General Information
June 2020 1-10 P/N 06-237620-001
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1-4.4 IG-55 (Nitrogen and Argon)
Natura IGS systems with IG-55 are fixed fire extinguishing systems that use an inert, gaseous
mixture of 50% Nitrogen and 50% Argon known as Argonite
®
, UN number of 1956.
Specification for IG-55 is an Argon/Nitrogen 50%/50% ratio by volume. Tolerance of mixture
in air is as follows:
• Argon: 50% +/- 5%
• Nitrogen: 50% +/- 5%
1-4.4.1 Purity of Argon and Nitrogen
Each element shall conform to the following purity specification:
Argon:
• Argon greater than or equal to 99.99%
• Oxygen less than or equal to 10 ppm
• Water less than or equal to 10 ppm
Nitrogen:
• Nitrogen greater than or equal to 99.7%
• Oxygen less than or equal to 10 ppm
• Water less than or equal to 10 ppm
Note: Only principal contaminants are shown. Other measurements may include: Carbon
Monoxide, Carbon Dioxide, Nitrogen Oxide, and Nitrogen Dioxide most < 20 ppm.
Figure 1-9. IG-55 Pressure/Temperature Curve Isometric Diagram for 200 bar, U.S. Customary Units