WHO Releases Draft on "GMP For HVAC Systems for Non-Sterile Dosage Forms"

This guidance follows the first edition of the WHO Guidelines on Good Manufacturing Practices for Heating, Ventilation and Air-Conditioning Systems for Non-Sterile Pharmaceutical Dosage Forms as the WHO Technical Report Series No. 937 in 2006. It was agreed to adopt part one, additionally the WHO found that additional guidance was required in the form of Part 2.

The draft document is intended to be a basic guide which can be used by pharmaceutical producers and GMP inspectors alike. Although certain specifications are given, the document should not be interpreted as a list of explicit requirements, it merely promotes a harmonized understanding of the WHO's expectations for HVAC systems.

Risk Assessments

As may be expected from most modern-day regulatory guidances, the WHO opens with Risk Assessments. The document outlines the requirement for a risk assessment of utilities such as HVAC installations. Not only should the overall installation be risk-assessed but all sub-components must be included as well. The draft guidance explicitly mentions sub-components such as; filters, heating coils, cooling coils and fans.

As a result of this risk assessment, appropriate controls should be identified and implemented. To ensure risk-assessments can thoroughly be conducted, the WHO expects manufacturers to clearly define the design parameters of their installations. This serves a dual purpose as it forces manufacturers to consider the required conditions for e.g. handling of materials and personnel requirements.


To ensure the proper functioning of a HVAC installation, the premises in which it is expected to function must be designed and maintained accordingly. Unidirectional staff and material flows should prevent a loss of environmental conditions. Furthermore, the guidance states that building finishes which shed particles should be avoided. To further limit a loss of environmental control, production areas should be maintained at a positive pressure relative to the outside.

To ensure this relative positive pressure is maintained, special care should be given to doors, which may include visual or audible alarms to prevent more than one door being opened simultaneously, resulting in a loss of the pressure regime.

Despite playing an important factor in maintaining environmental control, it cannot maintain this without "help". Specific controls and measures should be in place besides the HVAC installation.

Sample Diagrams

The document provides a number of sample diagrams and examples for implementation of the HVAC principles, on weighing/dispensing and sampling rooms for example the document states:

A room for weighing should be of appropriate design, it may be beneficial to associate several rooms with this specific set of activities. It is the manufacturer's obligation to ensure the HVAC installation maintains the same area classification in the rooms associated with weighing/dispensing/sampling activities as there is in production area's where the product comes into contact with the environment.

Read the Entire Document 

To find out more about the WHO's requirements for HVAC systems read Part One and Part Two.