Overview
ISO 7204:2023 - Specification for wetting agents for application on Class A fires - sets minimum performance, composition and marking requirements for liquid wetting agent concentrates used to extinguish and inhibit reignition of Class A fires (solid organic materials such as wood, vegetation, cloth and paper). The standard defines essential physical and chemical properties, test-fire performance and required manufacturer information so users and procurers can assess suitability and safety.
Key technical topics and requirements
- Scope and purpose: Defines wetting agent concentrates and wetting agent solutions for Class A fuels; specifies minimum performance on designated test fires (Annex F).
- Conditioning and stability: Sampling and temperature conditioning procedures are given (Annex A). Concentrates claimed resistant to freezing/thawing must show no visual stratification after cycling per Annex B.
- Sediment limits: Sediment must be dispersible through a 180 µm sieve; maximum sediment volumes are ≤ 0.25% before conditioning and ≤ 1.0% after conditioning (Annex C).
- Viscosity:
- Newtonian concentrates - viscosity determined per ISO 3104; containers must note if viscosity exceeds the specified threshold (marking for special proportioning equipment).
- Pseudo‑plastic concentrates - measured per Annex D; specific shear-rate dependent viscosity limits apply (example: marking requirement if ≥ 120 mPa·s at 375 s⁻¹).
- pH: Concentrate pH shall be 6.0 to 8.5 at (20 ± 2) °C; change after conditioning ≤ 1.0 pH unit.
- Surface tension: Wetting-agent solution surface tension at recommended concentration must be within ±10% of the characteristic value before conditioning and within 0.95–1.05× of that value after conditioning (Annex E).
- Fire testing: Solutions must extinguish a wood crib fire and pass deep‑seated fire tests (Annex F).
- Toxicology and environmental information: Manufacturers must supply toxicological and ecotoxicological data at highest recommended concentration (Annex G).
- Marking & packaging: Required container marking includes product designation, recommended concentration and any handling notes (Clause 13 and annexes).
Practical applications and users
- Who uses it: wetting‑agent manufacturers, testing laboratories, fire services (airport/industrial/municipal), procurement/specification engineers, safety officers and equipment manufacturers.
- Applications: Formulation control, batch acceptance testing, procurement specification, compliance for firefighting equipment and systems used to suppress or prevent reignition of Class A fires. Also used when assessing compatibility with seawater use or corrosion‑sensitive environments.
Related standards
Normative references include ISO 304 (surface tension), ISO 3104 (viscosity), ISO 7165 (portable extinguishers), EN 1568‑3 and other ISO firefighting standards cited in the document. For full test procedures and annex details refer to ISO 7204:2023.
