Do ASME B16.5 flange ratings include NEMA SM23 swings? 3

[btuchaser]

NEMA SM23 allows variations in steam pressure and temperature to exceed maximums by 20% pressure and 50 deg F. Do the ASME B16.5 ratings include these swings or are the B16.5 values absolute maximums? For A-217 GR WC9 (material group 1.10) Class 1500# at 950 F, the allowable pressure is 1885 psig. If the piping design requires 1750 psig @ 950 F is a 1500# flange acceptable or do you have to apply the NEMA variations? Applying the +50 F temperature variation would force a the design into a class 2500# flange as a 1500# flange at 1000 F has a rating of only 1305 psig.

 

[Ashereng]

NEMA SM23 is for steam turbines.
ASME B16.5 is for pipe flanges.

As long as your design pressure @ temperature falls below the ASME B16.5 class, that is it, as I interpret it.

Perhaps my mechanical colleagues can provide more information.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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[NozzleTwister]

Your piping code, ASTM B31.3 or B31.1 defines the allowable short term conditions that exceed the design values.

NozzleTwister
Houston, Texas

 

[Ashereng]

If you are in Canada, CSA Z662.03


"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[MJCronin]

btu....

Nozzle is correct.....it is the piping code of record that defines maximum pressure/tempersture transients above design

Give him a star !!

-MJC