Hazard type

Hazard type (HT) is central to both the safety provisions and the licensing requirements.

Hazard type defines and describes the nature of the hazard arising from an explosive in manufacture and storage conditions.

Hazard type Definition(regulation 2 ER2014) Explanation
Hazard Type 1 An explosive which, as a result of, or as a result of any effect of, the conditions of its storage or process of manufacture has a mass explosion hazard A mass explosion can be one:
  • in which the entire body of explosives explodes as one
  • where a substantial proportion of the explosives present could explode in such a way that the practical hazard should be assessed by assuming simultaneous explosion of all the explosives present
  • which is associated with a serious blast hazard
Hazard Type 2 An explosive which, as a result of, or as a result of any effect of, the conditions of its storage or process of manufacture has a serious projectile hazard but does not have a mass explosion hazard  
Hazard Type 3 An explosive which, as a result of, or as a result of any effect of, the conditions of its storage or process of manufacture has a fire hazard and either a minor blast hazard or a minor projection hazard, or both, but does not have a mass explosion hazard ie those explosives which give rise to considerable radiant heat or which burn to produce a minor blast or projection hazard
Hazard Type 4 an explosive which, as a result of, or as a result of any effect of, the conditions of its storage or process of manufacture has a fire or slight explosion hazard, or both, with only local effect ie those explosives which present only a low hazard in the event of ignition or initiation, where no significant blast or projection of fragments of appreciable size or range is expected

Hazard type represents the potential behaviour of the explosives in the form in which they are
manufactured or stored. This means that explosives do not have inherent hazard types that can be automatically ascribed without consideration. Hazard type will be dependant on:

  • the quantity of explosives
  • the types of explosives
  • the loading density
  • packaging (if any) or containment
  • the presence of barriers or other controls that will prevent rapid communication of an event between explosives;
  • orientation
  • how an event involving the explosives might progress or degrade any controls

How explosives of different hazard type can affect their surroundings can also depend on the orientation
of any packaging, additional confinement or building that they are in.

Determination of hazard type

For those explosives being kept as packaged for carriage, and that have been classified, there will generally be a direct correlation between the UN hazard division (HD) assigned them on classification for transport and the hazard type (HT) they should be allocated for storage, ie:

  • UN HD 1.1 = HT 1
  • UN HD 1.2 = HT 2
  • UN HD 1.3 = HT 3
  • UN HD 1.4 = HT 4

Explosives that have been assigned, on classification, the UN HD 1.5 and 1.6 will need to be considered in detail and on a case-by-case basis before a hazard type can be allocated.

Detailed information on the determination of hazard type can be found in the overarching guidance – safety provisions L150 and relevant sub-sector guidance[56].

