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I was reviewing a sprinkler plan using flexible house from an arm over. The head had a k factor of 5.6 and the flexible hose had a k-factor of 4.86 with the pressure and flow at the head. This seems like a mistake. Wouldn't you want a flexible hose with a k-factor of 5.6 or larger?
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5 Comments
Wayne Ammons
7/24/2019 06:45:56 am
Can you share what model flexible hose was used and where you saw a K-factor of 4.86?
PETE
7/24/2019 10:52:41 am
You're probably looking at the equivalent K factor of the head with the UL/FM 1" Schedule 40 equivalent feet of loss for the flexible hose assembly added. K for the hose and head would use the same Q required for the head per it's UL listing, and a P value that is some higher value than the head by itself to account for the friction loss in the flexible hose. Since K=Q/sqrt(P), an increase in P will correspond to some K lower than the K factor of the head by itself.
Max Newton
7/24/2019 08:54:17 pm
As Pete said the equivalent k factor of the flex drop at branch pipe will always be less than the sprinkler k factor. Flex drops are useful to lower over-discharge by maintaining smaller k factors.
John
12/5/2019 08:33:14 pm
Can a NFPA13R multi-residental apartment building use commercial concealed pendent sprinklers with standard response instead of quick response?
MODERATOR
12/6/2019 08:48:52 am
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