Installation Guide

Flow vs Head Loss
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Flow (GPM)
Head Loss (inHg)
For technical assistance call 1.800.621.5886 or contact your regional representative
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HOW SDX RETRO WORKS BETTER
SDX RETRO HIGH FLOW SAFETY DRAIN SYSTEM DESIGN
DUAL-DRAIN SYSTEM
Vacuum Breaker Backup. As with any dual-drain system, one drain is intended to be a vacuum breaker for the other in
the unlikely event a swimmer completely blocks one of the SDX drains. If this were to happen, the pump is able to safely
draw water from the second drain.
D
ual-Drain Spacing. Most suction safety codes require dual-drains to be installed three feet apart, pipe to pipe, however
s
ome codes require three feet between drain covers. For this reason, Dual SDX piping is spaced three (3) feet, ten (10)
inches apart.
Vertical Dual-Drain Installation. The purpose of the vertical dual-drain installation is to make it less likely two people can
approach two drains at once. Effectively, the second drain would be at an individual’s feet.
SDX RETRO is a circulation drain, not intended to remove debris. For this reason it is suggested SDX be
installed on walls whenever possible. SDX is a high flow safety drain system submerged suction outlet suitable
for Single or Multiple Drain use on the wall and floor. This is to keep debris and sand from collecting on and
around the low velocity SDX RETRO cover. Do not locate suction outlets on seating areas or on the backrest
of such seating areas.
The maximum flow rate for each pair of SDX RETRO drains is 200 gpm on the floor --192 gpm on the wall.
This flow rating allows for pumps up to 3 hp to operate efficiently. For pumps with higher flow rates or systems
with multiple pumps on a common manifold, additional SDX drains may be added. Do not exceed the maximum
allowable flow rate stated on the suction fitting. The velocity at the opening to the SDX drain at the maximum rated
flow of 200GPM is 1.485 feet per second. For multiple drain systems where more than two drains are used, the
maximum flow rate is calculated per ANSI/APSP-7 Section 4.6 as shown in the following chart.
DESCRIPTION
MAXIMUM SYSTEM FLOW
FLOOR
MAXIMUM SYSTEM FLOW WALL MINIMUM FLOW RATING OF
EACH COVER % MAXIMUM SYS-
TEM FLOW RATE
One SDX High Flow Safety Drain 200 gpm (756 lpm) 192 gpm (726 lpm) 100%
Two SDX High Flow Safety Drains 200 gpm (756 lpm) 192 gpm (726 lpm) 100%
Three SDX High Flow Safety Drains 300 gpm (1136 lpm) 288 gpm (1090 lpm) 66.7%
Four SDX High Flow Safety Drains 400 gpm (1514 lpm) 384 gpm (1456 lpm) 50%
SUCTION PIPE SIZE MAX RESIDENTIAL GPM MAX PUBLIC GPM
1½” 50 37
2” 82 62
2½” 117 88
3” 181 136
4” 313 (200 Max GPM) 234 (200 Max GPM)
*Table derived from ANSI/APSP-7 Section 4.6 Table 1
*minimum pipe size 1 1/2
Pipe size. To design an
efficient suction system
in accordance with
national swimming pool
standards, the following
pipe sizing guideline
should be followed:
HEAD LOSS CURVE