Link URLs in this page

  1. Explosiveshttps://www.hse.gov.uk/explosives/index.htm
  2. Explosives Regulations 2014 (Amendment) Regulations 2016https://www.hse.gov.uk/explosives/regulations2016.htm
  3. Overview - The Explosives Regulations 2014https://www.hse.gov.uk/explosives/new-regulations.htm
  4. Guidance structurehttps://www.hse.gov.uk/explosives/guidance-structure.htm
  5. Subsector guidancehttps://www.hse.gov.uk/explosives/new-regs-subsector.htm
  6. Explosives Legislative Reviewhttps://www.hse.gov.uk/explosives/explosives-legislative-review.htm
  7. Getting startedhttps://www.hse.gov.uk/explosives/getting-started.htm
  8. Overview - Authorisations/licensinghttps://www.hse.gov.uk/explosives/licensing/index.htm
  9. Hazard type https://www.hse.gov.uk/explosives/licensing/hazard-classification.htm
  10. Safety requirementshttps://www.hse.gov.uk/explosives/licensing/safety-requirements.htm
  11. Separation distanceshttps://www.hse.gov.uk/explosives/licensing/separation/index.htm
  12. Building and construction typehttps://www.hse.gov.uk/explosives/licensing/separation/separation-distance-tables.htm
  13. Applying for a licencehttps://www.hse.gov.uk/explosives/licensing/how-to-apply.htm
  14. Local authority assenthttps://www.hse.gov.uk/explosives/licensing/local-authority-assent.htm
  15. Explosives in portshttps://www.hse.gov.uk/explosives/licensing/licensing-explosives-in-ports.htm
  16. Information for enforcing authoritieshttps://www.hse.gov.uk/explosives/licensing/enforcing-authorities.htm
  17. Refusals and revocations of authorisationshttps://www.hse.gov.uk/explosives/licensing/refusals-revocations.htm
  18. Safeguarding planshttps://www.hse.gov.uk/explosives/licensing/safeguarding-plans.htm
  19. Manufacturinghttps://www.hse.gov.uk/explosives/manufacturing.htm
  20. Securityhttps://www.hse.gov.uk/explosives/licensing/storage/storage-security.htm
  21. Storing explosiveshttps://www.hse.gov.uk/explosives/licensing/storage/index.htm
  22. Overview - Classification for transporthttps://www.hse.gov.uk/explosives/classification/index.htm
  23. UN test resultshttps://www.hse.gov.uk/explosives/classification/un-test-results.htm
  24. UN test series FAQshttps://www.hse.gov.uk/explosives/classification/faq-conducting-un-test-series-6.htm
  25. Analogyhttps://www.hse.gov.uk/explosives/classification/analogy.htm
  26. Non-contracting partyhttps://www.hse.gov.uk/explosives/classification/non-contracting-party.htm
  27. UN default scheme for fireworkshttps://www.hse.gov.uk/explosives/classification/un-default-scheme-fireworks.htm
  28. How to applyhttps://www.hse.gov.uk/explosives/classification/how-to-apply.htm
  29. Overview - Fireworkshttps://www.hse.gov.uk/explosives/fireworks/index.htm
  30. Firework displayshttps://www.hse.gov.uk/explosives/fireworks/using.htm
  31. Storing and selling fireworkshttps://www.hse.gov.uk/explosives/fireworks/industry.htm
  32. Transfer of explosiveshttps://www.hse.gov.uk/explosives/transfer-of-explosives.htm
  33. Overview - Ammonium nitratehttps://www.hse.gov.uk/explosives/ammonium/index.htm
  34. Ammonium nitrate and COMAHhttps://www.hse.gov.uk/explosives/ammonium/comah.htm
  35. Storage of ammonium nitrate blasting intermediate (ANBI)https://www.hse.gov.uk/explosives/ammonium/storage-ammonium-nitrate.htm
  36. Notification thresholdhttps://www.hse.gov.uk/explosives/ammonium/notification-threshold.htm
  37. High nitrogen contenthttps://www.hse.gov.uk/explosives/ammonium/high-nitrogen-content.htm
  38. Land use planninghttps://www.hse.gov.uk/explosives/ammonium/land-use-planning.htm
  39. Discarding and disposalhttps://www.hse.gov.uk/explosives/disposal.htm
  40. Reporting losshttps://www.hse.gov.uk/explosives/reporting-loss.htm
  41. Placing civil explosives on the markethttps://www.hse.gov.uk/explosives/ce-marking/index.htm
  42. Market surveillancehttps://www.hse.gov.uk/explosives/market-surveillance.htm
  43. Record keeping requirementshttps://www.hse.gov.uk/explosives/record-keeping.htm
  44. Manufacture, storage and carriage of thermiteshttps://www.hse.gov.uk/explosives/manufacture-storage-carriage-of-thermites.htm
  45. Overview - Other topicshttps://www.hse.gov.uk/explosives/other.htm
  46. Exemptionshttps://www.hse.gov.uk/explosives/exemptions/index.htm
  47. Record of explosives incidentshttps://www.hse.gov.uk/explosives/eidas.htm
  48. Identification and traceability https://www.hse.gov.uk/explosives/traceability-itoer.htm
  49. Applying for a Site Identification Codehttps://www.hse.gov.uk/explosives/applying-for-site-identification-code.htm
  50. Overview - Resourceshttps://www.hse.gov.uk/explosives/resources.htm
  51. Formshttps://www.hse.gov.uk/forms/explosive/index.htm
  52. Publicationshttps://www.hse.gov.uk/explosives/publications.htm
  53. Useful linkshttps://www.hse.gov.uk/explosives/useful-links.htm
  54. Contactshttps://www.hse.gov.uk/explosives/contact.htm
  55. The UK has left the EU, and some rules and procedures have changed from 1 January 2021https://www.hse.gov.uk/explosives/ce-marking/index.htm
  56. overarching guidance – safety provisions L150 and relevant sub-sector guidancehttps://www.hse.gov.uk/pubns/books/l150.htm

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Updated2024-06-12