huangyhg

ansi 2 inch 900 / 1500 flanges
a 2 inch 1500 ansi flange was ordered. i rejected it for 2 reasons. 1) the flange was only stamped 900. b16.5 para 4.1.3 states that the applicable rating be stamped on the flange ie: 900, 1500 or 900/1500. 2) the mtr refered only to class 900. the supplier argued that because the two ratings (900 and 1500) were dimensionally the same that it was ok. i said not. whats the thoughts?
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hi garnet0 (mechanical)
the suppler is ok!
see asme b16.5 1996 page 103 table 21 dimisions of class 900 flange nps: 1/2", 3/4", 1", 1-1/4", 1-1/2", 2". 2-1/2" use class 1500 dimension in these sizes (11).
note (11) socket welding flanges may be provided in nps 1/2 through 2-1/2 using class 1500 dimensions
i agree with isthill in that the flange was dimensionally sound.
the problem i have with 900#/1500# flanges > 3" nps is down the road when someone decides to figure out what the line class is just by checking the ansi class stamped on the flange. if it's done by someone who doesn't know any better, they could wind up assuming a 1500# line was actually 900#, or even worse, the other way around.
i never did question the fact that the flange was dimensionally sound. it was the stamping that bothered me. i used para 4.1.3 to reject it as it didn't have 1500 stamped on it as required. as you said scipio, my biggest concern was down the road when someone decides he's working on a 900# line. i guess a trivial concern but i still think that if all the i's were dotted, these flanges should be stamped accordingly even though dimensionally they are correct.
i don't think the practice of one stamping for several classes of flanges is going to change any time soon. so later anyone will have the same problem as "garneto". he is going to put in a acceptable flange within the size range mentioned . the only problem will come if someone looks a 1" and then buys a 6" of the same class.
i always made it a practice to look at the installed flanges in the 3" to 8" range to verify the drawings.
p.s. we had one gasket to fit 150 class to 1500 class flanges.
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