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ISO 26261-4:2017 — Fireworks Category 4 Labelling Requirements and Instructions for Use
Mandatory safety labelling, parameter coding, and user documentation for professional pyrotechnics
ISO 26261-4:2017 specifies the minimum labelling requirements and mandatory instructions for use for Category 4 fireworks. In a domain where incorrect use can have catastrophic consequences, clear and unambiguous labelling is not merely an administrative requirement — it is a primary safety barrier. This standard ensures that every professional fireworks article carries the information needed to determine safe handling, storage, and display practices.
The most critical statement required on every Category 4 firework label is: “For use only by persons with specialist knowledge.” This must be emphasized through bold type, a heading, or similar highlighting — and must never be obscured by other text.
Minimum Labelling Requirements
Every Category 4 firework must carry, at minimum, 11 categories of information. These include the name and type of firework (using the standardized subtype or generic type from ISO 26261-1), the category designation and registration number, the net explosive content (NEC), the year of production, and the manufacturer’s or importer’s contact details (at least town and country).
The standard mandates that all labelling be “clearly visible, easily legible, indelible and on a contrasting background colour.” For very small items that cannot physically accommodate all this information, manufacturers may use a protective pack label — but with the important caveat that the article must only be supplied in that protective pack, which must be marked with: “Must be supplied as packaged.”
| Parameter Code | Status | Description | Example |
|---|---|---|---|
| A | Mandatory | Burst height / Effect height | A: 150 m |
| B | Mandatory/Optional | Sound pressure level at specified distance | B: 125 dB(AI) at 25 m |
| C | Mandatory | Projected debris distance | C: 50 m |
| D | Mandatory | Incandescent/burning matter reaches ground | D: ✓ |
| E | Mandatory/Optional | Effect range (aquatic fireworks) | E: 20 m |
| R | Mandatory (aerial wheels) | Overall duration | R: 30 s |
| W | Mandatory/Optional | Maximum firing angle (when not visible) | W: 15° |
| F | Optional | Effect broadness | F: 80 m |
| G | Optional | Calibre | G: 150 mm |
| J | Optional | Flight time | J: 5 s |
| K | Optional | Effect time | K: 8 s |
| M | Optional | Gross mass | M: 2.5 kg |
The parameter coding system (A through W, with I and O intentionally unused to avoid confusion with numerals 1 and 0) provides a compact, language-independent method for conveying essential safety data on labels where space is at a premium. This coding system is one of the most innovative features of the standard.
Safety Information Format and Parameter Coding
The mandatory safety parameters (A, B, C, D, E, R, and W where applicable) must be presented as a single textbox on the label, in the order specified, using the format “X: Y” where X is the parameter code and Y is the numerical value with its SI unit. This standardized format ensures that professional users can quickly locate and interpret the data needed for safety distance calculations, regardless of the manufacturer or country of origin.
Each parameter serves a specific purpose in the safety distance calculation. The burst height (A) determines the vertical clearance needed from overhead obstructions. The sound pressure level (B) drives the audience exclusion zone. The debris distance (C) defines the zone where physical impact is possible. The incandescent matter indicator (D) alerts to fire risk on the ground. For aquatic fireworks, the range (E) defines the water exclusion zone.
The standard requires two mandatory text statements on every label: “Minimum safety distance to be determined by user according to the supplied product data” and “Article to be used in accordance with written instructions and national regulations.” These statements shift the ultimate responsibility for safe use to the qualified professional — a deliberate engineering of accountability.
Operating Instructions and Compliance
The manufacturer or importer must supply comprehensive instructions for safe handling, storage, use, and disposal. For combinations with multiple initial fuses, each fuse must be clearly identified. When a specific mortar is required (e.g., for large-calibre shells), the label must state “Use specific mortar (see instructions)” and the user documentation must specify the mortar dimensions.
Additional information may be displayed on the labelling or instructions, provided it does not conflict with the mandatory information. This provision allows manufacturers to include branding, marketing copy, or supplementary technical data while preserving the integrity of the safety-critical information.
Engineering Perspective
The labelling requirements of ISO 26261-4 represent a systems-level approach to safety engineering. By standardizing the type, format, and coding of safety information, the standard ensures that a professional pyrotechnician can assess the hazards of any Category 4 firework — regardless of manufacturer or country — using a consistent mental model. The parameter coding system is particularly elegant: it compresses complex multi-dimensional safety data into a compact, machine-readable format that can be printed on articles as small as a few centimetres in diameter.
This standard also addresses a subtle but important failure mode in safety communication: information loss when packaging is opened. The requirement that protective packs “prevent loss of information when the label is broken” ensures that the critical safety data travels with the article throughout its lifecycle, from warehouse to firing site.
Spelling mistakes on labels are not treated lightly. A single spelling mistake that changes the meaning of the text renders the label non-compliant. Up to three spelling mistakes that do not change meaning are tolerated — reflecting the practical realities of international manufacturing while maintaining the integrity of safety communication.
Frequently Asked Questions
Q1: Why are the letters I and O not used in the parameter coding system?
A1: To avoid ambiguity with the numerals 1 (one) and 0 (zero), which could cause dangerous misinterpretation of safety-critical numerical values when labels are read under field conditions.
A1: To avoid ambiguity with the numerals 1 (one) and 0 (zero), which could cause dangerous misinterpretation of safety-critical numerical values when labels are read under field conditions.
Q2: Can a firework be sold without individual labelling if it is too small?
A2: Yes — very small items can have manufacturer/importer details on the article itself (if possible), with the remaining information on the protective pack label. However, the protective pack must then be marked “Must be supplied as packaged” to ensure the safety information always accompanies the article.
A2: Yes — very small items can have manufacturer/importer details on the article itself (if possible), with the remaining information on the protective pack label. However, the protective pack must then be marked “Must be supplied as packaged” to ensure the safety information always accompanies the article.
Q3: What language must the label information be in?
A3: The specified information must be given in the official language(s) of the member state in which the firework is placed on the market. Each language block must be presented as a whole without interruption by other text.
A3: The specified information must be given in the official language(s) of the member state in which the firework is placed on the market. Each language block must be presented as a whole without interruption by other text.
Q4: What is the difference between mandatory and optional parameters?
A4: Mandatory parameters (A, C, D) must always appear. Parameters like B (sound pressure) and E (range) are mandatory only for relevant article types. Parameters F through W are optional and may be added at the manufacturer’s discretion, as long as they are kept separate from the mandatory parameter block.
A4: Mandatory parameters (A, C, D) must always appear. Parameters like B (sound pressure) and E (range) are mandatory only for relevant article types. Parameters F through W are optional and may be added at the manufacturer’s discretion, as long as they are kept separate from the mandatory parameter block.
