Which type of traps are not permitted?

S-traps are not permitted primarily due to their tendency to create siphoning issues, which can lead to the loss of water seal necessary for preventing sewer gases from entering the living space. The design of an S-trap can cause it to easily lose its trap seal when waste flows through, particularly when there is a sudden rush of water due to flushing a toilet or draining a sink. This results in an unwanted situation where sewer gases can escape into a home, posing significant health hazards.

In contrast, other traps such as U-traps, J-traps, and P-traps are commonly used in plumbing systems. U-traps and J-traps have designs that help maintain a water seal more effectively, while P-traps are specifically designed to prevent siphoning and are widely accepted in residential and commercial plumbing. Understanding the unique designs and functionalities of different types of traps is crucial for maintaining effective plumbing systems and ensuring the safety and hygiene of living environments.