to 40 F, than an alternative has to be done

 

[madvb]

I'm not sure if SFM gave a reason. Our fire protection engineer passed the message to us and didn't give a reason. Our FPE also agreed with the SFM. I asked our FPE for a reason and asked the same questions I asked here, but have not gotten a response from the FPE.

 

[cdafd]

Is this a warehouse??

Is it some type of building that either is not Normaly heated or would take a lot to maintain a set temp??

Your paying the FPE so he should answer why a dry system is speced