API Valves Explained: API Gate, Ball, Check and Globe Valves for Industrial Projects

Selecting an API valve is not simply a matter of choosing a gate, ball, check, or globe design.

Industrial project teams must also confirm the applicable API standard, valve size, pressure class, body material, trim, seat design, end connection, operating method, inspection requirements, and service conditions.

An API gate valve may be an excellent choice for pipeline isolation, while an API ball valve may be preferred when fast shutoff and tight sealing are required. An API check valve prevents reverse flow automatically, whereas an API globe valve is designed for throttling and flow adjustment.

This guide explains how these four industrial API valve types differ, which API standards commonly apply, and what engineers and procurement teams should verify before placing an order.

What Is an API Valve?

An API valve is an industrial valve designed, manufactured, inspected, or tested according to an applicable standard published by the American Petroleum Institute.

API standards are widely referenced in oil and gas, petrochemical, refinery, chemical processing, power generation, pipeline transportation, and other demanding industrial projects.

However, “API valve” is not one single valve design. Different standards apply to different valve types and applications.

For example:

• API 600 is associated with steel gate valves.
• API 608 covers metal ball valves.
• API 594 applies to several industrial check valve configurations.
• API 623 covers steel globe valves.
• API 602 applies to compact gate, globe, and check valves in smaller sizes.
• API Specification 6D covers pipeline valves, including gate, ball, plug, and check valves.
• API 598 provides requirements for valve inspection and testing.

API’s official program documents identify API 594, API 600, API 602, API 603, API 608, and API 609 as separate standards covering specific industrial valve categories.

API-Compliant Valve vs API-Monogrammed Valve

These two descriptions should not automatically be treated as identical.

An API-compliant valve is generally offered as being designed or tested according to a specified API standard. The supplier should provide technical documents demonstrating that compliance.

An API Monogram valve must come from a facility licensed for the relevant API Monogram program scope and must follow the applicable marking and quality-system requirements.

For critical projects, buyers should verify the manufacturer and product scope through API’s official certification directories rather than relying only on a logo printed on a quotation or nameplate. API provides a Composite List for checking licensed companies and certified products.

API Gate, Ball, Check and Globe Valves: Quick Comparison

The correct choice depends first on the valve’s required function. Standards compliance cannot compensate for selecting the wrong valve mechanism.

Which API Standards Apply to Industrial Valves?

Industrial valve specifications often reference several standards at the same time. One standard may define the valve design, another may cover testing, and an ASME standard may control pressure-temperature ratings or dimensions.

Common API Valve Standards

API officially defines API 594 as covering flanged, lug, wafer, and butt-welding check valves; API 600 as covering steel gate valves; API 602 as covering small gate, globe, and check valves; and API 608 as covering metal ball valves.

API Standards and ASME Standards Work Together

An API product standard does not necessarily contain every requirement needed for a complete valve specification.

Industrial projects may also reference:

• ASME B16.34 for pressure-temperature ratings, materials, dimensions, nondestructive examination, testing, and marking.
• ASME B16.10 for face-to-face and end-to-end dimensions.
• ASME B16.5 for compatible pipe flanges and flanged fittings.

ASME states that B16.34 covers pressure-temperature ratings, materials, dimensions, tolerances, inspection, testing, and marking for flanged, threaded, welding-end, and certain flangeless valves.

ASME B16.10 helps ensure that valves of the same type, size, class, material, and connection can be installed interchangeably.

Therefore, a complete purchase specification might state:

API 600 gate valve, ASME Class 300, design and pressure-temperature rating per ASME B16.34, face-to-face dimensions per ASME B16.10, flanged ends per ASME B16.5, and inspection and testing per API 598.

The exact standard editions and addenda must always follow the project specification or purchase order.

API Gate Valve: Heavy-Duty Pipeline Isolation

An API gate valve uses a wedge or parallel gate that moves vertically into or out of the flow path.

When fully open, the closure element is removed from the main flow passage. This produces a relatively straight bore and low permanent pressure loss.

Where API Gate Valves Are Used

API gate valves are commonly selected for:

• Refinery process lines
• Oil and gas pipelines
• Petrochemical facilities
• Steam and condensate systems
• Hydrocarbon storage terminals
• High-pressure utility lines
• Power plant piping
• Chemical processing systems

Main API Gate Valve Standards

API 600

API 600 applies to steel gate valves with flanged or butt-welding ends and bolted bonnets. It is frequently specified for heavy-duty refinery and process applications.

The standard addresses areas such as valve construction, materials, wall thickness, stem dimensions, pressure classes, testing, and marking.

