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Explosives information bulletin no. 53 | 12 August 2020 | Version 6

Storage requirements for security sensitive ammonium nitrate (SSAN)

References and further information

A. Explosives Act 1999

B. Explosives Regulation 2017

C. Work Health Safety Act 2011

D. AEISG – Code of Good Practice for Precursors

E. Australian Standard AS 4326-2008 – The storage and handling of oxidizing agents

F. COAG Document “Principles for the Regulation of Ammonium Nitrate”

G. National Working Group SSAN Guidance Note No 2 Storage Nov 2004

H. Explosives Information bulletin No. 52, Transport of Security Sensitive Ammonium Nitrates (SSAN)

I. Australian Code for the Transport of Dangerous Goods by Road and Rail – 7th Edition

Purpose

This bulletin outlines the minimum safety and security requirements to store SSAN in Queensland under References A and B. The SSAN covered by this bulletin include technical grade ammonium nitrate (TGAN) and fertiliser grade ammonium nitrate (FGAN). These products have different physical explosive properties.

The storage of SSAN must also meet safety requirements as outlined in the Work Health Safety Act 2011 (Reference C) or, if on a mine site, the applicable mining legislation plus any particular requirements outlined in the manufacturer’s Material Safety Data Sheet.

This bulletin includes information to support siting of new facilities, and the appropriate separation distances that apply to them. If unable to achieve the distances shown, the licence holder or licence applicant must conduct a quantitative or qualitative risk assessment (QRA) to demonstrate an equivalent level of safety.

The precursor code (Reference D) is called up by Reference B and may be used for those items covered by the code. The requirements in this information bulletin override Reference E, AS 4326-2008 – The storage and handling of oxidizing agents, which is not called up in References A and B unless stated otherwise.

Ammonium Nitrate Emulsions (ANE) are an SSAN and must have the same security arrangements detailed in this bulletin. The precursor code (Reference D) called up by Reference B covers the storage and separation requirements of ANE.

SSAN storage must be conducted in accordance with environmental requirements and are to comply with the Environmental Protection Act. The Department of Environment and Science has regulatory control of this matter.

Scope

This information bulletin is applicable to all licence holders who store SSAN. Compliance with this bulletin is a condition of licence for all SSAN ‘storage’.

Background

Security Sensitive Ammonium Nitrates (SSAN) are administered under the Explosives Act 1999 (Reference A) as an explosive, not of Class 1. SSAN retains its dangerous goods classification under Reference A and is referred to as an explosive of class 5.1, class 9 or a non-dangerous good in the case of calcium ammonium nitrate. SSAN is also classed as a security sensitive explosive under Reference B.

On 25 June 2004 the Council of Australian Governments (COAG) agreed to a set of principles to limit access to SSAN (Reference F). Each state and territory agreed to introduce legislation to give effect to the COAG agreement. SSAN is defined in this bulletin under definitions. The guidance note on storage developed by the national working party on SSAN underpins this information bulletin.

Definitions

The following definitions are provided for ease of reference in this bulletin:

  1. Class A: Public street, road or thoroughfare, railway, navigable waterway, dock, wharf, pier or jetty, marketplace, public recreation and sports ground or other open place where the public is accustomed to assemble, open place of work in another occupancy, river-wall, seawall, reservoir, water main (above ground), radio or television transmitter, main electrical substation, private road which is the principal means of access to a church, chapel, college, school, hospital or factory.
  2. Class B: Dwelling house, public building, church, chapel, college, school, hospital, theatre, cinema or other building or structure where the public is accustomed to assemble, shop, factory, warehouse, store, building in which any person is employed in any trade or business, depot for the keeping of flammable or dangerous goods, major dam.
  1. Hazard Identification (What can go wrong and why?).
  2. Risk Analysis – Comparing the anticipated risks of intervention with the risks of no intervention result (How bad and how likely is it?).
  3. Risk Assessment – A systematic process for the identification, analysis and evaluation of a substance, thing or happening (hazard) that may under different circumstance lead to an accidental loss or security breach (How acceptable is it?).
  4. Risk Control (What can we do about it?).
  1. detectable theft;
  2. unexplained loss;
  3. deliberate interference; and
  4. unauthorised access.
  1. access to the secure store; and
  2. access to the keys to the secure store.
  3. Note: All those with unsupervised access to SSAN will need to be an authorised person.
  1. a compound with a security fence or
  2. a locked building ; or
  3. a secure shed with lockable entrances, and where relevant, windows that are locked or barred; or
  4. a secure and lockable freight container, silo or magazine; or
  5. in the case of ammonium nitrate emulsions, a lockable tank.
  6. Note: Quality security locks must be employed; electronic type locks may be acceptable.
  1. multistorey buildings, e.g. above 4 storeys;
  2. large glass fronted buildings of high population;
  3. health care facilities, child-care facilities, schools;
  4. public buildings or structures of major historical value;
  5. major traffic terminals, e.g. railway stations, airports;
  6. major public utilities, e.g. gas, water, electricity works.

2 Australian Standard AS 1725 – 2003: Chain Link Fabric Security Fences and Gates
3
The following standards apply to locksets, padlocks and security seals. Australian Standard AS 4145.2-1993 Locksets, Part 2: Mechanical Locksets for doors in buildings; Australian Standard AS 4145.4 – 2002 locksets, Part 4: Padlocks; Australian Standard AS 4255.1 – 1994 Security Seals, Part 1: Classification; Australian Standard AS 4255.2 – 1994 Security Seals, Part 2: Use.

Issues

Licence to store

Licence

The licence threshold for SSAN is 3kg. A licence to store is not required for quantities less than 3kg. This exception under National Guidance Note No 2 Storage, (Reference D), is only applicable to bona-fide laboratories including schools and other learning institutions where possession of a maximum amount of 3 kg is allowed without a licence. Good laboratory practices, dangerous goods handling and accounting procedures should be in place to ensure an appropriate level of security and safety for the product.

