Scheduled and Unscheduled Maintenance of Air Conditioners - Public Works

Returnable Documents:

for the Priced rates for servicing, repairs and maintenance on Air Conditioning and Ventilation Installations At VARIOUS INSTITUTIONS SITUATED IN NELSPRUIT REGIONAL OFFICE Contract Period: 24 months NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification PART 1 SCOPE OF CONTRACT NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification PART 1 1. SCOPE OF CONTRACT 1.1 This contract calls for the price rates for the servicing, repairs, maintenance of the Air conditioning and ventilation Installations at Various Institutions in accordance with the requirements as laid down in the specifications. It, furthermore, entails the servicing, maintenance and repair of said installations, in accordance with the requirements of the Department of Public Works and Infrastructure (DPWI). It furthermore requires that all the machinery covered in this specification initially be repaired and brought to an acceptable working condition. 1.2 The systems/equipment covered by this tender/contract are the following: • Fan Coil Units. • Heating and cooling coils. • Chiller Plants. • Cooling tower units. • Extraction fan units. • Air Conditioning control units. • Window units. • Split air conditioning units. • Cassette units, consoles etc. • Maintenance inside plant rooms (for air conditioning equipment). • All air filters banks in the system. • Diffusers right through the installations. • Air compressors and air dryers where applicable (Air controls purpose). • Chemical dosing systems used at cooling towers. • Condensers and chilled water pumps. • Chilled water and condenser water reticulation. • Building Management System • Yearly test for legionnaires disease on water cooled systems • Adherence to the Safety Regulations • Meetings with Management of DPWI. • Monthly reports to the DPWI. • Supply of al lubricants and cleaning material needed. • Supply of all hand tools and equipment needed for contract. 1.3 COMPETENT PERSON The person appointed as such under the Machinery and Occupational Safety Act no . (Refer to Annexure C) a) The successful Tenderer shall be required to maintain the complete installation and equipment in a proper and safe operating condition, to clean, adjust and lubricate the equipment as required in terms of the Contract, repair or replace all electrical and mechanical parts as necessary due to wear and tear. b) This shall include, but not be limited to the following: NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification i. Examine the system in accordance with any applicable regulation Promulgated under the Occupational Health and Safety Act and any amendment thereof. ii. Properly maintain, adjust and keep the installation and equipment in a safe and proper operating condition at all times, iii. Repair/replace all parts of the installation which may become necessary for the proper use and/or operation of the installation iv. Examine, adjust and lubricate the complete installation, supply of all lubricants, replacement parts and the cleaning of material as required for proper maintenance of the equipment. v. Any malfunction or defect occurring within a period of 60 days after any service or repair being executed will be for the account of the Contractor. vi. Examine, periodically and when necessary, all devices and perform any statutory safety tests at or before the expiring of the required intervals vii. Complete the services, maintenance or repair action report, which shall be submitted with any invoice(s) viii. Cooling water test in accordance with SANS 10147 1.4. CONDITIONS IN AIR CONDITIONING SPACES The contractor will ensure that all the various plants are operating satisfactorily to give the following conditions in the relevant areas. AREAS TEMPERATURE RANGE Courtroom and Chambers 20-26o Office Space 22-28o Server Room 18-22o Hospitals and Medical Storage 20-26o Controls in general may vary not more than 2o Relative humidity in wards 48%p2% Relative humidity in courtroom and chambers 50 to 55%p3% Relative humidity in burns ward Not less than 55% or as otherwise requested by the Medical Superintendent The contractor must undertake maintenance and adjustments, etc., in such a manner as to cause the least inconvenience to clients. Permission to work in any client site must be obtained from the client site manager. 