This publication details the methods that can be used to prevent the overpressurization of both transportable and static pressure vessels during filling.
This publication is intended to provide guidance to the filler/owner of either transportable or static cryogenic tanks, detailing the systems and procedures that can be used to prevent them being overpressurized during filling (i.e., causing a catastrophic failure by excessive pressure). Vessels for which the upper pressure limit (UPL) cannot be exceeded by the maximum allowable pump feed pressure (MAPFP) do not require any additional protection.
This publication is intended to address the issue of transportable or static cryogenic tanks greater than 264 gal (1000 L) water capacity for liquefied cryogenic gases and refrigerated liquids such as nitrous oxide and carbon dioxide. This publication should also be used for receiving vessels under 264 gal (1000 L) that are not designed for transport when full. This publication can also be used as guidance for other products and other transfer systems. It does not consider the hazardous nature of any product release, only the prevention of a failure of the tank due to pressure. This does not apply to cryogenic tanks with flat bottoms. For flat bottomed cryogenic tanks, refer to CGA P-8.9, Bulk Liquid Oxygen, Nitrogen, and Argon Storage Systems at Production Sites.
Protective measures that prevent the overpressurization of receiving vessels in service (e.g., by failure of the vacuum, pressure raising, flame engulfment, etc.) are detailed in other codes and standards, and are not considered further here.