Look into HVAC in GMP as per WHO

Introduction to HVAC Systems in Pharma GMP

In pharmaceutical manufacturing, precision, quality, and compliance are paramount. Ensuring the integrity of medicinal products throughout their lifecycle requires meticulous attention to detail in every aspect of the manufacturing process. One critical component that plays a significant role in maintaining the highest standards of pharmaceutical production is the Heating, Ventilation, and Air Conditioning (HVAC) system. This article delves into the world of HVAC systems in pharmaceutical Good Manufacturing Practices (GMP), as per the guidelines set forth by esteemed organizations such as the International Organization for Standardization (ISO), World Health Organization (WHO), and International Society for Pharmaceutical Engineering (ISPE).

Importance of HVAC System in Pharma GMP (short note)

1. Product Quality: HVAC systems play a crucial role in maintaining the integrity and quality of pharmaceutical products throughout the manufacturing process. They control air quality, temperature, humidity, and cleanliness, ensuring optimal conditions for production.

2. Regulatory Compliance: Adhering to GMP guidelines is essential for pharmaceutical manufacturers to meet regulatory requirements. HVAC systems are a key component of GMP compliance, as they help maintain controlled environments that meet the stringent standards set by regulatory bodies such as FDA, EMA, and other authorities.

3. Contamination Control: Contamination poses a significant risk in pharmaceutical manufacturing. HVAC systems prevent cross-contamination by creating controlled environments with proper air filtration, ventilation, and air pressure differentials, minimizing the potential for product contamination.

4. Worker Safety: HVAC systems contribute to the safety and well-being of personnel working in pharmaceutical manufacturing facilities. They help control exposure to hazardous substances, maintain comfortable working conditions, and provide adequate ventilation to remove potentially harmful airborne particles or gases.

5. Environmental Monitoring: HVAC systems incorporate monitoring mechanisms to continuously assess and maintain critical parameters such as temperature, humidity, and particle counts. Real-time monitoring ensures deviations are detected promptly, allowing for corrective actions to be taken, thus preventing any compromise in product quality.

6. Energy Efficiency: HVAC systems designed with energy efficiency in mind can contribute to cost savings and sustainability in pharmaceutical manufacturing. By optimizing airflow, temperature control, and system design, energy consumption can be minimized without compromising product quality or GMP compliance.

7. Risk Mitigation: HVAC systems are essential for risk mitigation in pharmaceutical manufacturing. They provide the necessary environmental control to reduce the risk of product contamination, maintain sterility in aseptic manufacturing, and ensure the stability of sensitive pharmaceutical ingredients.

8. Validation and Documentation: HVAC systems require thorough validation to demonstrate their performance and compliance with GMP guidelines. Documentation of system design, installation, operation, and maintenance procedures is crucial to ensure traceability, accountability, and regulatory audit readiness.

How HVAC maintains Temperature, Humidity, and Air Quality?

HVAC systems and filters play a vital role in maintaining temperature, humidity, and air quality in various environments. Here is a short mechanism explaining how they achieve these objectives: for further readings Readmore

Temperature Regulation:

Heating: There will be questions in your mind, Why heating is required in Pharma GMP?

Yes, heating is required in extremely cold areas of the world to prevent freezing and moisture in GMP areas. HVAC systems equipped with heating components, such as boilers or heat pumps, generate warm air or water that is circulated through the building’s ductwork. This heated air raises the ambient temperature in the controlled spaces.

Cooling: Cooling is achieved through refrigeration cycles. The HVAC system’s cooling components, such as chillers or air conditioners, remove heat from the indoor air and expel it outside, resulting in a reduction in temperature

Humidity Control:

Dehumidification: When the indoor air has excess moisture, the HVAC system engages the dehumidification process. It cools the air below the dew point, causing the moisture to condense and be collected or drained away in its outlet.

Humidification: Again here will be questioning in your mind, Why Humidification is required in Pharma GMP?

Obviously, In environments where humidity levels are too low like in Arab Countries, the HVAC system can incorporate humidifiers. These devices introduce moisture into the air, increasing humidity to the desired level.

