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Control measure

Separate oxidising materials from fuel sources

Control measure knowledge

Oxidising materials can be split into two groups, organic and inorganic oxidisers. Inorganic oxidisers are not themselves combustible, but will support combustion by reacting in a way that will yield oxygen, thereby supporting combustion. Therefore, in a scenario where fuel and oxidising agents are combined and this mixture is ignited, combustion is not only dependant on the availability of atmospheric oxygen. The oxidising agent will now provide oxygen to support combustion, enabling the fuel source to burn more fiercely and in atmospheres with reduced oxygen content. Therefore, extinguishing a fire through smothering to remove oxygen is not an option, leaving cooling or removing the fuel source as the key options.

Where the fuel and oxidising materials can be physically separated, caution should be taken as the friction created by moving the oxidising material will also add energy into the product, creating a risk of rapid decomposition.

In certain circumstances, it may be appropriate to establish a physical barrier between the two materials to prevent contamination and a reaction. With advice from the on-site specialist or hazardous materials adviser (HMA), personnel should ensure that there is no potential reactivity between the barrier and the oxidising product or fuel. This option will only be available where inorganic oxidisers are present as organic oxidisers have their fuel within the same molecule as its oxygen source.

Water used in the process of extinguishing a fire or cooling containers of combustible materials can dissolve the oxidiser. This can result in the oxidiser being transported to areas where combustible materials are located, creating the potential for spontaneous combustion to occur in the future, when the water has evaporated.

For guidance regarding fire-water run-off contaminating drains and watercourses, etc. see National Operational Guidance: Environmental protection.

Strategic actions

Fire and rescue services should:
  • Provide procedures, guidance and support arrangements regarding the hazards that may be encountered and actions to take to separate oxidising materials from fuel sources

Tactical actions

Incident commanders should:
  • Assess the possibility of increasing the distance separating oxidising materials from fuels

  • Consider separating the oxidising material from exposure to a heat source

  • Predict the flow of fuels or oxidising materials that are either molten or carried by contaminated water run-off if containment is lost

  • Evaluate the potential to put physical barriers in place between oxidising substances and fuels