Kidde Fire Protection 400 Series, Design, Installation, Operation, And Maintenance Manual

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General Information
July 2018 1-8 06-237518-001
1-5 EXTINGUISHING AGENT
Kidde IGS is approved for use with the following four Agents:
•
IG-100: Fixed fire extinguishing systems that use the pure inert gas Nitrogen
• IG-541: Fixed fire extinguishing systems that use inert, gaseous mixture of 52% Nitrogen,
40% Argon, and 8% Carbon Dioxide
• IG-55: Fixed fire extinguishing systems that use inert, gaseous mixture of 50% Nitrogen
and 50% Argon
• IG-01: Fixed fire extinguishing systems that use the pure inert gas Argon
The gases used in Kidde IGS occur naturally within the earth’s atmosphere. Carbon Dioxide
constitutes approximately 0.04%, Nitrogen constitutes approximately 78%, and Argon
approximately 0.9% of the atmosphere. As a result, the global warming effect of the Kidde IGS
is zero, the Ozone depleting factor is zero, and the atmospheric lifetime is not a consideration
as the gases are benign to the environment.
1-5.1 Design Concentration Safety Factor
The design concentration in most countries is accepted as the percentage of mixture of air and
extinguishing agent which is required to extinguish a fire in a cup-burner holding the flammable
liquid involved. The basic extinguishing concentration has in general been agreed to be that
which can extinguish an n-Heptane cup-burner fire.
Currently all international standards recommend that a safety factor of some kind is added to
the extinguishing concentration for use as minimum design concentration:
ISO 14520/EN 15004-1; safety factor of 30% for Class “A” fires, 30% for Class “B” fires
NFPA 2001; safety factor of 20% for Class “A” fires, 30% for Class “B” fires, 35% for electrical
Class C fires.
Other countries/authorities may have different requirements than above.
Note: There are certain Class B and EU Class C fuels which have cup burner values below that
of heptane. For agency compliance, systems designed to protect such fuels must still
use the MDC value of Heptane.