Solder joints use which solder composition?

• A. 95-5 solder
• B. 50-50 solder
• C. 60-40 solder
• D. 100% tin

Answer: (A)

The key idea is that sprinkler-system joints rely on a solder that provides reliable flow, strong bonding to copper/brass, and compatibility with the system’s service conditions. The 95-5 solder is a tin-based alloy used for these joints because it offers good wetting on copper surfaces, a suitable melting range for sweating installations, and a lead-free composition that supports durable, safe joints over the life of a residential system. Other solders with higher lead content or different tin-lead ratios can have less desirable properties for sprinkler work, such as environmental/health concerns or altered flow and strength characteristics. Using the 95-5 blend gives a dependable balance of ease of use, joint integrity, and compliance with typical NFPA 13R practices for solder joints.