The ISC WOME Glossary

NEQ

Net Explosive Quantity

Net Explosive Quantity (NEQ) is the total explosive content of an ammunition item or stack, expressed in kilograms, and it is the input that drives every storage and transport separation distance in NATO and UK explosive safety. AASTP-1 Edition D Version 1 and DSA 03.OME Part 2 both calculate quantity-distance from NEQ, not from gross weight.

NEQ is where an explosive safety case begins. Licence a building, site a magazine, plan a convoy or size a deployed field storage area, and the first number anyone asks for is the NEQ. It is deliberately not the gross weight of the ammunition, and it is not the weight of the packaging. NATO terminology publication AOP-38 defines it as the total explosive content of the ammunition unless trials have shown the effective quantity to differ significantly from the actual quantity, and it excludes substances such as white phosphorus, war gases, smoke and incendiary compositions unless those contribute significantly to the dominant hazard.

The common misreading is treating NEQ, Net Explosive Weight (NEW) and Net Explosive Mass (NEM) as three names for one quantity. They are not. AOP-38 carries all three separately and flags that NEM, a transport-side term, differs from NEQ, which is the storage-side term. US practice adds a further wrinkle: NEW is defined as the total weight of all Class 1 material in an item, stack, vehicle, aircraft or building, which is a broader measure than the NATO storage definition. A figure lifted from a US transport document and dropped into a UK storage licence is not automatically the same number.

In procurement this matters more than it looks. NEQ determines whether an existing licensed facility can accept a new nature of ammunition, whether a framework contract can be delivered into the storage estate a nation actually owns, and how much new infrastructure a capability decision quietly commits a ministry to build. Ammunition that cannot be stored has not been procured.

Governing source: AOP-38 (NATO terms and definitions for munitions safety); AASTP-1 Edition D Version 1 (STANAG 4440); DSA 03.OME Part 2. US equivalent term NEW under DESR 6055.09 Edition 1 Change 2 (2025).

HD

Hazard Division

A Hazard Division (HD) is the numbered classification, 1.1 through 1.6, that states the predominant hazard an explosive presents: HD 1.1 mass explosion, 1.2 projection, 1.3 fire, 1.4 no significant hazard, 1.5 very insensitive with mass explosion hazard, 1.6 extremely insensitive without one. AASTP-3 (STANAG 4123) assigns it for NATO.

The Hazard Division answers one question: if this goes wrong, what is the dominant way it hurts people. HD 1.1 means the whole stack functions essentially at once. HD 1.2 means the hazard is fragments and projections rather than a single mass event. HD 1.3 is a fire hazard with at most minor blast or projection. HD 1.4 is confined largely to the package. The two insensitive divisions, 1.5 and 1.6, exist because some modern fills are genuinely hard to initiate, and pretending otherwise would sterilise storage capacity for no safety benefit.

AASTP-3 uses the term Hazard Division rather than the bare UN word Division to preserve continuity with the older term Hazard Class, and the NATO scheme implements the UN model regulations rather than replacing them. National systems then implement AASTP-3: the US Joint Hazard Classification System, the UK through DSA 03.OME Part 2 Chapter 4, and Australia through the electronic Defence Explosive Ordnance Publication eDEOP 101. UK and NATO practice adds storage sub-divisions, for example splitting HD 1.2 at an individual item NEQ of 0.73 kg, which is invisible in the UN transport scheme but decisive for a magazine licence.

The frequent error is quoting a Hazard Division on its own. It is only half the answer. The Division combines with the Compatibility Group to form the Hazard Classification Code, and it is the code, not the number, that governs what may be stored with what.

Governing source: AASTP-3 Edition 1 Change 3 (STANAG 4123), Section 2.2.1; DSA 03.OME Part 2 Chapter 4; UN Recommendations on the Transport of Dangerous Goods, implemented through AASTP-3.

