S traps may not seem dangerous, but they are! They are now banned by many plumbing codes, including Massachusetts, Minnesota, and others. The reason for this is that the “S” shape of the trap, combined with the fact that it does not have a vent, means that water can be siphoned out of the trap.
S-traps are no longer used in modern plumbing because the water can be sucked completely out of the trap allowing sewer gas to enter your home. The risk from sewer gas can be much worse than just that terrible smell, as sewer gases can be poisonous or explosive.
The mechanical purpose of the trap is to hold water to prevent sewer gases containing viruses and bacteria from entering the home through the drain. With an “S” trap drain, the trap is easily siphoned dry with each use and the water seal no longer exists. A properly installed “P” trap will always maintain a water seal.
To ensure the safety of everyone in your home, as well as bring it up to date with building codes, it would be a good idea to replace all S-traps with P-traps. The P-trap garners its name from its actual shape, which resembles the letter "P".
This is a common SWR fitting used in combination with Pushfit & Solfit Pipes. It prevents transmission of unfavourable odours from the washroom to the living area. Can be connected to the shower area and WC if the branch line outlet is in the vertical position.
The J-bend is the section of the p-trap that resembles the letter J. The bend in the p-trap collects water in the curve, creating a 1-½-inch to 2-inch water seal at the weir, preventing sewer gasses and odor from entering the home.
With an S-trap, the drainpipe drops down from the sink and into a conventional trap. It then loops over and exits downward. In a P-trap configuration, the drain also comes down from the sink and into the trap, but instead of looping over and back down, the drain enters a horizontal run before exiting downward.
The “S” trap is prohibited under the Uniform Plumbing Code throughout the United States. This is because the “S” trap will siphon or suck water out from the trap which will end up releasing methane (sewer) gases into the home.
They are named as such due to the shape of the bend in the pipe. For example, the S bend trap has the shape of an S, while the U bend has a U shape, and the P bend is shaped like a P.
Kitchen sink P-Traps come in 1-1/2” standard size, while bathroom sinks use P-Traps of 1-1/4” standard size. The traps also come in different material types such as propylene, ABS, brass (chrome-plated or natural), and PVC. You should use the material that is currently in place when replacing a P-Trap.
P-traps are the only ones allowed by the Ontario Building Code in residential plumbing and S-traps as their predecessor are still quite common. In fact, I still see them installed in new DIY projects unfortunately.
Nahani trap is a floor trap that collects water and garbage from fixtures like bathtubs, sinks, showers and washing machines. In plumbing, traps play a crucial role. They stop illness from spreading through the structure by blocking the entry of sewage gas, insects, and rodents.
Anytime your drain goes up and down more than once, you have a double trap UNLESS you place an air vent between the two traps that vents ABOVE the drain inlet. The double trap causes drainage issues because air becomes trapped between the two traps, and air is lighter than water.
Advantages. - Maintains the minimum required water seal. A water seal prevents the spread of sewer gases in the living area and aids in the optimal movement of water. - Improves easy access for cleaning and maintenance.
Over time, things like hair, food, grease and mineral deposits build up and reduce the diameter of the drain pipe. Eventually, the drain will clog up and have to be thoroughly cleaned out. Another potential problem with P-traps is that they can eventually vent sewer gases into a living area.
An S-shaped trap is also known as an S-bend. It was invented by Alexander Cumming in 1775 but became known as the U-bend following the introduction of the U-shaped trap by Thomas Crapper in 1880.
The P-Trap has a P-Shape when viewed from an upright angle. It was first known as an S-Bend and invented in 1775 by Alexander Cummings. One hundred and five years later, Thomas Crapper modernized the S-Shaped pipe into a U-Shape design that's still in use today, but we know it as the P-Trap ever since.
House traps were a common plumbing device in homes that were built up to about 1989. Basically, it's a U-shaped piece of pipe that is installed with the sewer line that runs underground from the home to the municipal sewage main.
Prohibited Plumbing Traps - Bell trap, Crown-vented trap, Drum trap, Moving parts trap, Non-integral trap, S trap.
Determine your pan type
The trap is the bend in the toilet pipe that expels the waste. The S-trap has a waste pipe that's connected to the floor, while a P-trap pipe connects to the wall. A skew pan is sometimes found in older homes – it has a pipe that extends either side of the toilet bowl.
Unlike an S-trap, a P-trap features a pipe that exits the toilet through the wall. Instead of creating an S shape by going first up and then down, a P-trap creates a P shape by going down, curving up and then proceeding straightly. Its specific form makes it ideal for wall-hung toilets.
The trap is filled with water that prevents gases from coming back up the drain. However, if a sink isn't used for a while, water can evaporate from these traps and cause a dry drain. Once the drain is dry, sewer gas or vapors from improperly disposed chemicals can come up through the drain and cause an odor in a room.
Some bathroom drains have visible P-traps, such as the one under the sink, while others have a hidden P-trap, like a shower or a toilet. When a bathroom fixture or faucet is not used regularly, the P-trap eventually dries out, allowing the sewer odors to travel up the drain. It happens more frequently during winters.
S-traps are a type of plumbing trap that blocks sewer gases in sinks and other plumbing fixtures. The S-shaped pipe configuration traps wastewater before it drains to the sewer line, creating a water seal that prevents gases from flowing up through the drain.