Question

Which of the following trap is provided at the junction of house sewer and street sewer?

• A. Q-trap
• B. Gully trap
• C. Reflux valve
• D. Intercepting trap

Answer 1

The Correct Option is D

In plumbing systems, traps are essential devices used to prevent the backflow of unpleasant or harmful gases from the sewer system into a building. These traps create a water seal that blocks gases, but they allow wastewater to flow through.

Let's analyze each option:

• Option 1: Q-trap - A Q-trap is not commonly used in plumbing terminology. It could be a misinterpretation or confusion with other types of traps. There is no standard plumbing device known as a "Q-trap" for backflow prevention.
• Option 2: Gully trap - A gully trap is typically used at the connection between a building's drainage system and the public sewer system. Its main purpose is to prevent the entry of foul smells and gases into the building, making it an effective option for gas prevention. However, it does not provide the same level of prevention as an intercepting trap.
• Option 3: Reflux valve - A reflux valve is designed to allow water to flow in one direction and prevent backflow in the opposite direction. While it serves a similar function to a trap in preventing backflow, it is not typically considered a "trap" in the traditional plumbing sense. A reflux valve does not create a water seal like a trap does.
• Option 4: Intercepting trap - An intercepting trap is a type of trap that is designed to intercept and block gases, waste, or debris from flowing into the building's drainage system. It is commonly used in plumbing systems to prevent the entry of harmful gases into buildings. It is specifically designed for backflow prevention, making it the correct answer in this case.

Conclusion:

The intercepting trap is the most appropriate plumbing device for preventing backflow of gases and odors from the sewer system into a building. It is widely used in various plumbing installations for its ability to block foul odors and gases effectively.

Answer:

Option 4: Intercepting trap