How long must pressure be maintained when testing the DWB system by air completion?

• A. 10 minutes
• B. 15 minutes
• C. 20 minutes
• D. 30 minutes

Answer: (B)

When testing the drainage, waste, and vent (DWB) system with air, it is essential to maintain the pressure for a specified duration to ensure any potential leaks can be detected. According to plumbing codes, the testing period is typically set at 15 minutes. This timeframe is considered sufficient to assess the integrity of the system without allowing for excessive pressure drops that might lead to inconclusive results.

Testing for 15 minutes allows inspectors or plumbers to observe any pressure changes that may indicate leaks effectively. If the initial pressure is maintained consistently throughout this period, it verifies that the system is sound and capable of functioning as intended. Maintaining the pressure for a shorter time might not give enough opportunity for any possible issues to manifest, while a longer duration is often unnecessary and may lead to complications or failures unrelated to actual leaks.

Thus, the 15-minute test period is a balanced approach to ensuring system reliability while adhering to established plumbing codes and practices.