How should joints for the connection of copper tubes be treated in pre-action systems?

In pre-action systems, using braised connections for copper tube joints is the most appropriate method due to several factors. Braising involves joining metals using a filler material that has a melting point above 450°C (about 840°F), allowing for a strong, durable bond. This method creates a joint that is less likely to be compromised over time and offers excellent resistance to pressure and temperature variations, which are critical in fire protection systems.

Additionally, braised joints provide a secure seal that minimizes the risk of leaks, which is essential in a pre-action system where water is only released under specific conditions, such as during a fire alarm activation. This characteristic makes braised connections particularly suited for the reliable operation of the system, ensuring that the integrity of the piping is maintained under various environmental conditions.

In contrast, while screwed joints and flanged connections are common methods for assembling pipes, they may not offer the same level of reliability and strength in the long term as braised joints. Taped seals can be unreliable in high-pressure systems, as the tape can wear down or fail over time, leading to leaks. Therefore, braising is the preferred technique for ensuring the longevity and effectiveness of the joints in pre-action systems.