Overview
ISO 14520-17:2022 defines the physical properties and system design requirements for gaseous fire‑extinguishing systems that use Halocarbon Blend 55. The standard specifies the extinguishant composition (50 ± 3 % HFO‑1233zd(E) and 50 ± 3 % FK‑5‑1‑12 by mass), purity and quality limits, operating pressures, safety considerations and design methods for total‑flooding systems. It covers systems superpressurized with nitrogen at nominal pressures of 25 bar, 35 bar and 42 bar.
Keywords: ISO 14520-17:2022, Halocarbon Blend 55, gaseous fire‑extinguishing systems, HFO‑1233zd(E), FK‑5‑1‑12, superpressurized.
Key Topics and Requirements
- Extinguishant specification
- Composition: blend of HFO‑1233zd(E) and FK‑5‑1‑12 (50/50 by mass, ±3%).
- Purity: ≥ 99.5 % by mass and limits on acidity, water, non‑volatile residue and dimer content.
- Physical properties
- Molecular mass, boiling/freezing points, critical parameters and densities are tabulated (see standard for full values).
- Design concentrations & extinguishing data
- Extinguishing and minimum design concentrations are provided for Class B and Surface/Class A fuels (e.g., heptane cup‑burner extinguishment ~5.5 % vol; design concentrations incorporate a 1.3 safety factor).
- Tabled agent mass per protected volume (kg/m3) is given for temperatures and target concentrations (4–10 % vol).
- System storage & fill density
- Maximum fill densities and container working pressures are specified for 25, 35 and 42 bar systems (e.g., max fill density ≈ 1 308 kg/m3 for 25 and 35 bar; ≈ 1 201.5 kg/m3 for 42 bar).
- Exceeding fill density risks “liquid full” containers and rapid pressure rise.
- Superpressurization
- Containers shall be superpressurized with nitrogen to an equilibrium pressure of 25, 35 or 42 bar at 20 °C, with nitrogen moisture ≤ 60 ppm.
- Safety & toxicology
- Designers must assess hazards from the agent, combustion products and decomposition products.
- Toxicological reference values (e.g., NOAEL ≈ 8.7 % by volume, 4‑hour LC50 > 11 % by volume) are included.
Applications
- Design and commissioning of total‑flooding gaseous fire suppression systems in data centres, telecommunication rooms, engine rooms, electrical switch rooms, archives and other enclosed hazards where Halocarbon Blend 55 is proposed.
- Determining required agent mass, container specification, pressure/temperature relationships and safe discharge practices.
- Supporting compliance, procurement and risk assessments for facilities evaluating low‑residue halocarbon blends.
Who Uses This Standard
- Fire protection engineers and system designers
- Cylinder and system manufacturers
- Facilities managers and specifiers for protected hazards
- Testing laboratories and regulatory/approval authorities
- Safety and environmental compliance teams
Related Standards
- ISO 14520‑1 (General requirements) and other parts of the ISO 14520 series for gaseous fire‑extinguishing systems - consult the series for complementary design, testing and safety guidance.
For implementation, refer to the full ISO 14520‑17:2022 document for complete tables, figures and normative details.
Open preview (PDF)Gaseous fire-extinguishing systems — Physical properties and system design — Part 17: Halocarbon Blend 55
