Pipe Support for Compressor (Centrifugal) 2

There are usually no frequency issues associated with piping attached to a centrifugal compressor. Both pole passing (if electrically driven) and blade passing frequencies would normally be far too high to excite piping. The first support should be from structure and is normally a spring (preferably constant), or adjustable type if it's a horizontal restraint.

Personally I have never seen piping supported from the compressor casing.

C2it, it seems you're experienced in piping of centrifugal gas compressors. Is there any code or guideline on vibration analysis of this kind of pipings (especially on natural frequencies)?

No pump or compressor manufacturer will warranty this type of support if added after-market without a review at a minimum: The turbine, pump or compressor casing are NOT designed nor intended to support external loads - heavy loads kike piping in particular - without consideration for compressor welding, bending forces on the blade and impeller and seals and shaft bearing clearances/warping/distortion by point loads even on bolting flanges. Casing removal, machine access for maintenance, casing metal problems by casually welding on the pressure vessel walls cause problems. Welding even light instrument runs and cable trays with Unistrut bars is not desired.

Pipes attached to any rotating equipment should be "neutrally mounted" with as little forces transmitted to the nozzle at rest and at operation. The pipe supports should be external to the machine structurally, mounted ultimately to a foundation common to the pump/compressor if vibration of either is controlled, or separately if vibration must be isolated.

McDermott711,

API 617 is relevant to centrifugal compressor installations generally. The best source of information and analysis methods for vibration (vis-à-vis Piping) that I am aware of is the from the UK Energy Institute:

"Guidelines for the Avoidance of Vibration Induced Fatigue in Process Pipework" 2nd Ed.
ISBN 978 0 85293 453 1
available from:

Thanks C2it for your reply!

Generally pipe supports should not be on or near to a compressor flange. Different temperatures of the compressor and support could cause considerable thermal growth between nozzle and compressor base plate and the pipe support length. That can result in very high stress.