To obtain a licence to store SSAN, a security plan must be submitted to the regulatory authority along with the completed licence application, correct fee and Safety and Security Management System. The licence to store may also authorise the purchase, possession and disposal of SSAN, depending on the nature of the business. The licence application should indicate the full range of activities to be conducted. The security plan may be an element of the Safety and Security Management System, which is a requirement under section 46A of the Explosives Regulation 2017 (a licence holder without employees does not require a Safety and Security Management System). The proposed storage application should address the matters outlined in this bulletin.

Prior approval required

A licence to store is required prior to the storing of SSAN. For new facilities it is appropriate that the user ensure all requirements for the site are met. This may include development applications with other agencies such as Local Government and Emergency Services. When applying for a licence, the applicant must provide evidence of compliance with this Information bulletin and may include:

  1. technical specification of product;
  2. quantity of product to be stored (kg);
  3. distances to exposed sites (metres);
  4. number and locations of persons exposed to the storage site;
  5. security plan for the intended operations;
  6. safety and security management system for the intended operations; and
  7. detailed plans of storage activity.

What a licence to store allows

A storage licence allows the holder to possess the SSAN, purchase the SSAN, store the SSAN, handle and transport in the storage location and dispose of product resulting from spills and contamination in a non–explosive manner. The storage licence may be endorsed for other various categories of explosives and may include SSAN and blasting explosives on the same storage licence. A site may include several magazines or buildings. The table below summarises the activities covered by a licence to store explosives – SSAN.

Activities allowed under storage licence

Activity Description of activity Permitted
Possess May possess explosives under the Act Yes
Purchase Purchase where required to conduct licence activity Yes
Export Permitted to export No
Import Permitted to Import No
Sell Sell SSAN in accordance with the Act No
Store Store SSAN in accordance with Act Yes
Transport Transport SSAN in accordance with Act No5
Manufacture Manufacture SSAN No
Dispose Dispose of spills Yes6

4 Storage includes handling, repacking, conveying and materials handling.
5 For a storage licence it is not permissible to transport product on public roads.
6 This is for the disposal of spilled product in accordance with AS 4326.
7 A safety and security management system is required when one or more of the licence holder employees carry out activities under the licence, section 46A Explosives Regulation 2017, Reference B.

Obligations of a person or company holding a storage licence

A person or company holding a storage licence must meet the following obligations:

  1. Prepare and operate a security plan, based on risk assessment, including:
    1. location and details of storage facility
    2. nominated responsible person for operation of security plan for SSAN and contact details
    3. authorisation of persons having access to SSAN
    4. records of SSAN receipts, issues and stock on hand (products and quantities)
    5. records of product recipients and uses.
  2. Operate and maintain a Safety and Security management system (SSMS)5.
  3. Immediately report any loss, theft, attempted theft or unexplained discrepancy, or any incident to the Explosives Inspectorate and the police.
  4. SSAN must be stored in a locked facility/container or be under constant surveillance.
  5. The storage facility must conform to the Workplace Health and Safety Act 2011, the applicable Australian Standards and National or Industry Codes.

Requirements to store SSAN

Safety considerations

The storage of SSAN must meet both safety and security considerations. Separation distances must be adequate to ensure that in the unlikely event of a mass explosion, consequences are minimised. Separation distances are to be calculated using the guidance in this bulletin and the Separation Distance Tables outlined below:

  1. Annex A – Separation distances between ammonium nitrate (SSAN) and explosives magazines.
  2. Annex B – Separation distances in metres for the storage of ammonium nitrate to protected works and vulnerable facilities.
  3. Annex C – Separation distances in metres for the internal separation of ammonium nitrate storage stack/bunkers.

Quantities of SSAN at any storage site should be limited to minimum practical quantities as a means of minimising risk with regard to safety and security.

Siting requirements

SSAN storage sites represent significant capital investment. The construction of new facilities inside or outside the licence holder area may impact on the amount of SSAN that may be stored on a site. An example would be the construction of a hospital (a vulnerable facility) on the licence holder’s boundary that affects the amount of SSAN that can be stored. The construction of such facilities would require the licence to be reviewed to ensure that safety and security aspects are not adversely affected. It is a licence condition that the holder advises the inspectorate of any proposed changes in the vicinity of the storage site that would impact on its utility as a storage site.

To ensure that external developments do not impact on storage facilities the use of a buffer zone for the distances applicable in the tables is recommended. As internal development is under the control of the licence holder, there should be an internal plan that prevents internal development that could adversely impact on the storage or manufacturing facility.

The following factors may need to be considered when siting an SSAN facility:

  1. local planning authority and by-laws;
  2. maximum amount of intended storage;
  3. congestion of the area;
  4. number of persons exposed;
  5. available fire fighting facilities;
  6. assessment of risk from toxic fume hazards in the event of decomposition or fire;
  7. proximity of other facilities, buildings, dangerous goods storages, etc; and
  8. future and demand growth of the operation.

Note: Separation distances from explosives stores are provided in Annex A, Table A1. Separation distances from other neighbouring facilities are provided in Table B1, Annex B

Existing storage sites

Existing storage sites may not meet the requirements of this bulletin in terms of safety and security. The Explosives Inspectorate requires that operators of all storage and manufacturing sites conduct a safety and security review to determine the risk of ongoing operations. For existing sites the safety and security review should demonstrate that in the unlikely event of a fire leading to explosion or deliberate interference, the impact on the public, infrastructure and other businesses will be minimal (if the review indicates major safety and security concerns then the operator must take corrective action e.g. significantly increasing security).

Alternative safety and security measures

Licence holders may present alternative safety and security measures in accordance with section 9 of the Explosives Regulation 2017. The alternative safety and security measures must address the most likely contributors to a mass explosion which may include combustibles that would contribute to a fire, contamination of the product that could lead to decomposition or a fire, confinement of product and propagation of an explosion to adjacent stacks. It should also address the increased security arrangements. The alternative measures must provide an equivalent or lower risk. Internal separation distances are to conform with Annexes A, B and C and/or a quantitative risk assessment.

The possibility of deliberate interference must be considered as a credible scenario. Many of the existing storage facilities are not affected due to their isolation from the public. Each case should be considered on the likely threats and potential consequences. A copy of the safety and security review should be forwarded to the Explosives Inspectorate and thereafter held and maintained in the licence holder’s security plan. A review should be conducted on a regular basis (every two years) or when there is a change of circumstances, or an incident.

