Ask X3What does 49 CFR 173.319 (Cryogenic liquids in tank cars) require?
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As Ask X3, your fleet-compliance assistant, here are the key requirements for shipping flammable cryogenic liquids in tank cars under 49 CFR 173.319:
* Ownership & Loading Consent: A tank car containing a flammable cryogenic liquid cannot be shipped unless it is loaded by or with the consent of the car's owner.
* Determining and Checking Load Amounts: The loaded amount must be determined by direct measurement or calculation based on weight to ensure it does not exceed allowed filling limits. Except for hydrogen, the weight must be checked using scales after disconnecting the loading line.
* Late Shipment Notification: If a tank car containing a flammable cryogenic liquid is not received by the consignee within 20 days of shipment, you must notify the Federal Railroad Administration (FRA) via email at [email protected] or phone at (202) 493-6245.
* Loading Prohibitions: Do not load a flammable cryogenic liquid if it:
* May chemically combine with tank residue to create an unsafe condition.
* Is colder than the tank's design service temperature.
* Exceeded an average daily pressure rise of 3 psig during its prior shipment.
* Is not marked with the name of the contents in accordance with § 172.330.
* Outage & Pressure Requirements when Offered:
* At least 0.5 percent outage must be provided below the inlet of the pressure relief or pressure control valve at its start-to-discharge setting (with the car level).
* The absolute pressure in the annular space must be less than 75 microns of mercury.
* Temperature: Load the liquid at a temperature that ensures the average daily pressure rise during transport will not exceed 3 psig.
* DOT-113 Tank Car Special Requirements:
* Monitoring & Testing: Monitor each shipment for average daily pressure rise. If it exceeds 3 psig (0.2 Bar) per day, the tank must pass a thermal integrity test (either a pressure rise test or a calculated heat transfer rate test) before any subsequent shipment. Tanks failing this test must be removed from hazardous materials service.
* Rupture Discs: Replace each rupture disc every 12 months, and mark the replacement date near the pressure relief valve information.
* Pressure Relief Valves: Test pressure relief valves and alternate pressure relief valves every five years.