Overview
ISO 14520-14:2015 specifies the physical properties and system design requirements for gaseous fire‑extinguishing systems using IG-55 (nominally a 50/50 argon–nitrogen inert gas mixture). The standard covers composition and purity, how IG‑55 extinguishes fires (by reducing oxygen concentration), storage and fill pressures, quantities required for total‑flooding designs, personnel safety limits, and environmental properties. It applies to systems stored at nominal fill pressures of 150, 200 and 300 bar at 15 °C (design data for other pressures are not provided).
Key topics and technical requirements
- Extinguishant composition and purity: IG‑55 is an inert binary mixture (Argon ~50% / Nitrogen ~50% nominal, with specified tolerance) with high gas purity (>99.9%).
- Physical properties and design data: Includes tables and methods (e.g., Table 3) to calculate required agent volume per protected volume (m3/m3) and the specific vapour volume used for sizing cylinders and piping.
- Design concentrations: Extinguishing and minimum design concentrations are given for representative fuels (heptane, ethanol, methanol, various Class A fuels). Design concentrations incorporate a safety factor (typically 1.3 on extinguishing values) and are used to calculate agent mass/volume required.
- System pressures and container data: Provides fill pressure limits and maximum container working pressures for 150, 200 and 300 bar systems and pressure–temperature relationships for storage. Containers for IG‑55 are not superpressurized.
- Safety of personnel: Defines physiological guidance (NOAEL ~43% by volume; LOAEL ~52% by volume) and requires designers to assess hypoxia risks and combustion product hazards per ISO 14520‑1.
- Environmental profile: IG‑55 is inert with zero GWP and zero ODP (suitable where environmental impact is a concern).
Practical applications and users
- Who uses ISO 14520-14:2015: fire protection engineers, system designers, cylinder and valve manufacturers, installers of total‑flooding gaseous extinguishing systems, facility managers for data centers, museums, archives, marine and industrial enclosures, and regulatory authorities.
- Typical uses: Designing IG‑55 total‑flooding systems for enclosed hazards (Class A and B fires) where a clean, electrically non‑conductive extinguishant is required and environmental considerations favor inert gases. The standard provides the data to size storage, assess required agent quantities, set system fill pressures, and evaluate personnel safety.
Related standards
- ISO 14520‑1:2006 - General requirements for gaseous fire‑extinguishing systems (normative reference).
- ISO 14520 series (other parts) - covers CF I, IG‑541, HFCs and other extinguishants; useful when comparing agents or applying mixed‑system guidance.
Keywords: ISO 14520-14:2015, IG-55, gaseous fire-extinguishing systems, system design, physical properties, total flooding, design concentration, fill pressure, fire protection standard.
Open preview (PDF)Gaseous fire-extinguishing systems — Physical properties and system design — Part 14: IG-55 extinguishant