API 602

API 602 covers gate, globe, and check valves in sizes DN100/NPS 4 and smaller for petroleum and natural gas applications. It is commonly associated with compact forged-steel valve construction.

The official scope specifically identifies gate, globe, and check valves up to NPS 4.

API 603

API 603 covers corrosion-resistant bolted-bonnet gate valves with flanged and butt-welding ends.

It may be specified where corrosion-resistant materials and lower body mass are more important than the heavier construction traditionally associated with API 600.

API 6D

API 6D applies to pipeline valves, including steel gate, plug, ball, and check valves. It is particularly relevant to pipeline transportation systems rather than only plant process piping.

Advantages of an API Gate Valve

• Low pressure drop in the fully open position
• Full-bore configurations available
• Suitable for bidirectional isolation when properly designed
• Available in high-pressure classes
• Metal-seated designs available for severe temperature service
• Compatible with manual, gearbox, electric, pneumatic, or hydraulic operation

Limitations

• Slow multi-turn operation
• Requires greater vertical installation clearance
• Seat damage may occur if used repeatedly for throttling
• Large high-pressure models can be heavy
• Trapped pressure and bonnet design must be evaluated for specific services

When to Choose an API Gate Valve

Choose a gate valve when the primary requirement is dependable full-open or full-closed isolation with minimal flow restriction.

Do not select a standard gate valve for continuous flow regulation. Operating it partially open may produce vibration, turbulence, wire drawing, and seat erosion.

For additional guidance on seat construction, see our comparison of soft-seal and metal-seat gate valves.

API Ball Valve: Fast Shutoff and Tight Sealing

An API ball valve uses a bored spherical closure element that rotates 90 degrees between open and closed positions.

Ball valves are popular in industrial projects because they combine rapid operation, a compact operating cycle, and reliable shutoff.

Main API Ball Valve Standards

API 608

API 608 covers metal ball valves with flanged, threaded, and welding ends.

API-related inspection guidance recognizes floating-ball and trunnion-mounted configurations manufactured in accordance with API 608.

API 6D

API 6D is commonly specified for pipeline ball valves. Depending on project requirements, these valves may include features such as:

• Full-bore or reduced-bore construction
• Floating or trunnion-mounted ball
• Double-block-and-bleed arrangements
• Body cavity pressure relief
• Stem sealing systems
• Emergency sealant injection
• Welded or bolted body construction

These features must be stated clearly in the datasheet because “API 6D ball valve” alone does not define the complete configuration.

Floating vs Trunnion Ball Valve

Floating Ball Valve

In a floating design, the ball is supported mainly by the seats. Line pressure pushes the ball toward the downstream seat to create sealing contact.

This design is often selected for smaller sizes and lower-to-moderate pressure applications.

Trunnion-Mounted Ball Valve

A trunnion-mounted ball is mechanically supported by upper and lower bearings or trunnions. The ball remains in a fixed position while the seats move toward it.

This construction can reduce operating torque and improve stability in larger sizes or higher-pressure systems.

Advantages of an API Ball Valve

• Quarter-turn operation
• Fast emergency shutoff
• Tight sealing performance
• Low flow resistance in full-bore designs
• Easy integration with automation
• Suitable for frequent cycling
• Compact operating movement

Limitations

• Soft seats must be checked against temperature and chemical exposure
• Suspended solids may become trapped around the ball cavity
• Rapid closing can contribute to pressure surge
• Large trunnion valves may require cavity-relief provisions
• Standard ball valves are not always suitable for continuous throttling

When to Choose an API Ball Valve

Select an industrial API ball valve when the project requires fast isolation, frequent operation, low leakage, or easy automation.

For buried pipelines, long-distance transmission lines, gas systems, and welded piping, project teams may also consider a fully welded design such as a welded ball valve.

API Check Valve: Automatic Backflow Prevention

An API check valve allows flow in the intended direction and closes automatically when flow slows or reverses.

Unlike gate, ball, and globe valves, a check valve normally does not require an external operator.

Main API Check Valve Standards

API 594

API 594 covers check valves with flanged, lug, wafer, and butt-welding configurations. The standard applies to multiple industrial check valve arrangements rather than one single disc design.

API 602

Small forged or compact check valves up to DN100/NPS 4 may be specified under API 602.

API 6D

Pipeline check valves may be specified under API 6D when they are part of a pipeline transportation system.

Common API Check Valve Types

Swing Check Valve

A swing check valve uses a hinged disc that opens with forward flow and swings back toward the seat when flow reverses.