1.5 DESCRIPTION OF PLANTS TO WHICH THIS TENDER / CONTRACT APPLIES The following main items of equipment shall be checked, serviced and repaired as necessary at the intervals as stipulated. Plant consisting of compressors, cooling towers, cooling and heating coil fans and fan motors, filters, ducting and control systems and split and window units and Extraction fans. All material and spares used during these services will be covered on rates as quoted for in this specification on the scheduled spares list where applicable or the % mark-up where applicable. NOTE: ALL WORK IN THIS CONTRACT SHALL BE DONE ACCORDING TO THE STANDARD QUALITY SPECIFICATION FOR AIR CONDITIONING INSTALLATIONS. NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification PART 2 TECHNICAL SPECIFICATIONS NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification PART 2 TECHNICAL SPECIFICATIONS 2.1 SERVICE INTERVALS AND SERVICES Item Monthly Three Six Monthly Yearly Monthly Chillers X X X Diffusers X Centrifugal pumps X X Filter Banks X Hepa Filters X Chilled water pumps X X Belt driven fans X X X Electrical boards X X Cooling and heating coils X X Direct expansion units X X X Window & split units X Cooling towers X X Air Handling units X BMS X 2.2 The successful contractor must visit all sites covered under this contract and obtain the signature of the head of the site in a service book that must be kept for this purpose. 2.3 MONTHLY SERVICES 2.3.1 SCHEDULE A – DIFFUSERS: • Check and clean diffusers and return air louvers • Check condition of Temperature sensors and Humidity sensors. 2.3.2 SCHEDULE B - FILTER BANKS: • All washable filters must be cleaned monthly. • Primary, secondary and tertiary filters must be replaced when the airflow resistance over the filter bank reaches the maximum resistance as prescribed by the manufacturer of the filters. 2.3.3 SCHEDULE C – CHILLERS: • Check oil temperatures • Check for any oil leaks and repair • Check oil level and replenish if needed • Check for any refrigerant leaks and repair • Check refrigerant level and re-fill if required • Check condensing pressure • Test oil pressure cut-out NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification • Test refrigerant low temperature cut-out • Test recycle thermostat • Test control centre • Test flow switches • Test temperature control 2.3.4 SCHEDULE D - CONDENSOR WATER AND CHILLED WATER PUMPS • Check for water leaks • Check all guards and secure bolts • Check fluctuations in pressure and amperage • Check coupling and drivers • Attend to all other aspects For monthly and yearly services see maintenance on specific components 2.3.5 SCHEDULE E - BELT DRIVEN FANS • Check whether belts are tight and in good condition • Check tightness of bolts on guards, motors and bearings • Attend to all other aspects For monthly and yearly services see maintenance on specific components 2.3.6 SCHEDULE F – AIR HANDLING UNITS: • Clean filters if required. • Check belts for proper tension and pulleys for proper adjustment. Rectify as necessary. • Check fan shaft for end play, vibration and bearing wear. • Check coils for cleanliness, and clean accordingly. • Check fan blades for looseness and dirty condition. Rectify as necessary. • Clean and flush condensate pain and its drain lines properly. • Test heating valves, cooling valves and humidity valves for correct operation. • Clean in and outside of the units properly. • All plant rooms shall be properly cleaned after completion of the service. 2.3.7 SCHEDULE G – COOLING TOWERS: • Clean and remove all debris from unit without removing the fill packs. • Clean and flush sump properly. • Inspect spray nozzles, clean and report any damages. • Check condition and tension of v-belts and adjust the tension accordingly. • Lubricate fan shaft bearings. • Lubricate motor base adjusting screw. • Check motors for any loose electrical connections and tighten. • Check speed drives (if applicable) for any loose electrical connections and tighten. Clean speed drives properly with air. NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification • Check operation off speed drives and correct where required. The contractor shall make sure that all sensors where applicable, are in correct position and function properly. 