Pipe insulation

[PJKK]

I need a spec on pipe insulation. I have a 1.5" force main in a roadway that is crossing a culvert. The pipe will be burried the gravel shoulder with about 1' of cover.
Also any comments on a type of sleve/conduit (ie 8" PVC SDR35 ?) to place the force main into to act as a containment if the force main were to leak.

 

[mikolay]

How can you install the casing pipe, by open cut trench or must it be jacked uner the road? If jacking is required, then you have fewer pipe choices,perhaps steel casing pipe, or RCP. For insulation in Wisc., we use closed-cell extruded polystyrene boards with minimum thickness of 2 inches. You should consider your typical frost depth. If your frost depth is several feet deep, then your force main should be deeper, at least near the bottom of the typical frost depth. If this deeper profile results in a high spot in the force main profile, then you should provide an air release/vacuum valve on the force main line.
MIkolay

 

[dicksewerrat]

Have the force main installed by directional drilling. this way you can have it put in deeper and not even be close to that culvert. also you can put it futher away from the road. It always seems that the road will be widened before the main needs to be upsized or repaired. Put in a 6" hdpe carrier and the 1.5" main inside of it.