If you're nervous about the pipe you currently use and want to see if it will hold up to the punishment just put it to the test. Set up two stacks of plates about 18" apart, lay a section of the pipe across it, and then wack the hell out of it with a 10lb sledge! You could also fix it in place and drive over it by placing a ramp on it. If it doesn't deform or crack after these tests then you have nothing to worry about. Chances are you don't anyways coz that pipe is more than likely steel and you'll never ever be able to load that heavy enough with your weights to deform it.
"Lack of sleep makes cowards of us all."