compressed_breathing_air_monitoring
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GasmetTM FTIR application note Compressed breathing air analysis KEY WORDS • Breathing air • Diving • Aircraft • EN 12021, DEF STAN 68-284 issue 3 PRODUCTS • DX4040 Portable FTIR Gas Analyzer OVERVIEW Compressed breathing air is subject to strict limits of harmful contaminants defined in European standard EN 12021 and various defence standards such as DEF STAN 68-284 issue 3. The testing interval of breathing air compressors and associated equipment is 3 months and gases tested include carbon monoxide, carbon dioxide and oil vapour defined as hexane and heavier hydrocarbons. EN 12021 covers underwater applications including self-contained open circuit compressed gas breathing (SCUBA) and compressed gas line breathing (hard-helmet diving), respiratory equipment used on ground for escaping from toxic atmospheres and for working in contaminated atmospheres. It also covers breathing gas for hyperbaric operations and synthetic air. While EN 12021 does not cover aerospace applications, the British MOD publication DEF STAN 68-284 and its counterparts in other countries cover also the breathing gases used in aviation. TESTED GASES The tables below summarize gases with limit values in various applications. It should be kept in mind that in addition to these limits, the breathing air must comply with workplace health and safety regulations and typically the contaminant concentrations in compressed gas must be below 10% of the 8 hour time workplace exposure limit (WEL). EN 12021 and DEF STAN 68-284 list requirements for parameters such as dew point, odor, presence of oil mist and metal particles etc. which cannot be measured with FTIR and have been omitted from the tables. Also, the limit values and blending tolerance for Oxygen have not been shown as O2 is not infrared active and cannot be measured by FTIR. Copyright Gasmet Technologies

Typical tested gases and contaminant concentration limits in different applications Compressed natural air Heliox, Nitrox and Trimix Molecular sieve oxygen concentration system (MSOCS) generated breathing gases (aviation) CO2 CO Total hydrocarbons Oxides of Nitrogen Acrolein Aldehydes Unsaturated hydrocarbons Refrigerants Solvents (halogenated) Ozone

TESTING EQUIPMENT As the testing of breathing gas compressors is a periodic routine, a portable gas analyser with short set-up time and capability of simultaneous measurement of as many contaminants as possible is required. The battery powered Gasmet DX4040 portable FTIR multi-gas analyser is an ideal solution as it is capable of measuring the contaminants listed in the table above and also nearly any gas with a workplace exposure limit, which could be present as a contaminant in the cylinders or breathing air lines. The analyser does not require any consumables or span gases for...