Concentric vs Double Offset vs Triple Offset Butterfly Valves: How to Choose?

Introduction

When selecting a butterfly valve, determining whether to use a concentric butterfly valve, double offset butterfly valve, or triple offset butterfly valve is often one of the first decisions to make.

Although all three types use the rotation of the disc to shut off or regulate the pipeline medium, the geometric positions of the disc, stem, valve body centerline, and sealing surfaces are different. As a result, they differ significantly in terms of sealing contact method, sealing surface friction, seat wear, temperature adaptability, differential pressure capability, and suitable operating conditions.

In simple terms, concentric butterfly valves feature a simple structure and good cost-effectiveness; double offset butterfly valves can reduce friction between the disc and seat during opening and closing, making them more suitable for applications with higher requirements for seat life and industrial operating performance; triple offset butterfly valves further change the geometric relationship of the sealing surfaces, making them more suitable for high-temperature and severe industrial applications requiring metal sealing. This article compares the three butterfly valve designs in terms of structural differences, performance differences, and practical selection factors to help you determine which type is more suitable for your project.

Quick Answer

The core difference between concentric, double offset, and triple offset butterfly valves lies in the different geometric positions of the disc, stem, and sealing surfaces, which create different sealing contact methods and friction characteristics.

• Concentric Butterfly Valve: Simple structure, usually equipped with a soft seat, and suitable for water treatment, HVAC, and applications with relatively conventional temperature, pressure, and operating frequency requirements.
• Double Offset Butterfly Valve: The disc can disengage from the seat more quickly after opening begins, reducing sealing surface friction and seat wear. It is more suitable for frequent operation and applications requiring higher long-term industrial operating performance.
• Triple Offset Butterfly Valve: Further changes the geometric relationship of the sealing pair so that the sealing surfaces remain separated during most of the opening and closing process. It is more suitable for metal sealing, high-temperature, and severe industrial applications.

However, these three designs should not simply be regarded as a “low-level to high-level” progression.

Actual valve selection still needs to be based on a comprehensive evaluation of medium, temperature, pressure, maximum differential pressure, leakage requirements, sealing materials, operating frequency, and cost.

Table of Contents

1. What Are the Core Structural Differences Between Concentric, Double Offset, and Triple Offset Butterfly Valves?
2. What Are the Main Differences Between the Three Types of Butterfly Valves?
3. How Should You Choose for an Actual Project?
4. What Technical Limits Are Easily Overlooked During Selection?
5. FAQ

Keywords: Concentric Butterfly Valve, Double Offset Butterfly Valve, Triple Offset Butterfly Valve, High Performance Butterfly Valve, Industrial Butterfly Valve

You can watch the following videos for a quick overview:

1. What Are the Core Structural Differences Between Concentric, Double Offset, and Triple Offset Butterfly Valves?

The main difference between the three butterfly valve types is not their appearance, but the relative positions of the stem, disc, and sealing surfaces.

This geometric structure directly affects how the disc contacts the seat during opening and closing, which in turn affects sealing surface friction, seat wear, and suitable operating conditions.

1.1 Concentric Butterfly Valve

A concentric butterfly valve is also known as a centerline butterfly valve.

Its stem typically passes through the center of the disc, while the disc is basically positioned along the centerline of the valve body and pipeline, without any additional offset design.

When the valve is closed, the disc forms a seal by compressing the soft seat.

Because the disc needs to move through the seat during rotation, a certain degree of friction exists between the disc and the seat.

This is also why concentric butterfly valves feature a simple structure and reliable sealing, while seat wear deserves relatively more attention.

Common features include:

• Compact structure
• Light weight
• Easy installation
• Lower initial purchase cost
• Good soft-seat shutoff performance
• Relatively simple maintenance

Concentric butterfly valves typically use soft seats. Common materials include EPDM, NBR, PTFE, and other non-metallic soft sealing materials.

It should be noted that different materials have different temperature ranges and media resistance. Therefore, the specific material should still be selected according to the medium, operating temperature, pressure, and chemical compatibility.

