The PharmaTwin Blog
Insights on GMP zoning, HVAC engineering, and cleanroom facility design.
How to Calculate Air Changes per Hour for a Cleanroom
How to calculate cleanroom air changes per hour: ACH formula in metric and imperial units, a worked Grade C example, heat load, recovery and pressure checks.
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Environmental Monitoring in Pharma: Annex 1 Limits & Methods
Environmental monitoring in pharma explained: the four EM methods, EU GMP Annex 1 action limits by grade, alert levels and how to choose sampling locations.
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Cleanroom Gowning: Requirements by Grade and Room Design
Cleanroom gowning explained: EU GMP Annex 1 garments for each grade, the correct gowning order, gowning room layout and how operators are qualified.
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RABS vs Isolator: Differences and Annex 1 Requirements
RABS vs isolator compared: EU GMP Annex 1 background grades, open and closed designs, glove testing, decontamination and the impact on cleanroom layout.
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Cleanroom Validation: Qualification Tests and ISO 14644
Cleanroom validation explained: the EU GMP Annex 1 qualification tests, ISO 14644-1 sampling locations, microbial limits and requalification intervals.
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Pharmaceutical Facility Layout: Personnel & Material Flow
How to lay out a pharmaceutical facility so personnel, material and waste flows stay apart: FDA and EU GMP Annex 1 rules, corridor patterns, crossing checks.
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Cleanroom Airlock Design: Types, Pressure & GMP Rules
How to choose personnel, material, and air-shower cleanroom airlocks, and cascade, bubble, or sink pressure strategies that meet EU GMP Annex 1.
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Contamination Control Strategy (CCS): Annex 1 Guide
What a contamination control strategy is, the 16 elements EU GMP Annex 1 asks it to cover, who owns it, and how most of it is decided at facility design stage.
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Cleanroom HVAC Design for Pharmaceutical Facilities
How to size cleanroom HVAC for EU GMP Annex 1 and ISO 14644: air change rates, pressure cascades, HEPA filtration, and recovery time explained.
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GMP Cleanroom Classification: Grades A–D and Zoning
How EU GMP grades A, B, C and D map to ISO 14644 classes, what "at rest" and "in operation" mean, and how pressure cascades and airlocks make a zoning plan work.
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