Supporting of Pump Piping


A plant layout designer must have some basic knowledge of stress and pipe supports to generate a sound pump piping arrangement that will not be radically redesigned by a stress/support engineer.

Some simple rules, if followed, enable the designer to satisfy two of the most important considerations illustrated below: supporting the suction line under the elbow and supporting the discharge line within five diameters of the top elbow.

The suction line is commonly supported under the elbow adjacent to the pump nozzle. This may be a hard support (i.e., pipe or a structural steel member), adjustable type, or spring support for high-temperature pumps.

If pumps are located in poor soil areas or where differential settlement may occur, extending the pump block foundation may be necessary to pick up the base support.

The stress/support engineer and civil engineer need to be part of this decision. The discharge line should be supported as close to the top elbow as possible and should be within five diameters of that elbow.

Pump nozzle loading falls under the API-610 code. There are two ways of sup-porting the discharge line. One is to sit the spring support on the steel with a rod hanger and clamp; the other version is to place a base spring on the steel with the discharge line resting directly on the load flange of the spring.

Because the hanger rod could pose a danger during a fire, each project should be reviewed for such concerns. Loading on steam turbine nozzles falls under the NEMA-SM-21 code, which is
different from the allowable nozzle loads on pumps.

Inline pumps do not require a direct support but are held in place by the suction and discharge line supports, as shown below.

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