Application NoteThe Importance of Dewpoint Measurement in Breathing Gases Breathing gases are essential in a wide range of applications, from medical life support to industrial safety and diving operations. Ensuring the purity and safety of these gases is critical, with trace moisture measurement playing a vital role in maintaining gas quality and protecting users. Breathing gases refer to any gas mixture intended for human inhalation. Breathing gases include medical air, oxygen (O2), nitrous oxide (N2O) and mixtures like Heliox, delivered via pipelines or cylinders for applications such as: • Supplementary oxygen in hospitals, ambulances and aviation • General anaesthesia and respiratory support via ventilators • Hyperbaric/SCUBA diving and life-support systems These gases are supplied via cylinders, pipelines or centralised systems and their composition must meet strict safety and purity standards. These gases are delivered under strict control, following standards such as ISO 7396 (medical gas pipeline systems), ISO 18562 (biocompatibility of gas paths), European Pharmacopeia, CGA/ANSI G 7.1, and OSHA 1910.134. Trace moisture, even at very low levels, can cause significant issues in breathing gas supply systems: • Corrosion of Equipment and Pipework: Moisture promotes rust and degradation in cylinders, pipelines and valves, compromising equipment integrity. • Microbial Growth: Elevated levels of moisture within gas lines enable bacteria and mould growth, posing health risks. • Gas Quality Degradation: Water vapour can react with other gas components, leading to impurities. • Freezing: In cold environments, moisture in the gas supply can freeze, blocking regulators and delivery systems. • Respiratory Health Risks: Excess moisture may irritate airways or worsen respiratory conditions.

Application Note The Importance of Dewpoint Measurement in Breathing Gases Solutions Dewpoint measurement for breathing gases is critical to ensure dryness and prevent microbial growth or corrosion in pipelines. Here are two common solutions: Online Dewpoint Sensors: Continuous measurement using dewpoint transmitters installed directly in the medical air pipeline or sampling line, often used with real time alarms. Typical measurement range: -40 °C to -70 °C dewpoint for medical air compliance. Portable Dewpoint Meters: Handheld or portable dewpoint meters are used for spot check measurements...