CG

Compatibility Group

A Compatibility Group (CG) is the letter, A to H plus J, K, L, N and S, that states which explosives may be stored and transported together. AASTP-3 (STANAG 4123) defines thirteen groups; the letter I is omitted to prevent confusion with the numeral 1. Paired with the Hazard Division it forms the Hazard Classification Code, for example 1.1D.

Compatibility Groups exist because mixing the wrong two things in one magazine converts a fire into a mass detonation. The groups are constructed so that, with the deliberate exceptions of Groups L and N, everything inside one group is compatible with everything else in it. Group A is primary explosive substance. Group D is secondary detonating substance or black powder without means of initiation and without a propelling charge. Group K is the toxic-chemical case. Group L covers substances needing isolation of each type, which is why it does not follow the general compatibility rule. Group S is the packaged case where hazardous effects are confined within the package.

Groups E and F are the pair most often written down the wrong way round, including in otherwise careful technical copy. AASTP-3 is unambiguous. Group E is an article containing a secondary detonating explosive substance without means of initiation and with a propelling charge. Group F is an article containing a secondary detonating explosive substance with its own means of initiation, with a propelling charge or without one. The distinguishing feature is the means of initiation, not the propelling charge. ISC treats any parenthetical CG definition written from memory as an error waiting to be published: quote AASTP-3 or omit the parenthetical.

Of the 78 theoretically possible Division and Group pairings, DSA 03.OME Part 2 Chapter 4 lists 35 as valid Hazard Classification Codes. That constraint, rather than the raw tonnage, is usually what limits how much a depot can actually hold.

Governing source: AASTP-3 Edition 1 Change 3 (STANAG 4123), Section 2.3.4; DSA 03.OME Part 2 Chapter 4, Section 2.2.1 and Annex A.

QD

Quantity-Distance

Quantity-Distance (QD) is the minimum permissible separation between a Potential Explosion Site and an Exposed Site, derived from the Net Explosive Quantity present. Distances scale with the cube root of the quantity under the Hopkinson-Cranz law, so doubling the NEQ increases the required distance by roughly 26 per cent, not 100.

QD is the arithmetic that turns a quantity of explosive into a footprint of land. The governing relationship is the cube-root scaling law first stated by Hopkinson in 1915 and independently by Cranz in 1926, written in the form D equals k times Q to the power one third. The coefficient k, called Q in some International Ammunition Technical Guidelines (IATG) texts, encodes the degree of protection being bought. The mass term encodes how much explosive is present. Notation collides badly between documents: IATG uses Q for the coefficient, US Army publications use Q for the quantity itself. Read the definitions before reading the tables.

The practical consequence is counter-intuitive and it drives a great deal of infrastructure economics. Because the relationship is a cube root, small increases in stockholding cost surprisingly little extra land, while the first increment of explosive at a virgin site costs a great deal. Protective construction changes the picture again: an earth-covered magazine or a rated barrier can permit distances that an open stack of the same NEQ never could.

Edition currency bites here more than anywhere else in the glossary, because a QD table is not a definition that ages gently. AASTP-1 Edition D Version 1 (2025) carries revised tables, and UK adoption runs through Project COWLEY: DOSR Regulatory Notice 2025-07 sets the new quantity-distance tables as mandatory from 1 January 2028, with full transition expected to take around five years. Until then a UK licence may legitimately rest on either table set, and any analysis needs to say which.

QD is also the reason ammunition storage is a strategic constraint rather than a logistics detail. A nation can sign for the rounds, but if the licensed QD footprint does not exist, the rounds sit in the wrong place, on the wrong continent, or in hired commercial capacity nobody planned for.

Governing source: AASTP-1 Edition D Version 1 (STANAG 4440); IATG 02.20, 3rd Edition (March 2021); DSA 03.OME Part 2; DESR 6055.09 Edition 1 Change 2 for US siting.

IBD / IMD / PBD

Quantity-distance types

IBD, IMD and PBD are quantity-distance types. Inhabited Building Distance protects occupied buildings outside the explosives area; Inter-Magazine Distance prevents propagation between magazines; Process Building Distance protects operators in ammunition process buildings. Under IATG 02.20 the coefficients rank IMD 3.6, PBD 8.0, PTRD 14.8 and IBD 22.2.

