TRAINING TASK 1- for regional heat skill competition General Information Standards Complete the task within 2 hrs. The standard of work required to gain maximum marks are: it yourself or ask a fellow student or tutor to mark it with you The measurements should be within +/- 2mm of the specifications. present using the marking scheme provided The bends should be 90 o within +/- 1 of the specifications. The flame brazed joints should be full, and have no drips. The test is carried out in refrigeration quality copper and associated materials, and is designed to test the following skills Interpreting detailed drawings including pipe dimensions. Measuring, fitting and use of materials in an efficient way. ing out, cutting/flaring of copper tube to dimensions Bending copper tube using standard machine tooling Safe Working Jointing of copper fittings by flame brazing (oxygen and acetylene & mapp gas) methods Safe and correct use of Pressure testing equipment. All flame brazed joints should have capillary penetration at least 80%. All copper flares should be made to sit within the flare nut, not snag on the nut thread and have no burrs or splits at the end of the flared pipe. Cut & inspection the 7/8 end cap fitting after pressure test is completed. Pressure test duration time is 10 minutes, submerged fully in container of water. Candidates must work safely at all times and take the appropriate precautions when working with any tools that have a potential safety hazard. Carry out a risk assessment prior to commencing work. Calculate and perform pressure tests considering the part of system the fitting will be used. Evacuation procedures Pressure switch settings for different control applications Infrastructure Guide Workshop with benches and vices, Nitrogen cylinder Nitrogen pressure test regulator and hose set, Service manifold gauges and ¼ hoses Mapp gas torches and/or oxygen and acetylene brazing tool set as required. Battery powered drill 6mm high speed steel drill bit Required Materials 130mm x 7/8 copper tube, 250mm x 3/8 copper tube, 150mm x ¼ copper tube, 1 x ¼ Flare nut, 1 x ¼ male flare to female socket, 1 x 7/8 to 3/8 reducing socket, 1 x 3/8 to 1/4 reducing socket, 1 x 7/8 cap end, 1 stick Silver Solder rod, 1 stick Cupro or similar brazing rod, flux powder. Mapp gas and/or oxygen acetylene brazing gases
Detailed Pipe Work and Brazing Training task Nitrogen test rig set up at point K, establish test pressure by fitting test gauge at point E,
ing Schedule Measurement Criterion (+/- 2mm) Brazing Criterion (full, no drips or peaks) Are the bends at 90 Both = One = 0.5 7/8 copper end cap Tube length A to B 160mm 2mm to 4mm = 0.5 ¼ pipe into 7/8 tube Tube length C to D 100mm 2mm to 4mm = 0.5 Reducer to 7/8 tube at C Tube length D to E 38mm 2mm to 4mm = 0.5 Reducer to 3/8 tube at B Tube length F to G 75mm 2mm to 4mm = 0.5 3/8 pipe to reducer at I Tube length H to I 40mm 2mm to 4mm = 0.5 Reducer to ¼ tube at L Tube length B to H 75mm 2mm to 4mm = 0.5 ¼ pipe to brass fitting Tube length K to J 75mm 2mm to 4mm = 0.5 0.5 Correct solder rods used ¼ pipe depth into 7/8 tube >2mm = 0.5 All joints cleaned of flux ¼ Flare has no burrs or splits errors = 0 0.5 ¼ Flare fits within nut Tight = 0 7/8 end cap depth of braze penetration Always used nitrogen during brazing < 80% = 0 Total marks (max 11) Total marks (10) Tools & Materials Criterion Safety Criterion
Correct use of bending tool Use of safety glasses for working Correct set up and use of pressure test equipment to 1500kPa Use of the correct safety clothing when brazing? Less than 5% pressure drop when pressure tested to 1500kPa for 10 minutes 5-10% pd= 0.5 Greater pd = 0 Did the competitor always use safe work practices? 2.0 Efficient use of materials Additional materials required = 0.5 Work area clean and tidy? Total marks (5) Total marks (4) Criterion Score Actual Score Measurement 11 Brazing 10 Tools & Materials 5 Safety 4 Final Total 30 College / Training Provider: Competitors Name: Assessors Name & Signature:
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