Air Quality Maintenance:

Air Filtration: HVAC systems utilize air filters, such as pleated filters or HEPA filters, to capture and remove airborne particles, dust, allergens, Powders in tablet or capsule sections, and other contaminants. These filters trap particles as air passes through them, improving the air quality, by reducing the concentration of pollutants.

Ventilation: HVAC systems also facilitate proper ventilation to ensure a continuous supply of fresh outdoor air. Ventilation systems bring in outdoor air, filter it if necessary, and distribute it throughout the building, diluting and replacing indoor air and reducing the accumulation of indoor pollutants.

 Air Exchange: The HVAC system can implement air exchange rates, ensuring a specific number of air changes per hour in different areas. This helps remove stale air and replace it with fresh air, promoting better indoor air quality.

Specific types of HVAC filters with Specific Area Applications:

  • Fiberglass Filters: Fiberglass filters are commonly used in pharmaceutical sections due to their cost-effectiveness. They consist of layered fiberglass fibers that capture larger particles such as dust and pollen. While they provide basic filtration, they may not be suitable for capturing smaller particles or contaminants requiring higher levels of air purity.
  • HEPA Filters: as per WHO guidelines, The HEPA filters in such an application should have an EN 1822 classification of at least H13 or equivalent1. High-Efficiency Particulate Air (HEPA) filters are widely recognized for their exceptional filtration capabilities. They can capture over 99.97% of particles as small as 0.3 microns in size. HEPA filters are essential in maintaining critical environments such as cleanrooms and sterile manufacturing areas, where the highest levels of air purity are necessary to prevent contamination. HEPA filters may not be required to control cross-contamination where evidence that cross-contamination would not be possible has been obtained by other robust technical means, or where the air-handling system is serving a single-product facility1.
  • Pleated Filters: Pleated filters are popular in pharmaceutical settings for their enhanced filtration capabilities. They feature a larger surface area due to their accordion-like design, allowing for improved particle capture efficiency. Pleated filters can effectively remove smaller particles, including mold spores and bacteria while maintaining adequate airflow.
  • Electrostatic Filters: Electrostatic filters use an electrostatic charge to attract and trap airborne particles. They can be either disposable or washable and are particularly effective in capturing smaller particles, including allergens and fine dust. Electrostatic filters provide higher filtration efficiency and are beneficial in pharmaceutical sections where stricter air quality, control is required.
  • Activated Carbon Filters: Activated carbon filters are used in pharmaceutical sections to address specific air quality, concerns, such as odor and chemical vapor removal. They contain a layer of activated carbon that absorbs and neutralizes gases and volatile organic compounds (VOCs). Activated carbon filters complement other types of filters by providing additional chemical filtration capabilities.
  • Washable Filters: Washable filters offer a reusable option for pharmaceutical facilities. They are typically made of foam or synthetic materials that can be cleaned and reused multiple times. Washable filters provide moderate filtration efficiency and can be cost-effective in the long run, as they eliminate the need for frequent filter replacements.

Short Intro on Parts of HVAC Duct Systems:

We are explaining this to introduce you to parts of HVAC to identify the root cause if any problem is evolved in your premises.

HVAC duct systems consist of various components that work together to distribute conditioned air throughout a building. These components ensure proper airflow, minimize pressure losses, and maintain the desired temperature and air quality, Here is a short note on some of the key components of HVAC duct systems:

