February 10, 2012
As you may know, the 2010 FBC goes into effect March 15, 2012. For residential swimming pools, it requires compliance with the new ANSI/APSP/ICC-15 2011 standard for RESIDENTIAL SWIMMING POOL AND SPA ENERGY EFFICIENCY.
The 2010 FBC brings a third standard for the velocities in pool piping. Recall that ANSI/APSP-7, the STANDARD FOR SUCTION ENTRAPMENT AVOIDANCE IN SWIMMING POOLS, WADING POOLS, SPAS, HOT TUBS, AND CATCH BASINS, requires the maximum flow of the pumps to be used to size “branch” piping and “trunk” suction piping. Also, there are three allowed methods for determining that maximum flow, be it the maximum flow defined by the end of the pump curve, or the flow determined by either detailed or simplified calculation of the “total dynamic head” of the system.
Using that max flow, ANSI-7 expects “branch” piping to be sized at 6 FPS, and “trunk” suction piping at 8 FPS. This standard is silent on the “return” piping.
Now, ANSI-15 requires the simple calculation of the allowed filtration flow, and expected auxiliary flow. The greater of that flow is to be used to size all “suction” piping at 6 FPS, and “return” piping at 8 FPS. These become minimum pipe sizes that might be increased by the ANSI-7 analysis.
The ANSI-5 standard limits both “suction” and “pressure” piping to 8 FPS, without definition of the flow basis. Consequently, meeting ANSI-15 and ANSI-7, meets ANIS-5.