ISO 14520-5:2024

Overview

ISO 14520-5:2024 - Gaseous fire‑extinguishing systems - Physical properties and system design - Part 5: FK‑5‑1‑12 extinguishant specifies physical, safety and system‑design requirements for using FK‑5‑1‑12 (dodecafluoro‑2‑methylpentan‑3‑one) in gaseous fire‑extinguishing systems. The fourth edition (2024) updates specifications (including dimer limits) and is applicable to total‑flooding systems operating at nominal container pressures of 25, 34.5, 42 and 50 bar using nitrogen propellant. It complements the general requirements in ISO 14520‑1.

Key topics and technical requirements

• Extinguishant specifications: minimum purity 99.0% mol/mol; limits on acidity, water, non‑volatile residue, visible sediment and dimer content.
• Physical properties: molecular mass (316.04), boiling/freezing points, critical temperature/pressure/density, liquid density and vapour data - used for storage, piping and discharge calculations.
• Design concentrations and mass‑per‑volume tables: published m/V values across temperatures (‑20 °C to 100 °C) and concentrations (3–10% by volume), plus reference extinguishing and minimum design concentrations for specific fuels (e.g., n‑heptane extinguishment 4.5% - design 5.9%).
• Fuel‑specific guidance: extinguishment/design concentrations for Class B and Class A fuels (heptane, wood crib, PMMA, PP, ABS), other fuels (acetone, ethanol, methanol, diesel) and inerting concentrations (e.g., methane inerting 8.8% - design 9.7%).
• System design factors: container fill density limits, superpressurization, extinguishant quantity calculations (m = c·V / [(100 − c)·S]), and alternate fill/superpressurization options.
• Safety and toxicology: personnel safety considerations (hazards from the agent, combustion and breakdown products). Toxicological values: 4 h LC50 >10% (rats), NOAEL 10%, LOAEL >10%.
• Environmental properties: dedicated section addressing environmental aspects of FK‑5‑1‑12.

Practical applications

• Design and specification of total‑flooding gaseous suppression systems for sensitive enclosures where water or powder is unsuitable, such as:
  • data centres and server rooms
  • telecommunications equipment rooms
  • museums, archives and cleanrooms
  • engine rooms and control centres
• Use for both extinguishment and inerting applications where precise concentration control is required.

Who should use this standard

• Fire protection engineers and system designers
• Specifiers, manufacturers and installers of gaseous suppression systems
• Risk assessors, safety managers, regulators and insurance assessors
• Compliance teams working with ISO 14520 series requirements

Related standards

• ISO 14520‑1: General requirements for gaseous fire‑extinguishing systems
• Other parts of the ISO 14520 series addressing different extinguishants and test methods

Keywords: ISO 14520‑5:2024, FK‑5‑1‑12, gaseous fire‑extinguishing systems, system design, physical properties, fill density, design concentration, total flooding, nitrogen propellant.