A plumber is preparing to join two lengths of 25 mm Type L copper tubing using a solder joint for a potable water system. What is the maximum allowable gap between the fully inserted tube and the fitting shoulder to ensure a capillary action for proper solder flow according to Canadian plumbing practices?

Question: A plumber is preparing to join two lengths of 25 mm Type L copper tubing using a solder joint for a potable water system. What is the maximum allowable gap between the fully inserted tube and the fitting shoulder to ensure a capillary action for proper solder flow according to Canadian plumbing practices?

Answer options:

• 0.02 mm to 0.05 mm ✅ 0.05 mm to 0.15 mm
• 0.15 mm to 0.50 mm
• 0.50 mm to 1.00 mm

Correct answer: 0.05 mm to 0.15 mm

Explanation: For effective capillary action, which draws solder into the joint, a gap between 0.05 mm and 0.15 mm is considered ideal. A gap that is too small or too large will hinder the proper flow of solder, potentially leading to a weak or leaky joint.