Ask X3What does 49 CFR 173.115 (Class 2, Divisions 2.1, 2.2, and 2.3—Definitions) require?
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According to 49 CFR 173.115, the regulation defines the materials and criteria for Class 2 gases, specifically covering Divisions 2.1, 2.2, and 2.3, as well as related terms and testing criteria for motor carriers:
* Division 2.1 (Flammable gas): Defines a flammable gas as a material that is a gas at 20 °C (68 °F) or less and 101.3 kPa (14.7 psia) of pressure (or has a boiling point of 20 °C or less at that pressure) and is either ignitable in a mixture of 13% or less by volume with air, or has a flammable range with air of at least 12% regardless of the lower limit. Specific testing methods (like ASTM E681-85) are outlined for determining these limits.
* Division 2.2 (Non-flammable, nonpoisonous compressed gas): Defines non-flammable, nonpoisonous compressed gases (including liquefied, pressurized cryogenic, in solution, asphyxiant, and oxidizing gases) as materials that exert a gauge pressure of 200 kPa (29.0 psig/43.8 psia) or greater at 20 °C (68 °F), are liquefied gases or cryogenic liquids, and do not meet Division 2.1 or 2.3 definitions. Oxidizing ability must be determined by tests or calculations in accordance with ISO 10156:2017(E).
* Division 2.3 (Gas poisonous by inhalation): Defines a gas poisonous by inhalation as a material that is a gas at 20 °C (68 °F) or less and 101.3 kPa of pressure (or has a boiling point of 20 °C or less) and is either known to be toxic enough to humans to pose a health hazard during transport, or is presumed toxic to humans based on laboratory animal testing with an LC50 value of not more than 5000 mL/m³.
* Additional Definitions and Classifications: Provides practical definitions for non-liquefied compressed gases, liquefied compressed gases (further broken down into high and low pressure), compressed gases in solution, cryogenic liquids, flammable ranges, service pressure, refrigerant/dispersant gases, and adsorbed gases.
* Aerosols: Outlines specific mass percentage and heat of combustion criteria for assigning aerosols to Division 2.1 or Division 2.2, details testing requirements, prohibits Division 2.3 gases and certain Division 6.1/Class 8 substances in aerosol containers, and explains subsidiary hazards.