The importance of high-quality compressed air in manufacturing


Gardner Denver’s Keith Atkinson outlines the importance of air purity in pharmaceutical manufacturing, the standards that apply to the sector and options available to owners and operators of sites wishing to maintain compressed air of the highest possible quality

Compressed air is vital to many processes when manufacturing pharmaceuticals. If contaminated, this compressed air can lead to reduced performance, product spoilage and damaged production equipment, resulting in additional costs and unexpected downtime for site owners and operators. Compressed air is often referred to as the “fourth utility,” which underlines its huge importance to the pharmaceutical manufacturing industry. The sector requires reliable, high-quality compressed air to power manufacturing processes … and in vast quantities. This quality is further prioritised because compressed air is in direct contact with pharmaceutical products, meaning contamination is easily possible.

The risk of contamination and its consequences should not be understated. Even the smallest possible risk of contamination can impair processes such as material handling, process air and product drying, and harm air curtains, control valves and cylinders and other tools. These adverse effects can often only be resolved at significant expense, burdening factory owners and operators with costs that could otherwise be avoided.

Taking this into account, it is clear that avoiding contamination should be a priority in any production facility, not just those manufacturing goods that will be ingested. As such, there are exceptionally stringent standards in place to help govern compressed air performance and provision at manufacturing sites. These standards have been designed to ensure production environments are pollutant-free — to avoid the costs and unscheduled downtime that might be caused by product spoilage or impaired equipment. They include ISO 8573, a group of international standards stipulating compressed air purity and quality.

The standards contained within ISO 8573 can be broken down into nine separate parts. Part one addresses the level of contamination that can be tolerated within one cubic metre of compressed air. In particular, it sets out the allowed particle count, pressure dewpoint and amount of oil allowed within this sample.

The remaining eight specify the methods of testing for a range of contaminants, including oil vapour, solid particles, organic solvents, gaseous contaminants, microbiological contaminants and liquid water, as well as aerosol content and humidity levels. They also ensure that air quality test results are comparable within a given tolerance of measurement.

Hazard analysis and critical control point

Although ISO 8573 is extremely stringent, a number of sites are now going further than these standards in their efforts to ensure compressed air of the highest quality. Specifically, they are adopting the principles of the hazard analysis critical control point (HACCP). Originally developed for food safety, the HACCP system prioritises integrating contamination control into production processes instead of simply checking finished products.

The control can be broken down into seven principles, which ensure that facilities comply with hygiene legislation by eliminating potential hazards or reducing them to an acceptable level. Under this system, stakeholders must first analyse what hazards may contaminate the end product and how likely this hazard is to occur.

They must then determine critical control points or steps in the manufacturing process when control can prevent, eliminate or acceptably reduce a hazard risk. Appropriate limits must also be established for these control points — easily defined metrics such as time, temperature and humidity that the hazard should not exceed or fall beneath to prevent, reduce or eliminate it. Furthermore, monitoring procedures should be established for these control points. Following this, site stakeholders should establish corrective actions that employees may execute to prevent problems before they occur, and set out verification procedures to ensure the HACCP system is being followed.

Examples of these procedures include inspecting product samples, monitoring records and the calibration of monitoring equipment. Finally, a report system detailing HACCP records should be set up so site owners and operators can identify patterns, problems and deviations, and ensure continued system compliance.

Going oil-free

Beyond adhering to these standards, there are further steps that site owners and operators can take to guarantee a reliable supply of high-quality compressed air. These include adopting certain compressor technologies that prioritise air purity.

For example, the demand for uninterrupted high-quality air can be met by oil-lubricated compressors using filtration. This process protects products and equipment from being compromised by any oil present in the system.

However, investors using oil-lubricated compressors in sensitive production environments are subject to guidelines set down in European Hygienic Engineering & Design Group (EHEDG) 23 Production and the Use of Food-Grade Lubricants, Part 1 and 2 (2009).

The effort it takes to consistently comply with these guidelines may present a logistical challenge to some owners and operators. Additionally, the trend toward tightening these regulations means investors may find that their filtration systems are quickly no longer fit for purpose and therefore should review and upgrade when necessary.

Oil-free compressor technology offers a solution to these potential challenges, delivering compressed air of the highest possible quality and purity. By virtue of their design, oil-free compressors exude fewer contaminants that could compromise the purity of compressed air. This means oil-free systems are a more suitable option in environments wherein contaminant-free air is vital.

Furthermore, oil-free technology is adaptable to the needs of different manufacturing sites, with multiple compressor designs and systems available. For example, Gardner Denver offers compressors that utilise scroll technology, water-injected rotary screw technology and the revolutionary Ultima system, which uses two high-efficiency permanent magnet motors with separate inverters to optimise performance throughout the complete volume range.

Vacuum pumps

Alongside adhering to ISO 8573, implementing a HACCP system and adopting oil-free technology, further measures can be adopted to lessen the risk of contamination, such as focusing on ancillary operations and utilities alongside direct production processes. For example, vacuum pumps are typically oil-lubricated and situated next to production lines. Although many will operate with no issues, poorly maintained or faulty pumps may discharge oil from the exhaust. Oil can also be transferred from an open-ended inlet port and separator elements may fail as a result of misuse or the use of non-genuine parts.

These issues can be avoided with regular maintenance and by using genuine spares. Alternatively, owners and operators could consider fitting a downstream exhaust filter to remotely pipe exhaust air away or purchasing a specialist oil-free vacuum pump. Elmo Rietschle’s VSI range, for example, comprises totally oil-free, dry running screw vacuum pumps for packaging under protective gas and need no coolant or sealing medium in the suction chamber. The pump is water-cooled and offers low heat emission into the environment.

Prioritising oil-free systems

In conclusion, although air purity is undoubtedly important in the sensitive environments associated with pharmaceutical production, avoiding contamination should be a priority in any production facility. Indeed, this key rule should be kept in mind at all times — compressed air quality is as important as its consistency.

Site owners and operators can use oil-lubricated models and filtration techniques to help deliver this high-quality air. However, adhering to stringent air quality regulations, adopting oil-free technology and recognising the contamination risks of ancillary processes can better guarantee contaminant-free compressed air.

By adopting such a holistic approach to air quality for manufacturing processes and equipment, stakeholders can ensure production environments remain free from potential pollutants and the disruption they might cause.

This article appeared in the September issue of Manufacturing Chemist.