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Candidate’s Name: _ a to a 5 ey Nis Ss ae ore ef st, 1305314 Candidate's Signature:, PLUMBING CRAFT THEORY, , June/July 2015 ORCS ee a on eae, Time: 3 hours, , THE KENYA NATIONAL EXAMINATIONS COUNCIL,, PLUMBING CRAFT CERTIFICATE, PLUMBING CRAFT THEORY, , 3 hours, , INSTRUCTIONS TO CANDIDATES ee, , Write vour name and index number in the Spaces pirovided above., , Sign anc write the date of examination in the Spaces provided above., , You should have drawing instruments and Mathematical tables(catculator for this examination., Answer any FIVE of the following EIGHT questions in the spaces provided in this question paper, ALL questions carry equal marks, , Maximum marks for each part of a question are as shown, , Do NOT remove any pages from this booklet., , Candidates should answer the questions in English,, , , , , , For Examiner’s Use Only, Question 1 2 3 4 $ 6 K 8 TOTAL, SCORE, Candidate's, Score, , , , , , , , , , , , , , , , , , , , , , , , , , This paper consists of 16 printed pages., , Candidates should check the question paper to ascertain that all, the pages are printed as indicated and that no questions are missing,, , ©2015 The Kenya Nationet Examinatione Councit, Turn over

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(b), (c), , (b), , {c), , 3. {a), , (b), , {c), , (b), , Explain the safety precautions observed in the plumbing workshop with regards to:, , (i) clothing,, (ii) _injuries;, {iii) behaviour. (6 marks), List four classifications of fire and state the heat source for each. (6 marks), Explain four design considerations for direct cylinder system of hot water supply., (8 marks), Explain three physical properties of metals, (6 marks), Differentiate between the two classes of metals and state two examples in cach, classification. (4 marks), (i) Sketch and label a direct cold water system in a domestic house,, (ii) State three characteristics of a domestic cold water supply system., (10 marks), , (i) Name twe classes of mild steel pipes stating the colour codes and use of each., , (ii) Outline four characteristics of a drainage system., , (9 marks), With the aid of a sketch differentiate between leftward and rightward welding, techniques. (6 marks), With the aid of a sketch explain the operation of an arch welding set. (5 marks), , Sketch and label the connection of a:, , (i) distribution pipe to a water tank; Os Ds, , t= Wa: ==), (ii) outlet from botiom of a cistern. NE or ay, Se eee <6, @ Explain the phenomenon of buck siphonage;, (ii) Outline four strategies of preventing back siphonage., (8 marks)

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5. (a), , ; (b), , (e), , 6. (a), , ” (b), , {c), , (b), , Watcr is discharged at the rate of 700 litres per hour. Using the data provided in tuble 1,, calculate the diameter of the discharge pipe., , , , , , , , , , , , , , , , , , , , , , , length of pipe 36m, waterbead 200m, frictional losses__ 30%, (6 marks), Calculate the amount of heat lost when 500 litres of drinking water cools from 100°C to, 20°C, Take specific heat capacity of water = 4.18 kJ. (4 marks), State four Kenyx building requirements for sanitary appliances, (4 marks), Sketch and label « single stack drainage system ina two-storey building for common, appliances. (12 marks), Outline four reasons for using felt in copper roofing. (6 marks), Sketch and label a metal weathering flashing. (6 marks), , Estimate the cost of installing sanitary appliances using the data given in table J., , Table 1, , , , SERIAL | DESCRIPTION | QUANTITY, NO., , , , , , , , , , , , , , , , , , , , , , 1. Water closet 2, , 2. Bath tub 1 a, , 3. Wash bind basin [2 <, Take: 5, , (i) labour at 15% of cost of appliance;, {ii) overheads at 5% cost of appliance; Siar, (ili) _ profit at 10% of cost of appliance, Fe, , , , {8 marks), Outline four situations that require the installation of manholes, (6 marks), State five functions of an expansion pipe, {5 marks), , Outline the process of purification of drinking water.

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State four reasons for coating electrodes, (4-marks), , With the aid of a labelled sketch, outline the procedure of repairing a crack., (12 marks), , Calculate the output of a centrifugal which can tift 200 litres of water from, aatlalignt wel 5 tooeox lap ato seconde = (4 marks)