Disk Strength test 1

[ksg1]

Hi,

I have come across the " Disc strength" test requirements for triple offset valves. This is listed in both BS5155 and ISO 12266-1. The problem is that the test calls for testing of valve at 1.5 times the rated pressure. Seals of TOV's are not designed for this. The standard says that some leak is allowed during the test. However it does not say about how the setup is and how is the result judged - based on leakage or based on failure of disc strength. Does any one in this forum know.

 

[gerhardl]

I am not familiar with the test, but: Are you sure you have the latest issue, refer for instance to :

http://www.valveuser.com/974-bs-en-12266-12012.htm

? Are you sure the test is valid for BFL valves?

All BFL valves I know of, including double and trippel offset valves, will not allow any tests above (or possible slightly above?) normal working pressure, at least if they have resilient seats. As you states this will possibly permanently damage the sealing and give leakages.

 

[MGZmechanical]

Hi, I think EN 12266-2 optional tests says to test the obturator at 1,5 times (just like the hydrostatic test). This is optional not mandatory and just to chack obturator strentgh so maybe you can talk to your client of a way not to damage the seal.. Leak test (mandatory)are always at 1,1 times the design pressure at ambient temperature. If the test is with air then it must be at 6 bar +- 1 bar