Materials and Safety Practices
Scope
This domain tests material selection and safe work habits: recognising pipes and fittings, knowing which material suits potable water, hot water, drainage or buried service, and applying PPE and safe procedures.
Core rules
- Potable water: use marked potable-water pipe such as UPVC, CPVC or HDPE with lead-free fittings; never cross-connect with non-potable lines.
- Hot water: CPVC, PPR or copper; ordinary PVC softens and is not for hot lines.
- Buried drainage: UPVC, CI or HDPE as specified; GI is corrosion-prone in aggressive soil.
- Store cement, solvent and pipes off the ground, shaded, with caps; keep solvent away from flame.
- PPE: helmet, safety shoes, gloves, goggles and dust mask; use harness and shoring in deep trenches; gas-test and ventilate confined spaces.
- Isolate, drain, lock/tag and verify before opening a line; never trust a closed valve.
Worked example
A 60 °C hot-water branch is specified for a bathroom. PVC is rejected because its service temperature is too low; CPVC or PPR is selected with matching solvent or heat-fused joints. The line is insulated to reduce heat loss and protect users. Reason: material temperature rating, joint compatibility and safety matter more than price alone.
Traps
Using drainage pipe for drinking water; solvent cement near an open flame; entering a septic tank without breathing apparatus; no lockout; mixing fittings from incompatible systems.