WOG or CWP Valve for Steam 1

[colar]

I have an existing system that needs evaluation for compliance to B31.3 (as referenced by our local boiler code). The system is a deaerator for boiler feed water. One thing I have noted is that all of the ball valves on the unit do not have WSP ratings. Four have a CWP rating (1500 psi) and the other a WOG rating (2000 psi).

The deaerator has twin 25 psi relief valves and contains water and steam used for spray type deaeration.

The spec sheets on the valves list a max operating temp of 450F and 380F.

Are these adequate for the service?

 

[rneill]

The four that have a CWP rating of 1500 psi, what standard are these made to - are these ASME B16.34 Class 600 valves ? If so, you can review that standard to determine the working pressure rating at elevated temperatures.

For the WOG rated valve, you would need to determine what standard it was made to (likely an MSS standard, perhaps SP-108) and see if that standard could provide you working pressure ratings at elevated temperatures.

Unfortunately, knowing the cold working pressure rating and the max temp doesn't actually tell us anything about pressure ratings that may apply between ambient and the max rated temperature.

 

[colar]

Both valves are made to B16.34.

I missed adding in my original post that those temps are at 25psi. The valve spec has a temp vs pressure graph.

 

[rneill]

Not sure what the problem is if you have a valve temperature vs. pressure graph. Compare the valve rated working pressure at your design maximum temperature to the required design pressure ?

Am I missing something ?

Or is the question that you want to validate the temp vs. pressure charts you have ?

 

[colar]

My concern was that the valves don't have an official WSP rating. I didn't know if this was a requirement. Or if this could be overcome with temp vs pressure rating.

 

[rneill]

We use ASME B16.34 valves quite regularly in steam services based upon the pressure / temperature ratings.