Floating vs Trunnion Ball Valve: Which Design Fits Your Application?
A floating ball valve is generally considered for small-to-medium sizes and suitable pressure conditions where a straightforward, economical design is preferred. A trunnion ball valve provides additional mechanical support to the ball and is commonly evaluated for larger sizes, higher pressures and applications requiring lower operating torque.
However, valve size or pressure class alone should not determine the selection. Process medium, operating temperature, pressure differential, seat design, actuation and project specifications must also be reviewed.
This guide explains the differences between floating and trunnion ball valves for industrial buyers, engineers, EPC companies and procurement teams.
Floating vs Trunnion Ball Valve: Quick Comparison
Selection factor | Floating ball valve | Trunnion ball valve |
Ball support | Ball is supported primarily by the seats | Ball is mechanically supported by the stem and lower trunnion |
Sealing action | Line pressure moves the ball towards the downstream seat | Seats move towards the supported ball |
Operating torque | Can increase as pressure differential rises | Generally lower under comparable demanding conditions |
Typical size range | Commonly selected for smaller and medium sizes | Commonly selected for larger pipeline sizes |
Pressure application | Suitable for approved low-to-high-pressure duties depending on design | Frequently used for high-pressure pipeline duties |
Construction | Comparatively simple | More complex internal construction |
Initial cost | Generally lower | Generally higher |
Actuation | Manual or actuated | Manual, geared or actuated |
Maintenance features | Depends on design | May include seat or stem seal injection and body cavity relief |
Final selection | Based on complete operating data | Based on complete operating data |
These are general engineering differences. Actual performance depends on the manufacturer’s design, valve size, pressure class, seat construction, materials and operating conditions.
What Is a Floating Ball Valve?
A floating ball valve contains a perforated ball positioned between two valve seats. The ball is connected to the operating stem but is not mechanically fixed by a lower support.
When the valve is closed, upstream pressure creates a small downstream movement of the ball. This movement presses the ball against the downstream seat, producing the shut-off seal.
Floating ball valves are commonly considered for:
General industrial isolation
Chemical and process pipelines
Water-treatment systems
Utility services
Oil and gas applications
Skid-mounted equipment
Small-to-medium pipeline sizes
The comparatively simple construction can make a floating ball valve compact and commercially efficient. However, the force between the ball and downstream seat increases with pressure differential. This may increase operating torque and seat loading.
What Is a Trunnion Ball Valve?
A trunnion-mounted ball valve supports the ball mechanically at the top and bottom. The ball rotates in a fixed position instead of moving downstream against the seat.
In many trunnion designs, spring-loaded seats move towards the ball to maintain sealing contact. Because the process pressure is not used to push the entire ball against the downstream seat in the same manner as a floating design, operating torque can remain more manageable in larger or higher-pressure valves.
Trunnion ball valves are frequently evaluated for:
Oil and gas pipelines
Petrochemical facilities
Gas-processing plants
Large-diameter pipelines
High-pressure isolation
Compressor and pumping stations
Critical process applications
Available features depend on the selected design and may include double block and bleed arrangements, body cavity pressure relief, emergency sealant injection, anti-static construction and fire-safe configurations.
These features must be specified and confirmed rather than assumed for every trunnion valve.
What Is the Main Difference Between Floating and Trunnion Ball Valves?
The main difference is how the ball is supported and how sealing force is generated.
In a floating ball valve, the ball has limited freedom to move with line pressure. This movement pushes it against the downstream seat.
In a trunnion ball valve, the ball is held in position by mechanical supports. The seats are designed to move towards the ball and establish the seal.
This construction difference influences:
Operating torque
Seat loading
Practical valve size
Pressure capability
Actuator selection
Valve weight
Construction cost
Maintenance requirements
Which Ball Valve Is Better for High Pressure?
A trunnion ball valve is often preferred for larger, higher-pressure pipeline applications because its supported ball construction can reduce the torque created by pressure acting on the ball.
However, this does not mean that every high-pressure application automatically requires a trunnion valve. Floating ball valves can also be engineered for demanding pressure ratings within their approved design limits.
Engineers should evaluate the pressure class together with:
Nominal valve size
Maximum pressure differential
Operating temperature
Process medium
Seat and seal materials
Required operating torque
Actuator capacity
Applicable valve standard
The selected valve must be verified against manufacturer data and the project specification.
Which Design Requires Less Operating Torque?
Under comparable demanding conditions, a trunnion-mounted design generally requires lower operating torque because the ball is mechanically supported.
