floor drain

[tigbencher]

redoing the concrete floor in a shop i built years ago and will be installing a floor drain.the area where the floor is being done had/has a poured concrete oil change pit that will be used as a large dry well.apprx.18'x3'x6' to be filled with washed stone and concrete from the old floor around it that is being replaced /pitched to the new floor drain.holes will be put in the bottom of the old pit for drainage.my question to you guys is should i put a trap in the drain pipe from the sump box where the grate will be?thanks in advance.

 

[pstnbly]

A trap will probably cause problems, the bell in a floor drain grate creates a trap as long as liquid is present

( same with a P-trap by the way if the liquid in a P-trap is allowed to evaporate by inattention. Virtually every house I've built with a second floor laundry with a floor drain I had a call back for sewer smell. People don't want to pay for automatic trap fillers, and it doesn't matter what I tell them they never fill the trap)

 

[kbs2244]

No need for a P trap.
Their purpose is to keep sewer gas from coming up into the building.
You are not conecting to a sewer, no no sewer gas, so no need.

 

[hockey88fan]

I just installed 2 floor drains in my freshly poured garage floor, no p-trap or bell trap for that matter, ran a pipe to the outside for the water to go.

 

[Frank The Plumber]

If you are discharging to a sewer, Trap it. If you are discharging outdoors by gravity clean water no Trap.

However, if you are discharging to a storage box that may collect leaf litter, soils or other organics that may decompose, you may get a smell from the break down of that organic material within that container. This may result in an annoying odor.

 

[hockey88fan]

If you are discharging to a sewer, Trap it. If you are discharging outdoors by gravity clean water no Trap.

However, if you are discharging to a storage box that may collect leaf litter, soils or other organics that may decompose, you may get a smell from the break down of that organic material within that container. This may result in an annoying odor.

Good point, wish I would have thought about the odors from the storage bin coming back up into the garage. My pipes are going to a collection basin, wish I had put atleast a drain with a bell trap in my floor. Didn't even think about that aspect.

 

[akdiesel]

Frank may be able to correct this but I believe you are not allowed to tie floor drains or sump pumps to the sewer lines, in fear of people dumping hazardous waste (antifreeze) down the drain.

 

[Frank The Plumber]

In a garage or shop that parks a vehicle within it you are not supposed to tie a drain directly into a sewer.

You are supposed to use a triple basin drain and have a separate vent out the roof.

Here is why:

In the event that a flammable liquid is spilled, a fuel tank rupture, the first best safety thing to do is to contain this flammable liquid.
This is because a flammable liquid is emitting vapors which are flammable. We seek to contain these vapors. We seek to isolate these vapors and this liquid from the rest of the sewer system.

What could happen?

A back flash could occur within the sewer system in which an ignition of vapors travels through the sewer system. At points of exit the gases will expand. This translates directly to you being on the pot, minding your own business and a bomb goes off under your *** from within the piping of the house.

Or, You are half awake and shaving your face, your p trap is a bit short of water, you notice a strong fuel smell as it travels into your home from the sewer. before you can turn off your shaver, your incendiary device, your whole bathroom is a fire ball. No more shaving for you. Not nice.

Physics...is a *****.

So we have to consider it and protect ourselves from this crazy stuff.

The other thing that I might add is that if you have a container that is holding these litters that smell, the smell may be methane gas based, for this reason you may also want to vent this basin to eliminate these gases.

I do not advise putting your drain from your garage into your sewer or any sewer drains, I do not advise putting your garage drain into any type of basin. I do not advise the use of french drains. I do not advise running the drain out the pipe live.

The only safe way of putting a drain in a garage within motor vehicles is to use a triple basin or other proper code legal system.

In my own garage my floor is pitched to the door.

This is all about spilled fuel and it's affects upon others. If you discharge out doors who really knows where the spilled fuel could go?

What you ultimately do in your own shop is up to you, all I am doing is explaining why the code sees this as such a problem.

I hope you understand.