Any issues with sanitary main freezing above ceiling?

[jimtheengineer10]

I am working on a project where the underground sanitary main needs to be replaced. The main is inside a strip mall and goes through five tenant spaces. The owner would like to install upflush toilets and have the new 4" pvc sanitary main run above the suspended ceiling to avoid having to bust up the concrete slab inside the tenant spaces. Should we be worried about the sanitary main freezing as there is no heat above the suspended ceiling or will enough heat from the heated space go up through the suspended ceiling? Thanks.

 

[PEDARRIN2]

It depends on where the insulation is located. If the insulation is at the underside of the roof deck - there should be no problem. If the insulation is at the ceiling level, there could be issues.

Where is the water piping supplying the toilets? If it is above the ceiling, and never frozen, there is little likelihood the sanitary piping would freeze.

 

[cvg]

kind of depends whether the strip mall is located in Texas or North Dakota, doesn't it? generally speaking, it is not good practice to run a water or sewer line through an unheated space, especially above a ceiling, without adequate insulation or heat tracing

 

[bimr]

As long as the pipe is installed below the insulation, it should not be a problem.

Consider using a 2-Inch force main instead of a gravity pipe. The upflush toilers should be able to pump approximately 150 feet horizontally. The gravity pipe will be difficult to install because of the required slope.

You can always heat trace and insulate the pipe as well.