Question 12

No fixture may be double-trapped

Double trapping occurs when a fixture has two traps in series, which can lead to poor drainage and potential sewer gas issues. Therefore, no fixture should be designed to be double-trapped to ensure proper function and safety in plumbing systems.

A) Kitchen sinks

Kitchen sinks should not be double-trapped as this can create drainage problems and trap odors. Only one trap should be used to ensure that waste flows properly and does not back up into the sink.

B) Laundry sink

Similar to kitchen sinks, laundry sinks must also avoid double trapping. The presence of two traps can negatively affect the drainage efficiency and lead to malodorous conditions due to improper venting.

C) Water closets

Water closets, or toilets, cannot be double-trapped either. Having multiple traps can cause blockages and hinder the effective removal of waste, making this option incorrect.

D) No fixture may be double-trapped

This option is correct because plumbing codes universally prohibit double trapping to maintain optimal drainage and prevent the risk of sewer gas entering the living space.

Conclusion

The correct answer is that no fixture may be double-trapped, as it ensures efficient drainage and prevents hazards associated with sewer gases. All other options incorrectly suggest that specific fixtures can be double-trapped, which goes against established plumbing practices and safety standards.