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Pressure-Temperature Ratings Standard for Threaded Ends Ball Valves
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The Obturator
Mechanical
The Process Piping Specification ASME B31.3 Provides some pointers in terms of Valves, Threaded Ends and Minimum Wall thickness against Schedule etc. But being ASME is very broad.
Per ISO-4126, only the term Safety Valve is used regardless of application or design.
Per ISO-4126, only the term Safety Valve is used regardless of application or design.
The Obturator
Mechanical
Your original question intrigued me further...
It could well be ASME B16.11
Note that threaded connections do not have ratings of the order 300/600/900 like flanges.
Also worth keeping this web page on file for future reference
Per ISO-4126, only the term Safety Valve is used regardless of application or design.
It could well be ASME B16.11
Note that threaded connections do not have ratings of the order 300/600/900 like flanges.
Also worth keeping this web page on file for future reference
Per ISO-4126, only the term Safety Valve is used regardless of application or design.
Not sure why you think B16.34 is only for low class rating on thread end valves. Please check Table 4 in ASME B16.34-2017. This Table provides the minimum wall thickness for socket welding and threaded ends up to Class 4500 in sizes up to NPS 2-1/2. Maybe you have a larger size valve?
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ASME B16.11 does not provide Pressure-Temperature rating for Threaded and Welding Ends. Although ASME B16.34 does provide that information, it states that Flanged Ends valves can only be classified as Standard Class valves. Can Threaded and Welding Ends also fall under Standard Class for Pressure-Temperature ratings if their wall thickness meet the requirements of Table 4 in ASME B16.34?
moltenmetal
Chemical
Ball valves with soft components (packings, seats, stem seals) always have pressure/temperature limits which drop steeply with temperature. Unlike metal seated gates and globes, they do not have "body limited" designs, i.e. in accordance with a given ASME class all the way up to a maximum permissible operating temperature. That's true whether the valves are threaded or flanged by the way.
Most threaded end ball valves do not have an ASME class, but rather have a MSS "water oil gas" (WOG) recommended maximum room temperature operating pressure. The P/T dependence of those WOG designs vary depending on the nature of the soft goods in the valve and are not developed with reference to any standard I've personally ever seen. Doesn't mean there isn't one, just means I've asked valve manufacturers to provide such a standard and have received puzzled looks. The issue was in relation to new fill materials (metal-filled teflon seats) that some vendors claimed to have higher P/T ratings than the limits of other reinforced teflon materials.
If the valves are metal seated, the ratings should be body limited and reference to an ASME standard may be possible. But again I've never bothered to look at the root standard, always deferring to the vendors' own P/T ratings as for all other ball valves.
Most threaded end ball valves do not have an ASME class, but rather have a MSS "water oil gas" (WOG) recommended maximum room temperature operating pressure. The P/T dependence of those WOG designs vary depending on the nature of the soft goods in the valve and are not developed with reference to any standard I've personally ever seen. Doesn't mean there isn't one, just means I've asked valve manufacturers to provide such a standard and have received puzzled looks. The issue was in relation to new fill materials (metal-filled teflon seats) that some vendors claimed to have higher P/T ratings than the limits of other reinforced teflon materials.
If the valves are metal seated, the ratings should be body limited and reference to an ASME standard may be possible. But again I've never bothered to look at the root standard, always deferring to the vendors' own P/T ratings as for all other ball valves.
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