METHOD STATEMENT INFORMATION REQUIRED

Transcription

1 METHOD STATEMENT Prepared for : DSG Retail Ltd Maylands Avenue Hemel Hempstead Hertfordshire HP2 7TG Project details : Split Air Conditioning condenser relocation Site : Dixons Wandsworth Date : 7 th March

2 METHOD STATEMENT INFORMATION REQUIRED 1. PROJECT (a) Client Name and Address DSG Retail Ltd Maylands Avenue Hemel Hempstead Hertfordshire HP2 7TG Tel : (b) Project Details Relocation of 3 condenser units (c) Location Dixons 0437 Wandsworth (d) Contract Personnel One fully trained operative and a semi-skilled hand will be in attendance during the siting of condensers. A lone fully trained operative will complete the necessary hot works and the full commissioning of condensers. (e) Contract Site Supervisor Mr David Prout and Mr Chris Ridler will be responsible for site safety during the contract as outlined in Section 2.0 of our Company Policy Document. 2

3 2 SEQUENCE OF WORKS The maintenance engineers, in attendance must sign into the store, where applicable and make the site Manager, or representative, aware of the works to be undertaken and the areas in which the engineer wishes to work before commencing with any works. The engineer must also be fully aware of the client s fire, health and safety and specific store requirements. As the engineers will be working within unfamiliar buildings he must also make himself aware of the positions of fire alarm call points, fire evacuation assembly points, fire extinguishers or blankets and the nearest fire escape routes. The engineer must also familiarise himself with the emergency isolation points of all main services, electrical, gas and water. (a) Setting to Work The engineer will carry out the following tasks to each refrigerant system. Isolate locally the electrical supply to the unit being worked on for safety reasons using the local isolator. Clear the area around each unit to be worked upon. Ensure that there is a means to extinguish any fire that may occur during the brazing of any components. Take a power supply through an RCD to the system to be decanted. (b) Reclaiming of the Air Conditioning Systems Refrigerant Prior to reclaiming of the system refrigerant the engineer should ensure that all components are available (or should source during the decanting process). These should include. Liquid Line Drier (2 way for heat pumps) Large Reclaim Cylinder. Enough Virgin Refrigerant to fully re-commission the system. Oil, Acid test kit. The Replacement Components. Condenser Coil Cleaning Solution. Evaporator Coil Cleaning Solution. The engineer should record the cylinder Tare weight and the serial number of the reclaim cylinder, and all materials to be used on the Work Record Sheet. 3

4 Check the maximum fill potential of the cylinder (de-rate the maximum fill weight of refrigerant by 25%. Do not exceed the derated maximum weight of refrigerant). Check the refrigerant system for any harmful contaminants. Before connecting the Reclaim unit, also ensuring that lines are purged. Start the reclaim process. Ensure that a vacuum of at least 15 Hg is achieved prior to disconnecting any line components. This will ensure that there is no negligible loss of refrigerant. Whilst the system refrigerant is being reclaimed the evaporator coil should be cleaned. (c) Cleaning of the evaporator coil Isolate the electrical supply to the unit for safety reasons using the local isolator. Remove the system filters. Access the evaporator coil through access panels located adjacent to the evaporator section. Brush all loose debris from coil. Regulate to a low pressure and using a nitrogen cylinder and hose to blow debris lodged between the evaporator coil fins. Apply Hydro-coil evaporator coil cleaning agents diluted as per the container instructions. Rinse thoroughly. Wash the condense tray. Remove the condense drain trap, take to the cleaners sink and wash through, ensuring that no debris remain in the pipe work. Check and clean fan/motor. Check and if necessary replaces the evaporator drive belts. Check all electrical connections for soundness. Clean unit generally. Ensure correct operation of system ventilation dampers. 4

5 Re-energise the electrical supply. (d) Fitting new components Advise the store manager of your intention to carry out Hot Works, and ensure that the relevant fire alarm circuits are disabled. Ensure that the system is completely void of refrigerant. Using a braising torch remove all faulty components. With the assistance of a semi-skilled hand lift the new components into place. Also site the line valves, and driers. Braise all the new components in place, ensuring where relevant the direction of any line components match the flow of refrigerant. Carry out a leak pressure test on all new welds, and the system as a whole. This should be carried out in accordance to BS4434 at approximately 0.95 AP, and should be maintained for a period of no less than 1 hour. Condenser (Outdoor Unit) Removal and relocation of condenser units to lower level using appropriate transportation and lifting machinery. Isolate the electrical supply to the unit for safety reasons using the local isolator. Check condenser coil for cleanliness and purge through with nitrogen. Check and lubricate condenser fan/motor where applicable and clean. Check all electrical connections for soundness. Re-energise the electrical supply. Functional test generally, checking all safety devices (HP/LP cut-out switches), refrigerant pressures. Set up fan speed on head pressure control. Check control settings. Clean out generally. 5

6 (c) Controls Systems and Panels The engineer will carry out the following tasks to the control systems. Isolate the panels where work is to be carried out for safety reasons using the local isolator. Check electrical connections. Check set points. Inspect all fuses for correct size and application. Remove dust and derbies from inside the control panel(s) using a vacuum cleaner. Re-energise the electrical supply. Check operation/calibration of all controllers and time clocks. Check air temperature sensors and re-calibrate if required using hand held digital thermometer. Test relays and contactors for correct operation. Check operation of pumps, flow switches and gas solenoid valve/emergency stop. 3 POTENTIAL HAZARD AND CONTROL MEASURES (a) Hazard Control Measure Accident caused by maintenance operations. Electrical shock. Refrigerant injury. Eye injury. Mouth (inhalation, ingestion) Personal protection equipment issued and worn at all times. Isolate electrical circuits where work is to be carried out. Personal protection equipment issued and worn at all times. Safety Goggles Disposable Facemask 6

7 (b) Foot injury. Head injury. Hand injury. Noise (in excess of 82 db) Cuts and abrasions Specialist Equipment Safety Footwear Safety helmet Standard Riggers Gloves. Ear defenders First aid kit supplied with each vehicle. None Required during this operation. (c) Protection of Personnel Personal protection equipment. (d) Services Electrical power from sales area ring main. (e) Hazardous Materials Refrigerant (R22/R407C) Air borne particulate from the cleaning of filters. High pressure Nitrogen. Hydro-coil evaporator. (f) Access Engineers will use own steps to access cassette units and fascia. Inspect before commencing work. The majority of work to be conducted at ground level. (g) Lifting Tackle Trained operatives using forklift currently present on site will carry out lifting and transportation of units to lower level. (h) Work on Pressure Systems Refrigerant gas circuits. 7

8 Use of Nitrogen to clean coils 4 COST As per contract details. 5 NOTES (I) (II) (III) (IV) (V) (VI) At all times Center / Principal Contractor regulations are to be adhered to at all times. Whilst within the site DSG site regulations to be adhered to at all times. This site is very busy with both traffic and pedestrians. Great care and thought must be given to public safety at all times. The use of barriers and/or cones together with warning signs must be used in the immediate working areas. After liaisons with the Store management it may be possible to restrict public movement in the work areas temporarily. On completion of the works and before leaving the store the engineer will ensure that he signs out of the visitors book. Return all keys to the person who issued them, ask the manager or representative to sign the relevant paper work and make the manager aware of any unfinished work which may need to be attended to. 5 ENDORSEMENT Authorised Signature SHAUN LOCK Date /03/ Position Held SENIOR ENGINEER

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