Handling fluids at extreme low temperatures demands components that perform reliably where standard valves fail. Cryogenic valves are engineered specifically for service at temperatures where ordinary materials become brittle, seals lose their integrity, and conventional designs cannot maintain the shut-off performance that safe operation requires.
This guide covers what cryogenic valves are, how they work, the main types available, the materials and design features that define them, the standards they must meet, and the selection criteria that matter when specifying for cryogenic duties.
What Is a Cryogenic Valve?
A cryogenic valve is a valve designed to operate reliably at extremely low temperatures, typically below -40°C (-40°F) and in many applications as low as -196°C (-320°F) for liquid nitrogen service, or lower still for liquid hydrogen and liquid helium applications.
Standard valves are not suitable for cryogenic service. At very low temperatures, carbon steel and many alloys lose ductility and become brittle, elastomeric seals contract and lose sealing performance, and lubricants solidify. Cryogenic valves address these challenges through specific material selection, extended bonnet designs, and construction methods suited to the thermal and mechanical demands of the duty.
Browse the full range of cryogenic valves from Measure Monitor Control, covering manual, self-acting, and solenoid-operated designs rated to -196°C.
What Are Cryogenic Valves Used For?
Cryogenic valves are found wherever gases are liquefied, stored, transported, or processed in their liquid state. The principal reason for working with cryogenic fluids is density: liquefied gases occupy a fraction of the volume of the same gas at ambient temperature and pressure, making storage and transport considerably more practical. The low pressures at which liquefied gases can be stored, compared to high-pressure gas storage, is an additional advantage.
LNG and industrial gas facilities. Liquid natural gas (LNG), liquid nitrogen (LN2), liquid oxygen (LOX), and liquid argon are all handled and transferred through cryogenic valve systems in gas production, liquefaction, and distribution plant.
Industrial gas distribution. Cryogenic valves appear on storage vessels, road tankers, fill stations, and pipeline systems wherever industrial gases are handled in liquid form.
Cryogenic processing. Cryogenic treatment is used in the production of certain metals and engineered materials to improve hardness and wear resistance. Food processing and pharmaceutical cold chain applications also use cryogenic cooling.
Aerospace and defence. Liquid hydrogen and liquid oxygen are used as propellants in rocket and launch vehicle systems. These are among the most demanding cryogenic applications, operating at the lowest temperatures and subject to strict safety and reliability requirements.
Medical and research. Liquid nitrogen is used extensively in medical, laboratory, and research settings for cryopreservation, cooling, and processing.
How Do Cryogenic Valves Work?
The operating principle of a cryogenic valve is the same as its standard counterpart: a closure element moves to open or restrict flow, operated either manually or by an actuator. What distinguishes cryogenic valves is how they are designed to maintain safe and reliable operation at the temperatures involved.
The critical design feature common to virtually all cryogenic valves is the extended bonnet or extended stem. Rather than positioning the stem packing and gland at body level, where it would be exposed to cryogenic fluid temperatures, the extended bonnet places the packing well above the valve body. This allows the temperature at the packing to remain close to ambient, even when the body and trim are at cryogenic temperatures. Without this extension, the packing would contract and lose its sealing integrity.
A secondary consideration is the management of pressure build-up from trapped fluid. Cryogenic liquids that become trapped in valve cavities will vaporise as temperature rises slightly, with a rapid and large increase in pressure. Gate valves and other designs where fluid can become trapped in the bonnet cavity require internal venting provisions to prevent this from over-pressurising the valve.
Types of Cryogenic Valve
Globe valves
Cryogenic globe valves are well suited to flow control duties on both liquid and gas lines. The disc and seat arrangement provides consistent throttling performance and reliable shut-off. Stellite trim is specified for wear resistance, since cryogenic fluids lose lubricity at low temperatures and accelerate wear on standard materials. Available with screwed, flanged, or weld end connections.
Ball valves
Ball valves are the most widely used type for liquid gas applications, offering good flow characteristics, fast operation, and reliable shut-off. Double-seal designs are common in cryogenic service to manage the risk of trapped fluid in the ball cavity. Ball valves are preferred where unrestricted flow path and tight shut-off are both required, though seal wear over time is a consideration in applications with frequent cycling.
Gate valves
Cryogenic gate valves provide a full-bore flow path with minimal pressure drop when fully open. They are preferred for larger bore applications and where cost of equivalent ball valves becomes significant. Gate valves should be operated either fully open or fully closed, not throttled. Internal venting of the bonnet cavity is a standard requirement to manage trapped fluid pressure build-up. Full Stellite trim is recommended to resist erosion in cryogenic service.
Needle valves
Needle valves provide precise flow control and are used on instrument and sampling lines, small-bore circuits, and anywhere that fine flow adjustment is required. Their compact body and precise control make them well suited to analytical and instrumentation duties.
Check valves
Cryogenic check valves prevent reverse flow, protecting equipment such as pumps and compressors from backflow damage. They operate automatically in response to flow direction and require no external actuation.
Butterfly valves
Triple-offset butterfly valves are well suited to cryogenic service. The metal-to-metal sealing arrangement provides bubble-tight shut-off without the soft seal materials that perform poorly at low temperatures. They offer fast opening and closing, compact installation, and are well suited to remote and automated operation.