It offers a relatively open flow path, but its longer disc travel may result in slower closure.

Dual-Plate Wafer Check Valve

A dual-plate valve uses two spring-assisted plates mounted around a central hinge. Its compact body and shorter plate travel can provide faster response than a traditional swing design.

See the H76X wafer check valve for an example of a compact pipeline check valve structure.

Piston or Lift Check Valve

A piston or disc moves vertically away from the seat under forward-flow pressure. These valves are generally suited to specific installation orientations and cleaner fluids.

Axial or Nozzle Check Valve

An axial-flow check valve uses a streamlined, spring-assisted closure element. It is often considered for fast closure and reduced check-valve slam in critical pipeline or compressor applications.

Why Check Valve Sizing Matters

A check valve should not be selected only by matching the nominal pipe diameter.

If the valve is oversized, the disc may not reach a stable fully open position. This can cause:

• Disc flutter
• Hinge or shaft wear
• Noise and vibration
• Repeated impact
• Increased pressure loss
• Premature seat damage

If it closes too slowly after a pump trip, reverse flow may accelerate before the disc reaches the seat, increasing the risk of valve slam and hydraulic shock.

For pump applications, review our guide to check valves for pump stations before selecting the valve structure.

Advantages of an API Check Valve

• Automatic operation
• Prevents reverse flow
• Protects pumps, compressors, and equipment
• Multiple body and disc designs available
• Can be installed without an external actuator

Limitations

• Performance depends heavily on flow velocity
• Some designs are orientation-sensitive
• Incorrect closure characteristics may cause water hammer
• Disc movement cannot normally be controlled externally
• Solids may prevent complete seating

When to Choose an API Check Valve

Use an API check valve wherever reverse flow could damage equipment, contaminate a process, drain a system, reverse a pump, or create an unsafe operating condition.

API Globe Valve: Flow Regulation and Throttling

An API globe valve uses a disc or plug that moves toward or away from a stationary seat.

The internal flow path changes direction through the valve body, producing more pressure loss than a full-bore gate or ball valve. However, the relationship between stem travel and flow area makes the globe valve much better suited to throttling.

Main API Globe Valve Standards

API 623

API 623 covers steel globe valves with flanged or butt-welding ends and bolted bonnets.

It is a globe-valve product standard—not a general control-valve standard. API’s international standards documentation identifies it specifically as “Steel Globe Valves—Flanged and Butt-welding Ends, Bolted Bonnets.”

API 602

Compact small-bore globe valves up to DN100/NPS 4 may be specified under API 602.

Common API Globe Valve Configurations

• Straight-pattern globe valve
• Y-pattern globe valve
• Angle-pattern globe valve
• Plug-disc globe valve
• Needle or fine-control configuration
• Bellows-sealed globe valve

For toxic, high-temperature, vacuum, or emission-sensitive service, a bellows-seal globe valve may provide an additional containment barrier around the stem.

Advantages of an API Globe Valve

• Good throttling capability
• More predictable flow adjustment
• Positive shutoff
• Shorter disc travel than many gate valves
• Suitable for frequent regulation
• Different disc profiles can be selected for specific control characteristics

Limitations

• Higher pressure drop
• Higher operating thrust
• Greater energy loss in continuously flowing systems
• Flow direction may be important
• Large sizes can require substantial actuators

When to Choose an API Globe Valve

Choose a globe valve for bypass lines, steam systems, cooling water regulation, process flow adjustment, sampling systems, drain systems, and applications where controlled throttling is more important than minimum pressure loss.

For highly accurate automatic process control, a dedicated control valve may still be more appropriate than a manually operated API globe valve.

How to Choose Between an API Gate, Ball, Check and Globe Valve

Start with the function the pipeline must perform.

Choose an API Gate Valve When:

• Full isolation is the main requirement.
• The valve will normally remain fully open or fully closed.
• Low pressure loss is important.
• A full-bore flow path is preferred.
• Slow multi-turn operation is acceptable.

Choose an API Ball Valve When:

• Fast quarter-turn shutoff is required.
• Tight sealing is a priority.
• The valve will cycle frequently.
• Pneumatic or electric automation is needed.
• A compact operating movement is preferred.

Choose an API Check Valve When:

• Reverse flow must be stopped automatically.
• Pump or compressor protection is required.
• No external operator is needed.
• The closure response can be matched to system dynamics.

Choose an API Globe Valve When:

• Flow must be throttled or adjusted.
• Pressure drop is acceptable.
• Frequent regulation is expected.
• Stem travel must provide controllable changes in flow area.

