7-4 September 2004
Argonite
®
Engineered Fire Suppression System
38-KFSARG-000
The minimum design concentration used to inert atmospheres involving flammable liquids
and gasses shall be the normal design value plus an added 10% safety factor.
7-7 EXTINGUISHING VALUES
Class A: 31.6%
Class B: 30.1% - n-Heptane
7-7.1 Class A and Class C
Flammables require a safety factor of 20%. Design concentration 37.9% (Oxygen
Concentration = 12.97%).
7-7.2 Class B
Flammable liquids require a safety factor of 30% above the extinguishing concentration
or 30% above the cup burner value established for the fuel. Design concentration
39.1% for n-Heptane (Oxygen Concentration = 12.72%).
7-7.3 Equation Formula for Specific Requirements
X = 2.303 * (V
S
/s) * Log
10
(100/(100-C) = V
S
/s * Ln (100/(100-C))
Where:
X = Volume of agent required per m
3
of protected volume to produce the indicated
concentration at temperature specified.
V
S
= Specific volume of Argonite at 70°F (21.1°C) = 0.71086 m
3
/kg at 1013 mbar.
C = Design concentration of Argonite in the protected area
s = Specific volume of superheated Argonite vapor. Can be approximated by the
formula:s = 0.6598 + 0.00242t
t = Temperature in the Hazard (C).
For further details regarding specific vapor volumes at various temperatures, refer
to NFPA 2001, Appendix A.
M
x
= X/s
Where:
M
x
= The mass of Argonite/volume of protected area [See Tables 7-3 and 7-4 for M
x
(kg/m
3
and kg/ft.
3
) values at various temperature and design concentration
conditions.]
7-8 DESIGN CONCENTRATIONS
7-8.1 NFPA Design Concentrations
Class A: The minimum design concentration for a Class A surface fire hazard
shall be the extinguishing concentration times a safety factor of 1.2.
Class B: The minimum design concentration for a Class B fuel hazard or an only
manually actuated system shall be the extinguishing concentration times a safety
factor of 1.3.
Class C: The minimum design concentration for Class C hazards shall be at least
that for a Class A surface fire.
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