  1. Ductwork/ Duct Map: Ductwork refers to the network of channels that transport conditioned air from the HVAC unit to different areas within a building. It is typically made of Iron, galvanized steel, aluminum, or flexible materials such as fiberglass duct board or flexible ducting. Ductwork is designed to provide a pathway for air to flow efficiently and effectively to reach each space.
  2. Duct Insulation: Insulation is often applied to the exterior of ductwork to prevent heat transfer or condensation. Insulated ducts help maintain the desired temperature of the conditioned air as it travels through the system, reducing energy losses and preventing moisture-related issues.
  3. Dampers: Dampers are adjustable plates or valves within the ductwork that regulate airflow. They can be manually or automatically operated to control the amount of air flowing into specific zones or areas. Dampers help achieve a balanced distribution of air and enable zoning capabilities within the HVAC system.
  4. Grilles and Registers: Grilles and registers are the visible components through which air enters or exits the duct system. Grilles are usually fixed in place and cover the openings, while registers are adjustable, allowing occupants to control the airflow and direction. They provide a means for air distribution and help ensure comfort in individual spaces.
  5. Diffusers: Diffusers are similar to registers but are specifically designed to disperse conditioned air in a specific pattern. They help evenly distribute air throughout a room and ensure proper air mixing for optimal comfort. Diffusers come in various styles, including ceiling-mounted, floor-mounted, or wall-mounted, depending on the specific application.
  6. Turning Vanes: Turning vanes are used in the ductwork to redirect the airflow around bends and corners, minimizing pressure losses and maintaining smooth air movement. They help improve the efficiency of the system and ensure consistent airflow throughout the ductwork.
  7. Access Panels: Access panels are strategically placed openings in the ductwork that provide access for inspection, maintenance, and cleaning. They allow technicians to access the interior of the duct system for inspections, filter replacements, and repairs.

SOP for HVAC Operations & Validation as per WHO1

HVAC system validation is a critical aspect of pharmaceutical Good Manufacturing Practices (GMP) to ensure the integrity of the manufacturing environment. It involves the use of various tools and methods to verify that the heating, ventilation, and air conditioning systems meet the required standards and regulatory guidelines. Here is a guidance note on commonly used tools and methods for HVAC validation in Pharma GMP: Accurate measurement of various parameters is crucial in HVAC systems within Good Manufacturing Practices (GMP) areas to ensure compliance, control environmental conditions, and maintain product quality. Here’s a short note on how to measure the following parameters in HVAC GMP areas:

