Air Velocity Test Parameter and Procedure -HVAC Validation in Pharma

following the procedure of the Air Velocity
- This test is performed to determine the air flow supply rate in non unidirectional clean room and the air velocity distribution in a unidirectional clean room.

-Typically either airflow velocity or airflow rate testing will be performed and results will measured in average velocity, average air flow rate or total air flow rate.

-Total airflow rate may in turn be used to determine the exchange rate (in change per hour) for non unidirectional installation.

-Air velocity test is performed to measure the Velocity of air supplied by the AHU. By using the Air velocity Air change per hour can be count.

-Air changes per hour (ACPH) mean the volume of air supplied to a room, in m³/hr, divided by the room volume, in m³.

-Test is carried out by using calibrated anemometer.

 -Anemometer should be sanitized with 70% IPA along with its carrying case and connecting cables.

-The anemometer should be handled in such a way that it will not obstruct air         supply.

- Filter area should be divided into grids of equal filtration zones.

-The reading should be taken approximately 6 inch from the surface of the grill at its centre and corners.

-Measure the velocity and record the reading.

	S1		S2
	1                     2               5                      4                    3		1                 2               5                      4                   3
B
	A

 Where, S_1, S₂ are supply air ducts of dimensions A x B respectively.

-The air supply volume is calculated as follows:

Air Supply Volume = Mean air velocity (FPM) X Grill Area (Ft²)

                               =______CFM

-Where mean air velocity is the average of all velocity readings of the filter.

-Air Changes per Hour (ACPH) = Air supply volume (CFM) x 60

            Room Volume (ft³)

-Minimum Air Changes per Hour shall meet the acceptance criteria.

-If not, HEPA filter shall be checked, flow shall be adjusted as necessary or if required HEPA filter shall be replaced.

-Any corrective action taken as a result of investigation shall be recorded. Major changes to air supply system must be undertaken by authorized personnel only.

- Filter integrity  ,Non viable particle count , Recovery Test are the another important test to perform the HVAC Validation.