Concentric butterfly valves are commonly used in:

• Water supply and drainage
• Water treatment
• Cooling water
• HVAC
• Air pipelines
• General industrial fluids

For applications with relatively conventional temperature, pressure, differential pressure, and operating frequency requirements, concentric butterfly valves can usually meet basic shutoff and control requirements at a relatively low cost.

1.2 Double Offset Butterfly Valve

A double offset butterfly valve adds two geometric offsets to the concentric design.

The main purpose is to change the rotational path of the disc so that the disc can disengage from the seat more quickly once opening begins.

This can significantly reduce the amount of time during which continuous friction occurs between the disc and seat.

Therefore, compared with conventional concentric butterfly valves, the double offset design generally helps to:

• Reduce sealing surface friction
• Reduce seat wear
• Improve long-term opening and closing performance
• Improve adaptability to frequent operating conditions
• Expand the range of industrial applications

One important point should be noted:

Double offset butterfly valves cannot simply be considered equivalent to all “high performance butterfly valves.”

A more accurate statement is: the double offset design is a common structural form used in high performance butterfly valves.

In the KST product range, high performance butterfly valves use a double offset design and are mainly intended for applications with higher requirements for operating frequency, seat life, temperature, and industrial operating performance compared with conventional concentric butterfly valves.

Depending on the specific product design, double offset high performance butterfly valves can be equipped with PTFE, reinforced PTFE, or other suitable non-metallic seat materials.

However, the specific sealing materials and allowable temperature and pressure ranges should be confirmed according to the corresponding product datasheet.

Double offset butterfly valves are commonly used in:

• Oil and gas
• Chemical industry
• Petrochemical industry
• Power generation
• Industrial water treatment
• Thermal systems
• Process pipelines

Therefore, for many industrial projects, double offset butterfly valves provide a relatively balanced choice between performance, long-term operating capability, and cost.

1.3 Triple Offset Butterfly Valve

A triple offset butterfly valve adds a third geometric offset to the double offset design.

The third offset further changes the spatial relationship between the disc and seat sealing surfaces, creating a specific geometric sealing structure.

As a result, once the disc begins to open, the sealing pair can disengage relatively quickly, while during closing, primary sealing contact is usually established only when the disc approaches the final closed position.

This structure can further reduce friction and scraping of the sealing surfaces during opening and closing.

Its main advantages include:

• Relatively low sealing surface friction during most of the travel
• Helps reduce sealing pair wear
• More suitable for metal sealing structures
• More suitable for evaluating high-temperature applications
• More suitable for severe media
• More suitable for critical industrial shutoff applications

Therefore, when conventional soft sealing materials cannot meet requirements because of temperature, media compatibility, or long-term stability, a metal-seated triple offset butterfly valve can be further considered.

Common applications include:

• Oil and gas
• Refining
• Petrochemical industry
• Power generation
• High-temperature steam
• High-temperature process pipelines
• Severe chemical media
• Critical industrial shutoff systems

For LNG or cryogenic systems, special attention is required:

Conventional triple offset butterfly valves are not inherently suitable for all cryogenic applications.

Only triple offset butterfly valves specifically designed for cryogenic service and meeting project requirements for materials, temperature, sealing structure, and relevant testing can be used in corresponding LNG or cryogenic applications.

Therefore, the differences between the three designs can be understood as follows:

Concentric Butterfly Valve: Relies on compression of the soft seat to achieve sealing

Double Offset Butterfly Valve: Reduces seat friction by changing the rotational path of the disc

Triple Offset Butterfly Valve: Further changes the sealing geometry so that the sealing pair remains separated during most of the travel

However, the number of offsets is not the only criterion for determining the quality of a butterfly valve.

What really matters is: which design is more suitable for the actual operating conditions.

2. What Are the Main Differences Between the Three Types of Butterfly Valves?

The three butterfly valve types can be quickly compared in the following table.

