Question 31

Every plumbing fixture that is directly connected to the drainage system must have a water seal trap.

A water seal trap is essential for every plumbing fixture connected to the drainage system, as it prevents sewer gases from entering the living space while allowing wastewater to flow freely.

A) a water seal trap

This option is correct because a water seal trap is designed to maintain a water barrier that blocks harmful gases from the drainage system. The presence of this trap is a critical component of plumbing codes to ensure health and safety in residential and commercial buildings.

B) an individual vent

While individual vents are important for proper drainage and air circulation in plumbing systems, they are not mandatory for every fixture. Vents help prevent siphoning of traps but do not serve the primary purpose of blocking sewer gases, which is the focus of the question.

C) an air gap

An air gap is used to prevent backflow and contamination in water supply systems, but it is not a requirement for every plumbing fixture connected to the drainage system. This option does not address the need for a barrier against sewer gases, making it incorrect in this context.

D) an overflow

An overflow is designed to prevent water from spilling over from fixtures but does not play a role in preventing sewer gases from entering a space. Therefore, while it might be a useful feature, it is not a requirement for all plumbing fixtures connected to the drainage system.

Conclusion

The requirement for a water seal trap is crucial for maintaining safety and hygiene in plumbing systems, as it effectively blocks sewer gases from entering living areas. Other options, while relevant to plumbing, do not fulfill the specific requirement of preventing gas intrusion, thus making them incorrect in this scenario.