Industrial API Valve Selection Matrix

Seven Parameters to Specify Before Requesting an API Valve Quote

A supplier cannot select a reliable industrial API valve from the valve name and pipe diameter alone.

Provide the following information in your request for quotation.

1. Valve Type and Applicable Standard

State whether the project requires:

• API 600 gate valve
• API 608 ball valve
• API 594 check valve
• API 623 globe valve
• API 602 compact valve
• API 6D pipeline valve

Also identify the required edition when it is defined by the project.

2. Nominal Size and Pressure Class

Specify the nominal size and ASME pressure class, such as:

• NPS 2 Class 600
• NPS 6 Class 300
• NPS 12 Class 150

Pressure class alone does not represent one fixed allowable pressure at every temperature. The valve material and design temperature affect the actual pressure-temperature rating.

Our valve pressure-rating guide explains why pressure designations must be evaluated together with material and operating temperature.

3. Fluid and Process Conditions

Provide:

• Fluid name and composition
• Normal pressure
• Design pressure
• Normal temperature
• Design temperature
• Flow rate
• Flow direction
• Solids content
• Corrosion risk
• Toxicity or flammability
• Required shutoff performance

4. Materials

Specify the required:

• Body and bonnet material
• Ball, gate, disc, or plug material
• Stem material
• Seat material
• Packing
• Gasket
• Bolting
• Hard-facing or overlay
• Corrosion allowance

Review our valve material selection guide when comparing carbon steel, stainless steel, alloy steel, and corrosion-resistant options.

5. End Connection

Common options include:

• Raised-face flanges
• Ring-type-joint flanges
• Butt-welding ends
• Socket-welding ends
• Threaded ends
• Wafer body
• Lug body

Flange drilling, facing, finish, and dimensional standards must match the adjoining piping.

6. Operation and Actuation

State whether the valve requires:

• Handwheel
• Gearbox
• Chain wheel
• Electric actuator
• Pneumatic actuator
• Hydraulic actuator
• Spring-return fail-safe operation
• Position indication
• Limit switches
• Solenoid valve
• Emergency shutdown integration

7. Testing and Documentation

List the required inspection and documentation package, including:

• Hydrostatic shell test
• High-pressure closure test
• Low-pressure air-seat test
• Material certificates
• Positive material identification
• Nondestructive examination
• Hardness testing
• Impact testing
• Fire type-test certificate
• Fugitive-emission qualification
• Coating report
• Dimensional report
• Functional test
• Manufacturing record book
• Third-party inspection or witness points

API 598 Valve Inspection and Testing

API 598 is widely referenced for industrial valve inspection and pressure testing.

Depending on valve type and project requirements, testing may include:

• Shell pressure testing
• Backseat testing
• High-pressure closure testing
• Low-pressure closure testing
• Visual examination
• Leakage evaluation
• Marking and documentation checks

API 598 is a testing standard. It does not replace the product design standard.

For example, a gate valve may be designed to API 600 and tested to API 598. A ball valve may be designed to API 608 and also undergo testing under API 598.

The purchase order should identify both standards instead of stating only “API tested.”

Fire-Safe and Fugitive-Emission Requirements

Some industrial projects require additional qualifications beyond normal pressure testing.

Fire-Safe Testing

Fire-safe requirements may be specified for valves handling flammable liquids or gases.

API 607 covers fire type testing for quarter-turn valves and valves equipped with nonmetallic seats. API documentation lists it as a fire-test standard for these valve categories.

API 6FA may also be referenced for fire testing of valves, depending on the product and project specification.

A supplier’s fire-safe statement should be supported by a valid type-test report that matches the valve design family, size range, pressure class, material, and seat construction being offered.

Fugitive-Emission Testing

Stem and packing leakage can be a major concern in hydrocarbon, toxic-fluid, and emission-controlled plants.

Common references include:

• API 624 for rising-stem valves, such as gate and globe valves
• API 641 for quarter-turn valves, such as ball valves
• API 622 for process-valve packing qualification

The exact required standard, temperature range, cycle count, leakage limit, and qualification scope should be included in the project specification.

Common API Valve Procurement Mistakes

Mistake 1: Specifying Only “API Standard”

There is no single universal API valve standard.

The purchase order must identify the applicable number, such as API 600, API 608, API 594, or API 623.

Mistake 2: Treating API 598 as a Design Standard

API 598 primarily addresses inspection and testing. It should be combined with the relevant valve design standard.

