Best Ball Valves for Hydrogen Service | Material Embrittlement Prevention and Certified Supplier List

This article mainly covers gaseous hydrogen used in electrolysers, compressors, storage systems, tube trailers, pipelines and refuelling stations. Liquid hydrogen is stored near −253°C and requires a dedicated cryogenic valve rather than a standard gaseous-hydrogen valve.^[3] CARILO’s forged cryogenic ball valves show common cryogenic features such as an extended stem and low-temperature sealing parts, but suitability for liquid hydrogen must be confirmed for the exact valve.

Quick Selection

ISO 19880-3 covers safety and testing requirements for high-pressure gas valves used in gaseous-hydrogen stations up to the H70 designation.^[1] It does not certify every valve used in an industrial hydrogen plant.

ISO develops standards but does not certify products. Certification is written assurance from an independent certification body that a specific product meets stated requirements.^[2]

Pressure Reference

These are direct unit conversions. They do not show whether a valve is certified for a particular H35 or H70 station location.

A valve marked 700 bar may still be unsuitable if its certificate does not cover the required bore, connection, temperature, cycle class or operating function.

Service Data

Give the supplier the real operating conditions instead of asking only for a “hydrogen valve.”

• Hydrogen concentration
• Complete gas composition
• Normal operating pressure
• Maximum allowable working pressure
• Design pressure
• Maximum pressure difference across the valve
• Minimum and maximum fluid temperature
• Minimum and maximum ambient temperature
• Normal and maximum flow
• Required bore or flow coefficient
• Cycles per day
• Total design cycles
• Required internal leakage
• Required external leakage
• Manual or automatic operation
• Required fail position
• Applicable standards and local rules

A 30-bar electrolyser outlet and a 700-bar refuelling-station valve are both used with hydrogen, but they should not use the same design or purchasing specification.

Example: Electrolyser Outlet

The following values are an example only. They are not universal design limits.

In this example, cleanliness, moisture, electrolyte carryover and low-pressure seat sealing may matter more than buying a 700-bar valve.

Example: Compressor Discharge

The following values show how pressure, temperature and cycles must be considered together.

A valve with a 700-bar room-temperature rating may still be unsuitable if it cannot operate at 85°C, complete 30,000 full-pressure cycles or provide acceptable torque at the minimum temperature.

Example: H70 Station

The following example is a project specification, not a statement that every ISO 19880-3 valve must meet the same values.

The buyer should confirm that the certificate covers the exact pressure, temperature, bore, connection, seat, seal and cycle class. A product name containing “700” does not prove H70 approval.

Gas Quality

Pure, dry hydrogen is different from wet industrial hydrogen. Possible contaminants include:

• Water
• Oxygen
• Carbon monoxide
• Carbon dioxide
• Methane
• Ammonia
• Hydrogen sulphide
• Chlorides
• Compressor oil
• Electrolyte droplets
• Solid particles

Water can increase corrosion. Hydrogen sulphide introduces sour-service cracking risks. Chlorides can attack some stainless steels. Oil can damage seals or contaminate fuel-cell hydrogen. Particles can scratch the ball and cut a soft seat.

A valve selected for dry, high-purity hydrogen should not automatically be used with wet refinery hydrogen or hydrogen containing corrosive impurities.

Hydrogen Blends

A natural-gas valve should be reassessed before hydrogen is added to the gas.

• Check the hydrogen percentage and partial pressure.
• Check total pressure and pressure cycles.
• Review the body, stem, bolts and spring materials.
• Review packing and elastomer compatibility.
• Check the existing leakage class.
• Consider valve age, repairs and service history.

Hydrogen can increase fatigue-crack growth in some carbon steels. The result depends on material condition, stress, hydrogen pressure and loading frequency.^[7]

A low hydrogen percentage alone is not enough to approve an existing natural-gas valve.

Main Failure Risks

• A metal part cracks.
• A seat deforms or wears.
• Hydrogen leaks through the stem or body joint.
• An O-ring blisters during rapid depressurisation.
• Hydrogen slowly passes through a polymer.
• Pressure becomes trapped in the valve cavity.
• The actuator cannot move the valve under full pressure.
• Released hydrogen finds an ignition source.

