PVC vs HDPE- buried under slab
PVC vs HDPE- buried under slab
(OP)
GeneralAssociate (Mechanical) 22 Aug 05 21:50
Value Engineering was requested by CM/Owner. Commercial Project includes methane mitigation using air intake/exaust/blower system, slab on grade, 3/4" washed stone bedding, new construction.
One item sticks out - 8500LF 4" Perforated SDR 17 HDPE pipe. Using Perforated PVC under slab would lower project costs, seems logical. Engineer prefers HDPE?. But only on perforated? Make sense?
Cost savings would be substantial enough to include in proposed VE. Any thoughts on industry/design standards.
Thanks All, Steven
Value Engineering was requested by CM/Owner. Commercial Project includes methane mitigation using air intake/exaust/blower system, slab on grade, 3/4" washed stone bedding, new construction.
One item sticks out - 8500LF 4" Perforated SDR 17 HDPE pipe. Using Perforated PVC under slab would lower project costs, seems logical. Engineer prefers HDPE?. But only on perforated? Make sense?
Cost savings would be substantial enough to include in proposed VE. Any thoughts on industry/design standards.
Thanks All, Steven





RE: PVC vs HDPE- buried under slab
RE: PVC vs HDPE- buried under slab
RE: PVC vs HDPE- buried under slab
RE: PVC vs HDPE- buried under slab
I also have a project where I have to divert runoff from very large roof through down spouts and under a 6" concrete slab to a catch basin. 185' x 245' roof area. 8 down spouts spaced along the 185'. 185 x 180 concrete slab for a staging area.
Would you specify sch. 40 PVC or sch. 80 PVC?
What would be your minimum cover over the pipe?
1.5 feet, or 2 feet perhaps?
This slab is used as a staging area for loading tractor trailors, large fork lifts will be rolling back and forth.
(2500 psf allowable bearing capacity)
Would it be best to tie all the down spout into a single juntion box and then run concrete pipe to the catch basin? (this would shorten the required PVC)
OR just run PVC from each down spout to the junction box (more PVC to run)
How about a trench drain that all the down spouts tie into at the drip line, then run concrete pipe over to the catch basin?
RE: PVC vs HDPE- buried under slab
RE: PVC vs HDPE- buried under slab
Very good points, and I need to do my homework on this one.
Thanks
RE: PVC vs HDPE- buried under slab
I am in agreement with TerraSouth. PVC is the way to go, keep in mind that you are designing a pathway for methane migration, with appropriate cover 4" PVC will do just fine. I have seen and used this method for air sparging units and piliot studies in which I have placed PVC under active rail lines to conduct soil vapor studies. As long as you make sure that you have proper depth and appropriate cover and compaction of that cover you will be fine.