Twenty Eighth Report Contents

Appendix 1: Additional information from the Department for Food, Environment and Rural Affairs

Q1: Could you set out please why DRTs and DR certificates are a requirement? What do DRTs demonstrate? This is not really explained in the EM.

A1: Ammonium Nitrate (AN) can be volatile and is strictly regulated. The DRT is the method of assessing the stability of the AN and ensuring its resistance to detonation within specified limits. The test is undertaken to ensure that the AN (when properly handled according to HSE guidance) can be safely transported, stored, or handled without exploding. The DR certificate provides evidence that the relevant AN has successfully passed the DR test performed by an accredited ISO laboratory.

Q2: What types of AN products require such tests and certificates – is this linked to the AN content of the products and is there some form of categorisation that indicates whether products are covered?

A2: The detonation resistance testing and certificate requirements under the Ammonium Nitrate Materials (High Nitrogen Content) Safety Regulations 2003 (“the 2003 Regulations”) apply to “relevant ammonium nitrate”, which is defined in regulation 2. This is ammonium nitrate in solid form (or material in solid form, comprising a mixture of components, one of which is ammonium nitrate), where its nitrogen content (derived from ammonium nitrate) is more than 28% of its weight and the material has a total weight of five hundred kilogrammes or more, but does not include material which is a classified explosive. Each detonation resistance certificate should relate to a sample from each production run batch. A ‘batch’ means the quantity of material manufactured without alteration of composition or characteristics, with a maximum batch run of 92 days.

Regulation 10 of the 2003 Regulations provides that, in some circumstances, HSE may grant an exemption from the requirement for relevant ammonium nitrate to be accompanied by a DR certificate (and certain other requirements under the Regulations), subject to the condition that the ammonium nitrate will not be supplied or used as a fertiliser. The granting of an exemption is also subject to any other conditions that HSE may impose. The exemption provision is intended to allow continued supply of technical grade ammonium nitrate, which will of necessity not pass the detonation resistance test. Technical grade ammonium nitrate can be used in the making of civil explosives such as those used for blasting and mining.

27 January 2022

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