What is Heating Ventilation and Air Conditioning?

Heating Ventilation and Air Conditioning - HVAC is a combined name of multiple smaller and bigger machines & tools to process & control the ambient environment in a pharma facility. It alters natural characteristics, such as particulates, temperature and humidity present in an environment according to the highest pharma industry requirements.

That, in turn, plays a crucial role in maintaining the product quality, efficacy and safety of the product (under process in their respective areas).

The performance criteria of HVAC depend on the area classification to which HVAC is being served, which ultimately depends on the product (process) requirements.

Designing an effective HVAC system for a Pharma facility

HVAC designing is the detailed planning and study of the area requirements before constructing and deploying the HVAC in that area.  It results in an optimized HVAC system that can fulfill all criteria in a pharma facility. On the contrary, if the design is not selected wisely, there will be deviations in the standard environmental parameters.

Let us briefly look at how an efficient HVAC system is designed

What is your target area?

The first step is the determining target area of your HVAC system. After the target area has been marked, it becomes easy to determine different environmental parameters, such as temperature, humidity and other relevant parameters.

In a pharma facility, it is common that different areas serve a single product or process, which are maintained at different environmental levels. For example, product filling and packaging have different area characteristics and require different HVAC design requirements.

Knowing which area, you want to incorporate the HVAC systems is essential for an effective and efficient performance.

Design parameters

Design parameters refer to the capability of HVAC for a specific area or a facility for which HVAC is being developed and installed. Standard design parameters include but are not limited to

Humidity

Humidity is the amount of water level in an area. For the pharma industry, humidity must be controlled under certain levels due to its danger it poses —for example, acceleration in microbial growth and the resultant product & process degradation.

The humidity levels can be controlled using an HVAC system employing suitable sub-components, such as cooling coils or dehumidifiers. These sub-components cool down the air, removing moisture from it. The extent to which humidity is maintained depends on the area requirements and the existing moisture.

When humidity is maintained at acceptable levels, the HVAC system continues to operate at its present state until humidity level changes are required.

Pressure Differential

The pressure differential is a condition where two adjacent areas are kept at different pressure profiles and to regulate the airflow between them. It enables professionals to have a unidirectional airflow, limiting the flow of contamination & un-filtered air inside the classified area or room.

The HVAC employs different mechanisms, such as airflow control  and dampers in an area, to maintain pressure differential. These components automatically regulate depending upon the pre-set value. Differential pressure sensors installed at various locations help to monitor the current value, and adjust it accordingly.

Temperature

Like humidity, temperature is also an integral environmental parameter in the pharma industry. It impacts the product & process quality in a given area and is a significant driver of microbial growth. For this reason and many more, the temperature is maintained at certain limits in all critical areas and departments of the pharma industry.

The HVAC system can control the temperature values in any given area. The cooling & heating mechanism in AHU can increase or decrease the temperature until the desired levels are achieved. Temperature sensors installed at different locations continuously monitor and give exact feedback for efficient control.

Particulate Matter

Particulate matter is a combination of different solids, vapors and chemicals particles that have specific physical mass. These particulates remain suspended in the air and can interact and react with the pharma process & product, altering their natural characteristics. The pharma industry must prevent particulate matter from entering the critical area, which is also a regulatory requirement.

One common method to prevent particulates is using filters. In the HVAC system, filters are employed at the AHU levels and where airflow is directed. In AHU, filters are commonly used to filter out high particulates by installing large-sized filters. In the production area, filters are used to filter out small particulates present.

An example of a filter used in AHU is a bag filter, while an example employed in the area is a HEPA filter.

Components of HVAC

As mentioned earlier in this article, HVAC is a combination of multiple sub-component working together to maintain the environmental parameters. The selection and inclusion of these components depend on the desired environmental parameters and area requirements.

Some standard components include but are not limited to

Air Handling Unit – AHU

Air Handling Unit: AHU is the primary sub-component where air is processed before being introduced into the desired area. It is rectangular in shape,  and consists of different parts that condition the air according to the requirements. Some common parts include

• Filter – to remove solid particles at different stages. Different filters, such as bags and HEPA, can be used depending on the area requirements.

• Heating – it consists of steam coils or electric heaters that heat the air when flowed across it

• Cooling – it consists of a coil in which cold water flows. When air flows across this coil, the temperature of the air is lowered and also decreases the area temperatures in which it flows.

• Blower – A blower driven by the motor to generate the desired airflow. Its speed can be adjusted according to the area requirements.

• Dampers – Dampers are plates to adjust the air flowing across them mechanically. They are primarily used to adjust pressure in the serving area.

Additional components

In addition to the components mentioned in the AHU section, these components can be solely deployed & used to maintain area requirements. This happens where there are strict requirements, and since AHU can maintain generic requirements, additional components can fulfil these rigorous requirements—for example, using a further de – dehumidifier in oral solid to keep humidity levels or additional filters in sterile filling areas.

Duct, Diffusers and Grills

The air from the AHU or HVAC systems flows in its respective area through appropriate ducting. The ducts are insulted to prevent leakage and run in appropriate diameters to cater to airflow requirements.

Diffusers are installed at the air entry in the area and distribute the conditioned air uniformly. Its shape can vary and include square, round or rectangle.

Grills are also mechanical structures installed at the area's return or supply path of air.

Electrical Control System

The electrical control system is the backbone of the HVAC system that executes the entire system's operation. It allows personnel to adjust the desired parameters and monitor its functionality.

An electrical control system can consist of various components, such as a thermostat, central controller and electrical power supply, to control the HVAC system electrically.

It also consists of an interface system, such as Human Machine Interface – HMI, that allows personnel to interact with the HVAC system. Personnel can use the interface system to input desired parameters and monitor the system’s existing parameters.

Sensors and Instrumentation

Sensors and instrumentation are electronic devices that monitor the current values and transmit them to the central controller, which uses them to control and execute the entire HVAC system. The central controller continuously monitors these sensors & instrumentation and adjusts different sub-components to compensate for the difference.

The placement of these sensors is critical and must be selected during the design phase. Once decided, it must remain in its specified location. If a change in placement location is required, it must be done after careful study and by expert personnel.

Different sensors are used, the selection of which depends on the area and process. It includes but is not limited to

• Temperature sensor – to monitor the temperature in the area. The central controller uses it to determine if there is any change in the temperature values and adjust it.

• Pressure and Differential Pressure – Pressure sensors are used to monitor the pressure in the area. If a differential pressure sensor is used, it is used to monitor the differential pressure.

• Humidity – to monitor the humidity levels in a particular area

• Airflow – to monitor the airflow in a particular area and adjust it, if required

• Gauges – gauges are manual devices to indicate environmental variables manually for personnel working in the area

Applications of HVAC

There are countless applications of HVAC in the pharma industry to maintain environmental conditions, including but not limited to

Sterile Filing area

An HVAC system maintains temperature, humidity and airflow in a sterile filling area. Differential pressure is also maintained to prevent contamination from corridors or change rooms into the filling room.

Oral Solid Powder packaging

Oral solid powder packaging requires specified humidity levels in the area to protect the product from being damaged. The HVAC system maintains the required humidity levels, and if there is any change, it automatically adjusts it according to the pre-defined algorithm.

About the Author:

Muhammad Asim Niazi

Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.