The set divides into Inside Quantity-Distance, applied within the designated explosives area, and Outside Quantity-Distance, applied beyond it. IMD and PBD are the inside pair. Public Traffic Route Distance (PTRD), Inhabited Building Distance and Vulnerable Building Distance are the outside set. The ordering is fixed and worth committing to memory: IMD is shortest, then PBD, then PTRD, then IBD, with VBD longest at a coefficient of 44.4. Each step buys a higher degree of protection for a more exposed or less consenting population.

PBD expands to Process Building Distance. This is a genuine trap, because a handful of historical texts use the phrase Public Building Distance, and in those sources it maps to IBD rather than to PBD. Reading it as an alternative name for PBD compounds two errors at once. IMD carries a second caveat that is routinely dropped: it prevents immediate propagation between stacks by blast, flame or missile, but it does not promise protection against later reactions from burning debris, high-angle fragments or structural collapse.

AASTP-1 adds an important controlling rule for IBD. The distance must be the largest of those required for protection against airblast, debris and thermal effects, which means a debris-driven answer can override a blast calculation that looked comfortable.

Governing source: IATG 02.20, 3rd Edition (March 2021), Tables 2 and 4; AASTP-1 Edition D Version 1 (STANAG 4440); DSA 03.OME Part 2.

PES

Potential Explosion Site

A Potential Explosion Site (PES) is any location holding explosives whose detonation or fire would affect something else: a magazine, stack, vehicle, wagon or transit shed. Its counterpart is the Exposed Site (ES), the facility hazarded by that event. Every quantity-distance calculation is a statement about one PES and one ES pair.

PES and ES only mean anything as a pair. IATG 02.20 defines the PES as the location of a quantity of explosives that will create blast, fragment, thermal or debris hazard on explosion of its contents, and the ES as the magazine, cell, stack, vehicle, process building, inhabited building, assembly place or public traffic route exposed to those effects. DSA 03.OME Part 2 uses the same construction in shorter operational language.

The pairing is why a site licence is not a single number. One magazine is simultaneously a PES with respect to the village beyond the fence and an ES with respect to the magazine next to it. Change the contents of one building and the calculation cascades across the whole estate. This is also why analysing a struck depot from overhead imagery is tractable: the crater and the debris field identify the PES, and the surviving or destroyed structures around it reveal what separation was, or was not, in place.

Governing source: IATG 02.20, 3rd Edition (March 2021); DSA 03.OME Part 2 Chapter 11; AASTP-1 Edition D Version 1 (STANAG 4440).

IM

Insensitive Munitions

Insensitive Munitions (IM) reliably meet their performance and readiness requirements while minimising the violence of any inadvertent initiation. AOP-39 Edition D (STANAG 4439) sets six threat stimuli; for four of them the munition must respond no more severely than Type V burning, and no worse than Type III explosion for the other two.

The six threats are fast heating, slow heating, bullet impact, fragment impact, sympathetic reaction and shaped-charge jet impact. They were chosen to span the credible hazard mechanisms a munition meets in a magazine, a vehicle, a ship or an aircraft. The response scale runs from Type I detonation, the most violent, through Type II partial detonation, Type III explosion and Type IV deflagration, to Type V burning, where the energetic material ignites and burns non-propulsively. Compliance means the first four threats produce no response worse than Type V, while sympathetic reaction and shaped-charge attack must produce no propagation worse than Type III.

IM is frequently sold as a binary. It is better read as a risk gradient. UK guidance makes the point explicitly: achieving a Type IV deflagration instead of a Type III explosion is not full compliance, yet it can still be a worthwhile and defensible reduction in risk under the ALARP (as low as reasonably practicable) principle. Procurement documents that treat IM as a yes or no checkbox lose that nuance and often the negotiating room with it.

