Pharmacy Courses

Validation of HVAC System in Pharmaceutical Industry

The HVAC system is an important part of a pharmaceutical manufacturing to maintain the required environment with desired temperature, RH, and air classification.

HVAC system Validation Tests

Air Flow Pattern or smoke pattern

- The test shall be performed in Rest as well as Dynamic condition.

- Video recording shall be performed for the airflow pattern test.

- The air should flow unidirectionally from supply towards the return air filter or grill within the room.


- Once in a year.

Air velocity/airflow measurement and calculation of air changes

- Calculate the ACPH is as follows:

Air changes per hour (ACPH) = Total CFM X 60

- Using Anemometer for air velocity

- The volume of the room is calculated and the air changes per hour are obtained by dividing the total air change by the volume of the room.

- A variation in air volume shall not be ±20% from the design CFM


- Once every six months.

- At Every Filter replacement.

Filter leak test

- For the leak test of the HEPA filter, aerosol calibrated photometer shall be used

- AHU system and the air velocity is checked at all the corners. In case it is found to exceed the upper limit, a gas cut (silicon) is used to decrease the leakage.


Earlier to carry out this test, DOP was used. But nowadays, it is replaced by the PAO (poly alpha olefin) taking into consideration the carcinogenicity of the DOP.


- Once every six months.

- At Every Filter replacement.

Viable monitoring (microbial monitoring) Passive /Active Air sampling

- To determine the viable particle count test by exposing the settle plate and air sampling in the defined areas.

Passive Air Sampling

- Plates shall be exposed on plate exposure stand at the pre-defined locations mentioned in individual format for each stream for not less than 4 hrs.

- Exposed plates shall be recovered after 4 hrs. of exposure and incubate at specified condition 20-25ºC for 72 hrs. Then 30-35ºC for 48 hrs.

- Plates shall be observed for any microbial growth after 5 days.

Active Air Sampling:

- The plate shall be recovered after sampling and incubate at specified conditions : 20-25ºC for 72 hrs. then 30-35ºC for 48 hrs


-Once in every six months for three consecutive days for ISO classes 5, 6, 7, and 8 at defined location. Continuous monitoring in critical / core areas.

Non Viable Particle count


- Once in every six months for three consecutive days at a defined location.

- At Every Filter replacement.

Differential pressure test

It is calculated by use of the manometer


For 3 days (Every six month) Continuous monitoring

Recovery study


- Once in a year.

Temperature and humidity control test


-For 3 days (Every six month) Continuous monitoring

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Resource Person: Hassan Hussein

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