69. What type of vent is used at the sink
Answer: A
Individual vent is used at the sink.
An individual vent is specifically utilized for a sink to allow for proper drainage and to prevent the buildup of sewer gases. This type of vent ensures that air can enter the drainage system, maintaining the necessary pressure balance.
A) Individual vent
This option is correct as an individual vent is designed to serve a single fixture, such as a sink. It connects directly to the sink's drain and allows for efficient drainage while preventing the escape of harmful gases into the living space.
B) Stack vent
A stack vent is not the correct choice for a sink as it is used to ventilate the entire drainage system. It serves multiple fixtures and extends through the roof, which does not specifically address the needs of an individual sink.
C) Vent stack
Similar to the stack vent, a vent stack is designed to provide ventilation for multiple drainage fixtures. It is not suitable for a single sink application, making it an incorrect option for this question.
D) Back vent
A back vent is also not appropriate for a sink. This type of vent typically refers to a venting method that might be used to relieve pressure in a drainage system but does not specifically cater to the requirements of a sink's drainage.
Conclusion
The individual vent is essential for the effective operation of a sink's drainage system, as it directly connects to the sink and prevents issues such as siphoning and gas leaks. In contrast, the other options cater to broader or different applications within plumbing and are not suited for single fixtures like sinks. Thus, the individual vent is the only appropriate choice.