Plumbing Materials, Joints, and Connections
Materials and Their Limits
Know common piping materials: cast iron, PVC, ABS, copper, PEX, CPVC, galvanized steel, and their approved uses. Understand that material must be compatible with the waste or water it carries and with the joining method. Learn about transition fittings between dissimilar materials and dielectric unions to prevent galvanic corrosion.
Joints and Connections
Know solvent cementing for PVC and ABS, soldering and brazing for copper, mechanical joints for cast iron, and press or crimp fittings for PEX and copper. Understand that joints must be accessible where required, and that underground joints need approved methods. Learn about expansion joints, flexible couplings, and the need for thrust restraint.
Traps in Questions
Distractors mix incompatible materials (copper directly to steel without a dielectric union) or use the wrong joining method (solvent cement on PEX). Watch for questions on which joints may be concealed, and on the requirement for accessible cleanouts and valves. Another trap: assuming any approved material works in any application.
Worked Example
Rule of thumb: "Match the material, the method, and the environment." Before choosing a joint, confirm the pipe material, the approved joining method, and whether the location is buried, concealed, or exposed. If any one is wrong, the answer is wrong.