Security plan and risk assessment

A security risk assessment is a necessary preamble to developing a security plan. This assessment will describe existing security measures and examine the level and type of security risks to your particular business. In clarifying those risks it is necessary to consider outside threats and also the security risk from staff or contractors who have access to your premises and SSAN. You should consider whether current security arrangements leave the SSAN vulnerable to theft, fraud or deliberate interference, and consider security improvements appropriate to manage the assessed risk. Security risk assessments should be reviewed periodically, and must be reviewed after security incidents.

The security plan is to be based on a security risk assessment that provides information to the licence holder and the regulatory authority about current security measures and about the risk of theft, unexplained loss, deliberate interference and unauthorised access. Companies and individuals that are also storing Class 1 explosives should include them in their security plan.

Security plan overview

The security plan will describe how you will meet the minimum requirements and any other security measures to be introduced. The security plan will include sensitive information and the individual or company operating the Security Plan should ensure that it is a controlled document, limited to people in the organisation that must know the detail and it must be handled in a confidential manner. The security plan must include a system of checks and balances to ensure individuals cannot remove SSAN without arousing suspicion. The security plan will have four main elements:

  1. risk management;
  2. personnel management;
  3. site security; and
  4. procedures.

Note: The security plan may be integrated into the Safety and Security Management System.

The security plan will provide information to the regulatory authority about how you will meet security requirements. Employees should understand their role in security by the licence holder incorporating the Security Plan requirements into their operating procedures. The plan should stipulate who in the organisation has access to its constituent parts.

A key requirement of the security plan is that theft can be detected quickly and advised to authorities. The basic security principles to be addressed include:

  1. SSAN must be kept in a secure store;
  2. there must be procedures for controlling access to the secure store including access to relevant keys;
  3. there must be procedures for checking and authorising persons with unsupervised access to SSAN, including :
    1. designating a responsible person to maintain the security plan,
    2. instruction of workers on the security plan procedures; and
    3. ensuring people with unsupervised access to SSAN are authorised persons;
  4. record keeping to reconcile incoming and outgoing quantities of SSAN and to ensure that SSAN is obtained from an authorised person and removed by an authorised person; and
  5. procedures for reporting to authorities any unexplained loss, theft, attempted theft or any other security incident involving SSAN.

Additional measures

Annex D details additional security measures that may need to be considered in relation to a storage location. It is not meant to be exhaustive and applicants may find that other measures provide an appropriate response to identified risks.

Minimum security requirements for the storage of SSAN

This part details the minimum security requirements in relation to the storage of SSAN (Reference G). The risk assessment that is conducted may dictate that additional measures are required to maintain a necessary level of security. Any departure from the requirements of this bulletin must be subject to a thorough and competent risk assessment that justifies such a departure.

  1. Minimum requirement 1 : List of authorised persons. Employees having unsupervised access to SSAN must hold a security clearance. The security plan must contain a list of all those who will have unsupervised access to SSAN. Employees having unsupervised access to SSAN must be 18 years or older and either hold a security clearance or be in the presence of and under the direct supervision of someone who holds a security clearance. This list will include the licence holder and some employees. Those persons involved in the administration of SSAN, including purchasing, stock control, despatch, import, export, risk management, and other areas where information is sensitive, should be considered to hold a security clearance. This list must be kept up to date. Licence holder applicants must hold a security clearance at the time the application is decided. Where persons do not have unsupervised access to the product or sensitive information, a security clearance is not mandatory. Note: A person may only have unsupervised access to product associated with authorised tasks under the employer’s control. Unsupervised access does not mean unimpeded access to any SSAN.
  2. Minimum requirement 2 : Staff recruitment. The security plan must include the provision for adding new workers or contractors to the list of authorised persons. Should the licence holder wish to add new workers or contractors to the list these persons will be required to hold a security clearance and can be added to the security plan in the form of a dated amendment to the list of authorised persons. The security plan must not allow uncleared persons to have unsupervised access to products or sensitive information. The security plan must also detail the checks that will be made to confirm the identity of new workers who will have unsupervised access to SSAN. Identification of new workers must be confirmed using the approach at Annex E, and checks should also be made (and recorded) with the applicant’s referees and previous employers .
  3. Minimum requirement 3 : Maintaining the security plan. The security plan must include the nomination of a responsible person/security manager to implement and maintain the security plan, including the instruction of workers in the relevant access controls, recording procedures and reporting of security incidents. This person should ensure that appropriate checks and audits are conducted to verify that the security plan is operating effectively. Depending on the company circumstances it may be appropriate to ensure there is a back up responsible person.
  4. Minimum requirement 4 : Details of your secure storage arrangements for SSAN. The security plan must contain details of your secure storage facility, including type and dimensions of structure, number and type of doors and windows, type of lock etc. SSAN must be in a secure store under lock and key or constant surveillance (refer to definitions). As an exception to the above requirement, Intermediate Bulk Containers (IBCs) are permitted in open air/ uncontained/outdoor compounds as long as :
    1. the IBCs are sealed with tamper-proof seals so that theft of product is easily detectable;
    2. a security fence is in place. (It should be separated from the nearest IBCs by at least 3000 mm). Refer AS 1725 – 2003: “chain-link fabric security fences and gates”; and
    3. regular checks of the bags are conducted to determine if there has been unauthorised access.
  5. Minimum requirement 5 : Controlling access to the secure store. Procedures for supervised and unsupervised access to the secure store of SSAN must be developed and checks put in place to monitor the effectiveness of these controls. In particular :
    1. Persons having unsupervised access to the secure store must be clearly identified in the security plan. These people will require a security clearance.
    2. A ‘key plan’ must exist that identifies who has access to the keys to the secure store compound and where the keys are securely kept.
  6. Minimum requirement 6 : Record keeping and inventory procedures. Records must be kept for a minimum of five years and there must be systems and procedures in place to record :
    1. purchases/acquisitions and sales/supply of SSAN, to ensure that changes in custody occur only between licence holders or persons having authorised access; (Drivers must carry current photographic ID issued by a government agency - this can include an Explosives Driver Licence)
    2. records of product loss due to container damage and/or spills are to be recorded and written off by a nominated person in the security plan. Note: The nominated person for write off is not to be directly involved in the activity that resulted in the loss.
    3. movements of SSAN into and out of the secure store are to be recorded so that records can be reconciled (after appropriate investigation); and
    4. security incidents, including thefts, attempted thefts, unexplained losses, deliberate interference or attempted deliberate interference, breaks-in, attempted breaks-in and any other security incidents, so that these incidents are recorded, investigated and reported to the regulatory authority. This authority may be contacted on the Explosives Inspectorate Response number 1300 739 868, and the local police station must also be advised. If the situation is an emergency, life-threatening or in progress dial “000”.

