TESTING AND COMMISSIONING
- Test Equipments for HVAC Testing & Commissioning
- Calibrated Test Hood
- Anemometer
- Pilot Static Traverse
- Electronic Flow Meter for Water Flow Measurement
- Phase Rotation Detector
- Multi-meter
- Duct Work Leakage Testing Apparatus
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Pipe Work Pressure Testing
The pressure will be applied to the complete piping including all connections of valves, fittings, joints, etc. under a minimum pressure of 100 psi or 1.5 times the operating pressure whichever is greater. While pressure testing is carried out all fitting connections of automatic valves, diaphragm valves, relief valves and pumps, heat exchangers, cooling coils of air handling units and fan coil units are to be isolated from pressure testing. This can be done by providing blank off plates, temporary by pass lines. No valves provided in the system to be used for isolation. All valves must be kept in open position.
Remove all automatic air vents if installed in the system. Keep all valves provided near vents in the system in open position. Provide PVC hose with the valves provided in the vent points to avoid water spreading down while air is vented.
Fill the system with water. All the air to be vented through all vents points at all levels. Finally make sure there is no air being vented from the highest vent point. Close the valves at the vent points with dummy caps.
Pressurize the system with pressure pumps to the required level. Observe the whole systems for any leak. Mark the points if there is any leak occurs. Rectify the leaks if and wherever required. Re-pressurize the system after ensuring all the leaks are rectified. Get the system certified by the Engineer in the relevant format. Allow the system to hold the pressure in the system for 24 hours and get certified by the Engineer for completing the pressure testing.
Once the pressure testing is completed drain the system and blow out and clean for all dust and foreign matters.
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Flushing and Cleaning
Before the flushing and cleaning commences ensure all cooling coils, heat exchangers are isolated with blank of plates and by closing the isolating valves. Open the by pass lines manually wherever possible. Fill the system with water and drain once from the lowest drain points to allow dust and solid particle to be removed. Refill the system again. Make sure the air in the system is completely vented. Refill and drain the water a couple of times to get the water clear.
Fill the system with water and add the pre-commissioning chemical into the system. Run the pumps and flush the system to the required period as per the recommendation of the chemical manufacturer. Drain, refill and flush the system for few hours and drain again. Repeat flushing and draining till we get the water visibly clear.
Take the sample of water and get it tested to ensure the water is clear from any chemical.
Fill the system with fresh water and add the post commissioning chemical into the system. The quantity will be as per the recommendation from the supplier depending on the system’s volume.
Test the water sample and ensure adequate quantity is introduced to the system. Submit the test certificate to the Engineer for approval.
L.P. Gas System
Tank Yard
Storage
The liquid gas will be stored in 12,000 ltrs. Water capacity tanks at a pressure of 50 to 80 PSIG. The maximum volume of the gas will be 85% of the total water capacity of the tank.
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Filling
The tanks will be provided with liquid fill line and vapor equalizing line.
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Gas withdrawal from the tanks
The tank vapors outlet will be fitted with First Stage Regulator to maintain a down stream pressure of 10-20 PSIG. The liquid outlet from the tank is connected to the vaporizer where the liquid gas is vaporized by the heater to suffice the gad consumption. 1st stage regulator is fixed on Vaporizer outlet. The vapor service line can be maintained in a range of 10-20 PSIG.
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Second Stage Regulators
This will be fixed on the vapor service lines inside the building to maintain required equipment pressure which is generally less than 1 PSIG.
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Safety Features
The system will be provided with Gas Detection system, which is connected.
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Chlorination and Sterilization System
Isolation the system to be treated from public use. Attach a suitable hazard warning notice to all outlets, e.g. “ DANGER DO NOT USE”.
Drain the complete distribution system fully to remove all deposits of rust slime, sediments, scale and other fouling, as far as is practicably possible.
Close the make-up supply. Chlorinate the water in the distribution system to give a measured free chlorine level of at least 50ppm in the water.
To chlorinate the water, injection of chlorine solution should be done as follows:
Remove the pressure gauge at the inlet line and fix up an injection fitting in that tapping point. The injection fitting will be connected to pump, start the pump and start pumping the chlorine solution into the water line.
After injection the chlorine solution, allow it to stand for an hour for the effective distribution of the chlorine to all draw off points, at get free residual chlorine of more than 50 ppm.
After an hour after the distribution, each tapping point has to be successfully opened to get chlorinated water. The taps should be closed when the water discharging begin to smell of chlorine. Allow it to be closed for 24 hours.
Check for the connection of free residual chlorine and if found less than 30 ppm, the chlorine injection should be repeated to get more than 30 ppm.
After value, allow it to stand for 24 hours and then start flushing the system till the chlorine level drops down to less than 0.5 ppm
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Oil-fired Water Heaters
It has been designed to provide domestic hot water and central or process heating from one unit. The water it contains is Neutral water, which is heated in the storage tank. This Neutral water is never consumed.
The storage tank is open vented to atmosphere by connection to an expansion tank located above the storage tank. The expansion tank holds a reservoir of Neutral water and allows for expansion and contraction that occurs when the Neutral water is heated. A float valve inside the system introduces a small amount of water if any evaporation occurs.
The neutral water in the storage tank is heated by thermostatically controlled forced draft oil that fires into a mild steel combustion chamber located near the bottom of the storage tank. The burner is a single stage (on/off) burner. The heat then travels vertically upwards through a number of fire tubes. These fire tubes are designed to maximize the amount of heating source in contact with the Neutral water and when operating on oil is fitted with tabulators which “swirl” the hot air inside the tube which increases the efficiency. The hot air then flows out of the system via the flue outlet. This method of heating is termed “single pass”.
The neutral water in the storage tank can be used for Central or Process heating. The Neutral water is pumped out of the topside of the tank and is circulated around the heating circuit for use, then returns back to the lower side of the Storage Tank for re-heating.
The system will be tested at minimum 1½ times the working pressure and will be purged with nitrogen prior to commissioning.
The pipeline will be seamless Carbon Steel pipes API 5L Gr. B with all welded joints and screwed joints for the fittings. Welding shall be carried out by qualified welders already on similar jobs.
Commissioning Of Refrigeration System
The refrigeration system is to be kept ready after pressure testing, vacuuming and initial charging for breaking the vacuum.
Once power supply is available, check the voltage available at the isolator. Before energizing the electrical circuit of the A.C. unit check the electrical termination for proper tightness. Check terminals of all motors for tightness, continuity, etc. isolate the power circuit to the compressor and check the functioning of the control circuit. After all circuits are found O.K., energize the crank case heater of the compressor for 24 hours.
Start the air handling unit and check the operation. Start the condensing units and top up the refrigerant. Check running amps of all motors and ensure all are within the limit. Check the operating refrigerant pressure and top up if necessary.
Check all safety devices for proper functioning. Check the units are cutting off and on at thermostat setting. Check the interlocking of condensing unit and air handling unit. Check the interlocking of condenser fan motor and compressor.
Once the system is on steady operation take one set of test readings and ensure all readings are with in the operating parameters. Submit the test readings to the Engineer for approval.
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