Fire Brigade checking on farm fertiliser storage
Some of our clients have recently received unannounced visits from their local fire brigade, to check on the storage of nitrogen fertilisers on their farm.
We would therefore like to remind you of the rules on storing these products, to keep you safe and ensure any such visits are short and sweet.
You should always inform the local fire authority that ammonium nitrate is stored on your farm, and agree with them the arrangements for giving early warning of a fire, providing suitable access to the site and ensuring that an adequate supply of water is available, or can be made available, to tackle an incident.
The HSE guidance Storing and Handling Ammonium Nitrate states that: Where a site contains 25 tonnes or more of dangerous substances, the Dangerous Substances (Notification and Marking of Sites) Regulations 1990 require the person in control of the site to notify the fire authority and the enforcing authority of certain details.
Regulations & Guidelines on storage
Fertilisers that contain 28% or less nitrogen do not normally present an explosion hazard and therefore, ammonium nitrate-based fertilisers are usually divided into two groups:
Fertilisers that contain more than 28% nitrogen. Most of these are straight ammonium nitrate types, although they include a small number of compound fertilisers.
Fertilisers that contain 28% or less nitrogen. Compound fertilisers form the major proportion of this group. The straight nitrogen types are usually a mixture of ammonium nitrate with limestone or similar inert materials.
Ammonium nitrate will not explode during normal handling, but it can be detonated under heat, confinement, or severe shock. For example, in a fire, pools of molten ammonium nitrate may be formed and if the molten mass becomes confined (e.g. in drains, pipes, plant or machinery) it could explode, particularly if it becomes contaminated.
Storage areas
Ammonium nitrate should normally be stored in single storey, dedicated, well-ventilated buildings that are constructed from materials that will not burn, such as concrete, bricks or steel, and have no internal drains.
Storage should be away from possible sources of heat, fire or explosion, such as oil storage, gas pipelines, timber yards, flammable liquids, flammable solids and combustible materials including hay, straw and feedstuffs.
Stores should be cleaned before they are used for storing ammonium nitrate.
Prohibit smoking in all storage areas and display prominent NO SMOKING notices.
It is also recommended to display signage showing where the fertiliser is stored and signs to show there is a product in storage which is ‘highly flammable’.
Stacks
Self-confinement of straight ammonium nitrate in large stacks can increase the risk of a detonation of the whole stack in a fire, so limit stacks to a maximum of 300 tonnes.
Do not store ammonium nitrate that contains more than 28% nitrogen in the same stack as other products.
Where a site contains 25 tonnes or more of dangerous substances, the Dangerous Substances (Notification and Marking of Sites) Regulations 1990 require the person in control of the site to notify the fire authority and enforcing authority.
For more information and source, see https://www.hse.gov.uk/pubns/indg230.pdf