    9 See Annex E based on the 100 point identification system and verification process.
    10 Ideally, a suitable padlock should be pick-protected and shackle protected (e.g. concealed shackle using case hardened steel body with raised shoulders) and not be re-keyable. Ideally a padlock should also be bolt cutter resistant and have protection against the lock being drilled out. Further information regarding padlock specifications and locksets for doors in buildings can be found in Australian Standards AS 4145.4 – 2002 and AS 4145.2 – 1993 respectively.

Storage of SSAN

The most critical aspects for the safe storage of SSAN are good housekeeping, fire prevention and emergency response planning. Spills, contamination of the product plus fire are the most likely conditions that may lead to an uncontrolled fire and possible explosion. The probability of a fire and an explosion is very low if stringent attention is paid to good housekeeping and fire prevention, however if an explosion does occur the consequences may be severe.

Note: SSAN with >0.2% combustible material is classified as an Explosive Class 1.1 product and is to be managed accordingly.

Licence holders handling SSAN must have in place arrangements that ensure contamination is not likely to occur. If SSAN does become contaminated, it must be quarantined from other SSAN and treated as a non conforming product until disposed of.

Manufacturers and importers must ensure that test results with certificates from recognised laboratories demonstrate that the SSAN product is Class 5.1 or 9 or, in the case of CAN, not a dangerous good.

The licence holder must verify the quality of the product throughout the supply chain. This can be verified by sampling analysis and achieved by effective packaging, good access control, appropriate handling techniques, quarantining out of specification product, clean storage and transport facilities and segregation from contaminants by barriers, etc.

Storage conditions and locations

Australian Standard AS 4326–2008 (Reference E) – The storage and handling of oxidizing agents includes general requirements for oxidizers and specific requirements for ammonium nitrate which is an oxidizer but can have explosive properties under certain conditions. The requirements of the standard are not repeated in this document. This standard does not cover explosives precursors such as UN 3375.

The following provides guidance to the sections to be complied with from the standard:

  1. Section 1 – Scope and General. Required.
  2. Section 2 – Minor Storage. Not applicable to ammonium nitrate.
  3. Section 3 – Transit Storage. Required. Section 3.4 regarding transit stores in continual use to be treated as permanent storage areas.
  4. Section 4 – Storage and Handling of Packages. Required. This includes general requirements and notes that additional requirements for the storage of ammonium nitrate in IBC’s and packages is given in Section 9.
  5. Section 5 – Storage in intermediate bulk containers. Required. This includes general requirements and notes that additional requirements for the storage of ammonium nitrate in IBC’s is given in Section 9.
  6. Section 6 –. Bulk storage of Solids.  Required. Earth or compacted road base floors are not allowed for bulk products. The bulk SSAN retaining wall of 200mm concrete is deemed to be equivalent to the free air space required between packaged product and building walls Additional requirements for the bulk storage of ammonium nitrate are given in Section 9.
  7. Section 7 – Storage and Handling of Liquids in Tanks. Required. This includes general requirements with additional requirements of the storage of ammonium nitrate solutions in tanks are given in Section 9. (refer to AEISG Code of Good Practice Procedures for Precursors).
  8. Section 8 – Storage of Hydrogen peroxide. Not required.
  9. Section 9 – Specific Requirements for Ammonium Nitrate. Required. ALL except 9.4(b) Queensland requirements apply. See Annex C of this information bulletin. Table 9.3 Stack separation to read 16m on combustible pallets or 8m on non-combustible pallets.
  10. Section 10 – Operational and Personnel Safety. Required. These matters must be incorporated into the SSMS of the holder as appropriate to Ammonium Nitrate.
  11. Section 11 – Emergency Management. Required. These matters are to be incorporated into the emergency plan and integrated into the SMS.
  12. Section 12 – Fire Protection. Required. 12.2(b) Separation distances are to conform with Annex C of EIB 53. 12.2(c) Risk of destruction of storage may be acceptable if all controls are effectively in place and adequate separation distances are available. The note on availability of fire fighting equipment to enable rapid extinguishment of fires in its initial stages is critical. Elimination of fire sources such as matches, lighters and cigarettes shall be effective. Control of heat sources such as vehicles, forklifts, MHE and hot work shall be effective.
  13. Section 13 – Waste Storage and Disposal. This section provides general oxidizer requirements and should be considered. Clause 9.7 covers Ammonium Nitrate and is to be followed..
  14. Appendix A – Informative and to be noted
  15. Appendix B – Specific to ammonium Nitrate Informative and to be noted and appropriate measures taken in the SMS and emergency Plan.

The code frequently refers to regulatory requirements that may differ from the code. EIB53 is a condition of licence and in this regard stipulates the Queensland regulatory requirements..

Storage of bulk SSAN in a bunker system may be up to 5000 tonne capacity in 500 tonne sections. The sections should be designed to prevent cross contamination, fire and detonation communication. When bunker systems are not used or the storage exceeds 500 tonnes specific approval from the Explosives Inspectorate is required for conditions and location. The licence applicant must submit a risk assessment when seeking approval above this limit.

For packages and IBC's stacked on wooden pallets, storage shall be in maximum stack sizes of 200 tonnes, separated from each other by a minimum air space or a concrete wall of not less than 200mm thickness. Minimum separation distances between stacks are shown in Annex C. It is the store operator's responsibility to ensure stack stability is maintained in all stack configurations. For packages and IBC's stored on either non-combustible (steel) pallets OR without any pallets the maximum stack size is 500 tonnes. All other conditions in this paragraph remain unchanged. Existing storage sites are to ensure that the minimum separation distances in Annex C are met by 1 Dec 2009.

