RIVERSIDE, Calif. (August 1, 2008)—It has been reported to Luxfer that an older aluminum alloy CO2 beverage cylinder has failed due to over-pressurization when filled with a nitrogen/CO2 (N2/CO2) gas blend. Since the use of such gas blends to dispense beverages (e.g., beers, ales and lagers) is becoming increasingly popular in the United States, Luxfer is issuing the following guidelines concerning this usage:
- In accordance with Federal regulations, a cylinder with “CO2” stamped on its crown must be filled only with CO2 and equipped with a valve suitable for CO2. The same restriction applies to older Luxfer beverage cylinders stamped with the names of specific beverage companies (e.g., Coca Cola, Pepsi Cola, etc.); these cylinders were intended for use only with liquid CO2 filled by weight.
- Mixing liquid CO2 with gaseous nitrogen in a standard Luxfer CO2 beverage cylinder can cause a rapid pressure increase that exceeds the 1,800-psi operating pressure of the cylinder. Do not mix liquid CO2 with gaseous nitrogen in a Luxfer cylinder.
Luxfer aluminum alloy beverage cylinders may be filled with nitrogen or N2/CO2 blends under the following conditions:
- The cylinder must not be stamped, marked or otherwise identified as containing only liquid CO2; this includes cylinders stamped with the names of specific beverage companies.
- For authorized transportation, the gas mixture must meet all applicable federal and state labeling and manifesting requirements.
- Any gas mixing or blending must be done with equipment designed for that purpose prior to filling the cylinder. A Luxfer gas cylinder should not be used as a ‘mixing’ container. The cylinder must only be filled with the final gas mixture—not with separate, unmixed gases—such that at 70 degrees F, the gas mixture does not exceed the stamped or marked service pressure of the cylinder.
In all cases, never fill a cylinder such that gas pressure at 70 degrees F exceeds the allowable pressure stamped or marked on the cylinder crown. (The service pressure for standard Luxfer beverage cylinders, whether stamped for CO2 use or not, is 1,800 psi.)
For nitrogen and N2/CO2 gas blends used in the beverage industry, Luxfer recommends the use of higher-pressure cylinders, which need to be exchanged and filled less often. Valves on such higher-pressure cylinders must be rated for the cylinder service pressure and be suitable for the gas being used. Luxfer offers appropriate cylinder models rated at 2,215 psi and 3,000 psi.
Please address questions concerning this subject to Luxfer customer service at 800-764-0366.