Summary
A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas, but other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed habitats such as scuba equipment, surface supplied diving equipment, recompression chambers, high-altitude mountaineering, high-flying aircraft, submarines, space suits, spacecraft, medical life support and first aid equipment, and anaesthetic machines. Oxygen is the essential component for any breathing gas, at a partial pressure of between roughly 0.16 and 1.60 bar at the ambient pressure. The oxygen is usually the only metabolically active component unless the gas is an anaesthetic mixture. Some of the oxygen in the breathing gas is consumed by the metabolic processes, and the inert components are unchanged, and serve mainly to dilute the oxygen to an appropriate concentration, and are therefore also known as diluent gases. Most breathing gases therefore are a mixture of oxygen and one or more metabolically inert gases. Breathing gases for hyperbaric use have been developed to improve on the performance of ordinary air by reducing the risk of decompression sickness, reducing the duration of decompression stops, reducing nitrogen narcosis or allowing safer deep diving. A safe breathing gas for hyperbaric use has four essential features: It must contain sufficient oxygen to support life, consciousness and work rate of the breather. It must not contain harmful contaminants. Carbon monoxide and carbon dioxide are common poisons which may contaminate breathing gases. There are many other possibilities. It must not become toxic when being breathed at high pressure such as when underwater. Oxygen and nitrogen are examples of gases that become toxic under pressure. It must not be too dense to breathe. Work of breathing increases with density and viscosity. Maximum ventilation drops by about 50% when density is equivalent to air at 30 msw, and carbon dioxide levels rise unacceptably for moderate exercise with a gas density exceeding 6 g/litre.
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Related courses (4)
ChE-402: Diffusion and mass transfer
This course aims to provide an in-depth understanding of diffusion and mass transfer, an essential tool for the chemical engineers.
CIVIL-708: UHPFRC for structures - Fundamentals & Properties
This course aims at giving students the fundamental knowledge necessary to design, model, and apply Ultra High Performance Fiber Reinforced Concretes (UHPFRC) in structures, in a sustainable way. It p
BIO-377: Physiology by systems
Le but est de connaitre et comprendre le fonctionnement des systèmes cardiovasculaire, urinaire, respiratoire, digestif, ainsi que du métabolisme de base et sa régulation afin de déveloper une réflect
Show more
Related publications (69)