Hazard Class 1 — Explosives
Cartridges, squibs, escape-slide initiators and other Class 1 articles encountered in aviation MRO.
Overview
Class 1 covers explosive substances and articles intended to produce a practical effect by explosion or pyrotechnic reaction. The class is split into six divisions (1.1 to 1.6) reflecting the type and severity of the hazard, and into compatibility groups (letters A to S) that describe how items may be stowed together.
In air transport, most Class 1 items are forbidden as passenger-aircraft cargo. A limited set of articles in Division 1.4 compatibility group S — broadly meaning 'no significant hazard outside the package' — may be carried under specific IATA packing instructions.
Divisions within Class 1
| Division | Description |
|---|---|
| 1.1 | Mass explosion hazard |
| 1.2 | Projection hazard |
| 1.3 | Fire / minor blast or projection hazard |
| 1.4 | No significant hazard beyond the package |
| 1.5 | Very insensitive substances, mass explosion hazard |
| 1.6 | Extremely insensitive articles, no mass explosion hazard |
Aviation context
Aviation MRO and operators handle a narrow but recurring set of explosive articles: cartridge actuated devices in escape slides and emergency exits, squibs for fire-bottle activation, and signal cartridges for survival kits. These are almost always supplied pre-packaged by the OEM with the correct UN number, division and compatibility group printed on the package.
Because acceptance rules differ sharply between passenger and cargo aircraft, MRO shipping clerks must verify the UN number against the current IATA DGR Table 4.2 before booking — and never substitute one cartridge part number for another based on visual similarity.
Typical UN numbers in aviation MRO
| UN Number | Proper Shipping Name | Notes |
|---|---|---|
| UN0012 | Cartridges for weapons, inert projectile / Cartridges, small arms (1.4S) | Often carried under 1.4S provisions when properly packaged |
| UN0323 | Cartridges, power device (1.4S) | Typical aviation cartridge-actuated device |
| UN0454 | Igniters (1.4S) | Used in fire-suppression squibs |
| UN0432 | Articles, pyrotechnic for technical purposes (1.4S) | Survival signalling devices |
Packaging and marking essentials
- Packing instructions for Class 1 are highly article-specific — always look up the exact UN number, not 'class 1 in general'.
- Original OEM packaging is normally UN-spec tested for the specific article. Repacking into a generic UN box invalidates the approval.
- Mandatory marks include the UN number, proper shipping name and the Class 1 hazard label with the division and compatibility group.
Frequently Asked Questions
Are any Class 1 items allowed on passenger aircraft?
Yes, but only a limited subset — typically Division 1.4 compatibility group S articles, in UN-approved packaging and under the specific packing instruction listed in IATA DGR. Always verify against the current edition before booking.
Can I ship escape-slide cartridges without a DGD?
No. Class 1 articles require a fully completed Shipper's Declaration for Dangerous Goods signed by a certified shipper, plus full Class 1 marks and labels. There is no Excepted Quantity provision for Class 1.
What is a compatibility group?
A letter (A–S) added to the division number that indicates which Class 1 items may be stowed together. For example, 1.4S items may be transported with most other cargo, whereas 1.1A items have very restrictive stowage rules.
Need to classify a specific part?
DG Copilot identifies the UN number, hazard class and air transport status from a part number — in seconds.
Other hazard classes
This information is provided for guidance only. Always verify against the current IATA DGR edition. Final classification and DGD must be validated by a certified DG specialist.