Position of the vertical sprinkler frame?

[Bagge]

I have a question regarding the position of the sprinkler frame. Should the two vertical frames on a sprinkler be positioned along the branchline or acoss the branchline? As I see it, the frame should be positioned across the branchline because the branchline works as an obstruction for the spray pattern. If the vertical frame is positioned with the frame along the lines, this works also as an obstruction. Of course it also works as an obstruction across the line, but not as big as if it would be placed along the line, because of the "double obstruction".
What are your thoughts on the subject, and are there actually written any criteria for this some where in NFPA 13?

 

[SprinklerDesigner2]

From NFPA 13 "Standard for the Installation of Sprinkler Systems" - 2002 Edition

8.3.1.3* Upright sprinklers shall be installed with the frame arms parallel to the branch line, unless specifically listed for other orientation.

 

[cdafd]

been missing that one for a long time

glad it only applys to uprights.

 

[TravisMack]

The frame arms for uprights are parallel per NFPA 13 as stated above. An 'old' fitter once told me that he trains his guys to install the pendents with the frames parallel to the branch line as well. That way, when they go in to do a tenant improvement or anything, he can usually tell which way the branch lines run before he gets above any ceilings.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com