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IS 15525:2004 is the Indian Standard (BIS) for gaseous fire extinguishing systems - ig 100 extinguishing systems. This standard specifies the requirements for the design, installation, operation, testing, and maintenance of IG-100 gaseous fire extinguishing systems. These systems use 100% Nitrogen to suppress fires by reducing the oxygen concentration in a protected enclosure, making them suitable for areas where water or other agents would damage sensitive assets.
Gaseous Fire Extinguishing Systems - IG 100 Extinguishing Systems
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Room integrity is critical for system effectiveness. A Door Fan Test (as described in Annex D) must be conducted to ensure the enclosure can hold the required gas concentration for a minimum of 10 minutes.
! The system design must ensure the resulting oxygen concentration does not fall below 12% in normally occupied areas (NOAEL) to allow for safe egress of personnel.
! Proper integration with building management systems is essential for automatically shutting down HVAC systems and closing dampers prior to gas discharge to prevent agent loss.
ISO 14520-15:2019International Organization for Standardization (ISO), International
HighCurrent
Gaseous fire-extinguishing systems — Physical properties and system design — Part 15: IG-100 extinguishant
Both standards provide specific requirements for the design and installation of IG-100 (Nitrogen) fire extinguishing systems.
NFPA 2001:2022National Fire Protection Association (NFPA), USA
HighCurrent
Standard on Clean Agent Fire Extinguishing Systems
Covers multiple clean agents, including IG-100, with detailed design, installation, and maintenance requirements.
EN 15004-8:2017European Committee for Standardization (CEN), Europe
HighCurrent
Fixed firefighting systems - Gas extinguishing systems - Part 8: Physical properties and system design of gas extinguishing systems for IG-100 extinguishant
Harmonized European standard for IG-100 systems, technically almost identical to ISO 14520-15.
BS EN 15004-8:2017British Standards Institution (BSI), United Kingdom
HighCurrent
Fixed firefighting systems. Gas extinguishing systems. Physical properties and system design of gas extinguishing systems for IG-100 extinguishant
The UK national adoption of the European standard EN 15004-8, with no technical deviations.
Key Differences
≠IS 15525 recommends that an enclosure integrity test 'should be conducted', whereas NFPA 2001 mandates that the enclosure 'shall be tested' to verify the agent holding time.
≠While IS 15525 specifies systems based on 150 bar and 200 bar cylinder pressures, modern ISO and EN standards widely include and promote the use of 300 bar systems for greater storage efficiency.
≠NFPA 2001 and the EN 12094 series (referenced by EN 15004) provide more detailed and stringent requirements for control panels, detection systems, and electrical actuation compared to the general references in IS 15525.
≠The methodology for calculating Class A design concentration in NFPA 2001 is based on the tested extinguishing concentration plus a 20% safety factor, which can result in slightly different final values compared to the fixed concentration specified in IS 15525.
Key Similarities
≈All standards are based on the same extinguishing mechanism: reducing the ambient oxygen concentration below the level that supports combustion but keeping it above levels immediately dangerous to life and health.
≈The specified physical properties and minimum purity level (typically 99.9% by volume for Nitrogen) for the IG-100 agent are identical across all standards.
≈Core personnel safety requirements, such as the need for pre-discharge alarms, time delays for occupied spaces, safety signage, and lockout procedures for maintenance, are fundamentally consistent.
≈All standards mandate the use of an approved hydraulic calculation software program to design the pipe network, ensuring the agent is distributed within the specified time (e.g., 60 seconds for Class A fires).
≈The physiological safety limits, the No-Observed-Adverse-Effect-Level (NOAEL) of 43% and the Lowest-Observed-Adverse-Effect-Level (LOAEL) of 52%, are universally recognized and referenced in all standards.
Parameter Comparison
Parameter
IS Value
International
Source
Minimum Design Concentration (Class A, Surface Fire)
36.5% (results in 13.8% O2)
Typically 37.3% (based on 31.1% extinguishing concentration plus a 20% safety factor)
NFPA 2001:2022
Maximum Discharge Time (Class A Hazard)
60 seconds
60 seconds
ISO 14520-1:2015
Agent Purity (Nitrogen)
99.9% minimum by volume
99.9% minimum by volume
ISO 14520-15:2019
No-Observed-Adverse-Effect-Level (NOAEL)
43% concentration (12% final O2)
43% concentration (12% final O2)
NFPA 2001:2022
Enclosure Integrity Test (Door Fan Test)
Recommended ('should be conducted')
Mandatory ('shall be tested')
NFPA 2001:2022
Common Cylinder Storage Pressure
150 bar or 200 bar at 21°C
200 bar or 300 bar at 15°C
EN 15004-8:2017
Pipe Material Requirement
Specifies seamless steel tubes conforming to IS 1239 (Part 1) or IS 3589
Specifies compliance with standards like ASTM A53/A106 or ISO 65
NFPA 2001:2022
⚠ Verify details from original standards before use
Key Values7
Quick Reference Values
Agent Composition100% Nitrogen (N2)
Typical Design Concentration (Class A Surface Fire)37.5% volume
W = (V/S) * [C / (100 - C)] — Formula for calculating the mass of extinguishing agent required, where V is volume, S is specific volume, and C is design concentration.
Tables & Referenced Sections
Key Tables
Table 1 - Physical Properties of IG-100
Table 2 - IG-100 Design Application Parameters
Table 3 - Typical Data for Pipe Schedule Systems
Table A.1 - Typical IG-100 Design Concentrations for Class A and B Fuels
Key Clauses
Clause 4 - Characteristics and Uses of IG-100
Clause 5 - System Design
Clause 6 - Components
Clause 8 - Safety
Clause 10 - Installation, Commissioning and Acceptance
IG-100 is an inert gas fire extinguishing agent consisting of 100% Nitrogen (N2), designated as 'N' in ISO 14520 and NFPA 2001.
What is the maximum discharge time for an IG-100 system?+
For most hazards (surface fires), the system must discharge to achieve 95% of the design concentration within 60 seconds (Clause 5.5.2).
Is an IG-100 system safe for occupied spaces?+
Yes, when designed correctly. The system must not exceed the No Observed Adverse Effect Level (NOAEL) of 43% concentration (12% oxygen) in normally occupied spaces, which allows time for egress (Clause 8.1.3).
How often does the system need to be inspected?+
A comprehensive inspection and servicing schedule is provided in Clause 11, including weekly visual checks, monthly checks on pressure gauges, and annual checks of all components and enclosure integrity.