The Guideline of the WHO that was initially issued in 2006 targets HVAC systems operated in non-sterile production sites, and predominantly in production of solid dosage forms. The issued version was published as Annex 5 of the Technical Report 961 und comprises feedback from regulators and users as well as the harmonisation with ISO documents.
The practical Guide has been extended by the following chapters:
4.6 Displacement concept (low pressure differential, high airflow)
4.7 Pressure differential concept (high pressure differential, low airflow)
4.8 Physical barrier concept
7.2 Air distribution
7.5 Additional system components (in HVAC systems)
For the first time Chapter 8.2 Qualification refers to the ISO Standard Series 14644 with regard to the verification for Particles, Air Change, Pressure Difference, Leak Test and Air Velocity.
For further details please see the Annex 5 - Supplementary guidelines on good manufacturing practices for heating, ventilation and air conditioning systems for non-sterile pharmaceutical dosage forms.
Dr. Robert Eicher