Where adequate spacing is provided between stacks and all other mitigations are firmly in place the explosives separation distances can be calculated on a single stack. For example four stacks of 500t (total 2000t) that have adequate separation and all other controls are effectively in place can be regarded as a single 500t stack.

Note: This assumes the Ammonium Nitrate has not been sensitised through poor storage practice, thermal cycling, moisture absorption or been contaminated.

This separation seeks to prevent a mass explosion of stacks but it may result in fires and explosions in other stacks which should be considered in the emergency response plan.

Class 1 Explosives or dangerous goods of other than Class 5.1 shall not be stored within the SSAN store. If the ammonium nitrate store is located near explosives then it should be separated from those explosives by minimum separation distances in Annex A, Table A1.

Dangerous goods of Class 5.1 which react dangerously, i.e. are incompatibles are also to be excluded or adequately separated within the storage area. Such dangerous goods include but are not limited to chlorates, nitrates and some ingredients for emulsion explosives. Reference E, Section 9.3.4. provides additional guidance.

The open floor of every store, including any vehicle access area shall be kept clean of any spilled SSAN at all times i.e. spills must be cleaned up immediately. All spills should be regarded as contaminated and be disposed of in an appropriate manner.

Explained losses

SSAN lost through handling incidents is to be accounted for as an explained loss. This may be the result of containers becoming unserviceable or through damage to the container. The spills must be cleaned up and disposed of in accordance with the safety and security management system which may be based upon AS 4326. The amount disposed of must be recorded and written off by a person who is authorised to do so in the security plan and SSMS.

Note: Spills and explained losses must be formally recorded.

Use of shipping containers to store SSAN

This section is designed for the storage of small quantities by shotfirers and small quarries. All stores must have a minimum clearance of 900mm between the top of the pile (or stack) and the roof or lowest support beam of the building. Use of shipping containers as a store is permitted if the following precautions are taken:

  1. if the floor is wooden it should be covered with either steel, aluminium, a plastic sheet or a suitable sealed coating such as epoxy paint. This is to facilitate cleaning and the prevention of fires ;
  2. the container is structurally sound and does not leak;
  3. vents are operable to release gases in the event of decomposition or fire;
  4. locks or seals are fitted to the Australian Standards mentioned previously such that theft can be prevented or detected;
  5. the use of wooden pallets should be minimised to reduce the presence of combustible material ;
  6. containers of SSAN do not normally require lightning protection, however the matter should be considered in accordance with the Australian Standard AS/NZS 1768:2007 – Lightning protection;
  7. the container provides protection against thermal cycling;
  8. containers are to be stable, on firm ground, with no vegetation within 5 metres (see AS 4326 9.3.1(b)); and
  9. signage requirements are to be met as for a storage building.

The long term storage of SSAN in standard shipping containers is poor practice and is detrimental to the long term quality of the product due to thermal cycling and the absorption of moisture.

SSAN in transit stores

This part covers transit stores, while Explosives Information Bulletin 52 – Transport of Security Sensitive Ammonium Nitrates (SSAN) deals with transit in the transport context. SSAN in transit is to meet the general storage security requirements. The transit provisions for ammonium nitrate are laid down in Section 3 of AS 4326:2008. The transit definition in AS 4326 is from twelve hours to five working days. If the transit area is in continual use ie: it is usual to have product in that area it is to be considered as a permanent storage area and treated accordingly in terms of safety and security risks.

A security risk assessment is to be conducted to cover the operation of the transit store. The key security aspects to consider are the potential consequences form unauthorised access or interference. The transit store should not be sited where an event would cause significant disruption to dwellings and vulnerable facilities. Appropriate security and emergency response systems are adequate and in place.

Construction and operation of storage facilities

Storage areas of ammonium nitrate may lead to possible ground run off of ammonium nitrate in solution that could have harmful effects upon the environment. The site is to have appropriate environmental plans in place to manage such run off.

Depending on the storage method drains and dams may be required to contain and dilute contaminated AN run-off from storage areas. The environmental management of run off from the site will need to be monitored and subject to review by the Department of Environment and Science.

Fire Protection

Section 12 Fire Protection in AS 4326 provides detailed information. Fire protection strategies for ammonium nitrate (SSAN) stores need to be designed around the chemical properties of ammonium nitrate i.e. it does not burn but is a strong supporter of combustion of any combustibles (such as pallets) that may be present. If the storage conditions are of a high quality the ammonium nitrate may simply decompose but if contaminants and fuel are present there is an increased likelihood of fire and in the event of fire it is possible that deflagration and possible transition to detonation may take place.

Note: Ammonium Nitrate that is contaminated or includes carbonaceous material may behave as an explosive of Class 1.

Fires involving ammonium nitrate cannot be extinguished by oxygen deprivation i.e. attempts to smother fires with dry chemical C02 or foam will be useless. Water is the only effective means of fire fighting in product storages but some dry chemical extinguishers must be on hand to deal with electrical or vehicle fires.

Decomposition or fires involving ammonium nitrate (SSAN) may result in toxic fumes and a low probability of explosion. When a fire involving Ammonium Nitrate is judged to be out of control it is recommended that evacuation is conducted to a distance equivalent to the separation distance outlined in Annex B, Table B1, Column 4 (Protected works class B). This distance must be listed in the emergency response plan for the organisation and understood by all employees, contractors and visitors. The local medical facilities should be informed of the particular hazard posed by the oxides of nitrogen released in decomposition, fire or explosions.

Note: There is a danger from the noxious fumes released by ammonium nitrate if it is decomposing or burning. Care should be taken to ensure people are not within the fume area.

In store locations remote from associated works, dwelling houses and vulnerable facilities the requirement for fire fighting resources may be dispensed with by agreement with the Chief Inspector of Explosives. The licence holder will need to support this with a risk assessment.

Fire control with ammonium nitrate is best achieved by eliminating (preferably), isolating or minimising combustible materials present in the form of either :

  1. materials of construction (see construction section);
  2. packaging materials and stacking aids such as pallets;
  3. machinery, plant and equipment;
  4. flammable and combustible liquid stores; and
  5. good housekeeping.

