pipe spacing in trench?

[CVW]

I am replacing the original 1-1/2" flex PVC hose between the pool and the equipment pad with rigid 2" Sch 40 PVC pipe. When I excavated to remove the old flex hose lines I found they had been direct buried in the soil with no sand fill around them. I am digging a trench to run the replacement rigid PVC lines. This trench must accommodate a minimum of four (4) lines: skimmer 1; skimmer 2; main drain; return.
Here are my questions:
(1) what spacing should I use in the trench between the lines (clear space between adjacent lines);
(2) what backfill material should I use between the lines, [sand?, gravel? or original soil?];
(3) assuming sand or gravel, what depth of bedding and what depth of cover over the lines should I use before I can backfill the trench with the original soil?

Any suggestions will be appreciated. Thanks.

 

[blakeusa]

No real need to worry about the spacing on the pipes. Most lay them right next to each other... more so when they exit the ground and come up you have good space to install pump plumbing valves etc.

Sand is best to lay down before pipes and on-top. 4-6 inches is plenty. Also depends if you have a rocks in your normal dirt and freeze thaw that can move a rock to penetrate a pipe.

 

[CVW]

Thanks for the information!