6
Water Velocity
The maximum water velocity through the suction fitting or cover for any suc-
tion outlet must be 1.5 feet per second unless the outlet complies with the lat-
est ASME/ANSI Specification for
Suction Fittings For Use in Swimming Pools,
Spas, Hot Tubs, and Whirlpool Bathtub Applications.
In any case, do not ex-
ceed the suction fitting’s maximum designed flow rate.
If 100% of the pump’s flow comes from the main drain system, the maximum
water velocity in the pump suction hydraulic system must be six feet per sec-
ond or less even if one main drain (suction outlet) is completely blocked. The
flow through the remaining main drain(s) must comply with the latest
ASME/ANSI Specification for
Suction Fittings For Use in Swimming Pools,
Spas, Hot Tubs, and Whirlpool Bathtub Applications.
Testing and Certification
Suction outlet covers must have been tested by a nationally recognized testing
laboratory and found to comply with the latest ASME/ANSI Specifications for
Suction Fittings For Use in Swimming Pools, Spas, Hot Tubs, and Whirlpool
Bathtub Applications.
Fittings:
Fittings restrict flow; for best efficiency use fewest possible fittings (but at least
two suction outlets).
Avoid fittings which could cause an air trap.
Pool fittings must conform to International Association of Plumbing and
Mechanical Officials (IAPMO) standards.
Use only non-entrapping suction fitting or double suction.
At Least
3 Feet
Suction Outlet
(Main Drain)
Suction Outlet
(Main Drain)
IAPMO Certified
Anti-entrapment
Cover or Suction Fitting,
screw-fastened to
Main Drain Sump
IAPMO Certified
Anti-entrapment
Cover or Suction Fitting,
screw-fastened to
Main Drain Sump
Pump
Valves OK between
pump and Tee
No valves between
Tee and Main Drains
2762 0197
Figure 2 – Recommended pump suction layout.
