Journeyman Plumber ExamDrainage, Waste, and Venting (DWV) SystemsMedium
A plumber is designing a DWV system for a new medical laboratory. The lab will generate corrosive chemical waste from various sinks. Which of the following materials is most suitable for the drainage piping carrying this waste?
- AAcid-resistant borosilicate glass
- BCast Iron
- CCopper
- DPVC (Polyvinyl Chloride)
Show answer & explanationAnswer & explanation
Correct answer: A. Acid-resistant borosilicate glass
For highly corrosive chemical waste, acid-resistant borosilicate glass or specially formulated high-silicon cast iron are typically the most suitable materials due to their superior chemical resistance. PVC has limited chemical resistance, and standard cast iron and copper are not appropriate for strong acids.
Why the other options are wrong
- B. Standard cast iron is susceptible to corrosion from acidic waste, leading to premature failure.
- C. Copper is readily corroded by many chemicals, especially acids, and is unsuitable for chemical waste drainage.
- D. PVC has good general chemical resistance but can be degraded by strong acids, solvents, and high temperatures commonly found in labs.
Chemical Waste Piping Materials
Specialized materials used for drainage systems that transport corrosive or hazardous chemical waste, requiring high resistance to chemical attack and temperature.
- Borosilicate glass for strong acids/solvents.
- High-silicon cast iron for chemical resistance.
- Polypropylene (PP) or PVDF for specific chemicals.
Memory trick: Lab waste needs glass, not just any class.