Majority of the candidates were able to:
- state the principles of a drainage scheme;
- list the waste appliances used in plumbing.
However, they failed to explain terms relating to concrete works. The expected response to question 4 is as given below:
(a) Principles of a drainage scheme are:
- Inspection chamber should be constructed at change of direction or gradient to facilitate cleaning and inspection.
- Pipes should be laid in straight lines between chambers.
- The pipe should be non-absorbent, smooth in bore, durable and of adequate strength.
- The pipe should be well ventilated to prevent accumulation of foul gases.
- Traps must have adequate water seal.
- Drains should be water tight and air tight.
- The drainage system should be accessible for cleaning and inspection.
- Branches should be connected to the main line in an inspection chamber.
- The three types of waste appliances used in plumbing system are
- wash hand basin
- bath
- kitchen sink
- bidet
- shower tray
- belfast sink.
- Explanation of terms in concrete works:
- Batching is the process of measuring the quantities of each of the materials in a concrete mix.
- Compaction is the process of tamping or vibrating fresh concrete to obtain a dense mass.
Curing is the method of keeping a newly placed concrete moist until it gains sufficient strength. 
