ANSI Flanges #900 & #1500

One hopes you haven't ruptured a 1500 psi pipeline yet by using only a Class 900 flange in it.

If the flange is dual stamped 900/1500, it can be used in either class of piping.
If stamped 1500 only, it can still be used in either class of piping.
If stamped 900 only, it cannot be used in class 1500 piping.

Thank you for your reply

but i have something with the code ,the two flanges have the same dimensios

which means that 900 can be replaced by 1500

or there is another factor than the dimensions

regards

It might also depend on the material and method of manufacture.

Are you sure ALL the dimensions are the same? (Not just bolt pattern, but thicknesses, tapers if any, and fillet radii.)

Sorry,i forgot to tell you that they are identically in the code but only for 1/2" to 2 1/2" only

regards