Compressed air quality

Compressed air is energy that has to be produced. Like any product, it has measurable parameters that define its quality.

Some air consumers have few quality requirements; others have very demanding ones.

Industrial air quality is assessed under ISO 8573-1. In simple terms, the standard evaluates three types of contamination. First are solid particles, such as dust drawn in from the atmosphere and corrosion released from pipework. The second parameter is water content, which can cause corrosion, droplets during rapid exhaust or even frost. The third is residual oil, particularly important in paint shops, food production and pharmaceuticals. With oil-lubricated compressors, an activated carbon filter is often installed before the consumer to capture residual oil vapour. Its effectiveness, however, is commonly managed by estimating the filling's life and replacing it at predetermined intervals. Replacement may therefore be unnecessarily early or too late, both of which can be costly.

Machine and process-equipment manufacturers should specify air quality at delivery. In demanding applications, air quality and regular checks should also form part of preventive maintenance, audits or certification. In our experience, this often does not happen, leaving operators with unnecessary process problems that have relatively simple solutions.

For these cases, we provide comprehensive checks of air generation and filtration performance, as well as authorised, documented measurements of all three air-quality parameters from collected samples.

The measurement evaluates solid-particle size and quantity to check filter performance and, when samples are taken at consumers, detect secondary contamination from pipework. It determines the actual pressure dew point of air from the distribution system and the dew point after expansion, showing whether the dryers work correctly.

Oil content is measured at oil-lubricated compressors to check their operation. A sample taken after activated carbon filtration shows whether the filter is working and whether its cartridge is saturated.