The standards split by role. AOP-39 is the NATO policy and assessment methodology, adopted by the UK through DSA 03.OME and by Australia. MIL-STD-2105E, the 2022 revision, is the US test sequence and aligns with AOP-39 for interoperability. Citing MIL-STD-2105D is a dated reference.

Governing source: AOP-39 Edition D (STANAG 4439 Edition 4); MIL-STD-2105E (2022); response descriptors per AOP-39 as implemented in UK MAP 01-103 Part 1 Issue 3.

UXO

Unexploded Ordnance

Unexploded Ordnance (UXO) is explosive ordnance that was primed, fuzed, armed or otherwise prepared for use, or used, and which remains unexploded through malfunction, design or any other reason. The definition is set out in IMAS 04.10 and traces to CCW Protocol V, in force since 12 November 2006.

The decisive word is prepared. UXO has been through the arming sequence. That is what separates it from Abandoned Explosive Ordnance, which was left behind without ever being used, and it is why UXO is treated as the more immediately dangerous of the two. A fuze that has partially functioned, or that has been armed and then subjected to impact, is in an unknown state, and that unknown state is the reason render-safe procedures exist.

The operational problem is rarely the ordnance itself; it is finding it. Ferrous volcanic soil defeats standard magnetometry. Seabed burial defeats visual survey. Legacy contamination from conflicts eighty years old still closes construction sites across Europe and the Pacific each year. Clearance methodology has moved with the constraint: the UK now defaults to low-noise deflagration for marine clearance to limit harm to marine mammals, which trades speed for environmental compliance.

Governing source: IMAS 04.10 Edition 2 Amendment 12 (glossary of mine action terms); CCW Protocol V on Explosive Remnants of War (2003, entered into force 12 November 2006).

ERW

Explosive Remnants of War

Explosive Remnants of War (ERW) is the collective legal term for Unexploded Ordnance and Abandoned Explosive Ordnance. It was created by CCW Protocol V, adopted in 2003 and in force from 12 November 2006, the first multilateral instrument to deal specifically with post-conflict unexploded and abandoned munitions.

ERW is an umbrella, not a third category. Under Protocol V it is exactly UXO plus AXO, which is why writing ERW where the technical situation is specifically UXO discards information a disposal team needs. It also excludes mines, booby traps and other devices covered by Amended Protocol II, so ERW is not a synonym for everything explosive left on a battlefield.

Protocol V matters because it created obligations rather than merely definitions. States Parties and parties to an armed conflict are required to clear, remove or destroy ERW in territory they control, and to record, retain and transmit information on the ordnance they used. That recording duty is the part most often overlooked, and it is the part that determines how quickly a clearance operation can be planned once the shooting stops.

The timescales are the argument. Baltic seabed contamination from the Second World War is still being surveyed. Okinawa still yields legacy ordnance to Japanese disposal teams. Contamination created in a single week of missile exchanges takes years of methodical work to resolve.

Governing source: CCW Protocol V on Explosive Remnants of War (2003, in force 12 November 2006), Article 2; IMAS 04.10 Edition 2 Amendment 12.

AXO

Abandoned Explosive Ordnance

Abandoned Explosive Ordnance (AXO) is explosive ordnance not used during an armed conflict that has been left behind or dumped by a party and is no longer under that party's control. CCW Protocol V Article 2 adds that AXO may or may not have been primed, fuzed, armed or otherwise prepared for use.

AXO is the abandoned stockpile problem rather than the battlefield dud problem. A retreating force leaves a depot. A dissolved unit dumps its holdings. A magazine is simply walked away from. What remains is often packaged, sometimes still on pallets, and in quantities that dwarf what a typical UXO clearance task involves.

Because AXO may never have been armed, it is frequently in better condition than UXO, and that creates a second-order risk that dominates the current picture. Serviceable abandoned ordnance is a supply source. Explosive harvesting from abandoned stocks feeds improvised device manufacture, which is why counter-improvised-explosive-device (counter-IED) programmes and stockpile security programmes increasingly operate as one activity rather than two.

