What is the importance of Pharmaceutical HVAC

Pharmaceutical HVAC is used to condition the environment of a pharma manufacturing to provide clean air. Let’s look at some functions of HVAC. In the end, the article discusses the Air Handling Unit and Ducting for a Pharmaceutical HVAC.

Heating Ventilation and Air Conditioning (HVAC) systems control the environmental conditions in different industries, including pharmaceutical. These systems provide necessary environmental conditions for drug manufacturing in a pharma facility. They also help to eliminate contamination and hazardous foreign particles in the surrounding air of the manufacturing area.


Environmental control in the pharmaceutical industry is essential for a safe and reliable production process. It enables pharmaceutical professionals to maintain clean, contamination-free air for a safe and secure product. Additionally, it provides product-specific requirements such as temperature and humidity for effective drug development and production.

Before installing and using it for pharmaceutical operations, validation must be carried out for the Pharmaceutical HVAC system. It tests the HVAC system and helps to point out any deviation before using it for pharma manufacturing operations.

Functions of Pharmaceutical HVAC

There are various applications of a pharmaceutical HVAC. The requirement of HAVC for a particular area depends on the manufacturing pharma product.

Some common functions of an HVAC system include the following


Maintaining Temperature

Temperature control is the basic and integral function of HVAC in the pharmaceutical industry. This is necessary because uncontrolled temperature conditions can stimulate microbial growth. It can also increase the water activity in the area, which is also the basis of microbial growth.

Pharmaceutical HVAC provides suitable temperature conditions for a safe pharma product. It also prevents energy wastage by optimizing the temperature regulation process.

HVAC controls the temperature by continuously monitoring the area. When the temperature exceeds the required value, the AHU supplies cool air to reduce the area’s temperature. Similarly, the supply air temperature increases when the temperature becomes lower than the desired value. In this way, the HVAC system regulates the area temperature.

There are two common methods in temperature control – On / OFF and PID Control.

The On/OFF method is the simplest and least complex method. This method applies full power until the temperature reaches the desired value. When AHU achieves the temperature, the total power is curt-off. This cycle repeats continuously throughout the entire production cycle.

PID Control is a closed-loop temperature control method. It monitors the feedback signal continuously and applies gain to the feedback’s error (or difference) and required temperature value. The value of gain controls the temperature’s value. It also applies derivative and integral to the error. The sum of all three functions becomes the input to the system.

Maintaining Humidity

Humidity control is also a critical feature of a Pharmaceutical HVAC system. Like temperature, humidity also stimulates microbial growth and increases contamination.

HVAC must maintain adequate humidity levels for pharma products and processes. If no product or process is involved, human comfort levels are considered.

A common humidity control method is supplying cooled air into a particular area. In this method, chilled water is supplied to cooling coils in AHU. When the supply air passes through the cooling coil, its temperature drops and dehumidifies. When exposed to a particular area, this air lowers the dew point and decreases the relative and absolute humidity.

Regulating air inside an area

Pharmaceutical HVAC also regulates the airflow inside a designated area to provide a uniform airflow. It is necessary because non-regulated air flow can cause dust particles or foreign bodies to re-enter the air stream.

The blower maintains the airflow in the air handling unit. The required airflow is fed into the main control of the HVAC, and different sensors continuously monitor the airflow in an area. If the airflow inside an area changes, for example, due to man or material flow, the sensors sense the change and send the signal to the main controller, which calculates the difference. The main controller regulates the blower motor driver, such as the Variable Frequency Drive – VFD, to increase or decrease the blower speed.

AHU Blower

Airflow can also be adjusted by opening or closing the air dampers installed at the supply air. Opening a damper increases the airflow, and conversely, closing the damper decreases the airflow. Dampers can be adjusted automatically through the main controller or by manual method.

Pressure regulation

Pressure regulation is another primary function of Pharmaceutical HVAC. Pressure regulation prevents air from uncontrolled areas to enter into controlled or clean area.

Pressure regulation is achieved by supplying air with higher volumes than adjacent areas. It makes the area more pressurized (also called positive pressure) than other areas and prevents air infiltration from non-critical or uncontrolled areas.

Pharmaceutical HVAC – Air Handling Unit & Ducting

There are many components of a Pharmaceutical HVAC system for regulating the environment in the Pharma industry. The most critical of them is the Air Handling Unit and ducting system.

Air Handling Unit

The air handling unit is Pharmaceutical HVAC’s brain and performs major area conditioning functions. It consists of a filter, coils, and a fan section in a single casing. The casing is sealed and insulated to prevent leakage from and into the AHU. It also contains access doors and view ports for maintenance and inspection purposes.

Two types of coil in an AHU are cooling and heating. Commonly, chilled water circulates in cooling coils and hot water in heating coils. When the supply air passes through the cooling coils, it lowers its temperature and, as a result, decreases the temperature of the serving area. Similarly, when supply air passes through the heating coil, it heats the air and, as a result, increases the temperature of the serving area.

Air Handling Unit also contains filters for air purification. There can be different classifications of filters depending on the area requirement.

Blowers in the AHU are used to create airflow. They can operate at varying speeds to create the desired airflow. These blowers can operate manually or automatically through the main controller. Sensors installed across different locations of AHU and in the area constantly monitor the airflow. The main controller immediately compensates for any difference in the required airflow.

The conditioned air from the HVAC flows through the ducting to the target area. If ducting is not designed carefully, it will disturb the characteristics of airflow and will also contaminate the conditioned air. The characteristics and cleanliness requirements of a particular area define the ducting’s design and profile.

Ducts in the pharmaceutical industry can be square or round-shaped. They are made up of Stainless Steel or Aluminum. Stainless Steel is expensive, so Aluminum is often used.

Ducting in Pharmaceutical HVAC must be clean and must not shed particles or become a source of contamination. Ducting is often installed in sections, so each unit must be sealed to prevent air leakage.

Grills and diffusers are installed in the serving area at the duct opening. Grills prevent infiltration at the duct opening, while diffusers enable the uniform flow of air into the serving area.

Dampers are installed at different locations in a ducting system. They are mechanical assemblies that face the airflow in a duct. Their position can be OPEN or CLOSE. When Open, they allow the airflow to pass, and in the Close position, they restrict the airflow through that particular section. Dampers can be manual or motorized. The motorized dampers take the signal from the main controller and can position the damper automatically to adjust the airflow.


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