These problems require different controls. A thicker body cannot correct a weak stem, damaged seat or unsuitable O-ring.

Metal Cracking

Hydrogen molecules can split into atomic hydrogen at a metal surface. Atomic hydrogen can enter the metal and move towards defects, highly stressed areas and crack tips.

Hydrogen exposure can reduce:

• Ductility
• Fracture toughness
• Fatigue resistance
• Tolerance of small defects

Risk normally rises with:

• High strength
• High hardness
• Cold working
• Residual tensile stress
• Sharp corners and grooves
• Threads and pin holes
• Surface scratches
• Weld defects
• High hydrogen pressure
• Repeated pressure cycles

Sandia’s hydrogen materials database shows that performance depends on alloy, strength, heat treatment, microstructure, pressure, temperature and loading method.^[4]

A hydrostatic test only shows that the valve held pressure during the test. It does not prove long-term fatigue life in cycling hydrogen.

Manufacturing Damage

Hydrogen can enter a component before the valve is installed.

• Acid pickling
• Electroplating
• Electrochemical cleaning
• Corrosion
• Poor surface treatment
• Inadequate baking after plating

This is especially important for springs, high-strength bolts, Belleville washers, pins and retaining rings.

The supplier should control both the base material and the finished component. A suitable alloy can become unreliable after the wrong plating process, heat treatment or cold-working operation.

316 and 316L

316 and 316L austenitic stainless steels are common starting materials for gaseous-hydrogen valves. Sandia identifies Type 316 as having better resistance to hydrogen-assisted fracture than many other austenitic stainless steels, although its performance still changes with heat treatment and material condition.^[5]

316L contains less carbon than 316 and is often preferred for welded parts because it reduces sensitisation risk during welding.

Do not accept “316 stainless steel” as a complete description. Check:

• UNS number
• ASTM or EN specification
• Forged, wrought or cast product form
• Solution-annealed or cold-worked condition
• Yield and tensile strength
• Hardness
• Welding process and filler material
• Heat treatment
• Material certificate

A solution-annealed 316L body and a heavily cold-worked 316L stem can behave differently in hydrogen.

CARILO’s high-pressure forged ball valves provide general floating and trunnion configurations. Hydrogen use still requires a separate review of every wetted and highly stressed component.

Material Comparison

This table gives a comparison only. It does not set universal material limits.

XM-19

XM-19, also known as Nitronic 50, is a nitrogen-strengthened austenitic stainless steel. It provides more strength than annealed 316 and is used in some hydrogen valves for stems, balls and trunnions.

The supplier should provide:

• Exact material specification
• Heat-treatment condition
• Final strength and hardness
• Hydrogen test basis
• Material traceability

An austenitic structure does not make every strength level automatically safe.

17-4 PH

17-4 PH stainless steel is strong and easy to machine, so it is often considered for valve stems. It needs careful review in high-pressure hydrogen.

Sandia reports large losses in fracture toughness for specific 17-4 PH conditions tested in hydrogen. The result depends on heat treatment, strength, hydrogen pressure and loading method.^[6]

This does not mean every 17-4 PH component will fail. It means that normal air-service data are not enough.

• Request the exact heat-treatment condition.
• Request final hardness and tensile strength.
• Check the hydrogen test pressure and temperature.
• Check the specimen type and loading method.
• Review the real component stress.

Carbon Steel

Carbon steel is used in some industrial hydrogen systems and large pipelines. Its suitability depends on:

• Steel grade
• Strength and toughness
• Weld quality and hardness
• Defect size
• Hydrogen partial pressure
• Pressure cycles
• Temperature
• Required life

Hydrogen can speed up fatigue-crack growth, and welds can behave differently from the base material.^[7]

ASME B31.12 covers piping and pipelines carrying gaseous hydrogen, gaseous hydrogen mixtures and piping in liquid-hydrogen service.^[10] It is a piping code, not a certificate for a specific valve model.

