Overview
ISO 14520-11:2016 specifies requirements for gaseous fire‑extinguishing systems using the HFC 236fa extinguishant (1,1,1,3,3,3‑hexafluoropropane). The third edition (2016) covers the physical properties, specification, usage and safety aspects of HFC 236fa and addresses system designs for containers superpressurized with nitrogen at nominal pressures of 25 bar and 42 bar. The standard complements the general requirements in ISO 14520‑1 and is intended for total‑flooding applications.
Key topics and technical requirements
- Extinguishant specification: Minimum purity and contaminant limits (e.g., purity ≥ 99.6% by mass; limits on acidity, water, non‑volatile residue and suspended matter) are defined.
- Physical properties: Molecular mass, boiling/freezing/critical points, vapour and liquid densities, and specific volumes are tabulated to support design calculations.
- Extinguishing and design concentrations: Reference extinguishing concentrations and minimum design concentrations (including the standard 1.3 safety factor on extinguishment values) are provided for Class A and Class B fuels and a range of common fuels (heptane, acetone, ethanol, kerosene, methanol, propane, toluene, etc.).
- Agent quantity calculations: Table 3 and the method of ISO 14520‑1:2015 (clause 7.6) specify how to compute required agent mass per unit volume (m/V) for target concentrations and temperatures.
- Container fill density and pressure/temperature relationships: Limits on maximum fill density are given to prevent “liquid‑full” conditions and excessive pressure rises; example container characteristics are provided for 25 bar and 42 bar systems (e.g., maximum fill density ~1202 kg/m3; max working pressures at 50 °C shown).
- Superpressurization: Containers are required to be superpressurized with nitrogen to specified equilibrium pressures at 22 °C; the standard also mandates controls on nitrogen quality and moisture content.
- Personnel safety and toxicology: Minimum safety provisions for personnel and toxicological data (e.g., NOAEL and LOAEL concentrations) inform design and risk assessments.
Applications and users
ISO 14520‑11 is used by:
- Fire protection engineers and system designers sizing HFC 236fa total‑flooding systems
- Manufacturers of storage containers, valves and distribution hardware for superpressurized HFC 236fa systems
- Facility owners and safety managers in data centers, telecommunication shelters, archives, laboratories and other protected enclosures
- Regulatory authorities and testing laboratories validating performance and safety
Practical benefits include accurate agent quantity calculation, safe container filling practices, validated extinguishing concentrations for common fuels, and guidance to minimize personnel and environmental risks.
Related standards
- ISO 14520‑1:2015 - General requirements for gaseous fire‑extinguishing systems (normative reference)
- Other parts of the ISO 14520 series for specific agents and general test methods
Keywords: ISO 14520-11:2016, HFC 236fa, gaseous fire‑extinguishing systems, physical properties, system design, superpressurized nitrogen, fill density, extinguishing concentration, total flooding.
Open preview (PDF)Gaseous fire-extinguishing systems — Physical properties and system design — Part 11: HFC 236fa extinguishant
