Safety, Materials, and Special Plumbing Systems
Material Standards and Joining
Material questions test which pipe and fittings are permitted for each service and how they must be joined. Know that potable water materials must be listed for potable use, that dissimilar metals need dielectric protection, and that solvent cement and primer must match the pipe material. Traps include using drainage fittings on a pressure system or mixing materials without approved transition fittings.
Safety Practices
Safety questions cover trenching and excavation, confined spaces, and protection of the potable supply during repairs. Know that trenches need sloping or shoring, that confined spaces require atmospheric testing, and that hot work requires permits and fire watch where applicable.
Special Systems
Special plumbing systems include medical gas, laboratory waste, grease interceptors, and rainwater harvesting. Know that medical gas piping requires specialized brazing, verification, and installer certification, and that grease interceptors must be sized by fixture load and maintained. Traps include applying standard drainage rules to acid waste without corrosion-resistant materials.
Worked Example
A laboratory sink discharges corrosive waste. The correct answer uses corrosion-resistant piping and neutralization, not standard PVC drainage, because the waste stream attacks ordinary materials.