Solenoid valves
Cryogenic solenoid valves regulate cryogenic media via an electrical signal to the solenoid coil, allowing remote and automated control. Available in brass and stainless steel bodies, they are used where electrically actuated shut-off or control is required. Solenoid protection to IP65 and ATEX Ex d certification is standard for cryogenic service.
Cryogenic economisers
Economisers manage pressure in cryogenic storage vessels by recirculating gas back into the liquid phase. As liquid in a storage vessel warms slightly, pressure builds due to vapour formation. The economiser uses this pressure to deliver gas to the supply system before venting occurs, recovering value from what would otherwise be lost product. They are standard equipment on liquid gas storage installations.
Materials for Cryogenic Service
Material selection is critical in cryogenic valve design. The primary requirement is that all materials in contact with cryogenic fluid maintain adequate mechanical properties, particularly ductility and toughness, at the minimum service temperature. Materials that exhibit a ductile-to-brittle transition within the operating temperature range are not acceptable.
Austenitic stainless steels (304, 316, and their variants) are the most widely specified body and trim materials for cryogenic valves. They retain ductility at very low temperatures and offer good corrosion resistance. 316 stainless steel is preferred where corrosion resistance is a priority.
Copper alloys and bronze are used in some applications at more moderate cryogenic temperatures. Materials containing more than 70% copper are not permitted in contact with acetylene mixtures.
PTFE is the most common non-metallic seal and packing material for cryogenic service. It retains flexibility at very low temperatures and is chemically inert to most cryogenic media. Seat and packing designs must account for the cold flow behaviour of PTFE under sustained load.
Stellite hard-facing on valve seats and discs is standard practice in cryogenic globe and gate valves to provide wear resistance where fluid lubricity is reduced.
Standards and Certifications
Cryogenic valves for industrial service must conform to recognised standards covering design, materials, testing, and performance.
BS 6364 is the relevant British Standard, specifying requirements for the design, manufacture, and testing of cryogenic valves. Key requirements include extended bonnet designs of sufficient length to maintain packing within its operating temperature range, pressure relief provision for cavities where fluid entrapment could cause overpressure, and requirements for electrical continuity to prevent static build-up in flammable service.
ISO 21011 is the international standard covering cryogenic valve design, materials, and testing. It sets requirements for both metallic and non-metallic materials, design performance across the full temperature range from ambient to rated minimum, and testing procedures including prototype and production tests.
MSS SP-134 is the dominant standard in North American applications, covering material, design, dimensions, fabrication, pressure testing, and non-destructive examination requirements for cryogenic valves with body/bonnet extensions. Extended bonnet designs are mandatory for operating temperatures below -73°C (-100°F).
ASME B16.34 covers pressure-temperature ratings, materials, dimensions, and testing for valves including those in cryogenic service. It is referenced by both MSS SP-134 and ISO 21011 for shell and closure testing requirements.
ATEX certification is required for valves installed in potentially explosive atmospheres, which includes many cryogenic applications involving liquefied flammable gases and oxygen-enriched environments. Cryogenic valves from Measure Monitor Control are ATEX certified as standard.
Testing of Cryogenic Valves
Cryogenic valves undergo both prototype testing and production testing before being approved for service.
Shell testing confirms the pressure integrity of the valve body and bonnet at the required test pressure, with all external surfaces checked for leakage.
Seat closure testing verifies shut-off performance at the required test pressure. Acceptance criteria for seat leakage in cryogenic service are typically more stringent than for standard valve duties.
Cryogenic functional testing is carried out on prototype valves and may be required on production valves for critical applications. The valve is cooled to its rated minimum temperature using liquid nitrogen or the relevant cryogenic fluid, and operation, shut-off performance, and packing leak-tightness are all verified at temperature.
Non-destructive examination (NDE) of welds, including radiographic or ultrasonic testing, is required for welded construction cryogenic valves in accordance with the applicable standard.
Key Selection Criteria
When specifying cryogenic valves, the following parameters need to be established:
- Minimum operating temperature. This determines material requirements, bonnet extension length, and the applicable design standard.
- Fluid. The specific cryogenic medium affects material compatibility, cleaning requirements (oxygen service requires grease-free construction), and valve type selection.
- Required function. Isolation, flow control, non-return, or pressure management each point towards different valve types. Frequency of operation is relevant too, as valves cycled frequently have different wear requirements from those used only for isolation.
- Connection type. Screwed, flanged, and weld ends are all available. Weld connections are preferred where leak integrity is the priority; flanged connections where maintenance access is required.
- Actuation. Manual, solenoid, or pneumatically actuated options are available. ATEX-rated actuators are required in flammable or oxygen-enriched atmospheres.
- Standards compliance. Confirm which standard governs the installation, BS 6364, ISO 21011, or MSS SP-134, as this informs the design and testing requirements the valve must satisfy.
For valve selection support across cryogenic duties, contact our sales team, or browse the full range of cryogenic valves, covering manual, solenoid, and self-acting designs rated to -196°C.