Hidden Parts

Do not check only the valve body. Review:

• Stem
• Body and gland bolts
• Springs
• Belleville washers
• Retaining rings
• Pins
• Trunnions
• Seat carriers
• Actuator couplings

The bill of materials should show the material, heat treatment and hardness of every hydrogen-wetted, pressure-retaining and highly stressed part.

Pay close attention to stem shoulders, thread roots, keyways, pin holes, grooves and deep machining marks. These areas create local stress and can become crack-starting points.

Seat Materials

PEEK is common in high-pressure hydrogen valves, but virgin PEEK, carbon-filled PEEK and glass-filled PEEK do not have the same properties.

Ask for the exact seat grade, pressure-temperature chart, maximum pressure difference, cycle count and leakage limit.

CARILO’s forged soft-seated valves show general soft-seat construction. Its forged metal-seated valves are intended for hotter, dirtier or more abrasive service. Hydrogen suitability must still be confirmed for the exact configuration.

Seat Selection Example

The following is an example of the data a buyer should give the valve supplier.

This table does not prove that every PEEK seat is suitable for 500 bar. The supplier must show that the exact seat grade and valve design meet these conditions.

O-Rings

Hydrogen can dissolve inside an elastomer under pressure. During rapid depressurisation, the trapped gas expands and can blister or split the O-ring. This is called rapid gas decompression, explosive decompression or RGD.

Specifying only FKM, EPDM or NBR is not enough. Two compounds from the same polymer family can perform differently.

ISO 19880-7:2025 covers rubber O-rings and housing dimensions for high-pressure hydrogen devices in refuelling stations. It applies up to 70 MPa nominal working pressure and an O-ring system operating-temperature range of −40°C to 65°C.^[8]

The standard also notes that the sealed hydrogen can briefly reach higher temperatures, potentially up to 180°C.^[8]

• Check the exact compound code.
• Check hardness.
• Check pressure and temperature range.
• Check the RGD gas and decompression rate.
• Check groove width and depth.
• Check compression and groove fill.
• Check the extrusion gap and backup rings.

Stem Sealing

The stem is a moving pressure boundary and a common external leak path.

A suitable hydrogen stem design normally includes:

• Blowout-resistant construction
• Controlled stem hardness
• A smooth sealing surface
• Live-loaded or load-compensated packing
• Anti-static continuity
• Low actuator side load
• A second sealing barrier where required

ISO 15848-1 covers type testing of external leakage from valve stems and body joints.^[11] ISO 15848-2 covers production acceptance testing.^[12]

These standards do not test internal seat leakage, hydrogen embrittlement or complete hydrogen cycle life.

Floating or Trunnion

In a floating ball valve, line pressure pushes the ball against the downstream seat.

A trunnion design is often preferred for high pressure, larger bores, frequent cycles and automatic emergency isolation. Small-bore valves can also use a trunnion design when the pressure is very high.

See CARILO’s floating versus trunnion ball valve comparison for more detail on torque, cost and size.

On-Off Use

A standard ball valve is mainly an isolation valve. It should normally be fully open or fully closed.

Long-term throttling can cause:

• High local gas velocity
• Seat-edge erosion
• Noise and vibration
• Ball damage
• Rapid seat wear
• Unstable downstream pressure

Use a V-port ball valve, control valve, pressure regulator or metering valve when the system requires flow control.

Cavity Pressure

Hydrogen can become trapped between the two closed seats. Pressure can rise because of temperature change, seat leakage or pressure migration.

The design should state:

• Seat direction
• Cavity-relief direction
• Maximum cavity pressure
• Vent connection
• Safe vent destination
• Maintenance depressurisation method

A self-relieving seat allows excess cavity pressure to return to one side of the line. A double-piston-effect seat gives stronger isolation but may trap pressure, so a separate relief path can be required.

Double Block and Bleed and Double Isolation and Bleed are not the same function. Define the required seat direction, test direction and vent function rather than using only the letters DBB or DIB.