  1. Temperature & temperature mapping: Temperature mapping involves the use of temperature data loggers or thermocouples placed at strategic locations within the facility to monitor and record temperature variations. This helps determine the uniformity of temperature distribution, identify any hot or cold spots, and ensure that the HVAC system maintains the desired temperature range. Use calibrated temperature sensors, such as thermocouples or digital thermometers, to measure the air temperature at different locations within the GMP area. Ensure sensors are placed in representative areas, away from heat sources or direct sunlight.
  2. Relative Humidity: Employ calibrated hygrometers or humidity sensors to measure the relative humidity within the GMP area. Place the sensors at appropriate locations to capture the average humidity level and avoid areas with direct moisture sources.
  3. Supply Air Quantities/ Return Air or Exhaust Air Quantities: Anemometers or airflow capture hoods are used to measure airflow velocity at supply and return/Exhaust air vents. These tools help verify that the HVAC system provides adequate air exchange rates and ensures proper air circulation within the facility.
    • Method 1 -Airflow Capture Hoods:
    • Airflow capture hoods, also known as balancing hoods or flow hoods, are widely used for measuring air supply quantities. Here’s how to use them:
      • Select an appropriate airflow capture hood with a size that matches the dimensions of the supply air outlet.
      • Position the airflow capture hood directly over the supply air outlet, ensuring a tight seal to capture all the airflow.
      • Ensure the hood is held steady and level during the measurement.
      • Read the airflow measurement on the hood’s display or connect it to a manometer to obtain the airflow rate in cubic feet per minute (CFM) or Liters per second (L/s).
      • Repeat the measurement at multiple supply air outlets to obtain an average airflow rate.
    • Method 2 -Anemometers or Airflow Measurement Devices:
    • Anemometers or other airflow measurement devices can also be used to measure supply air quantities. Here’s how to use them:
      • Select an appropriate airflow measurement device, such as a hot-wire anemometer or vane anemometer.
      • Position the measurement device at a suitable location downstream from the supply air outlet.
      • Ensure the measurement device is oriented perpendicular to the airflow direction for accurate readings.
      • Take multiple measurements at different locations across the supply air outlet to account for any variations in airflow distribution.
      • Calculate the average airflow rate based on the measured velocity and the cross-sectional area of the outlet.
  4. Room Air-Change Rates: Determine room air-change rates by measuring the airflow entering or leaving the GMP area using airflow capture hoods or anemometers. Calculate the air-change rate based on the volume of the space and the measured airflow.
  5. Room Pressures and Pressure Differentials: Use calibrated pressure gauges or manometers to measure room pressures and pressure differentials between different zones or areas. Place the gauges strategically to capture accurate readings and monitor for compliance with specified differentials. Differential pressure gauges or manometers are employed to measure and monitor pressure differentials between different zones, cleanrooms, or critical areas. This helps ensure that the system maintains the required air pressure differentials to prevent cross-contamination and maintain the integrity of controlled environments.
  6. Airflow Pattern Tests: Smoke testing or airflow visualization techniques involve releasing non-toxic smoke or using visual indicators to assess the direction and pattern of airflow within the facility. This method helps identify airflow disruptions, stagnant zones, or improper air circulation, enabling corrective actions to be taken to optimize the HVAC system’s performance.
  7. Unidirectional Airflow Velocities: Measure unidirectional airflow velocities, particularly in controlled environments like cleanrooms, using calibrated anemometers or velocimeters. Place the sensors at specific locations to capture velocities within the laminar airflow zone.
  8. Containment System Velocities: Use calibrated anemometers or velocimeters to measure airflow velocities within containment systems, such as fume hoods or bio-safety cabinets. Measure velocities at designated positions to ensure proper containment effectiveness.
  9. HEPA Filter Penetration Tests: Conduct HEPA filter penetration tests by introducing aerosol particles of known size upstream of the filter and measuring particle concentrations downstream using particle counters. Compare the results against acceptance criteria to verify filter efficiency.
  10. Room Particle Count Tests: Measure the concentration of airborne particles within the GMP area using calibrated particle counters. Follow standard sampling methods and measure at representative locations to assess compliance with specified particle limits.
  11. Duct Leakage Tests: Perform duct leakage tests using specialized equipment to measure air leakage within the ductwork system. Conduct tests in accordance with applicable standards and guidelines to assess system integrity and identify potential leaks.
  12. Materials of Construction: Identify and document the materials used in the construction of HVAC components within the GMP area. Ensure materials are suitable for the intended application, considering factors such as cleanliness, corrosion resistance, and compliance with regulatory requirements.
  13. Microbiological Counts: Collect samples from surfaces or air within the GMP area for microbiological testing. Follow appropriate sampling methods, such as swabbing or air sampling, and employ accredited laboratories to analyze the samples for microbial counts as per USP.
  14. De-dusting and Dust Extraction Systems: Evaluate the performance of de-dusting and dust extraction systems by assessing the efficiency of dust removal. Conduct visual inspections and particulate monitoring to ensure the effective removal of dust and airborne contaminants.
  15. Data Logging and Trend Analysis: Data loggers are employed to continuously monitor and record temperature, humidity, pressure differentials, and other critical parameters over an extended period. Trend analysis of this data helps identify any deviations or trends that may require corrective measures, allowing for proactive maintenance and optimization of the HVAC system’s performance.
  16. Documentation and Protocols: Comprehensive validation protocols should be developed, specifying the testing methods, acceptance criteria, and procedures to be followed during HVAC system validation. Detailed documentation, including test results, deviations, and corrective actions, is crucial to maintain a complete validation record.
  17. Online Monitoring and Alarms: Nowadays many facilities are installing innovative Online Monitoring and Alarms in GMP premises, especially Storage rooms. Storage rooms should be equipped with temperature and humidity monitoring systems to continuously monitor and record environmental conditions. Alarms and alert systems should be in place to notify personnel of any deviations from the recommended storage conditions, allowing for prompt corrective actions instantly and preventive action in the future.

