Kidde IG-55 - IG-55 (Nitrogen and Argon); Purity of Argon and Nitrogen

General Information
06-237619-001 1-11 April 2020
1-5.3 IG-55 (Nitrogen and Argon)
Kidde IGS using 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.
The 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%
1-5.3.1 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 1-5. IG-55 Pressure/Temperature Curve Isometric Diagram for 200 bar, U.S. Customary Units