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Operation Qualification of Air Handling Unit

To demonstrate that the HVAC system installed in XYZ PVT LTD. made up of Air Handling Unit models operates according to specifications, and to record all relevant information and data to demonstrate its functions as expected.

To be performed after the installation qualification has been completed and approved.

Project Engineer is responsible for writing the protocol, supervising the performance of OQ, verifying the data and writing the OQ report.
QA of XYZ PVT LTD. is responsible for approving the protocol and reviewing and approving the data and conclusions.

Environmental Performance Test

Air Flow Velocity, Uniformity & Air Change Profile

  • To demonstrate that the air system is balanced and capable of delivering sufficient air volume to maintain minimum cross sectional velocity.
  • Air is moving in designed direction and path.
  • To establish that the air is re-circulated sufficiently to clean the contamination Generated within the area.
  • To verify that the air velocities are reaching up to at least 40” above the floor level or up to an obstacle.

Equipment Used
  • DIRECT READING Thermo Anemometer or Propeller type Anemometer sensitive to lower velocity of 30 to 150 FPM.
  • Measuring Tape.
Method of Testing
  • A factory trained and approved personal should conduct this test.
  • This test is generally carried out where Terminal Grill are used.
  • Draw a grid in the room or on a paper as per the room diagram and mark all filter positions.
  • Check the velocities at 4” to 6” below or away from the filters. Record the same.
  • No object shall be present below the anemometer while taking the Reading, except the built-in equipment. Minimise personnel movement during “at rest” testing.
  • Each measurement should be taken for at least 15 seconds.
  • Each filter should be checked at least for 5 test spots pre-established and marked.
  • Each filter velocities should be averaged.
  • Add all the filters placed in the specific room and average the velocity and multiply with the filter effective area to achieve the room total airflow.
  • The sum of Airflow in the room shall be multiplied by 60 and divided by the volume of the room to achieve the air change rate in the specific room.

Acceptance Criteria
  • Average measured clean air velocity shall be higher than 90 FPM and should not exceed 120 FPM at any cost for a unidirectional flow.
  • However, for conventional air flow check the design parameter before conducting the test.
  • The uniformity between each terminal grill should not vary more than 25%.
  • The air changes should be established by calculation and it should not be less than the design parameters initially.

To demonstrate the capacity of the air handling and circulation system to control pressure levels within the specified limits.

Equipment Used For Testing
Magnahelic gauges with a resolution of 0.5 mm of W C.

Methods of Testing
  • All HVAC and Laminar Air flow workstations should be in Operation while conducting this test.
  • All doors should be closed in the connected or interconnected areas where test is performed.
  • No Traffic is permitted during the test, so that performance base line can be arrived.
  • Locate low pressure sensitive areas for test probing so as to achieve the optimum results.
  • Open and close the doors to check the pressure reaches the base line within 30 seconds. Repeat the test for reliability of the system.
  • The aggregate differential pressure with respect to atmosphere or to the location of the Magnahelic gauge/Manometer shall be established.
Acceptance Criteria
  • The pressure differential between adjacent areas should match with design parameters under static conditions.
  • The variation permitted during operating condition shall be documented in the design level.
  • It is suggested that a minimum of 0.5 mm of differential pressure should be maintained between rooms of the same cleanliness class with air cascading towards the least critical area and 1.5 mm between areas of different cleanliness class levels.
  • The system will not be acceptable if, at any time during normal dynamic or static or stress condition the pressure in the primary environment becomes less than zero.
  • Supply air, Return air & Fresh air CFM should be as per design CFM. If you want more pressure then slowly close the Riser damper.
  • The system should not at any cost equalize or show reduction between 2 adjacent areas where a positive pressure is maintained under normal conditions and all doors are closed.

To demonstrate the ability of the air handling system to maintain & control the
Temperature, subject to the condensing systems/CHW. Working.

Equipment Used For Testing
Calibrated digital thermometer or dry bulb thermometer (Sling Psychrometer).

Methods of Testing
  • The air conditioning system should have run without a break for at least 24 hours before conducting the test.
  • All lights in the specified area to be put ‘ON’ while testing.
  • All machines should be in operational condition while testing.
  • The required personnel as per the basis of design should be present in the area of operation.
  • Operational air velocity should be verified and adjusted before conducting the test. Required fresh air system should be adjusted and established before starting the test.
  • Required return air velocities have to be adjusted and established prior to the test
  • Test should be conducted every 60 minutes interval and for a period of 6 hours at a minimum of 5 locations or as indicated in each room.
  • Test should be repeated "at rest" and under working conditions for at least 2 times.
Acceptance Criteria
The system should be capable of maintaining a dry bulb temperature within design temperature throughout the testing period and everyday of operations subject to design level of occupancy and heat generation.

  • Clean the fan wheels and fan shaft. Remove rust with an emery cloth and apply a coat of anticorrosive lacquer.
  • Inspect the condensate drain pan and drain line, remove foreign materials that might obstruct proper drainage.

  • Check damper linkages, set screws and blade adjustment. Clean, but do not lubricate the nylon damper rod bushings.
  • Clean damper operators.
  • Clean the Air cooled condenser every month.

  • Clean the filter every month.
  • Before cleaning the filter, stop the AHU by pressing the red button.
  • Open the access door of AHU of the Pre filter section.
  • Remove the Wing nuts of the Pre filter and keep them aside.
  • Remove the filter.
  • Clean the filter with water and light detergent.
  • Dry the filter.
  • Place the filter in the AHU and slide it in the opening.
  • Screw the Wing nuts tightly and check if the filter is firmly placed.
  • Close the access door.
  • Start the AHU.


To determine and rectify the leaks in the ducts after their fabrication and installation on site.

Qualified and designated personnel are responsible for performing the leak test and site engineer inspects the same.

Following steps are followed for conducting leakage test
  • All the ducts are fabricated as per relevant IS Codes followed in the industry.
  • These ducts are fabricated and installed as per the respective drawings.
  • Once the system is connected and before final installation of ducting light test is conducted.
  • In this test, the engineer/person carries out the test taking the illuminator through the duct.
  • This test is essential to be conducted during night.
  • Due to the darkness outside, if there is any pin hole in the duct, the light travels outside through the hole in the joints.
  • The testing authority physically checks the ducts from all the 4 surfaces and looks for any rays of light coming though inside of the duct.
  • If any pin holes/any opening observed during this light test are seen, then they are sealed with RTV dark coloured sealants.
  • After having done first round of sealing light test, it takes again to check for the further left out openings.

There are no pinholes present in the ducts, hence the ducts are accepted.

Thus the tested ducts are capable for carrying the conditioned air through it.

Operational Qualification Approval Report:
Approved / Not Approved

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