Can you tell me what the best practice or plumbing code for residential construction for bedding material a 4" pvc sewer line to prevent deflection of the pipe?

I've heard some people say to lay the pipe in a bed of 4 inch deep #57 stone or pea gravel bring the gravel/stone half way up the side of the pipe. then on top of that use more stone, soil and finally a 4 inch concrete slab. Thanks in advance.