Pressure Balance 1

[adson]

NFPA 13 - 22.4.2.4 states that "Pressures at hydraulic junction points shall balance within 0.5 psi (0.03 bar)" . I was not able to clarify what it refers to. On an elbow or on a tee how am i going to do that ?

 

[NightME]

This is in reference to grid systems and juctions points in particular. Since elbows are not junctions they are not a concern, but Tee's are. When running calculations the balance factors are important when determining flow through loops or grids. Most software for calculations sprinkler systems have this function built in, or at least have a dialog box to input this information.

Otherwise you can always fall back on the "Hardy Cross Method" which is very cumbersome and a pain in the neck.

 

[adson]

is it the pressure balancing that we make on branch line junction points or in other words is it like, by selecting bigger pressure of two intersecting branchline and arranging the flow by K factor of the junction for the less pressured branch line ?
But in that case, how can 0.5 psi difference be possible , if i have five sprinkler on one branch line and only one on the other branchline ?

 

[SprinklerDesigner2]

"is it the pressure balancing that we make on branch line junction points or in other words is it like, by selecting bigger pressure of two intersecting branchline and arranging the flow by K factor of the junction for the less pressured branch line ?
But in that case, how can 0.5 psi difference be possible , if i have five sprinkler on one branch line and only one on the other branchline ?"

Balancing only applies to gridded systems.