Follow
Objective: To establish a standard procedure for checking the air velocity.
Scope: This SOP is applicable for checking the air velocity in the rooms catered by the HVAC system of (Company Name).
Responsibility:
1. Maintenance Engineer shall be responsible to follow the procedure strictly.
2. Supervisor shall be responsible to ensure that the SOP is followed properly.
Precautions: Concerned personnel should be trained on the SOP.
Procedure:
=>> Ensure that the Pre filters are Cleaned and installed properly.
=>> Ensure that the Line Dampers are open.
=>> Ensure that Blower is “ON” and rotating in the direction to deliver the air.
=>> Carry out the following steps for the air velocity measurement with Anemometer:
=>> Ensure the Anemometer is calibrated; check the Certificate of Calibration to Ensure the Traceability as per the Standards in the Certificate.
=>> Hold the anemometer’s sensor probe / fan near supply grill at selected point at distance of 4”- 6” from the grill face to get turbulent free air flow.
=>> Hold the Anemometer till the Reading on the display is constant.
=>> Take the readings at five Locations of the air Outlet.
=>> Note the Readings and calculate the mean Reading.
=>> Measure the air velocity at each supply grille / Terminal filter grill.
=>> Calculate the filter / grille area in sq.ft.
=>> Multiply the mean reading of the Velocity with filter / grill Area to calculate CFM through the grill.
=>> Add CFM through all the grilles of the single area.
=>> Calculate Volume of the Area in Cub Ft by measuring Length, Width and Height in Feet.
=>> Calculate air changes per hour with following formula:
Total C.F.M. x 60
Air Changes per Hour = —————————
Room Volume in cubic feet
=>> For measuring the Air flow with the help of Flow Hood, follow SOP No.: EG093-00. After taking all the data, calculate the Air Change per Hour (ACH) with the following formula:
ACH = Total air flow in Liter/sec x 3600 / (Total volume of the roomsx1000)