Governing source: CCW Protocol V on Explosive Remnants of War, Article 2; IMAS 04.10 Edition 2 Amendment 12.

FBO

Future Business Opportunity

A Future Business Opportunity (FBO) is the advance notice the NATO Support and Procurement Agency publishes on its eProcurement portal for requirements it expects to solicit. NSPA publishes FBOs for potential requirements valued at Financial Level D, 160,000 euro, or above, ahead of any Request for Proposals.

The FBO is the earliest public signal in the NSPA acquisition cycle, which makes it the single most useful open source for anyone tracking alliance ammunition demand. It carries a reference in the form 26LBS052, an outline of the requirement, an indicative quantity and often the list of participating nations. Industry days and requests for information are also published as FBOs. A related instrument, the Notification of Intent (NoI), performs a similar advance-warning role, and Notifications of Procurement Opportunity cover requirements governed by NATO procurement regulations rather than NSPA's own.

An FBO is a statement of intent, not a contract. Requirements are withdrawn, re-scoped, split or quietly allowed to lapse. The analytical value lies in the shape of the requirement rather than the certainty of it: participating-nation counts reveal which capitals are aggregating demand, and quantities reveal whether a nation is topping up or re-equipping. Read across several FBOs and the alliance's actual priorities surface well before any ministerial announcement.

Governing source: NSPA eProcurement portal, Future Business Opportunities; NSPA procurement regulations, Financial Level D threshold of 160,000 euro.

AQAP

Allied Quality Assurance Publication

Allied Quality Assurance Publications (AQAPs) are the NATO quality-assurance requirements a supplier is contracted against, mandated through STANAG 4107, now at Edition 14 (2025). AQAP-2110 is the workhorse for design, development and production. All are aligned to ISO 9001 and owned by AC/327, the Life Cycle Management Group.

AQAPs are contractual, not certifiable. This is the single most expensive misunderstanding in NATO defence supply. A supplier does not become AQAP certified in the way it becomes ISO 9001 certified, because there is no accredited certification scheme behind an AQAP. Compliance is established by the customer nation's National Quality Assurance Authority through Government Quality Assurance, delegated between nations under STANAG 4107. Certificates issued by commercial bodies claiming AQAP certification carry no standing with NATO, and nations answer the question in noticeably different ways.

The suite covers the lifecycle: AQAP-2110 for design, development and production, AQAP-2131 for final inspection and testing, AQAP-2105 for deliverable quality plans, AQAP-2210 as the software supplement, AQAP-2310 for aviation, space and defence, AQAP-2070 for the mutual Government Quality Assurance process, AQAP-2190 Edition A for disposal, AQAP-4107 as implementation guidance, and AQAP-2000 as the strategic policy document rather than a contractual one. Cancelled publications, including the former AQAP-2009, 2120 and 2130, should not be cited.

The gap ISC returns to repeatedly sits underneath all of this. AQAPs demand competence and inherit ISO 9001 Clause 7.2, but neither defines what technical competence means for ammunition. That definition lives with AC/326 on the safety side, and no standard bridges the two committees.

Governing source: STANAG 4107 Edition 14 (2025), Mutual Acceptance of Government Quality Assurance and Usage of the Allied Quality Assurance Publications; AQAP-2110 Edition D.

STANAG

Standardization Agreement

A STANAG (Standardization Agreement) is the NATO instrument by which nations agree to adopt a common standard, process or procedure. The STANAG is the ratification instrument; the technical content usually sits in a separate Allied Publication. STANAG 4439 covers insensitive munitions; STANAG 4107 covers quality assurance.

The most useful thing to understand about a STANAG is the split between the agreement and the content. STANAG 4439 is the agreement; AOP-39 holds the methodology. STANAG 4440 is the agreement; AASTP-1 holds the storage guidance. Citing the STANAG number alone is correct for the obligation and unhelpful for the technical detail, which is a common source of confusion in tender documents.

