Question 69

Individual vent is used at the sink.

An individual vent is specifically designed for a single fixture, such as a sink, allowing for proper drainage and air circulation to prevent siphoning and odors.

A) Individual vent

This option is correct because an individual vent is specifically installed for individual plumbing fixtures like sinks. It ensures that the sink operates efficiently by allowing air to enter the drainage system, which prevents the formation of negative pressure that could disrupt drainage.

B) Stack vent

A stack vent is not suitable for individual sinks as it serves multiple fixtures and extends vertically through the roof. While it plays a role in venting the entire plumbing system, it does not provide the targeted functionality that an individual vent does for a single sink.

C) Vent stack

A vent stack is a vertical pipe that carries air from multiple plumbing fixtures to the outside. Although it is important for overall system ventilation, it does not directly vent a single sink like an individual vent does, making it an incorrect choice for this question.

D) Back vent

A back vent is a term that refers to a vent installed behind a fixture to help with drainage, but it is not commonly used or recognized in standard plumbing terminology. Thus, it does not serve the specific purpose of venting a sink as effectively as an individual vent.

Conclusion

The individual vent is the most appropriate choice for sink venting because it directly addresses the specific needs of the sink, ensuring proper drainage and preventing odor issues. All other options either serve multiple fixtures or do not provide the necessary functionality for individual sinks, confirming that option A is the definitive correct answer.