When isolated trap sections of system piping exceed 5 gallons, how many valves must be included in the auxiliary drain?

In the context of sprinkler systems, when isolated trap sections of system piping contain more than 5 gallons of water, two valves need to be included in the auxiliary drain. This requirement is essential for ensuring proper drainage and maintenance of the system. The first valve is typically used to isolate the trap for maintenance or inspection, while the second valve allows for proper draining of the system. This setup enhances safety and operational efficiency, preventing potential issues such as water stagnation or pressure problems.

Including two valves ensures that any water trapped in the system can be effectively managed while allowing for the maintenance of system integrity. If only one valve was used, it might not provide for safe isolation and drainage, especially if service needs arise. Thus, the requirement for two valves is crucial for compliance with safety standards and effective system management in sprinkler fitting practices.