“A tubular P-trap and S-trap are both plumbing components used in drain systems to prevent sewer gases from entering a building while allowing wastewater to flow out. They are commonly used in sinks, bathtubs, and other fixtures where a trap is necessary to maintain a water seal and block odors.
Tubular P-trap:
The P-trap is named after its shape, resembling the letter “”P”” when viewed from the side. It consists of a horizontal inlet and a vertical outlet connected by a curved section of pipe. The curved section holds water, creating a water seal that prevents sewer gases from traveling back up the drain and into the building. The P-trap is widely used in modern plumbing installations due to its efficiency and ease of installation. It is commonly found under sinks and other fixtures.
Tubular S-trap:
The S-trap gets its name from its shape, which resembles the letter “”S”” when viewed from the side. It consists of a horizontal inlet and a vertical outlet, just like the P-trap. However, instead of having a curved section of pipe, the S-trap has a sharp bend that resembles an “”S”” shape. In the past, S-traps were commonly used in plumbing systems, but they have largely fallen out of favor in modern installations due to some disadvantages.
Differences between P-traps and S-traps:
Design: The primary difference lies in their design and shape. P-traps have a smooth curved section, while S-traps have a sharp bend.
Performance: Both P-traps and S-traps serve the same purpose of trapping water to prevent sewer gases from entering the building. However, P-traps are generally more effective in maintaining the water seal due to their design.
Code compliance: In many regions, S-traps have been prohibited by plumbing codes due to potential siphoning issues. When the water flows rapidly down the vertical outlet of an S-trap, it can create a suction effect that can break the water seal and allow sewer gases to enter the building. P-traps are less prone to this problem, making them a preferred choice in modern plumbing installations.
Installation: P-traps are easier to install and maintain than S-traps. S-traps require careful installation to ensure that the outlet remains higher than the trap’s weir to avoid siphoning issues.
In summary, while both P-traps and S-traps serve the same function of trapping water to prevent sewer gases from entering buildings, the P-trap is the more common and preferred choice in modern plumbing due to its superior design and performance. S-traps have fallen out of favor and may not comply with current plumbing codes in many areas. If you are installing or replacing a trap, it is essential to use a P-trap or check local building codes to ensure compliance.”