Fire hazards of powered mobile machinery in the store are addressed in AS 4326, however any fuel or oil leaks must be cleaned up immediately. Any machinery or vehicle used in this area must be well maintained to eliminate the possibility of fires.

Proactive preventative maintenance and stringent housekeeping rules are critical to minimise the risk of fire. The licence holder should ensure a Risk Assessment is conducted with competent personnel and reviewed every 12 months or after a change of circumstances, or incident. The expectations for fire fighting must be clearly documented in the Safety and Security Management System and emergency plan.

Seperation distances

The general risk of SSAN exploding is low, however, in the unlikely event of an explosion occurring, the consequences may be catastrophic. The risk can only remain low if security measures remain effective, deliberate interference can be discounted and that housekeeping of the store is at a consistently high standard. Research into incidents with ammonium nitrate that have resulted in an explosive event usually indicates the presence of contaminants.

The explosive properties of Ammonium Nitrate require appropriate separation distance because of the significant consequences that can occur with ammonium nitrate incidents such as the tragic explosion at Toulouse in Sep 2001. This was fertiliser grade ammonium nitrate (FGAN) and not the higher concentrated, technical grade (TGAN). It is critical in the event of an accidental explosion that adequate separation distances are in place to minimise damage and casualties.

Separation distances are based on ensuring that in the event of a store of ammonium nitrate exploding the effects will not result in significant casualties or property damage. This is to be applied for associated works, protected works and vulnerable facilities. The overpressures used for these definitions for the storage of SSAN are listed below. The calculated distances for these items are a considered relaxation appropriate to a product that is not Class 1 but can explode under certain conditions and circumstances.

Type of workOverpressure D Calculation
Associated works 21kPa D = 8.0 Q1/3
Protected works class A 14kPa D = 10.4 Q1/3
Protected works class B 7kPa D = 17.8 Q1/3
Vulnerable facilities 2kPa D = 44.4 Q1/3

Table 2: Overpressure Calculations

The table and Annex B, Table B1 is based on the overpressures outlined in Hazardous Industry Planning Advisory Paper No 4 (HIPAP). These overpressures have been adopted as it is a recognised standard and will ensure reasonable levels of safety in relation to overpressures if the low risk high consequence explosion in SSAN occurs. It is appropriately less stringent in separation distances for some of the categories used for Class 1 explosives.

External and internal separation distances

The separation distances need to be considered from an internal and external view. The table A1 at Annex A is based upon definitions used in AS 2187 and defined in this information bulletin. Associated works relate to internal separation distances while Protected Works Class A/B and Vulnerable facilities relate to external separation distances. Persons inside a facility exposed to associated works distance are at risk of injury and possible death. The licence holder must have in place emergency procedures that can provide for associated works employees to be evacuated to safe locations.

Annex A, Table A1 indicates the separation distances to be applied from an ammonium nitrate store to an explosives store. These distances are based on the ammonium nitrate being seen as a receptor rather than a donor.

SSAN is less sensitive to explosive propagation than Class 1 explosives. Existing technical advice indicates that an explosive propagation is possible from one stack of AN to another. The distances are relatively small and allow large volumes of stock to be stored in close proximity. While propagation may not occur at the distance indicated there would be significant effects on neighbouring stacks that could lead to contamination, decomposition, fire and/or possibly further explosions. These consequences may have significant effect on the licence holders business continuity plans and should be considered.

Note: Ammonium Nitrate subjected to temperature cycling and/or moisture absorption will be more sensitive. In which case, additional separation distances should be applied.

When stacks of up to 500 tonnes are involved. Annex C Table C1 provides separation distances from AN to AN regardless of the storage configuration. The distance is regarded as being adequate to prevent the propagation of an explosion. It may not be adequate to prevent a decomposition or burning event in the exposed stack.

Separation distances - equivalency and efficiency

For the purposes of calculation, ammonium nitrate in a store (bulk, packaged or containerised) is regarded as having a Trinitrotoluene (TNT) equivalency factor of 0.32 at an efficiency factor of 1. In these consequence calculations no additional allowance is made for efficiency of the explosions, as this efficiency has already been included in the factor. In the absence of any definitive evidence this factor of 0.32 is to be used for all equivalency calculations.

Note: The use of 0.50 TNT equivalency for transport under the Australian Explosives Code is still considered appropriate as there are other risk factors at play and also for storage with explosives in Annex A. Also in AS 2187 Part 1 the use of 0.50 TNT equivalency is used when AN is stored with high explosives

Sample Calculation of Storage Site

For a large storage site, if the stack size is 500 tonnes and the separation distances comply with Annex C, the consequences for an event is based on 500 tonnes, maximum, of SSAN exploding. The basis is that the donor stack will not communicate to the adjacent receptor stack. The distance to be provided is to be measured from the extremity of the storage site in all directions. The mass of the SSAN is to be adopted in the calculation of separation distance to a vulnerable facility from an SSAN store e.g. an SSAN stack of 120,000kg (largest stack) in a shed of 2,000,000 kg capacity of 100% by mass of ammonium nitrate at an equivalency of 0.32 TNT. using the formula in Table 3 under:
D = 44.4 x (Q) 0.33333 where D = Distance and Q = Quantity in kg of TNT (Mass of AN in kg x TNT equivalency)
Q = 120,000 x 0.32 (Equivalency Factor) x 1.0 (% mass of AN)
= 38,400 kg equivalent of TNT
Looking at table D1, Column 4 for Vulnerable Facilities
D = 44.4 x (38,400) 0.33333
= 44.4 x 33.74
= 1,497 metres
Separation distances are to be measured from the edge of the stack of the Potential Explosive Site (PES) to the Exposed Site (ES) Max OP kPa Effect of overpressure Q/D formula for max OP
Associated works 21 Reinforced structures distort
Storage tanks fail
20% chance of fatality to a person in a building
Chance of eardrum rupture
D = 8Q1/3
Protected works class A 14 House uninhabitable and badly cracked
Temporary loss of hearing
(very low chance of eardrum rupture)
D = 10.4Q1/3
Protected works class B  7 Damage to internal partitions and joinery work, but can be repaired
Probability of injury is 10%
No fatality
D = 17.8Q1/3
Vulnerable facilities 2 No significant damage, injuries or fatalities
Up to 50% of window panes broken
D = 44.4Q1/3

Table 3: Quantity / Distance relationship to Maximum Allowable Overpressures at Exposed Sites Where OP = Overpressure in kPa, Q = NEQ (TNT Equivalent in kg) and D = distance (metres)

Special allowances for shotfirers

Shotfirers storing greater than the 30kg of a blasting explosive precursor allowed under the Explosives Regulation 2017 Schedule 4, on a property of 2ha or larger, must comply with this bulletin. It is a condition of licence that a shotfirer may store up to 2000kg of ammonium nitrate in accordance with this bulletin.

