Plumbing Tools, Materials and Pipe Fittings
What is tested
Questions ask you to identify hand tools, select pipe material for a service, recognise fitting symbols and match nominal sizes. You should know the difference between nominal bore (NB), outside diameter (OD) and wall thickness, and why the same NB can have different OD in different materials.
Tools and materials
- Cutting: hacksaw with 18–24 TPI blade for GI/CI; wheel cutter for copper; plastic cutter or fine saw for PVC/CPVC.
- Holding: pipe vice, chain vice, bench vice; use jaw inserts to avoid crushing plastic.
- Threading: stocks and dies, reamer, cutting oil; BSP taper dies for GI.
- Measuring: steel tape, try square, spirit level, plumb bob.
- Common materials: GI steel for supply, PVC for soil/waste, CPVC for hot water, copper for hot/cold, PPR for hot-water distribution, CI for heavy drainage.
- Fittings: elbow, tee, reducer, coupling, union, nipple, bushing, cap, plug, bend, valve.
Worked example
A hot-water line at 60 °C and 3 bar is required inside a house. PVC is unsuitable because it softens at hot-water temperature. CPVC or PPR is selected for the rated temperature and pressure; solvent-cement CPVC needs the correct primer and cement, while PPR needs heat fusion. The fitting must match the pipe standard, not just the nominal size.
Traps
Do not join GI to copper without an insulating union; galvanic corrosion follows. Do not use drainage PVC for hot water. Do not judge pipe size by external diameter alone. Do not use a worn die or a pipe wrench as a hammer.