ISO 14520-5:2019

Overview

ISO 14520-5:2019 specifies physical properties and system design requirements for gaseous fire‑extinguishing systems that use the FK-5-1-12 extinguishant (dodecafluoro-2-methylpentan-3-one). It covers purity and contamination limits, storage and container characteristics, extinguishing and inerting concentrations, safety of personnel, and system design rules for systems using nitrogen‑pressurized storage at nominal pressures of 25 bar, 34.5 bar, 42 bar and 50 bar.

Key topics and technical requirements

• Extinguishant specification: FK-5-1-12 purity and quality limits (e.g., purity ≥ 99.0 % mol/mol; strict limits on acidity, water content, non‑volatile residue and suspended matter).
• Physical properties: molecular mass, boiling/freezing/critical points, vapor pressure and liquid density used for hydraulic and thermodynamic calculations.
• Extinguishing and design concentrations: measured extinguishment concentrations (e.g., n‑heptane ≈ 4.5 % by volume) and minimum design concentrations with safety factors (tables provide values for Class B, Surface Class A, other fuels and inerting).
• System design:
  • Minimum extinguishant quantity per protected volume as a function of temperature and concentration (total flooding mass requirements are tabulated).
  • Fill density limits for storage containers at each nominal pressure (e.g., maximum fill densities specified per pressure class).
  • Superpressurization and charging requirements using nitrogen propellant (standard specifies superpressurization practice and moisture control for the propellant).
  • Container pressure/temperature relationships and maximum allowable working pressures at elevated temperatures.
• Safety of personnel: toxicological metrics are provided (e.g., 4 h LC50 > 10 %, NOAEL ≈ 10 %), and designers must consider hazards from the agent, combustion products and agent breakdown products.
• Environmental properties: addressed in the standard (see Clause 7 for details).

Practical applications and who uses this standard

ISO 14520-5 is essential for:

• Fire protection engineers and system designers specifying FK-5-1-12 total‑flooding systems
• Manufacturers of storage vessels, cylinder packs and discharge hardware
• Installation contractors and commissioning teams calculating agent quantities and storage requirements
• Facility owners/operators and asset managers in data centers, museums, telecommunications, clean rooms and other enclosures requiring clean-agent total flooding
• Test laboratories and regulators assessing compliance with ISO 14520 series

Using this standard ensures safe, reproducible design and installation of FK-5-1-12 systems, proper storage/pressurization practices, and documented extinguishing performance for specific fuel classes.

Related standards

• ISO 14520-1 (Gaseous fire‑extinguishing systems - Physical properties and system design - Part 1: General requirements) - normative reference for general design methods and definitions.
• Look up the rest of the ISO 14520 series for complementary parts and test methods.

Keywords: ISO 14520-5, FK-5-1-12, gaseous fire‑extinguishing systems, total flooding, fill density, superpressurization, nitrogen propellant, extinguishant concentration, fire protection design.