What is inertization? – Definition

Inertization, or inerting, is an explosion protection process that uses inert gas to prevent the formation of an explosive mixture.

Inerting systems are used to prevent:

  • vapors from escaping into the atmosphere (contamination)
  • air from penetrating into the plant (oxidation)

When substances are processed whose vapors can form a highly flammable mixture with atmospheric oxygen, any risk of explosion must be prevented. In practice, the air is replaced by an inert gas.

What is an inert gas?

Inert gases are non-combustible gases (also called protective gases) which do not react with the fuel and do not promote combustion.

In inertization, the inert gas displaces the atmospheric oxygen in the plant to such an extent that an explosive atmosphere is prevented. As a rule, nitrogen is used as the inert gas.

The inert gas is introduced into the space that should be protected from explosion. The presence of the inert gas reduces the oxygen volume fraction below the limiting oxygen concentration (LOC) or the maximum allowable oxygen concentration (MAOC) so that the mixture can no longer ignite.

Safety measures for the use of inert gases

During inertization, MAOC should not be exceeded at any time. Suitable safety concepts ensure that the MAOC in the plant to be protected (such as centrifuge) is maintained during normal operation and during startup and shutdown. These protective measures must take effect, for example, when a defined alarm threshold is reached.

Since there is a danger of suffocation in inerted apparatus, suitable personal protection measures must be taken:

  • Safety measures to prevent the inert gas from having a harmful effect on health
  • Precautions to be taken if there is a risk of leakage or overpressure operation outside the plant
  • Protective measures for the entire operating room in the event of major leaks

Typical application areas of inerting systems

  • The chemical and pharmaceutical industry
  • In the mineral oil industry when working with highly flammable organic solvents or harmful volatile components
  • To prevent oxidation in the processing of products in the food and beverage industry and in edible oils



[1] Heinz Brauer: Handbook of Environmental Protection and Environmental Technology, Volume 3

[2] Employers' Liability Insurance Association for Raw Materials and the Chemical Industry: Explosion Protection Knowledge: What Zones Are Required in Inertization