In a floating valve, increasing pressure differential can press the ball more firmly against the downstream seat. The resulting seat friction may increase the torque required to operate the valve.
Actual torque also depends on:
Valve size
Pressure differential
Seat material
Fluid characteristics
Operating temperature
Frequency of operation
Required safety factor
The actuator must be selected using the valve manufacturer’s approved torque data—not a general estimate based only on valve size.
How Do the Sealing Systems Differ?
Floating ball valves generally use downstream-seat sealing. Pressure pushes the ball against the downstream seat to stop flow.
Trunnion ball valves use an anchored ball with pressure-energised or spring-assisted seats. Depending on the design, the valve may provide single-piston-effect or double-piston-effect seating.
The required sealing arrangement should be confirmed when an application involves:
Bidirectional isolation
Double block and bleed
Body cavity pressure
Gas service
Fire-safe performance
Emergency sealing requirements
Very low allowable leakage
Not every ball valve provides the same isolation or cavity-relief behaviour.
Floating or Trunnion Ball Valve: Which Should You Choose?
Consider a floating ball valve when:
The size and pressure conditions suit the approved floating design
A simpler and more economical construction is preferred
Operating torque remains within acceptable limits
The project does not require specialised trunnion features
Available space and lower valve weight are important
Consider a trunnion ball valve when:
The pipeline diameter is comparatively large
The pressure differential creates excessive floating-valve torque
Lower operating torque is important
The application requires a particular seat arrangement
Project specifications require trunnion-mounted construction
Emergency sealing or cavity-relief features are specified
The final decision should be made after reviewing the complete datasheet and operating conditions.
Information Required for Ball Valve Selection
Before requesting a quotation, provide:
Valve size and quantity
Pressure class
Floating or trunnion preference, if specified
Full-bore or reduced-bore requirement
Process medium
Design and operating pressure
Design and operating temperature
Body, ball, stem and seat materials
End connection
Manual, geared or actuated operation
Fire-safe or anti-static requirements
Inspection and documentation requirements
Applicable project standards
Providing complete information helps the manufacturer evaluate valve construction, materials, torque and testing requirements accurately.
Floating and Trunnion Ball Valves from KPI Valves
KPSHIV Industries Pvt. Ltd. manufactures floating and trunnion-mounted ball valves under the KPI Valves brand at its facility in Chandarda, Mahesana, Gujarat, India.
KPI supports industrial buyers, EPC companies, contractors and distributors with:
Datasheet and BOQ review
Material and configuration evaluation
Machining, assembly and testing
Project-specific documentation
Third-party inspection when agreed
Supply across India
International project enquiries
Explore KPI as a ball valve manufacturer in India, learn more about our industrial valve manufacturing capabilities, or request a ball valve quotation.
Frequently Asked Questions
Is a floating ball valve suitable for high pressure?
A floating ball valve may be suitable for high-pressure service when its design, size, pressure rating, materials and operating torque meet the application requirements. Manufacturer data must be reviewed before selection.
Why is a trunnion ball valve used for larger sizes?
Supporting the ball at the top and bottom helps control ball movement and operating torque. This makes trunnion construction practical for many larger and higher-pressure valves.
Does a trunnion ball valve always provide double block and bleed?
No. Double block and bleed capability depends on the seat arrangement and specific valve design. It should be clearly stated in the datasheet and confirmed by the manufacturer.
Which ball valve is more economical?
A floating ball valve generally has a lower initial cost because its construction is simpler. Total cost should also consider actuation, maintenance, service life and project requirements.
Can floating and trunnion ball valves be actuated?
Yes. Both designs may be operated using pneumatic, electric or hydraulic actuators when properly sized. Actuator selection must use confirmed operating-torque data.
Which ball valve is best for oil and gas pipelines?
Trunnion-mounted ball valves are frequently evaluated for large-diameter and high-pressure oil and gas pipelines. The correct design still depends on the medium, pressure, temperature, isolation requirements and project specification.
Request Technical Selection Support
Choosing between a floating and trunnion ball valve requires more than comparing size, pressure class or price.
Send your ball-valve datasheet, BOQ and operating conditions to KPI Valves for technical and commercial review.
KPI Valves — KPSHIV Industries Pvt. Ltd.
Chandarda, Mahesana, Gujarat, India
Email: sales@kpivalve.com
Phone: +91 90998 20967
Request a quotation: Contact KPI Valves
Comments