Water service insulation when crossing over large storm sewer

[cr1973]

I'm working on a project where I need to run a bunch of 1" copper services over the top of an existing 48" storm sewer. Crossing over the top will allow for about 5 ft of cover over the new water services. I plan to insulate over the top of each 1" service whenever the cover is less than 6 ft, but how about insulating between the storm sewer and 1" services?

Do large diameter storm sewers reach freezing temperatures inside over the winter months in Wisconsin? Or would you assume the sewer itself would maintain earth temps.

 

[CarlB]

Doesn't the water/sewer utility have standards for this? In Anchorage Alaska the requirement is to insulate between storm drain lines and crossing water or sewer lines when the separation is less than 3 feet. Like you I believe the temperature within a storm drain line is much closer to ground temperature rather than outside air temperature. An exception may be a large sort culvert.

 

[Compositepro]

Warm air rises and culverts are usually slightly sloped with both ends open to the environment. The temperature in them will fairly quickly equilibrate with the outdoor air.

 

[cr1973]

Thanks all for the comments. I think I'll encapsulate the service with insulation, that might be the safest bet.