-SQA-SCOTTISH QUALIFICATIONS AUTHORITY. Hanover House 24 Douglas Street GLASGOW G2 7NG NATIONAL CERTIFICATE MODULE DESCRIPTOR

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1 -SQA-SCOTTISH QUALIFICATIONS AUTHORITY Hanover House 24 Douglas Street GLASGOW G2 7NG NATIONAL CERTIFICATE MODULE DESCRIPTOR -Module Number Session Superclass- TH -Title- NON DOMESTIC GAS UTILISATION (x 1 1 / 2 ) -DESCRIPTION- Type and Purpose A specialist module to give technician level students on courses specifically related to or allied with the natural gas an understanding of industrial and commercial gas appliances and processes. Preferred Entry Level Domestic Gas Appliances or Gas Fired Central Heating Learning Outcomes The student should: 1. know the types and operating principles of non-domestic gas meters and the methods of installing and exchanging them; 2. know the construction and operation of industrial gas appliances and the application of processes; 3. know the construction, operation and application of commercial gas appliances; 4. know the method of operation and application of controls, flames and burners, flame protection and ignition used in industrial and commercial appliances; 5. know the ventilation and flue requirements for industrial and commercial appliances. 6. know the operational costs and utilisation of gas and alternative fuels when applied to commercial heating schemes and industrial processes.

2 Content/ Corresponding to Learning Outcomes 1-6: Context 1. the principles of operation, location, installation and exchanging of positive and inferential non-domestic meters: positive - eg. diaphragm operated; rotary displacement; inferential - orifice plate; venturi; pitot tube; turbine meter. 2. the construction and operation of furnaces, ovens and working flames. heat treatment processes and furnace atmospheres; 3. the construction operation and application of catering, radiant heating and large scale central heating boiler and warm air units. 4. the operating principles of controls for industrial appliances and burner systems; combustion control and gas flames; the types of industrial burner; electronic flame protection and ignition systems; 5. mechanical extraction and high dilution flue systems. Flue gas analysis, excess air and ventilation requirements. 6. Comparative operational costs for different fuels when applied to industrial and commercial processes; the relative advantages and disadvantages of gas and other fuels for industrial and commercial uses. Suggested Learning and Teaching Approaches Extensive use of gas equipment is essential to this module. Where appropriate student participation in the demonstration of equipment under supervision is highly desirable. Where possible site visits may be arranged to reinforce the learning content. Project work may be included. Learning outcomes 1-5 may be monitored by tutorials in student centred learning. -2 -

3 Assessment Procedures Acceptable performance in the module will be satisfactory achievement of the performance criteria for each learning outcome. Where cutting scores are stated these are intended to be for guidance. The precise cutting score for a test will depend on the difficulty of the test and will have to be decided by the Tutor aided by the Assessor. The following abbreviations are used below: LO Learning Outcome Instrument of Assessment Performance Criteria Where the instrument of assessment is a calculation and the student does not solve it correctly, credit should be given for an appreciation of the correct method of calculation and for any correct sections of the calculation. LO1 7 written short answer questions and 5 incomplete sketches: 2 questions and incomplete sketches on positive non domestic gas meters; 2 questions and incomplete sketches on inferential gas meters; 1 question and an incomplete sketch on the location and housing of a gas meter; 1 question on the procedures for installation or exchange of non-domestic gas meters. The will be based on accuracy of descriptions and sketching. Detail of construction and operation of diaphragm and rotary positive displacement meters. The incomplete sketch should include the outline of the meter. Answer requires the student to explain: diaphragm meter - operation of diaphragm linked to gas valves; rotary meter - rotation of impeller or vanes. -3 -

4 Detail of construction and operation of 2 from the following: orifice, venturi, pitot and turbine meter. The student lists 5 factors to be taken into account when deciding on meter location and sketches a meter housing to include ventilation, method of construction and accommodation of pipes; Student knows all correct procedures for installing or exchanging a meter with a bypass. LO2 7 written short answer questions and 4 incomplete sketches: 2 written questions and incomplete sketches on furnaces; 2 written questions and incomplete sketches on ovens; 1 question on the applications of working flames; 2 questions on heat treatment processes. The performance criteria will be based on the comprehensiveness of the descriptive answers and the accuracy of the sketches. While the sketches require to be accurate they should be seen as outline drawings and not detailed engineering drawings. from the range of furnaces - batch, car bottom, muffle and crucible furnace the student should correctly describe the general construction features and application with specific reference to relating the furnace design to its application. The sketch should indicate: (iii) (iv) general shape; burner location; refractory brickwork; flue arrangement. from the range simple box oven, forced convection oven, radiant panel oven the student should accurately describe the general construction features and application of the ovens with specific reference to: general design features; burner location; -4 -