Ratification is national and it is conditional. A nation may ratify with reservations, may implement on a stated future date, or may not ratify at all. A STANAG being promulgated therefore does not mean every ally is complying with it, and interoperability claims built on the existence of a STANAG rather than on national ratification status have a habit of failing on operations.

STANAGs are also cancelled and replaced, which is the reason ISC treats edition checking as a standing task rather than an occasional one. STANAG 4224 was cancelled and its role passed to STANAG 4761 and AAS3P-20. STANAG 4385 was replaced for 120 mm tank ammunition. STANAG 4172, which defines the 5.56 x 45 mm cartridge, sits under review pressure as national calibre programmes reopen the question.

Governing source: NATO Standardization Office; AAP-03, Directive for the Production, Maintenance and Management of NATO Standardization Documents.

AOP

Allied Ordnance Publication

An Allied Ordnance Publication (AOP) carries the technical content NATO nations agree to through a corresponding STANAG. AOP-39 Edition D holds the insensitive munitions methodology under STANAG 4439; AOP-15 Edition 3 holds the safety and suitability for service assessment under STANAG 4297; AOP-38 holds the agreed munitions safety terminology.

AOPs are where the engineering lives. An AOP will give the test sequence, the assessment methodology, the definitions and the acceptance criteria, while the STANAG that accompanies it does little more than record that nations have agreed to use it. For practitioners this means the AOP is the document to read and the STANAG is the document to cite when establishing obligation.

The publications interlock. AOP-15 is the safety and suitability for service baseline the UK, US and Australia all reference, and it carries the Life Cycle Environmental Profile questionnaire. AOP-39 governs insensitive munitions assessment from the concept and design stage, with national test sequences such as MIL-STD-2105E applied later. AOP-38 supplies the shared vocabulary that keeps the other two consistent, which is why it is the correct authority for terms such as Net Explosive Quantity.

Edition discipline applies here as much as anywhere. Citing AOP-39 without the edition is weak; citing a superseded edition is worse. ISC cites AOP-39 Edition D, issued under STANAG 4439 Edition 4, and treats the widely quoted Edition 3 as superseded.

Governing source: AOP-39 Edition D (STANAG 4439 Edition 4); AOP-15 Edition 3 (STANAG 4297 Edition 2); AOP-38, NATO munitions safety terms and definitions.

DSA 03.OME

Defence Code of Practice for Ordnance, Munitions and Explosives

DSA 03.OME is the UK Defence Safety Authority's regulatory framework for ordnance, munitions and explosives, regulated by the Defence Ordnance Safety Regulator (DOSR). Part 1 covers OME acquisition and the safety case; Part 2 covers explosives regulations for storage and handling. It supersedes JSP 520 and JSP 482, both of which are withdrawn and should not be cited.

The framework is goal-setting rather than prescriptive. It runs on the Duty Holder construct and the ALARP principle, and it drives safety management through the CADMID (concept, assessment, demonstration, manufacture, in-service, disposal) acquisition cycle rather than through a fixed rulebook of permitted arrangements. The central artefact is the Safety and Environmental Case Report, which is where an organisation argues, with evidence, that its explosive risk is tolerable and as low as reasonably practicable.

The withdrawn predecessors are the recurring citation failure in this domain. JSP 482 in particular remains widely quoted in consultancy documents, tender responses and training material, years after DSA 03.OME Part 2 replaced it. The lineage is documented inside the current regulations themselves, which title Part 2 as formerly JSP 482. Anyone citing JSP 482 as live UK regulation is signalling that their reference set has not been refreshed since before 2021.

DSA 03.OME also sets the UK's relationship to the NATO standards. It is the route by which AOP-39 insensitive munitions policy and AASTP hazard classification and storage practice become UK obligations, which is why a UK safety case reads as national regulation on top of an alliance technical baseline.

Governing source: DSA 03.OME, current Defence Code of Practice editions (2021 onward), UK Defence Safety Authority, regulator DOSR. Supersedes JSP 520 Part 1 and JSP 482 Part 2, both withdrawn.