2.4 THREE MONTHLY 2.4.1 SCHEDULE H – SPLIT TYPE AIR CONDITIONING UNITS • Check for undue noises or vibration and repair. • Check remote control / selector switch operation. • Check filter media and clean. • Check and observe operation of reversing solenoid valve and replace where required. • Check compressor termination and overload and repair if required. • Check and lubricate fan motor bearings where applicable. • Check all ‘start’ and / or ‘run’ capacitors and replace if required. • Clean all condensers properly with coil cleaner • Check for refrigerant leaks / restrictions and repair if necessary. Recharge units to the correct working pressure. • Check for any loose electrical connections and tighten. • Check all drain pipes and unblock if necessary. • Check for any water leaks and repair. • Clean all indoor and outdoor units properly. • Replace batteries on remote controls as required • Report all faults found during the service in writing to the Inspector handling the service. 2.5 SIX MONTHLY SERVICES: 2.5.1 SCHEDULE I - HEPA FILTERS: Every six months penetration test using hot emery 3004 and the correct testing equipment i.e., • TDA-ZA Particle detection apparatus and TDA-56 • Hot aerosol generator must be carried out on all Hepa Filter installations and test certificates must be issued to the Department. NB: ONLY FILTERS APPROVED BY DPWI REPRESENTIVE MAY BE USED 2.5.2 SCHEDULE J – CHILLERS: • Check oil temperatures • Check for any oil leaks and repair • Check oil level and replenish if needed • Check for any refrigerant leaks and repair • Check refrigerant level and re-fill if required • Check condensing pressure • Test oil pressure cut-out • Test refrigerant low temperature cut-out • Test recycle thermostat • Test control centre • Test flow switches NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification • Test temperature control • Change compressor oil (new oil) • Change oil filter • Change refrigerant filter • Clean condenser tubes (Chemical wash) • Renew filter dryers • Conduct meg-ohm stator winding test of compressor motors • Check motor and starter plugs and tighten as required. 2.5.3 SCHEDULE K - ELECTRICAL DISTRIBUTION BOARDS SUPPLY TO AIR CONDITIONING INSTALLATIONS THROUGHOUT THE INSTITUTION • Vacuum inside of boards thoroughly • Ensure that all indicator lights are working • Clean outside of panel • Check all bus-bar connections and ensure they are tight • Ensure that all connections to contacts are tight • Attend to all other aspects 2.5.4 SCHEDULE L – CHILLED WATER AND CONDENSING WATER LINES • Visually inspect all chilled water lines and lagging for any defects and report to Department • Visually inspect all condensing water lines for any defects and report to Department • Clean all strainers on chilled water and condensing water lines 2.6 YEARLY SERVICES: 2.6.1 SCHEDULE M - COOLING TOWERS • Remove side panels of cooling towers, remove fill packs and clean properly with chemicals and high pressure water. Re-install fill packs in position. Re-install side panels of cooling towers and make sure no water leaks are present. The contractor must allow for sealant on the panels. • Clean and flush sump properly. • Inspect spray nozzles, clean properly and report any damages. • Replace v-belts on cooling towers and adjust the tension accordingly. • Lubricate fan shaft bearings. • Lubricate motor base adjusting screw. • Check motors for any loose electrical connections and tighten. • Check speed drives for any loose electrical connections and tighten. Clean speed drives properly with air. • Check operation off speed drives and correct where required. The contractor shall make sure that all sensors where applicable, are in correct position and function properly. • All units shall be in good working condition after completion of the services. • The site shall be cleaned after completion of the service. NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification 2.7 MAINTENANCE ON SPECIFIC COMPONENTS Maintenance on components listed below shall be carried out as follows: 2.7.1 ROLLER BEARINGS a) Check for any excessive bearing vibration, noise and temperature. The normal operating temperature of a ball/roller bearing is between 40oC to 60oC in an ambient temperature of approximately 20oC. b) Should excessive vibration be present, check for external factor which may be the cause of the vibration such as the misalignment or out of balance rotating parts and condition of mountings. Defective bearings shall be replaced. c) Should excessive noise be present the bearing shall be removed, washed out in clean spirit and checked for damage. Undamaged bearings shall be re-packed with grease and re-fitted. Damaged bearings shall be replaced. d) Should bearings run at excessive temperatures, check for over greasing, incorrect assembly, misalignment, excessive