United States
Hong KongMechanical and Plumbing Systems
Six of 115 scored questions covering plumbing rough-in and venting, water supply and backflow prevention, HVAC and ventilation, and fire protection and sprinkler systems.
Six questions across four trades. Broad and shallow, which is exactly how a general contractor meets these systems in practice.
The four subtopics
- Plumbing rough-in, drainage and venting
- Water supply, backflow prevention and testing
- HVAC equipment, ductwork and ventilation
- Fire protection and sprinkler systems
What a general contractor is expected to know
Enough to coordinate, inspect and accept the work. Not enough to design it.
Questions reflect that. They ask about slope, testing, clearances and coordination rather than about sizing a system.
| Item | Figure |
|---|---|
| Common minimum drain slope | A quarter inch per foot on small diameter pipe |
| Common test pressure | 10 feet of water head on drain, waste and vent |
| Backflow protection | Required where a cross connection exists |
| Air gap | The physical separation between outlet and flood rim |
A cross connection is any point where potable water could be contaminated by non-potable water. A backflow preventer stops it, and an air gap is the simplest form of protection because it is physical rather than mechanical.
Sprinklers
Designed and installed to NFPA standards referenced by the building code. A general contractor coordinates rather than designs.
Questions tend to concern coordination: clearances, penetrations through rated assemblies, and who is responsible for what.
Where the answers live
Split between the building code and the mechanical and plumbing references on the approved list. Six questions does not justify heavy tabbing, but knowing which book to open does.
Common questions
How many mechanical and plumbing questions are there?
6 of the 115 scored questions.
What level of knowledge is expected?
Enough to coordinate, inspect and accept the work rather than to design it.
What is a cross connection?
Any point where potable water could be contaminated by non-potable water. A backflow preventer or air gap protects against it.
What is an air gap?
The physical separation between a supply outlet and the flood rim of a fixture, which protects by geometry rather than mechanically.
How much should I tab for this category?
Lightly. Six questions does not justify heavy tabbing, but know which book answers it.