CARILO’s DBB compact manifold combines two isolation points and a bleed path in one body. Hydrogen use still requires the exact materials, seals and pressure range to be reviewed.

Pressure Ratings

Do not compare valves using one large pressure number.

• Normal operating pressure
• Maximum allowable working pressure
• Design pressure
• Proof-test pressure
• Burst pressure
• Maximum operating pressure difference
• End-connection pressure rating

Proof pressure is a test value. It is not the allowed continuous working pressure.

Burst pressure is the pressure at which a test component fails. It is not a working rating.

Differential pressure is the pressure difference across the valve. It directly affects seat force and actuator torque.

H35 and H70 are refuelling-system designations. They should not be treated as simple substitutes for 350-bar and 700-bar catalogue ratings.

The maximum pressure and maximum temperature shown in a catalogue should not be combined unless the pressure-temperature chart allows that combination.

Cycle Life

Specify:

• Total design cycles
• Cycles per day
• Full-pressure cycles
• Emergency shutdown cycles
• Low-temperature cycles
• Full-differential-pressure operation
• Opening and closing time

A cycle number is useful only when the test conditions are known.

One hundred thousand unpressurised air cycles are not equal to one hundred thousand high-pressure hydrogen cycles at −40°C.

Actuator Sizing

Size the actuator using the worst expected torque, not the torque of a new valve at room temperature.

• Break-to-open torque
• Running torque
• End-to-close torque
• Maximum pressure difference
• Minimum temperature
• Seat ageing
• Packing friction
• Minimum actuator supply pressure
• Required safety margin

The following calculation is an example only:

Calculation: 80 × 1.20 × 1.15 × 1.25 = 138 N·m.

The actual correction factors must come from the valve and actuator suppliers.

Also define whether the valve should fail closed, fail open or remain in place if actuator power is lost. Very fast closure can create pressure transients, so closing time should be set by the system safety study.

End Connections

Every connection adds a possible leakage path.

Cone-and-thread: Check tube material, hardness, wall thickness, cone finish, gland engagement and assembly torque.

Tube fittings: Use tubing with the correct outside diameter, hardness, wall thickness and surface quality. Do not mix fitting parts from different manufacturers unless the combination has been qualified.

NPT threads: Check engagement, sealant compatibility, cleanliness and repeated-assembly limits.

Welded ends: Control the welding procedure, heat input, purge gas, distortion, weld examination and protection of soft seats.

Do not use the valve body to pull misaligned pipes into position. Pipe load can distort the body and cause high torque or seat leakage.

Leak Testing

A hydrogen valve purchase should include both type-test evidence and production testing.

Type tests can include:

• Proof and burst pressure
• Internal and external leakage
• Pressure cycling
• Temperature cycling
• Operating endurance
• Excess torque
• Fire testing
• O-ring and RGD testing

Production tests should include:

• Shell test
• Seat test in each required direction
• Stem leakage test
• Functional test
• Torque record
• Serial-numbered test report

ASTM G142 is a tensile test method for metals in high-pressure or high-temperature hydrogen-containing gas. It is a material test, not a complete valve qualification.^[13]

ISO 11114-4 provides test methods for selecting steels for seamless hydrogen gas cylinders. It is not a universal ball-valve certification standard.^[14]

Leak Test Example

The following example shows how to write a measurable leak-test requirement.

The values above are an example, not a universal standard requirement.

Do not specify only “zero leakage,” “gas tight” or “bubble tight.” State the gas, pressure, temperature, duration, method and allowed leak rate.

CARILO’s API 6D valve testing guide explains common shell, seat and functional tests. Hydrogen applications may require additional gas, cycle and low-temperature testing.

Key Standards

ISO 23826 covers ball valves used as closures for refillable cylinders, tubes, bundles and transport units. It does not cover cryogenic equipment.^[15]

ISO 10497 measures leakage, cavity-pressure relief and operation during a defined fire test.^[16] A fire-test certificate does not prove normal hydrogen tightness or long-term cycle life.

