End Loads

[BHMech]

Does anyone have any information on acceptable valve end loading due to piping stesses? We have customers who often ask for the allowable loads that valve ends can withstand.
Or, is there any guidelines to show the expected load that a given pipe may exhort on a valve due to pressure or temperature?

 

[RXH]

BHMech

There are no special end loading limitations for valves that I am aware of. Generally, the pipe and other pipe components are weaker, and they will fail first.

There are a few cases where loading limitations would help, for example large low pressure gate valves. If the valve is flangeless, body distortion may result if the piping is too stiff and this can prevent the gate from sealing effectively. Manufacturers don't give any limitations and it is up to the designer to recognize the potential problem and design around it.

What type of valves did your question want to address?

 

[unsy]

The easiest way to do this is to compare the section modulus of the pipe against the valve end and then take ino cosideration the applicable ratio of allowable stress values for the pipe and valve materials. (don't forget casting factors is volumetric testing is not carried out)