www. refrigerationandaircon. co. za RACA Journal I September 2025 39
Contributor
CLEANROOM CLASSIFICATION AND HVAC PERFORMANCE Most cleanrooms in South African pharmaceutical plants follow international cleanroom classifications such as ISO 14644, WHO TRS 961 and EU GMP Annex 1. Locally, SAHPRA( South African Health Products Regulatory Authority) aligns closely with WHO standards.
Each classification dictates specific performance metrics:
• Air Changes per Hour( ACH): ISO 8 cleanrooms typically require 15 – 20 ACH, while ISO 7 or aseptic areas require much more— up to 60 ACH or even higher.
• Differential pressure: Cleanrooms must maintain positive pressure relative to less critical spaces, typically 10 – 15 Pascals, to prevent unfiltered air ingress.
• Temperature and humidity: Many cleanrooms require tight control at 20 – 22 ° C and 40 – 60 % RH, especially during granulation or tablet coating.
Filtration also plays a vital role. A typical pharmaceutical HVAC system will use pre-filters( G4), fine filters( F8-F9) and HEPA filters( H13 or H14) at the terminal diffusers or inside the AHU, depending on classification and application.
ENVIRONMENTAL CONTROL STRATEGIES THAT WORK Controlling temperature and humidity in cleanrooms is not a onesize-fits-all task. For instance:
• Granulation and tablet compression areas need low humidity to prevent sticking or degradation of powders
• Sterile filling zones require stable temperatures and filtration integrity, often supported by laminar flow units or Restricted Access Barrier Systems( RABS)
A critical aspect of cleanroom operation is pressure cascades. For example, a sterile corridor may be kept at 20 Pascals above atmospheric, while the adjacent cleanroom sits at 30 Pascals. This graded approach keeps contamination flowing out, not in.
Case example: A pharmaceutical facility in Limpopo installed an ISO 8 cleanroom with 20 ACH and experienced relative humidity challenges during the summer. By integrating a dedicated desiccant dehumidification system and adjusting night-time AHU setback logic, they maintained GMP parameters year-round.
SYSTEM DESIGN CONSIDERATIONS IN AFRICA One of the smartest trends in South African pharma construction is the growing use of modular AHUs. These are built off-site in controlled factory conditions and shipped for installation, reducing site errors and installation time.
Choosing the right chiller or VRF condensing unit system is equally critical. In high ambient regions, systems must be rated for 40 ° C + ambient temperatures.
Airlocks, pass-throughs and gowning rooms should be sized not just for people, but for flow. An under-sized airlock may disrupt pressure zoning every time a door is opened. In highcontainment facilities, interlocks and time delays are used to further control air movement.
Local design must also factor in availability of maintenance staff. Complex systems with hard-to-source parts may become liabilities after commissioning. Wherever possible, use equipment with serviceable components available regionally.
VALIDATION, MONITORING AND COMPLIANCE No cleanroom is complete without robust Qualification and Validation( Q & V) processes. This includes:
• DQ / IQ / OQ / PQ( Design / Installation / Operational / Performance Qualification)
• Particle counting( non-viable and viable) during and after commissioning
• Airflow visualisation( smoke studies), filter integrity testing( DOP / PAO), and recovery tests
After validation, continuous environmental monitoring( EMS) must take over. Modern EMS systems log temperature, humidity, differential pressure and particle counts. Many are now cloudintegrated, providing remote alerts and automated deviation tracking for QA teams.
Importantly, SAHPRA inspections are increasingly rigorous on data integrity and compliance documentation. Investing in proper monitoring and recordkeeping now reduces audit risk later.
As pharmaceutical manufacturing expands across South Africa and the continent, HVAC systems must evolve beyond compliance. They must be resilient, energy-efficient and locally maintainable. Designing with lifecycle cost in mind— rather than just initial capex— is the key to long-term success.
Equally important is the investment in human capital. Even the most advanced HVAC system is only as good as the people who operate and maintain it. Training technicians, engineers and QA staff in cleanroom principles is not just good practice— it’ s essential.
The future of South African pharma is promising. But it will be built not just on molecules and machinery— but on clean, controlled air delivered by systems designed specifically for where we are. RACA
“ Complex systems with hard-tosource parts may become liabilities after commissioning.”
www. refrigerationandaircon. co. za RACA Journal I September 2025 39