On 1 1/2" schedule 40 PVC it states a pressure rating of 330 psi @ 73F. I believe this is a burst pressure (from the inside, out). Would this also be the same for it's crush pressure? (from the outside, in) It's of concern because I'm I need to do a shallow burial under a gravel driveway.

On 1 1/2" schedule 40 PVC it states a pressure rating of 330 psi @ 73F. I believe this is a burst pressure (from the inside, out). Would this also be the same for it's crush pressure? (from the outside, in) It's of concern because I'm I need to do a shallow burial under a gravel driveway.
This question has never been brought up before.
How shallow will the PVC be buried? I believe schedule#40 will be strong enough but If you're concerned about external strength then use Schedule #80 instead.
Regards, tom