Mistake 3: Assuming API Compliance Means API Monogram Licensing

Ask whether the valve is:

• Designed according to an API standard
• Tested according to an API standard
• Manufactured by an API-licensed facility
• Marked with an authorized API Monogram

These are different statements and require different supporting documents.

Mistake 4: Selecting by Pipe Size Alone

Check valves must be evaluated against flow velocity and system dynamics. Control and throttling valves require pressure-drop and flow-capacity analysis.

Mistake 5: Ignoring Temperature

A Class 300 valve does not have the same allowable operating pressure at every temperature. Material group and design temperature must be considered together.

Mistake 6: Failing to Define Seat Leakage

“Zero leakage” and “bubble-tight” are not sufficiently precise without an identified test standard, test medium, pressure, direction, and acceptance criterion.

Mistake 7: Accepting a Generic Certificate

Certificates should match the manufacturer, product design, manufacturing location, material, pressure class, size range, and standard edition applicable to the supplied valve.

API Valve Documentation Checklist

Before approving an industrial API valve supplier, request and review:

1. Completed technical datasheet
2. General arrangement drawing
3. Sectional drawing and bill of materials
4. Applicable API and ASME standards
5. Material certificates
6. Pressure-test procedure
7. Inspection and test plan
8. Welding procedures where applicable
9. NDE procedures and reports
10. Fire-safe certificates where required
11. Fugitive-emission certificates where required
12. Coating and painting procedure
13. Nameplate and marking details
14. Operating torque or actuator-sizing data
15. Spare-parts recommendation
16. Installation, operation, and maintenance manual
17. API Monogram license verification when specified

These records help the purchaser confirm that the delivered valve matches the approved engineering specification rather than only the commercial description.

Frequently Asked Questions About API Valves

What does API mean on an industrial valve?

API refers to the American Petroleum Institute. An industrial valve may be designed, manufactured, inspected, or tested according to one or more API standards.

Which API standard applies to gate valves?

API 600 is commonly specified for steel bolted-bonnet gate valves. API 602 applies to smaller gate, globe, and check valves, while API 603 covers corrosion-resistant gate valves. API 6D may apply to gate valves used in pipeline transportation systems.

What is the standard for an API ball valve?

API 608 covers metal ball valves with flanged, threaded, and welding ends. API 6D is commonly applied to ball valves used in pipeline systems.

What is the standard for an API check valve?

API 594 covers flanged, lug, wafer, and butt-welding check valves. API 602 may apply to small check valves, and API 6D may apply to pipeline check valves.

What is the standard for an API globe valve?

API 623 covers steel globe valves with flanged or butt-welding ends and bolted bonnets. API 602 covers smaller globe valves up to DN100/NPS 4 within its scope.

Is an API valve always suitable for oil and gas?

API valves are widely used in oil and gas projects, but suitability still depends on pressure, temperature, media, corrosion, operation, leakage requirements, and applicable project specifications.

Are API valves suitable for water projects?

They can be used where the project requires steel construction, high pressure, high temperature, industrial testing, or specific international standards. Municipal water projects may alternatively specify AWWA, EN, BS, ISO, or local water-industry standards.

Can a gate valve be used for throttling?

A conventional gate valve should normally be used fully open or fully closed. Extended partial opening can damage the gate and seats. A globe valve or purpose-designed control valve is usually more appropriate for regulation.

Which API valve has the lowest pressure drop?

A fully open full-bore gate valve or ball valve generally provides lower pressure loss than a globe valve. Actual pressure drop depends on the internal bore, geometry, size, and flow conditions.

How do I verify an API valve manufacturer?

Review the technical datasheet, drawings, material records, test reports, quality documentation, and applicable API licenses. When an API Monogram is required, verify the supplier and product scope through API’s official directory.

Conclusion

API gate, ball, check, and globe valves perform different functions in an industrial piping system:

• API gate valves provide full-flow isolation with low pressure loss.
• API ball valves deliver fast quarter-turn shutoff and tight sealing.
• API check valves prevent reverse flow automatically.
• API globe valves provide better throttling and flow regulation.

The valve type must first match the operating function. The correct API standard, material, pressure class, temperature range, seat construction, end connection, testing requirements, and documentation can then be selected.

For a reliable quotation, send the complete operating conditions and project specification rather than requesting only an “API valve.”

Norite supplies industrial gate, ball, check, and globe valve solutions for pipeline, oil and gas, petrochemical, power, water, and process-industry projects. Contact Norite to review your valve datasheet, material requirements, pressure class, testing package, and project-specific configuration.