AIESG guidance on AN storage

STOP THE ROT

AMMONIUM NITRATE • AFTER SOME HIGH PROFILE ACCIDENTS, AEISG HAS BROUGHT TOGETHER ITS KNOWLEDGE INTO A NEW CODE OF PRACTICE FOR THE STORAGE AND HANDLING OF AN MATERIALS

THE BEIRUT PORT explosion in August 2020 threw an unforgiving spotlight on issues surrounding the storage and handling of ammonium nitrate (AN) in all its forms; since then, authorities around the world have busied themselves with checking whether the same thing could happen in their territories. One general finding is that the explosives industry, which uses AN as a blasting explosive in mining and quarrying operations, performs well and has robust standards and best practice guidance in place; the less well organised agricultural sector, where AN is used as a fertiliser, lacks such common standards.

Those handling AN can, therefore, learn a lot from the explosives sector and, to help them in that endeavour, the Australasian Explosives Industry Safety Group (AEISG) has published a new Code of Practice on the storage and handling of solid AN; its aim is to provide the global industry with a risk-based approach to establishing best practice in the storage and handling of AN. The Code of Practice has been put together by AEISG’s AN Technical Panel, drawing on its members’ wide experience and using a scientifically based and verifiable risk-based approach, and is freely available from the AEISG website, www.aeisg.org.au.

LESSONS TO BE LEARNED The new AEISG Code of Practice focuses very much on the explosives sector and the needs of the Australian industry in particular, although the approach it takes should be of value to all those involved in the AN supply chain.

For instance, the Code contains a list of the significant incidents involving AN in manufacturing, transport and storage over the past 100 or so years; it also notes that, while none of them would have fallen within the scope of the recommendations, they would not have occurred had the basic principles for safe storage and handling of AN, as detailed in the Code, been followed. “All of the events reviewed indicate that multiple failures occurred in the preventative and mitigative layers of protection,” the Code states.

Those layers of protection begin with the proper design of any facility that is designed to be used for the storage of AN. The first step is to ensure that only the required amount of AN will be stored at any time. The site should be located at an appropriate distance from other activities or residential areas and, within the site, the AN should be segregated from heat sources, fuel, incompatible chemicals or other activities. Any storage facility should be construction of non-combustible materials and its electrical equipment must meet relevant standards. Fire extinguishers should be provided at approved locations (although the Code also notes that the ‘fight or flight’ decision should prevent any concerted effort by site personnel to fight a fire that may run out of control).

Just as important are administrative controls once a site is operating. The criteria of all licences, regulations and procedures need to be strictly observed and the stock of AN should be kept as low as is reasonably practicable. All operators should be fully trained and drilled, both in operations and evacuation plans. It is important to keep the site tidy and not to allow rubbish, vegetation or discarded pallets to collect in areas where AN is stored. Management of change is vital and operators should also be in touch with local emergency services so that they also understand evacuation and exclusion zone plans.

AEISG’s Code of Practice goes on to discuss in detail how a site should be arranged, how AN should be stored and segregated, what equipment is appropriate for use in an AN storage area, the necessary security requirements and plans, emergency response and planning, environmental controls and other factors. An appendix also provides a model risk assessment plan, which will be very useful to all those involved in the sector.