Note: By utilizing these tools and methods, pharmaceutical manufacturers can effectively validate their HVAC systems, verify compliance with GMP requirements, and maintain the necessary environmental conditions to safeguard product quality and patient safety. Further explanation can be found (Readmore)

Future Trends in HVAC Systems in GMP Facilities:

Future trends in HVAC systems for pharmaceutical GMP facilities are focused on enhancing efficiency, sustainability, and technological advancements. Some potential trends include:

  1. Energy Efficiency: There is a growing emphasis on energy-efficient HVAC systems to reduce operational costs and environmental impact. This includes the use of advanced controls, variable speed drives, energy recovery systems, and optimized system designs.
  2. Smart HVAC Systems: Integration of smart technologies and automation is becoming more prevalent. This includes advanced control systems, remote monitoring, predictive maintenance, and data analytics to optimize performance, detect anomalies, and improve overall system efficiency.
  3. Cleanroom Air Filtration: Ongoing advancements in air filtration technologies are expected. HEPA filters and other high-efficiency filtration systems will continue to be utilized, while innovations in filter media and antimicrobial coatings in GMP premises and HVAC ducts may further enhance air quality and contamination control.
  4. Sustainability and Green Initiatives: HVAC systems in pharmaceutical GMP facilities are increasingly incorporating sustainable practices. This includes the use of environmentally friendly refrigerants, energy-efficient equipment, renewable energy sources, and designing for minimum environmental impact.
  5. Airflow Visualization and Simulation: The use of advanced airflow visualization techniques and computational fluid dynamics (CFD) simulations can aid in optimizing HVAC system design, ensuring proper airflow distribution, and identifying potential areas of concern.

Protection of Environment

As per WHO recommendation, the Protection of the environment is mandatory. To avoid polluting the surrounding air, equipment such as fluid bed driers, dust extraction systems and facilities that produce exhaust air with dust particles should have proper filtration or other control technology installed. The waste from dust extraction and collection systems should be disposed of properly. Suitable methods, such as a drainage system or a waste removal contractor, should be used to remove dust slurry.


Each component of HVAC duct systems plays a crucial role in maintaining proper airflow, distributing conditioned air effectively, and ensuring comfort and efficiency within a building. Proper design, sizing, and installation of these components are essential to achieve optimal performance and maintain the desired temperature, air quality, and energy efficiency.

The combination of temperature regulation, humidity control, and air filtration in HVAC systems ensures a comfortable and healthy indoor environment. The system’s components, such as heating and cooling units, humidifiers, and air filters, work together to maintain optimal conditions for temperature, humidity, and air quality, contributing to the well-being of occupants and the quality of the controlled environment.

Important Notes:

  • Both the architectural design of the building and that of the HVAC system should be carefully considered when attempting to achieve the general objectives of preventing contamination and cross-contamination and ensuring an appropriate environment for the production and control of pharmaceutical products.
  • and the products’ susceptibility to degradation. Where a clean room classification is specified, the manufacturer should state whether the classification is rated for the “as-built”, “at-rest” or “operational” condition1.
  • Remember When selecting air filters for pharmaceutical sections, it is crucial to consider the specific requirements of the area, such as air quality standards, contamination risks, and regulatory guidelines.
  • The appropriate choice of filters, such as HEPA filters for critical areas and activated carbon filters for odor control, ensures the maintenance of clean and controlled environments conducive to pharmaceutical production.
  • The infiltration of contamination from outside air should be minimized by the use of appropriate filtration, room pressure differentials, and airlocks. Manufacturing facilities should normally be maintained at a positive pressure relative to the outside, to limit the ingress of contaminants.
  • Where facilities are to be maintained at negative pressures relative to the ambient pressure, special precautions should be taken to avoid ingress and egress of contaminants.
  • Risks of contamination should be controlled, especially in the case of potent contaminants, to ensure the protection of materials, products, operators, and the environment
  • It is important to note that the selection of tools and methods for HVAC validation may vary based on facility requirements, regulatory guidelines, and specific industry standards. Additionally, engaging qualified validation professionals and following established protocols and best practices is essential to ensure accurate and reliable validation results.
  • These future trends aim to improve the efficiency, reliability, and sustainability of HVAC systems in pharmaceutical GMP facilities while maintaining strict adherence to regulatory requirements and product quality standards.


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