The impulse from the jet from the fire sprinkler would still push the head up into the space, but the flexible connection would not transter that force back to the pipe. Depending on the orientation of the connection of the flexhead pipe to the branch line would determine what resulting force would be resisted by the branchline piping. That is, if the connection is facing down on the branchline piping, there is still a resulting upward force on the branchline pipe and visa versa if it is facing up.
Therefore, the head would still need to be restrained or it would whip around like crazy upon discharge (have you seen the youtube videos of the red-neck riding a fire hose hanging from a crane......pretty wild stuff). Kevin Law, PE Fire Protection Engineering WTP Project - Bechtel National Ph. 509-371-8296 Cell 509-531-0093 > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On > Behalf Of Mike Hairfield > Sent: Thursday, April 18, 2013 10:24 AM > To: AFSA SprinklerFORUM > Subject: NFPA 13-2007 Paragraph 9.2.3.4.4 > > Does anyone have data that says that flexible drops are an > approved for preventing the upward thrust thus preventing the > sprinkler head from lifting up into the concealed space. > > Thanks, > > Mike Hairfield > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-fir esprinkler.org > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