Sample calculation

For example, a shotfirer wishing to store 1500kg of Nitropril™ in relation to a nearby dwelling (Protected Works – Class B (Distance = 17.8 Quantity 1/3)), using the formula in Table 3 above.

From Table B1, D = 17.8 x (Q) 0.33333 is the formula for protected Works Class B

Establish the SSAN quantity into TNT Equivalency

Q = (1500 x 0.32 Equivalency Factor) x 1.0 (%mass of ammonium nitrate) x 1.0 (Efficiency Factor)
Q = 480 kg equivalent of TNT

Calculate the required separation distance from Table B1. Looking at table B1, Column 4 for Protected Works Class B :

D = 17.8 x (480) 0.33333
D = 17.8 x 7.8296
D = 140 metres (7kPa at that distance in the unlikely event of an explosion)

If the distance to the dwelling is less than 140m then the storage quantity should be reduced or the storage site moved to more than 140m from the dwelling.

The separation distances provided do not consider projection hazards which must be treated. Such treatments may include traverses or mounds. Further advice can be sought from the Explosives Inspectorate.

Note: Contaminated product is not to be stored but is to be disposed of immediately

Conclusion

The safe and secure storage of SSAN is dependent on licence holders maintaining a high level of safety and security with the product. It is particularly important that licence holders ensure that stringent house keeping measures are in place to prevent contamination and promote good fire revention.

Annexes

A. Separation distances between ammonium nitrate (SSAN) and explosives magazines

B. Separation distances in metres for the storage of ammonium nitrate to protected works and vulnerable facilities

C. Separation distances in metres for the internal separation of ammonium nitrate storage stacks/bunkers

D. Additional security measures to be considered

E. Identification checking of new employees (100 Point Identification System)

Annex A - Separation distances between ammonium nitrate (SSAN) and explosives magazines

Explosives magazine capacity (kg) Minimum safety distance to SSAN store (metres) Minimum thickness of mound (metres)
  Unmounded Mounded 
100 8 1 0.305
500 14 2 0.305
1,000 18 3 0.381
5,000 31 5 0.508
10,000 39 6 0.635
50,000 66 11 1.102
100,000 84 14 1.27
250,000 113 19 1.524
500,000 143 24 1.524

Note 1: Unmounded figures based on AS 2187 with the mounded figure and minimum thickness of mound (barricade in US Terms) being 6 times less in accordance with NFPA 495 (1985).

Ammonium Nitrate may be stored with explosives (other than those containing chlorates) but the total quantity (SSAN + explosives) must be regarded as explosives for separation distance purposes. For these requirements, calculations require SSAN as being 0.5 equivalent to TNT. E.g. 100 tonnes SSAN = 50 tonnes TNT (Efficiency Factor of 1 must be used).

Note 2: This table is for AN that conforms with the UN requirement of <0.2% carbonaceous material. Product not conforming to this specification is to be treated as a Class 1 Explosive.

Annex B - Separation distances in metres for the storage of ammonium nitrate to works and vulnerable facilities

Qty SSAN (kg) Associated works (metres) Protected works class A (metres) Protected works class B (metres) Vulnerable facilities (metres)
Overpressure 21KPa 14KPa 7KPa2KPa
Formula D = 8 Q1/3 D = 10.4 Q1/3 D = 17.8 Q1/3 D = 44.4 Q1/3
100 25 33 57 141
500 43 56 97 241
1,000 55 71 122 304
1,500 63 81 139 348
2,500 74 97 165 412
5,000 94 122 208 519
10,000 118 153 262 654
20,000 149 193 330 824
50,000 202 262 448 1119
100,000 254 330 565 1410
200,000 320 416 712 1776
500,000 434 565 966 2410

Note 1: Projectile hazard may exist beyond the separation distance shown. However the likelihood of being struck significantly decreases with distance due to dispersion over a larger area and projectile drag. A minimum distance of 400m should be applied for dwellings, 800 metres for vulnerable facilities if the likelihood of projectiles and debris is high.

Where the separation distance cannot be achieved the licence holder must put in place stringent housekeeping requirements, additional security requirements and an emergency response plan that ensures minimum effect on personnel and property. These should be documented, tested and acceptable to the Explosives Inspectorate.

Worked example 1 for Table B1 – e.g. Nitropril™ is 100% Ammonium Nitrate
To store 50,000kg in relation to an Associated Work.
D = 8 x (Q) 0.33333 where D = Distance and Q = Quantity
Q = (50,000 x 0.32 Equivalency Factor) x 1.0 (% mass of AN) x 1.0 (Efficiency Factor)
Q = 16,000 kg equivalent of TNT
Looking at table B1, Column 2 for Associated Works
D = 8 x (16,000) 0.33333
D = 8 x 25.198
D = 201 metres

Worked example 2 for Table B1 e.g., Nitram™ is 65% Ammonium Nitrate
To store 20,000kg in relation to a protected Work Class B (Dwelling)
D = 17.8 x (Q) 0.33333 where D = Distance and Q = Quantity
Q = (20,000kg x 0.32 Equivalency Factor) x 0.65 (%mass of AN)
Q = 4160 kg equivalent of TNT
Looking at table B1, Column 4 for Protected Works Class B and Vulnerable Facilities
D = 17.8 x (4160) 0.33333
D = 17.8 x 16.082
D = 287 metres

The risk of death or injury is most unlikely at 7kPa.

Note 2: This table is for AN that conforms with the UN requirement of < 0.2% carbonaceous material. Product not meeting the specification is to be treated as a Class 1 explosive.

