Compressed Air Is a Production Medium, Not an Auxiliary
In pharmaceutical manufacturing, compressed air touches the product directly: blowing out containers, conveying, drying, inside isolators. The same standard of care therefore applies to it as to room air – yet it is monitored systematically far less often. EU GMP Annex 1 lists utilities as one of the elements to be addressed in the contamination control strategy (2.5 iv). For gases, Chapter 6 makes this concrete: the risk of each utility must be determined by a risk assessment and documented as part of the CCS (6.1), and gases in contact with the product are subject to defined requirements for quality, point-of-use filtration and periodic microbiological monitoring (6.18–6.20).
Three Classes, One Designation
ISO 8573-1 does not rate compressed air with a single figure but with three mutually independent classes stated together – for example in the form [1:2:1]:
- Solid particulate: The first digit. In the stricter classes the particle count per cubic metre is limited in the size ranges 0.1 to 0.5 µm, 0.5 to 1.0 µm and 1.0 to 5.0 µm; in the coarser classes a mass concentration takes its place.
- Water content: The second digit, defined via the pressure dew point – from class 1 at no more than −70 °C and class 3 at no more than −20 °C through to classes defined by liquid water content.
- Oil content: The third digit, referring to total oil from aerosol, liquid and vapour: class 1 at no more than 0.01 mg/m³, class 2 at 0.1 mg/m³, class 3 at 1 mg/m³ and class 4 at 5 mg/m³.
Class 0 Does Not Mean "Free Of"
Class 0 is the most frequently misunderstood. It does not stand for "oil-free" or "particle-free" but for: stricter than class 1, with a specification to be agreed between user and supplier and documented accordingly. An equipment specification that merely states "class 0" without naming the agreed values is incomplete – and will not hold up in an audit.
Measure at the Point of Use, Not at the Generator
The purity class of a compressed air treatment system says little about the air that actually arrives at the product. Between compressor and point of use there are pipes, receivers, couplings and hoses – every one of these sections can introduce particles, residual oil or moisture. Only measurement at the point of use, under real conditions of use, is therefore meaningful.
How Moqlero Covers This
Physical environment monitoring in Moqlero covers the two compressed air parameters that are hardest to control in ongoing operation: oil content and pressure dew point. Both are stored with limits, evaluated automatically during the measurement, documented in the signed report and carried forward through trend evaluation. Calibration reminders for pressure dew point meters, water content sensors and oil vapour monitors run through the same service module as those for particle counters.
Compressed air at the product deserves the same attention as the air in the room!