Standard Hydro tests common elements & DIFFERENTIAL PRESSURE

By Mikeqc1 (****)

Date 11-25-2008 13:48 Edited 11-25-2008 14:19

Standard Hydrostatic tests

In UG -99 Standard Hydrostatic tests (e) 1
The second line of (1)
If the common elements of a combination unit are designed for a LARGER DIFFERENTIAL PRESSURE than the higher maximum allowable working pressure to be marked on the adjacent chambers , the hydro test shall subject the common elements to at least their design differential pressure , corrected for temp.........................
I may have this wrong so im looking for opinions on what this means, and can anyone give me an example of how to use this in a hydro test?
Please give an example of a common element.
Any input would help.
MDK

By johnnyh (***)

Date 11-25-2008 21:28

UG-19 and UG-21 gives the definition of common elements. I think some exchangers and strippers would fall into these categories. Common elements and their differential pressures are listed in the remarks section of the Manufacturer's Data Report and on the vessel. The pressures must be controlled to make sure that the design pressure isnt exceeded.