Selection, Handling, and Preparation of Plumbing Tools, Materials, and Fittings
Tools, materials, and fittings
This domain tests selection, inspection, handling, and preparation. The examiner wants to see that you choose the right tool and material for the pipe, and that you protect both before installation.
Core rules
- Match material to service: uPVC for cold DWV and cold water where allowed, PPR for hot and cold water, GI for some exposed and fire lines, copper for hot water and medical gas where specified, and PEX where approved.
- Use compatible fittings and joining methods. Solvent cement must match the pipe (uPVC cement for uPVC); use primer where the manufacturer requires it.
- Inspect tools before use: pipe cutter wheels free of cracks, threader dies sharp, wrench jaws clean, hacksaw blade tensioned, and cords undamaged.
- Store pipe on supports, capped, out of sunlight where the material is UV-sensitive, and away from solvents and flame.
- Use dielectric unions between copper and galvanized steel to reduce galvanic corrosion.
- Prepare the pipe: cut square, deburr, clean, and dry the joint surface before applying cement or sealant.
Worked example
A repair connects a copper tube to an existing GI line. The candidate selects a brass dielectric union rather than a direct threaded connection. The reasoning: copper and zinc-coated steel in the presence of water form a galvanic couple; the copper side becomes cathodic and the steel corrodes. The dielectric union breaks the electrical path. The candidate also checks that the union rating and thread type match the line.
Traps
Using PVC cement on ABS or PPR, overtightening plastic male threads, using a pipe wrench on plastic, mixing metal types without isolation, and installing a damaged O-ring all cost marks because they cause early failure.