Ask Me Help Desk - Legal and Commonly used trap

What are legal and commonly used traps?

Quote:

Originally Posted by tclimer

What are legal and commonly used traps?

"P" traps are the most commonly used traps today.
A "P" trap,(see image) is a device that maintains a 3" deep layer of water in the pipe to serve as a seal to prevent sewer gases from coming up the drain into the structure. The codes require all fixtures to be equipped with a trap, but in the case of a bathroom lavatory either a P-trap or a Bottle Trap can be used interchangably, depending upon what you desire.
A common trap uses an inverted U shape section to hold the water. A barrel trap or bottle trap is a round container with a standpipe up the center similar to the standpipe in the toilet tank. The drain water enters the trap near the bottom of the Bottle, as it enters the outer chamber the level in the chamber rises and it then spills over the inner standpipe and on down the drain line. Bottle traps are used where the trap's exposed and a decorative trap is desired.. A "S" trap is shaped like a horizontal "S", is unvented and is outlawed in all 50 states and Canada A drum trap works on much the same principle as a bottle trap but is limited to special fixtures and are subject to approval by the Plumbing Official.
Here are some of the outlawed traps, (see image). Hope this answers your question. Regards, Tom

Well Speedball, that was a good and interesting post, especially for us amateurs. Two questions:

1. Why are S traps not code? Wouldn't it accomplish the same thing as a P trap, other than routing wastewater downwards as opposed to horizontally?

2. Where can you find those clear P traps? That would be a nice thing to have if you suspect the drain is clogged at the trap. I have honestly never seen one.

S-traps drain too fast, this is the reason that they are not permitted under most codes, they drain so good that there is not enough water left to make the seal. A vent near the trap just increases this suction. Still your call, good luck.

John

Hi guys!

Best explanation I can offer up is that s-traps and the bag traps are illegal primarily because these trap designs were determined to actually create a suctioning effect by virtue of the draining water itself evacuating water from the trap and allowing sewer gasses to escape into the house! A major NO-NO in terms of protecting the health of the nation!

These traps are also famous for creating a siphoning effect on the traps themselves whenever string/floss/hair/soap-scum accumulate at the secondary curve in the traps. This siphoning effect occurs as a result of capillary action in which water effectively climbs the debris (string/floss/hair/soap-scum) and then migrates over the secondary curve and begins to SIPHON the trap in such a way that it partially drains the trap of water and finally allows sewer gasses to enter into the home... similar to the suctioning effect.

Also, mechanical traps (Tom's 1st picture) are made illegal 'cause the moving parts tended to gunk up or corrode (ones with metal parts) and cause clog in and of itself (although I have seen some pretty cool new mechanical types in some contractor magazines? ).

Hope that explained a little. Maybe Tom or others can offer up some other reasons they are illegal (such as VENTING, turbulent flow and self-scouring relationships... Hmmm? )

In terms of tclimer's question... like Tom said, P-traps (see 1st picture) are most common in America... some states still allow drum traps (see 2nd picture)... but usually only with permission... or if from Maine, if within 10 feet of a waste stack... ;) The U.K. has some other bottle type traps (see 3rd picture) I have seen online but I am unfamiliar with them (available in U.S. too... not commonly accepted by code).

Jlisenbe... check out the 4th picture. It is a CATCHALLHAIRTRAP... being sold online under that name. I only wish all traps were built like this... huh?

Have a great night all...

MARK

Hey John, its not the speed of an S trap that screws them up, they tend to siphon as the water falls down the verticle drain pipe. This sounds like another test question for an apprentice of home inspector, what's your bet.

Quote:

2. Where can you find those clear P traps? That would be a nice thing to have if you suspect the drain is clogged at the trap. I have honestly never seen one.

I put up a picture of a glassine trap. The last time I installed one of these it was in a chemical lab at a area high school. All the traps and tailpieces were glassine because a metal trap would be ate up by the chemicals the kids flushed down them. This was before PVC so I imagine they're using PVC now.
Regards, Tom

Thanks for the explanations. I am smarter now than I was two days ago (which still might not be saying much!).

:)

Quote:

Originally Posted by speedball1

"P" traps are the most commonly used traps today.
A "P" trap,(see image) is a device that maintains a 3" deep layer of water in the pipe to serve as a seal to prevent sewer gases from coming up the drain into the structure. The codes require all fixtures to be equipped with a trap, but in the case of a bathroom lavatory either a P-trap or a Bottle Trap can be used interchangably, depending upon what you desire.
A common trap uses an inverted U shape section to hold the water. A barrel trap or bottle trap is a round container with a standpipe up the center similar to the standpipe in the toilet tank. The drain water enters the trap near the bottom of the Bottle, as it enters the outer chamber the level in the chamber rises and it then spills over the inner standpipe and on down the drain line. Bottle traps are used where the trap's exposed and a decorative trap is desired.. A "S" trap is shaped like a horizontal "S", is unvented and is outlawed in all 50 states and Canada A drum trap works on much the same principle as a bottle trap but is limited to special fixtures and are subject to approval by the Plumbing Official.
Here are some of the outlawed traps, (see image). Hope this answers your question. Regards, Tom

Right on the money---thanks a bunch