In an NFPA 13 D system, how should copper tube joints be connected on dry pipe systems?

In NFPA 13 D systems, which are designed for the protection of residential occupancies, it is essential to connect copper tube joints appropriately to ensure the reliability and effectiveness of the fire sprinkler system. Braising is the correct method for connecting copper tubes in dry pipe systems. This technique involves joining metals by melting and flowing a filler metal into the joint at high temperatures, resulting in strong, leak-proof connections that can withstand the pressures involved in a sprinkler system.

Braising is particularly advantageous because it provides a more durable joint compared to soldering, especially in environments where pipes may carry water under pressure or where they could be exposed to temperatures lower than the freezing point. In dry pipe systems, which contain air in the pipes until activation, any leaks could lead to system failure, making the integrity of the joints paramount.

While soldering and welding are options for connecting pipes, they do not offer the same strength and temperature resilience as braising in this context. Soldering, for example, may not be suitable for high-pressure applications, and welding is generally used for joining heavier gauge metals rather than plumbing applications like those in fire protection systems.