How to read tables 2-32 in API 526?
How to read tables 2-32 in API 526?
(OP)
I am referring to API 526, 5th edition, June 2002
In table 16 for example, Chrome Molybdenum Steel: there are two rows both of which are 8T10 with 300x150 rating. why is it repeated?
It seems that the ratings (valve, bellows and flanges) are different between the two rows. shouldn't they are be the same?
IN other words, when I say a valve has 300# rating inlet and 150# rating outlet, shouldn't I have the same values for pressure ratings at different temperatures?
Thanks
In table 16 for example, Chrome Molybdenum Steel: there are two rows both of which are 8T10 with 300x150 rating. why is it repeated?
It seems that the ratings (valve, bellows and flanges) are different between the two rows. shouldn't they are be the same?
IN other words, when I say a valve has 300# rating inlet and 150# rating outlet, shouldn't I have the same values for pressure ratings at different temperatures?
Thanks





RE: How to read tables 2-32 in API 526?
The example you quote actually has different pressure/temperature limits on both inlet and outlet for the 2 300# inlet T orifices'. Bellows designs also limited the outlet available rating.
Generally, lighter rated components (spring, bellows etc.), are used for the lower pressure section and may well impact the vendor economically.
API 526 is a user standard. Not all manufacturers may meet all listed size, rating, actual pressure rating configurations. The idea of this standard is that specified valve types are supposedly interchangeable when specified to API 526.
As far as I recall, API added these higher pressure, albeit with the same rated flange, but to be distinct against the earlier availability. Some, but not all, suppliers could meet it.
In practice, the manufacturers body and bonnet designs may well be the same for all 300#. It is API's way of separating the listed availability for conformity reasons.
Per ISO, only the term Safety Valve is used regardless of design.
RE: How to read tables 2-32 in API 526?
EDIT : or can I specify ASME B16.34 ratings as the relevant design standard for flange ratings instead? It seems that ASME B16.34 is more stringent in this aspect than API 526 (for example the values in parentheses in API 526 are less than those in ASME).
RE: How to read tables 2-32 in API 526?
Per ISO, only the term Safety Valve is used regardless of application or design.