Last updated 04/08/2025
Cryogenic tanks are used for the storage of cryogenic liquids.
Cryogenic liquids are typically liquefied gases at -153 °C or lower. Common gases include oxygen, argon, nitrogen, hydrogen, and helium. They are stored in specially designed cryogenic storage tanks. Cryogenic tanks are also used for storing liquefied gases at slightly higher temperatures, examples of which include liquefied natural gas (LNG), carbon dioxide and nitrous oxide.
Cryogenic tanks act as a bulk gas source for a gas supply and distribution system, which allows connection to the user’s equipment, as well as for replenishment. The applications include metal processing, medical technology, electronics, water treatment, energy generation and the food industry. Cryogenic liquids are also used for low temperature cooling applications, such as engineering shrink fitting, food freezing and the storage of bio-samples.
Cryogenic tanks are designed and manufactured to a high specification following international design codes. They have to be strong enough to contain the gas under some pressure and in quantity, with very efficient insulation to minimise thermal leakage and to maintain the liquid at its cold temperature. They are available for static, mobile or transportable applications.
Static cryogenic tanks are designed for use in a fixed location. Smaller mobile tanks, mounted on wheels, are also common within workshops and laboratories.
There are specific requirements for the location and installation of a cryogenic tank. Refer to BCGA CP 26, for carbon dioxide, BCGA CP 36, for oxygen, nitrogen and argon, and BCGA CP 46 for flammable cryogenic gases. For the storage of biological materials, usually for the long term, refer to BCGA CP 45.
Before an installation can take place, suitable foundations are required for each cryogenic tank. The civil engineering requirements are agreed with the cryogenic tank supplier, but the responsibility for their installation is usually with the site owner or operator. There is also a requirement to ensure there is safe and adequate access for replenishment tankers.
Static cryogenic tanks are generally classified as pressure vessels, as such new tanks and their associated systems must be manufactured and put into service in accordance with the Pressure Equipment (Safety) Regulations.
Transportable cryogenic tanks that are, or are intended, to be used for the carriage of cryogenic liquids must comply with the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations.
There are a range of non-pressurised open vessels (storage vessels, dewar flasks. dewar freezers. etc.) available for those applications requiring direct access to the liquid. BCGA CP 30 provides best practice for the safe use of dewars containing liquid nitrogen.
Cryogenic tanks and their associated gas supply and distribution system(s) must have an examination, inspection and maintenance regime in place in accordance with relevant legislation, for example, the Provision and Use of Work Equipment Regulations and the Pressure Systems Safety Regulations. Advice is available in BCGA CP 39.
In support of this regime, the User must carry out regular safety checks to ensure the cryogenic tanks remain in a safe condition. Advice is available in Leaflet 11 and Leaflet 12.
Cryogenic tanks will have a validated design for a prescribed set of defined operating conditions. Changes can occur to the operating regimes of the cryogenic tanks, or to their physical structure, over the many years that the tank may be in service. For vacuum insulated pressure vessels, it is not possible to conduct a thorough internal examination as there is no means of access to the inner vessel and interspace pipework without affecting their integrity. To justify the continued use of these vessels, the elements that are not accessible for examination (in accordance with a Written Scheme of Examination) are subjected instead to a revalidation process. Typically, this is first carried out after 20 years in service. Advice is available in BCGA CP 39.
Within BCGA cryogenic tanks are the responsibility of Technical Sub-Committee (TSC) 1. Members can access information on TSC1 via the Committee Meetings page.
The design, installation, operation and maintenance of bulk liquid carbon dioxide storage systems at users’ premises. All tanks up to 250,000 litres capacity are included.
Go To Download PageThis code of practice applies to transportable, vacuum insulated, tanks of not more than 1,000 litres water capacity, for the following gases: Nitrogen, argon, oxygen, carbon dioxide, helium or nitrous oxide.This code provides guidance for the minimum requirements for: General safety precautions, design and construction, operation, tank management and filling, transportation, in-service examination, modifications/repairs and records.
Go To Download PageCovers the storage, maintenance, handling, filling and use of dewars. Specifically addresses the use of liquid nitrogen in open dewars and dewars fitted with liquid withdrawal devices operating at less than 0.5 bar.
Go To Download PageThis document covers the installation of cryogenic liquid storage tanks and associated equipment at customer sites. For liquid oxygen, nitrogen and argon. Tank sizes range from 0 to 125000 litre water capacity.
Go To Download PagePressure systems require regular examination, inspection and maintenance to ensure the continuing integrity of the equipment and the safety of personnel. This code covers the principles and a risk based methodology to meet these requirements. It includes guidance on Written Schemes of Examination, Ageing Pressure Equipment Assessments and Revalidation of pressure vessels.
Go To Download PageThe design, installation and operation of systems used for the storage of biomedical materials at cryogenic temperatures, using liquid nitrogen as a sacrificial refrigerant.
Go To Download PageThis document covers cryogenic flammable liquid storage tanks and associated equipment at customer sites. Tank sizes range from 0 to 125000 litre water capacity. It provides guidance on their design, installation, commissioning and the operation of cryogenic flammable liquid storage installations.
Go To Download PageDetails the responsibilities of the User, the Tank Owner and the Gas Supplier when filling third party owned tanks used for the storage of refrigerated liquefied gases at a User’s premises. It includes a procedure to inform BCGA members of tanks which are deemed unsafe to fill.
Go To Download PageClarification of the legislation in the UK for transportable pressure equipment, including the various type approval and conformity assessment requirements.
Go To Download PageBCGA Leaflet 11 outlines some daily safety checks that users responsible for cryogenic tanks are to carry out. These are independent of safety checks which gas supply companies’ drivers will conduct at delivery times.
Go To Download PageAn information leaflet which reminds users and owners of liquid gas storage tanks of their legal duties and responsibilities to ensure the equipment is installed, maintained and operated safely.
Go To Download PageOutlines the problems associated with an increasing quantity of ice formation within a cryogenic installation and provides a methodology for safely removing the ice.
Go To Download PageBCGA publish several publications providing advice and guidance on the on how to use, store, transport and handle cryogenic gases safely. All BCGA publications are accessible via the Publications page.
