Plumbing & Pipe Fitting 2 May/June 2014

Plumbing & Pipe Fitting Paper 2, May/June 2014

Questions:		1	2	3	4		Main

General Comments
Weakness/Remedies
Strength

Question 4
(4) (a) Sketch each of the following hand tools: (i) pipe wrench; (ii) hacksaw. (b) State two methods of maintaining hand tools. (c) List four types of pipe used in plumbing work. This question did not pose any problem to the candidates who attempted it. (5) (a) Describe each of the following terms used in welding operation: (i) backfire; (ii) sustained backfire; (iii) fusion welding (b) State two safety precautions to be observed in a plumbing workshop. (c) Sketch the symbol used to represent each of the following safety instructions: wear eye protection; do not extinguish with water.
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Observation
Candidates who attempted this question performed excellently well in parts (b) and (c) of the question. However, part (a) was extremely difficult for them. The required response to part (a) of the question is given below: (a) (i) The retrogression of the flame into the blowpipe neck or body with rapid extinction. The gas ignite right back in the blowpipe and loud squaking noise is emitted. The blowpipe will turn red hot and if not turn off immediately will melt. In fusion welding a filler rod of the same material is melted in the joint zone during the process to complete the joint.