Drains in parking garage

[Loumolito]

I'm working on a project with a heated building on top of an open parking garage. We heat traced and insulated all of the exposed traps. The inspector is quoting IPC section 305.6 and is questioning why all of the sanitary drain piping is not heated & insulated.

 

[PEDARRIN2]

My version says "protect such pipes from freezing by insulation or heat or both." So you are not "required" to do both.

If you are heating and insulating the traps, and if you can show that insulation is sufficient to prevent freezing, you should be ok.

I would advise keeping horizontal runs to a minimum size and length which will minimize the potential for freezing in pipe.

 

[Loumolito]

So you are saying that bare sanitary drain piping is not permissible in an open parking garage? You think that the pipe should be insulated. This is contrary to all of the installations that I've designed in the past. Also, I never saw this in any of the parking garages I've been in.

 

[PEDARRIN2]

If the piping is subject to freezing, per IPC, it must be protected.

Whether it is enforced - that is up to the AHJ.

This is usually an issue that should be addressed with the AHJ prior to installation to get their agreement.

I have a parking garage that I did - which the sanitary and storm is not insulated - and was not an issue when we discussed it with the AHJ.

Unless the garage is in an area where the temperatures can get really cold or can last for a long time, I don't think it is a realistic issue.

Even if the garage is open, since it is under a building, there should still be some heat in it. Even if the temperature gets down to below freezing at times for a short duration, the pipes are not full of stationary water - except the traps which you are protecting. The piping is designed to empty, if it is installed correctly, without dips or sags.

Talk it over with the inspector - maybe he will see reason. If not, then you at least have to insulate the piping.

 

[KarlitaMora]

Hi, I also working in a parking garage but it is underground, do you know how I have to design the storm water piping for underground levels??

Because It is underground, rain falls in the roof and I size the leaders for that but I do not know how calculate pipes for the water that coming with the cars and maybe some water for car wash. I can not find any data about it in Codes.

Any suggest??

Regards,

KMora

 

[Loumolito]

Underground garages have no sizing codes. Be careful with local inspectors interpreting the need for oil interceptors. Around the Chesapeake Bay Maryland & VA they are concerned with oil getting into the storm system.

Just run 4" system to 4" drains. In the NE, many building owners are omitting these systems saying the slabs are sloped to a trench drain at the door.

 

[PEDARRIN2]

If the garage is not heated, you might have problems with freezing (if in an area subject to freezing).

When we have that situation, we do not trap the drains, but run them to a combination solids/oil interceptor (just a modified manhole). Of course we get the approval of the AHJ.

Like previously stated, size the drains at 4" with 4" piping. Make sure the grates are traffic rated or place the drains outside of traffic areas.

 

[KarlitaMora]

Thank you for your help I feel more comfortable with what I am doing.

Have a nice weekend. Here in Costa Rica we get a little sunshine after 2 weeks of rain.

Regards,

KMora