Doc. No.: OMS500000104
Rev: A Page 10 of 42
Subject to contractual terms and conditions to the contrary, this document and all the information contained herein are the confidential and exclusive
property of FMC Technologies, and may not be reproduced, disclosed, or made public in any manner prior to express written authorization by FMC.
than the pump inlet. Long piping runs, low suction heads, or indirect pipe routing may
require even greater oversizing of the suction line for proper operation of the pump. In
some cases it may be necessary to install a booster pump in the suction line of the pump
to obtain sufficient pressure for the pump to operate successfully.
3. The suction line must be laid out so that there are no high spots in the line where gas or
air pockets could collect. These pockets can make the pump difficult to prime and cause
rough, erratic operation. A drain valve or plug should be installed at the low point of the
suction line to allow for drainage during freezing conditions or for maintenance.
4. FMC recommends that all piping be supported independently of the pump. By
supporting the piping this way, vibrations are reduced and stress on the pump is kept to a
minimum. The use of elbows, nipples, unions, or other fittings should be minimized.
Make sure that all joints and connections are airtight. Air leaks reduce the capacity of the
pump and can result in cavitation, rough operation, and/or loss of prime. To help isolate
mechanical and hydraulic vibrations, FMC recommends the use of flexible hose
connections between the pump and any rigid piping.
5. Always insure that calculated system net positive suction head available (NPSHa)
exceeds pump net positive suction head required (NPSHr) by at least 5 feet (1.5 meters)
of water for proper operation of the pump. NPSH requirements for each pump model are
provided on the product data sheets available through FMC or you authorized FMC
reseller. FMC does not recommend using the pump in static lift conditions without prior
approval.
4.4 Discharge Piping Recommendations
1. Route the
discharge piping in
as short and direct
a route as possible.
Use the same pipe
size as the outlet
of the pump. In
installations where
the discharge
piping is in excess
of 150 feet (50
meters), it is
suggested to use
the next larger size
pipe to minimize
friction losses
downstream of the pump. Always use pipe or hose that is designed for your particular
pressure requirements. Inadequate pressure ratings can allow hose or pipe to fail
resulting in personal injuries or equipment damage. Normal hose pressure ratings are
clearly marked on the outer surface of the hose. Working pressure ratings for steel pipe
can be obtained from the manufacturer or from the adjacent chart.
Allowable Working Pressure For Steel Pipe (PSI @ 100F)
Pipe Pipe Schedule Number
Size (inches) 40 80 120 160 XX
1/2 2,300 4,100 7,300 12,300
3/4 2,000 3,500 8,500 10,000
1 2,100 3,500 5,700 9,500
1 1/4 1,800 3,000 4,400 7,900
1 1/2 1,700 2,800 4,500 7,200
2 1,500 2,500 4,600 6,300
2 1/2 1,900 2,800 4,200 6,900
3 1,600 2,600 4,100 6,100
3 1/2 1,500 2,400 5,600
4 1,400 2,300 3,350 4,000 5,300
5 1,300 2,090 2,950 3,850 4,780
6 1,210 2,070 2,850 3,760 4,660
8 1,100 1,870 2,840 3,700 3,560