Note 3: These distances are based on the low risk of an explosive event. Where the licence holder has hazards associated from storage conditions or other hazards, the licence holder should increase the separation distance to provide an equivalent level of protection.

Annex C - Separation distances in metres for the internal separation of ammonium nitrate storage stacks/bunkers

Note: preliminary – further technical data being sought

Quantity SSAN (kilograms) Separation (metres)
50,000 5
100,000 5
200,000 8
500,000 8

The distances shown above are based on information researched with other regulators and research agencies.

Stacks may be closer together if there is a barrier to reduce the effectiveness of the explosives shock wave. Technical details should be submitted for consideration by the Chief Inspector of Explosives.

These separation distances are based on Ammonium Nitrate of high quality within specification. Ammonium Nitrate subjected to thermal cycling or absorption of water has changed properties including sensitivity and requires greater separation distances.

Note 1: This table is for AN that conforms with the UN requirement of <0.2% carbonaceous material. Product not meeting the specification is to be treated as a Class 1 explosive.

Annex D - Additional security measures to be considered

  1. Licence holders may be required by the regulatory authority to implement other security measures in addition to the minimum requirements outlined above. It is essential that a thorough risk assessment be conducted by the organisation in order that an effective security plan is developed. It is also important that the security risk assessment be reviewed at regular intervals or when an incident occurs.
  2. One important factor will be the location of the facility. If the location is in close proximity to population centres or critical infrastructure, so that a potential explosion caused by sabotage could lead to a disaster, consideration will need to be given to:
    1. reducing storage quantities and/or stack sizes
    2. increasing security measures beyond the minimum requirements, so as to deter, detect and prevent after-hours intrusion.
  3. On the other hand, there may be some flexibility within minimum requirement 4, for equivalent security outcomes to be achieved by alternate measures. This will most likely be in exceptional circumstances such as very remote locations. In this case the security plan must justify the departure from the minimum requirements.
  4. Additional measures could improve perimeter protection, stopping intruders at the edge of a facility's property long before they reach vital assets and operational areas. Measures to control the movement of people within the general facility can also greatly enhance security.
  5. Additional measures could include:
    1. Physical security
      1. upgrade fences with barbed wire
      2. install bollards and trenches that prevent vehicles from driving into the site at points other than official entrances
      3. vehicle gates with retractable barriers
      4. personnel gates and turnstiles
      5. lighting that makes it easier for employees and even passers-by to observe and possibly identify intruders
      6. employ natural surveillance by arranging reception, production, and office space so that unescorted visitors can be easily noticed
      7. install appropriate locks on exterior and interior doors
      8. install appropriate, penetration-resistant doors and security hinges
      9. install secure windows with appropriate locks
      10. install electronic security measures such as motion sensors, monitored alarms and CCTV.
    2. Procedures
      1. establish a system for determining which cars, trucks or rail cars may enter the site, through which gates, docks or other entrances, and under what conditions. Such a system may be part of the pedestrian access control system, relying on access cards carried by vehicle operators, or it may be an independent system relying on staffed security posts
      2. require visitors to be signed in and escorted
      3. pay close attention to access control at loading and unloading areas.
  6. The appropriate level of security can vary significantly from facility to facility. It depends on the number of employees, the level of pedestrian and vehicular traffic into and out of the facility, the attractiveness of the facility as a target of various threats, the proximity of the facility to populated areas, and many other factors.
  7. The security risk should be constantly reviewed based on advice from government agencies including the federal government threat assessment levels. The security plan should include arrangements to adjust the security arrangements to mitigate against an increased level of threat.
  8. The risk assessment to be conducted by the organisation is a good tool for ensuring that all security risks are identified and dealt with.

Annex E - Identification checking of new employees

The identification checking of new employees is a critical part of the security process. It is the security action that confirm the identity of the person that underpins the security checking and supports the determination of the applicant to be an appropriate person under the security plan.

The checks should include two or more of the forms of identification must display:

  1. full and current name
  2. date and place of birth
  3. gender
  4. current nationality
  5. photographic identification
  6. current address

Documents may include those listed in the table plus any documents authorising name changes.

If the new employee has been resident outside Australia (not including holidays or working holidays) within the past ten years then a copy of a criminal history check from a recognised law enforcement agency in that country is to be provided. (This is to provide the equivalent of an NCHC and ASIO PMV check. A new ASIO check is also to be run).

The documentation is to be sighted or certified copies obtained. The identity check of these documents should confirm the details are consistent across the documents provided. There should be no evidence of fraud or tampering with the documentation.

Copies of the original documents are to be taken and they should be certified by the person receiving the documentation and then file on the employee records. All original documentation should be returned unmarked to the new.

The table on the next page indicates how the applicant can meet the 100 point requirement. The preceding paragraphs provide guidance on how to check the documents.

DocumentDetails ID Points*
Full Name   
All other names used
(now or in the past)
  
Passport   70
Full Birth Certificate   70
Citizenship Certificate   70
  At least one of the above documents must be sighted  
An Australian Government issued ID card
(issued for financial benefits)
  40
Bank mortgage records over property   35
Drivers licence
(must contain photo and signature)
  25
Current credit or ATM card   25
Medicare card   25
Keypass photo identification card   25
Shopping store card   25
Current utility account for either:
- local council rates
- gas, or electricity
- water.
  25
Previous employer
(contact to confirm previous employment)
  Contacted: Yes/No
Referees
1
2
3
Contacted:
Yes/No
Yes/No
Yes/No

*Documents sighted need to total 100 points, including at least one of the documents (passport, full birth certificate or citizenship certificate) worth 70 points.

Authorised by Alex Mandl - Chief Inspector of Explosives

Contact:

Issued by Resources Safety & Health Queensland

General: This information is a guide only. It is not to be taken as a statement of law and must not be construed to waive or modify any legal obligation.

All information on this page (Storage requirements for security sensitive ammonium nitrate (SSAN) - https://www.rshq.qld.gov.au/safety-notices/explosives/storage-req-security-sensitive-ammonium-nitrate-ssan) is correct as of time of printing (Apr 20, 2024 6:14 pm).