What happens when we breathe inert gases

Oxygen deficiency is a risk associated with handling gases such as nitrogen, helium, carbon dioxide, neon and argon. It is important that best practices are followed here.

Gases that occur naturally in the atmosphere are not toxic. At higher concentrations, however, they do have an impact on living things and combustion processes (especially in the case of oxygen).

Oxygen itself is not flammable, but it promotes combustion. In contrast, nitrogen and argon inhibit combustion.

Changes in the concentration of these gases are imperceptible to the human sensory organs. If not handled properly, accidents can occur.

In order for these gases to be stored in liquid form, they must be cooled to extremely low temperatures (less than –180 ° C at atmospheric pressure). In this state, they can quickly cause cold burns and make certain materials brittle, which in turn can lead to the failure of structural parts.

Oxygen starvation hazards

Oxygen is vital. A healthy adult can survive briefly with an oxygen content of only approx. 16%, but an adequate supply of oxygen must be guaranteed in an atmosphere that is inhaled by humans. If the oxygen values ​​drop, there are no immediate clear symptoms, so that a deficiency cannot be recognized by the human sensory organs.

Oxygen, vol .-%Measures and symptoms
18Lowest limit for working without a fresh air mask
< 18Significant decline in physical and mental performance without you noticing anything unusual
< 10Risk of unconsciousness without warning after a few minutes
< 8Loss of consciousness within a few minutes;
Recovery is possible when the person is taken into fresh air immediately
< 6Almost instantaneous loss of consciousness

Causes and Avoidance of Oxygen Deficiency

Oxygen deficiency can be avoided by observing the following measures:

  • Gas leaks (except for oxygen leaks) automatically lead to a lack of oxygen. New devices and systems that use inert or other gases must be carefully checked for leaks. For this purpose, a test of the gas pressure drop and, in addition, a leak test with an approved leak detection liquid that is compatible with the device or system in question must be carried out.

  • All devices and systems, including pipes and hose connections, must be properly installed. Care must be taken with hoses and other components that they are leak-tight and protected from damage. All maintenance and repair work must be carried out by experienced and fully qualified personnel.

  • When the work phase is finished, the gas cylinder valve or the shut-off valve of the gas supply via pipes must be closed to prevent gas escaping between two work phases. Valves on welding devices are not reliable shut-off valves for the gas supply. Gas cylinders in use must not be handled roughly or knocked over.

  • A small amount of liquid gas can evaporate into a gas volume that is many times larger. Liquid gas spilled in confined spaces can therefore quickly lead to a lack of oxygen. Tanks and facilities for storing and handling liquid gas must therefore be carefully checked and maintained in accordance with the relevant regulations and recommendations.

  • Vent gases are often low in oxygen. An atmosphere with these gases is unsuitable as a work area.

  • Oxygen deficiency occurs when system components such as tanks are flushed with nitrogen or other inert gases in preparation for repairs.

  • In processes in which liquid nitrogen evaporates, for example when refrigerating food, freezing the ground, cryosurgery and conserving blood plasma, atmospheres in which there is a lack of oxygen are automatically created. People are not allowed to enter such areas without suitable breathing apparatus. This also applies when there is only a slight lack of oxygen in the atmosphere. Areas of this type must be equipped with suitable detectors and alarm systems.

  • All processes in which gas is used for welding and heating remove oxygen from the air. These procedures can lead to a lack of oxygen if the work area is too small or poorly ventilated.

  • Removing argon, carbon dioxide, or some other cold gas from large containers and deep shafts can be difficult because these gases are denser than air. When air is introduced at the bottom of these spaces, it normally rises through the dense gas without displacing it. This means that the flushing process can take significantly longer than expected.

Detecting oxygen enrichment or deficiency

Areas in which the oxygen content can change to dangerous levels must be continuously monitored with measuring devices that indicate increases and decreases in the oxygen concentration in the surrounding atmosphere.

In tight spaces, these gauges should be placed as close as possible to the workforce. Ideally, workers should be equipped with a portable meter attached to their clothing.

Non-continuous measurement methods may only be used if the tendency to dangerous changes in the oxygen content between two measurements can be recognized in good time.

Other gases

  • Oxygen is not the only factor that determines whether a room is safe or not. Other gases, such as fuel gases and nitrogen oxides, used in conjunction with cutting or gas torches can also affect an atmosphere. If necessary, such atmospheres must be monitored.

  • Preventive measures

  • Devices that are used in the production, distribution and use of inert gases must be installed and labeled in accordance with the current rules of technology.

  • All leaks must be handled by appropriately trained personnel using appropriate equipment.

  • Workers and rescue workers need to know what to do in the event of an incident.

  • The operating and operating personnel must adhere to the rules and regulations applicable at the site at all times and, if necessary, wear protective equipment.

  • All persons who work in rooms in which there are risks from oxygen deficiency or oxygen enrichment must be appropriately informed about the respective risks. It is particularly important to emphasize that these risks are not readily identifiable and that they can quickly develop into a real hazard without warning signs for the workforce.