5 (iii) (iv) flue arrangement; method of moving articles through conveyer type ovens. knowledge of what the term working flame means. Application of hand held torches and automatic mechanical machines incorporating working flames for high quantity production e.g. manufacture of electric light bulbs. knowledge of the terms: heat treatment annealing hardening, tempering, case hardening processes. furnace atmospheres - oxidising neutral, reducing and carbonising. LO3 8 written short answer questions and 2 sketches. The student is allowed to use reference materials such as the British Gas book 'A Student Guide to Catering Equipment'. 4 questions are on catering equipment. 2 questions and two sketches are on two commercial heating systems. 1 question in which the student, given a sketch of a large scale boiler, is required to describe the general operation of the boiler. 1 question in which the student, given a sketch of a large scale warm air unit, is required to describe the general operation of the unit. From the range of appliances: cooking range - open and solid top, boiling table, stockpot stand, hot cupboard, bains marie, boiling pan, steaming oven, grill and fryer, the student should state the applications and know the general construction detail. Information could be extracted from the reference source. From the range of industrial and commercial heating systems including incandescent radiant panel, radiant pipe and vacuum pump and forced convection air heater, the student should state the application and know the advantages and disadvantages of the various types. -5 -

6 Know the application and general operation of large scale central heating boiler. Controls used including overheat thermostat and the use of 'packaged' burner systems. Know the application and general operation of a large scale warm air unit including floor mounted and suspended overhead heaters. LO4 11 written short answer questions and incomplete sketches. 2 written questions and incomplete sketches on controls for industrial appliances; 1 written question which includes an incomplete sketch on combustion control; 4 written questions each of which includes incomplete sketches - 2 of the 4 questions will be on industrial burners and 2 on flame stabilisation techniques; 4 written short answer questions which include incomplete sketches of which 2 of the 4 questions will be on electronic flame protection systems and 2 of the 4 questions will be on electrically operated ignition systems; The performance criteria will be based on the comprehensiveness of the descriptive answer, accuracy of sketches and where appropriate the accuracy of calculation. From the range of controls - zero governor, safety shut off valve, injector, non return valve; for 2 of the controls, describe the main operating principles and complete the sketch to show the component parts. Description and sketch of the control arrangement for either an air blast burner or a nozzle mix burner. Description and sketch of two from the following burners: (iii) (iv) nozzle mix; air blast; immersion tube; package. -6 -

7 Description and sketch of two from the following flame stabilisation techniques: (iii) low velocity auxiliary flame; bluff body; hot gas recirculation. Description and incomplete sketches f the following electronic flame protection systems: photosensitive; flame rectification. Description and sketch of two from the following ignition systems: high voltage transformer system; electrical spark generation. LO5 Two written short answer questions, one of which includes an incomplete sketch and one calculations question. 1 question on testing of products of combustion and analysis of results; 1 question which includes an incomplete sketch, on mechanically assisted flue systems; 1 calculation on excess air during the combustion process, given a flue gas analysis. Description of the method of testing products of combustion from a gas appliance. This answer involves knowledge of flue testing apparatus such as the Draegar flue gas analyser or other types of apparatus e.g. Fyrite. The student must be able to analyse the results obtained to specify information about the combustion processes in the appliance. For either: mechanical extraction; or -7 -

8 high dilution flue systems the student must provide a correct description of the system and complete a sketch of the system. From a given flue gas analysis the volume and percentage of excess air present during the combustion process must be calculated. LO6 3 written short answer questions and four calculations of which: 2 calculations will be on the operational costs of industrial processes; 2 calculations will be on the operational cost of large central heating systems. 2 written questions on the advantages and disadvantages of various fuels in respect of each other for energy consuming tasks. 1 question on energy conservation. The student's answer should indicate accuracy of calculation and correct method of arriving of the answer. Specification of industrial processes, calorific value of fuels, thermal efficiency of process, quantity of fuel consumed per annum, tariff price of the competing fuels to calculate operational costs and permit compressions to be made, or to calculate from a given set of costs what would be the effect on the energy costs in the factory if gas was used for a process already being done by another fuel. Operational costs of large scale central heating boilers and warm air units using different fuels. Calculation should be based on annual hours of use, calorific value of fuels, tariffs and thermal efficiency of application. Advantages and disadvantages of various fuels for specified tasks. In addition some indication of energy conservation and long term security of supply of the fuel may be indicated. -8 -

9 Selection of one option, from a list of four, giving the greatest fuel saving over a given period for a given situation. 02/12/98 Copyright SQA