Asco Instruments

ASCO joined the CFD Group – a historic French manufacturer of railway equipment – in 2012 and can draw on the support of its engineers and technicians in a large number of fields (mechanical engineering, electronics and information technology, for example).

ASCO Instruments has five main fields of activity:

• Manufacturing sensors that take physical measurements,
• Manufacturing toxic and explosive gas detection control panels,
• Designing and manufacturing gas detectors for parking facilities, breathing air, biogas and the water treatment industry,
• Manufacturing test benches and special machines,
• Manufacturing and upgrading machines to meet ATEX standards.

One of ASCO’s specialities is the analysis of breathing air (gas that we can breathe, that can be used to breathe with). Breathing air must comply with standard EN 12021.

Standard EN 12021 on the quality of breathing air:

In an industrial setting, if workers are equipped with respiratory protective devices (masks, hoods, diving apparatus, etc.) supplied by a compressed air system, the limits set out by this standard must be adhered to.
The main requirements are given in the table below:

• Oxygen 21% (± 1%)
• Contaminants below the national exposure limit
• Oil mist/vapour 0.5 ml/m3
• Free from odour or taste
• Carbon dioxide (CO²) 500 ppm
• Carbon monoxide (CO) 15 ppm
• Water content (*) 5°C below the likely lowest ambient temperature

*There must not be any liquid water present, or risk of freezing. Where conditions of usage are not known, the pressure dew point must not exceed -11°C.

You can see that a ‘simple’ filtration system, such as pre-filter + air/oil separator + activated carbon, is not sufficient to produce breathing air.
A complete system which processes toxic gases such as CO and CO2 is needed to comply with this standard and prevent any accidents, which can, in the most serious cases, be deadly.