belt pull, excessive end thrust and position of bearing on shaft. Excessive loads on the bearing shall be reduced. e) Bearing housings fitted with grease nipples shall be greased. f) Plummer block housings with no provision for lubrication shall be greased by removal of the housing cap. Alternatively the housing shall be drilled and tapped to take a grease nipple. NOTE Unless bearing failure is expected, bearings shall not be removed for detail inspections during normal inspection services. Bearings in difficult accessible positions within enclosed assemblies such as gearboxes shall not be inspected individually unless the assembly is stripped for scheduled maintenance or repairs. 2.7.2 SLEEVE BEARINGS a) Check for excessive bearing vibration, noise and play b) Lubricate bearing. If oil wells are fitted check oil level and top up 2.7.3 ELECTRIC MOTORS a) Carry out the required inspections on bearings. b) Ensure that motor is not overheating. The maximum permitted temperature for class B insulation is 120oC and for class F insulation 140oC as measured by increase in stator winding resistance. NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification c) Compare measured full load current with nameplate value when supplied at rated volts and frequency d) Check that terminal connections are clean and tight and that motor is soundly earthed. Ensure that the plastic terminal base is clean and undamaged. e) Examine motor for corrosion and mechanical damage f) Ensure free unobstructed ventilation. Examine cooler tubes if the motor is of the closed air circuit air (CACA) type. g) Check that motor is free from dirt, oil, chemical or any contaminant that can be detrimental to the satisfactory operation. h) Remove drain plugs and re-fit after draining any condensate. i) For slip ring motors, in addition to the above: i) open slip ring inspection cover and check absence of sparking between brush and slip ring when the motor is operating on full load ii) with the motor isolated from the supply, ensure that the slip rings are not worn, grooved or pitted in any way iii) examine the brushes for wear, grooving or pitting etc., and for freedom of movement in their holders iv) unless the motor is fitted with constant pressure type brushes, check brush pressures using a spring balance. The pressure should be in the order of 750kPa. v) Ensure that the slip rings, brush holders and their enclosure is clean and free from any accumulation of carbon dust 2.7.4 GEARBOXES (including geared motors) a) Check for any excessive vibration, noise and temperature b) Check for possible overloads or excessive shock loads on gearbox c) Check oil level and ensure that housing is accurately filled with lubricant to the specified level d) Grease oil seals on units equipped with grease nipples e) Check for blockages in breather lines. Clean breather in a solvent. f) Check grade of oil and oil condition. Oxidized, dirty or oil with a high sludge content shall be drained and replaced with the correct grade as specified by the manufacturer. Clean oil filter. g) On forced feed systems ensure that oil pump is functioning. Check that oil passages are clear and permit free flow of lubricant. Inspect oil-line pressure regulators, nozzles and filters to be sure they are free of obstructions. Ensure that pump is not sucking air. h) Check for oil leaks: i) Replace worn oil seals. Check condition of shaft under seal and polish if necessary ii) Adjust or replace stuffing box packing. Tighten packing gradually to break in. Check condition of shaft and polish if necessary NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification iii) Reduce excessive flow of force-feed lubricant to bearing by adjusting orifices and/or iv) Tighten cap screws or bolts. If not entire effective, remove housing cover and caps, clean mating surfaces and apply new sealing compound and re-assemble i) Check for excessive play between drive and driven shafts j) Clean gearbox externally k) Check housing for signs of mechanical failure NOTE Should it be necessary to remove the housing cover in order to repair an oil leak, the complete gearbox shall thoroughly inspected as required for the scheduled maintenance. 