Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations IDS on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Issue ESFR sprinklers in standard rigid metal frame and 8" bent metal purlin building

Status
Not open for further replies.

SprinklerDesigner2

Mechanical
Nov 30, 2006
1,251
I already know the answer I need to ask again for a specific job.

Bent metal purlin building measuring 150'-0 wide by 266'-8 long with bays spaced at 25'-0" except for the two end bays that measure 20'-10" which brings us to the overall length of 266'-8".

Building has a 31'-0" eave which gives us a peak of 37'-3".

Rack storage of Class IV products and un-expanded plastic with the owner telling me the maximum height of storage will be 20'-0".

With the water supply being what it is an ESFR system with a fire pump is the only option.

With 25'-0" bays I space the ESFR sprinklers 8'-3" apart and I am never allowed to be closer than 8'-0" even if there is a rigid frame separating the sprinklers. If you have a 48" beam you are allowed to space sprinklers 2'-0" apart if you want as long as the beam separates the sprinklers but this is not the case when it comes to ESFR sprinklers. Whether the beam is there or not the minimum distance between sprinklers remains at 8'-0".

Where did I get this information? Six years ago I was taking a 4 day CEU class to maintain my NICET and in one of the classes given by Kenneth Isman, specifically having to do with ESFR sprinklers, he asked that particular question and 80% of us got wrong. We were told it had something to do with the heat plume (I think it was carrying water droplets to the near head) and it is something I always followed.

So what I can do is space heads 8'-0" apart with the line nearest the end bay 1'-10" off the end wall then 8'-0" until I can space 8'-4" again.

Thing is I know I am going to run into a problem getting some people to accept the fact this is the only way to do it or maybe something changed from six years ago?
 
Replies continue below

Recommended for you

I've always done it your way as well. Have been yelled at quite a few times when I point out that a baffle can't be used in lieu of the minimum 8'-0 spacing for ESFR sprinklers. FM Global gets pretty sticky on minimum spacing as well, especially when they impose a minimum area, not just minimum spacing. Sometimes it is as close as max area = 100 sq. ft, min area = 80 sq. ft. Those are tough layouts.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor