Look at your invoice. The SMYS is included in the piping designation. Grade B pipe has an SMYS of 35,000 psi, X42 has 42,000 psi, X52 is 52,000 psi, etc.
SMYS values are conservative (i.e., the pipe will not burst until you've exceeded the yield point by some amount), but that is not a bad thing. If you are looking for an actual burst point (hopefully not for piping design, but some other need) then your only valid approach would be to take a sample of pipe from the same mill run that you'll be using and test it to failure. I'm not sure what engineering application that data would have, but that is probably just my failure of imagination.