SAE J2579 covers design, construction, operation and maintenance requirements for on-road vehicle hydrogen storage and handling systems.^[17]

Supplier Shortlist

A supplier is not certified as a whole. Certification normally covers specific models, sizes, pressure ranges, materials and manufacturing locations.

The table below summarises public manufacturer positions reviewed in July 2026. The buyer should obtain the current third-party certificate and annex before treating a product as certified.

Evidence Levels

Level A: The buyer has reviewed the full third-party certificate and annex.

Level B: The manufacturer states that the product is certified, but the full annex still needs to be reviewed.

Level C: The manufacturer publishes hydrogen-compatible materials or application data, but the required product certificate is not confirmed.

A Level C valve may be acceptable in an industrial application where ISO 19880-3 is not required. It may be unacceptable in a refuelling-station location where the project requires that certificate.

CARILO Options

CARILO offers several valve platforms that can be assessed for project-specific hydrogen service:

• Forged soft-seated floating ball valves
• Forged metal-seated ball valves
• High-pressure floating and trunnion ball valves
• Forged cryogenic ball valves
• DBB compact manifolds

These platforms should only be approved for hydrogen after the body, stem, bolts, springs, seat, O-rings, pressure, temperature, cycle and test requirements have been agreed.

Buying Checklist

• Hydrogen concentration and impurities
• Normal, maximum and design pressure
• Maximum pressure difference
• Fluid and ambient temperature range
• Required flow and bore
• Total operating cycles
• Body, ball and stem materials
• Maximum stem and bolt hardness
• Exact seat and O-ring compounds
• Internal and external leak limits
• Test gas and test pressure
• Required certificate
• Actuator type and fail position
• Opening and closing time
• Hazardous-area classification

Also require:

• Certificate and full annex
• Complete bill of materials
• Material certificates
• Pressure-temperature chart
• Type-test summary
• Cycle-test conditions
• Serial-numbered production test report
• Cleaning and lubricant declaration
• Spare-parts list
• Design-change notification

The supplier should not change the stem, seat, O-ring, spring, lubricant, material source or manufacturing site without buyer approval.

Supplier Questions

1. Does the certificate identify the exact ordering number?
2. Does it cover the required size, bore and connection?
3. Does it cover the actual pressure and temperature?
4. Are the supplied seat and O-ring compounds the same as those tested?
5. What gas, pressure and temperature were used in cycle testing?
6. Was the valve operated under full pressure difference?
7. What internal and external leak rates were measured?
8. Does the production site match the certificate?

“Designed according to” is not the same as “certified to.”

Installation and Maintenance

Before installation:

• Check the serial number against the approved documents.
• Confirm the flow and seat direction.
• Confirm the cavity vent route.
• Inspect the valve for transport damage.
• Keep the ports protected until installation.

During installation:

• Support the piping.
• Do not force misaligned pipe through the valve.
• Avoid actuator side load.
• Follow the correct fitting or welding procedure.
• Protect soft seats from welding heat and debris.

Before introducing hydrogen, clean and purge the system, pressurise it in controlled stages, check external leakage and test the actuator’s fail position.

H2Tools warns against depressurising a hydrogen line by loosening a fitting because this creates a hydrogen-air mixture at the release point. Hydrogen should be vented to a safe location and the system should be purged before maintenance.^[18]

Hydrogen can be ignited by static electricity, impact, friction, hot surfaces or electrical equipment.^[9]

Replace seals with the exact approved compound. A visually similar O-ring can have different RGD, temperature and permeability performance.

Conclusion

The best hydrogen ball valve is selected from the complete operating envelope, not one pressure number. H35 and H70 station valves should have an ISO 19880-3 certificate covering the exact bore, connection, temperature, seat and cycle class. Transport valves need the correct ISO 23826 or TPED size range. Industrial valves need material, fatigue, cavity-relief, torque and leakage checks. A typical project may combine 30 to 700 bar pressure, −40°C minimum temperature and 10,000 to 100,000 operating cycles. Require the certificate annex, pressure-temperature chart, complete bill of materials and serial-numbered production test report before approval.