Ask X3What does 49 CFR 173.335 (Chemical under pressure n.o.s) require?
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Based on 49 CFR 173.335, a motor-carrier owner must ensure that a cylinder filled with a chemical under pressure is offered for transportation according to the following specific and practical requirements:
* General Requirements: Must comply with this section and § 173.301 (with an exception for cylinder valve cap requirements in §§ 173.301(a)(11) and (12)).
* DOT specification cylinders must also meet §§ 173.301a, 173.302, 173.302a, and 173.305, as applicable.
* UN pressure receptacles must meet §§ 173.301b, 173.302b, and 173.304b, as applicable.
* If more than one section applies, you must follow the most restrictive requirements.
* Filling Limits:
* At 50 °C (122 °F), the non-gaseous phase must not exceed 95% of the cylinder's water capacity.
* The cylinder must not be completely filled at 60 °C (140 °F).
* The internal pressure at 65 °C (149 °F) must not exceed the cylinder's test pressure.
* You must account for the vapor pressures and volumetric expansion of all substances in the cylinder.
* Minimum Service Pressure: Must match the design specifications in part 178 for the propellant, and the minimum test pressure must never be less than 20 bar.
* Periodic Inspection (Requalification):
* The maximum test period is generally 5 years.
* For cylinders with a maximum capacity of 450 L or less that are filled with fire extinguishing agents, the maximum test period is 10 years.