2.7.5 PUMPS The following pumps shall be included where applicable: a) Condenser water pumps b) Chilled water pumps MAINTENANCE REQUIREMENTS a) Check pumps for leaks b) Check bearing temperatures c) Check pump for excessive noise and vibration d) Check and adjust glands as necessary to maintain slight leakage e) Check oil level and top up if required f) Check pump coupling pins and bushes for wear g) Clean pump suction strainers h) Check condition of flexible suction and delivery connections i) Clean pump and pump base 2.8 ANNUAL SERVICE CHECK LIST 2.8.1 ROLLER BEARINGS Wash out old grease with white spirit and examine bearing and bearing housing. Replace rough bearings. Re-grease sound bearings with the manufacturer’s recommended lubricant. NOTE Re-lubrication of small bearings, particularly deep groove ball bearings, fitted with shields or seals are not required. These bearings shall however be thoroughly examined during the scheduled maintenance service. 2.8.2 SLEEVE BEARINGS NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification Replace oil in oil wells and/or sumps 2.8.3 ELECTRIC MOTORS (Fractional kW motors excluded) a) Strip the motor down completely, removing rotor from stator b) Blow out the stator, rotor, terminal box and fan cowl with an air jet to remove any internal dust etc. If contaminated with oil or grease, etc., wash with a recommended detergent. c) Carry out the required maintenance on bearings as specified in paragraphs 1 and 2 d) Measure winding insulating resistance using a 500 volt merger. If the reading is low, or if there is evidence of damp present (corrosion, etc.,) then consideration should be given to fitting motor heaters or at least, to giving the winding a double impregnation and baking. e) If oil seals are fitted, these shall be replaced, taking extreme care not to damage the lip of the seal when fitting. f) Re-assemble and ensure free rotation of the shaft. g) For slip ring motors, in addition to the above: i) If the slip rings are grooved or pitted etc., skim the rings in a lathe, true to the bearing seating on the shaft. Finish with a polished surface; ii) If the brushes are little worn and in a good condition, simply ensure freedom of movement in their holders and replace the brushes in exactly the same position from which they were removed iii) If new brushes are necessary, these shall be fitted such that they move freely in their holders and are bedded in after the motor has been re-assembled iv) Adjust the brush pressures to approximately 750kPa using a spring balance. v) Log details of inspections, replacements and repairs as well as parts recommended for replacement 2.8.4 GEARBOXES (including geared motors) a) Remove housing cover and caps b) Carry out the required inspections on bearings as specified in paragraphs 1 and 2 c) Check for misalignment of gears. The contact pattern on teeth must be over approximately 75% of face, preferably in the centre area. d) Check condition of teeth e) Check backlash and adjust to the manufacturers requirements f) Check that all shafts spin freely when disconnected NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification g) Disconnect couplings and check alignment. Re-align as required. h) Check lateral float on coupling. Adjust spacing between drive motor to eliminate end pressure on shaft or arrange for the replacement of the flexible coupling with a type allowing the required lateral float. i) Re-assemble gearbox and re-connect couplings j) Drain oil and replace with the correct grade oil as recommended by the gear manufacturer. k) Log details of inspections, replacements and repairs as well as parts recommended for replacement. 2.8.5 PUMPS a) Strip pump completely b) Check condition of impeller(s) or diaphragm c) Carry out the required inspections on bearings as listed in paragraphs 1 and 2 d) Examine gland and renew packing if required e) Examine condition of mechanical seals f) Check coupling alignment g) Re-assemble pump and ensure that mating surfaces are cleaned properly and provided with a durable sealing compound h) Replace lubricant with a grade as recommended by the pump manufacturer. i) Log details of inspections, replacements and repairs as well as parts recommended for replacement. 2.9 COOLING AND HEATING COILS Monthly schedule • Check for leaks and general conditions • Check door gaskets Six monthly schedule • Clean coil with appropriate solution and high pressure water • Remove all rusts and treat 2.10 CONTRACTOR’S / INSPECTORS MONTHLY REPORT A random inspection/s will be performed by a representative of the Department of Public Works and Infrastructure at which the contractor must be present. NDPWI Nelspruit Regional Office HVAC Systems - Technical Specification

No specific requirements found