How Many Particles? How Much Sample Volume?
How many particles are needed to demonstrate statistical confidence for cleanroom control and how much
sample volume is required to see them? There is increasing confusion over the requirements for compliance
with EC GMP Annex 1 limits on 5.0 μm particles, especially when compared with the ISO 14644-1 calculations
recommended for establishing conditions for such testing.
The problem arises when using the ISO 14644-1 calculations. The minimum sampling volume required by this
formula for EC GMP compliance is huge.