Comparison Item	Concentric Butterfly Valve	Double Offset Butterfly Valve	Triple Offset Butterfly Valve
Structural Features	Centerline structure, no additional offset	Two offsets	Three offsets
Sealing Contact Method	Disc seals by compressing the soft seat	Disc disengages from the seat relatively quickly after opening	Sealing pair remains separated during most of the opening and closing travel
Sealing Friction During Operation	Relatively noticeable	Significantly reduced	Further reduced during most of the travel
Common Sealing Method	Non-metallic soft seal	High-performance non-metallic seats, etc.	Metal sealing is more common
Actual Operating Torque	Depends on size, differential pressure, seat, and operating conditions	Depends on size, differential pressure, seat, and operating conditions	Depends on size, differential pressure, sealing structure, and operating conditions
Temperature Application Tendency	Commonly used in ambient and medium-to-low temperature applications	Can cover more demanding industrial applications depending on seat material	Metal-seated structures are more suitable for evaluating high-temperature applications
Pressure / Differential Pressure Application Tendency	Commonly used in conventional industrial pressure applications	Suitable for applications with higher requirements for differential pressure and long-term operating performance	Suitable for evaluating high differential pressure and severe applications
Seat Wear	Friction during opening and closing is relatively more noticeable	Usually helps reduce friction and wear	Friction of the sealing pair is further reduced during most of the travel
Service Cycle	Depends on material, temperature, differential pressure, and operating frequency	Under the same or similar operating conditions, it can help extend the effective service cycle of sealing components	Determined according to the metal sealing structure and specific operating conditions
Initial Cost	Lower	Medium	Usually higher
Typical Positioning	Conventional industrial applications	High-performance industrial applications	Severe industrial applications

There are two very important valve selection principles here.

First, reduced sealing surface friction does not necessarily mean that the actual operating torque of the entire butterfly valve will always be lower.

Actual torque is also affected by:

• Nominal size
• Seat structure
• Sealing material
• Operating pressure
• Maximum differential pressure
• Medium
• Temperature

and other factors. The report also specifically recommends removing the original “medium / lower / lower” torque comparison method.

Second, the offset design cannot be directly equated with fixed temperature and pressure ratings.

The actual allowable temperature, pressure, and maximum differential pressure should be determined according to the specific butterfly valve model, materials, pressure rating, and design standards.

Therefore, there is no rule that “more offsets are always better.”

For example, in a conventional water treatment system, if a concentric butterfly valve already meets the requirements for medium, temperature, pressure, and leakage, directly selecting a triple offset butterfly valve would usually only add unnecessary cost.

The truly reasonable principle is: select the structure that can reliably meet the operating requirements, rather than simply choosing the most structurally complex butterfly valve.

In addition, besides the offset design, soft sealing or metal hard sealing will also directly affect the butterfly valve’s temperature range, shutoff performance, and wear resistance.

3. How Should You Choose for an Actual Project?

In an actual project, the butterfly valve should not be selected solely according to whether it is concentric, double offset, or triple offset.

A more reasonable method is to evaluate the following key parameters.

3.1 Medium and Sealing Material

First, it is necessary to determine what medium the valve will handle.

For example:

• Water
• Air
• Steam
• Oil products
• Natural gas
• Chemical media
• Corrosive media

For general fluids such as water and air, if the temperature, pressure, and chemical compatibility are relatively conventional, a concentric butterfly valve can usually meet the requirements.

If the medium, temperature, or operating conditions place higher requirements on seat materials and long-term reliability, a double offset butterfly valve can be further considered.

If soft sealing materials can no longer meet media compatibility or temperature requirements, a metal-seated triple offset butterfly valve can be further evaluated.

Therefore, the medium alone cannot determine the offset design, but it directly affects the selection of valve body, disc, and sealing materials.

3.2 Operating Temperature

Operating temperature is also an important parameter in butterfly valve selection.

Concentric butterfly valves are commonly used in general fluid systems at ambient and medium-to-low temperatures.

Double offset butterfly valves can cover applications with higher temperature and industrial operating performance requirements depending on the specific seat material and product structure.

When soft sealing materials cannot meet operating temperature, media compatibility, or long-term stability requirements, a metal-seated triple offset butterfly valve can be further evaluated.

Therefore, it is not recommended to simply state:

“Use concentric valves for low and medium temperatures, double offset valves for medium and high temperatures, and triple offset valves for high temperatures.”

A more accurate approach is: first confirm the operating temperature, and then confirm whether the sealing material and specific butterfly valve model can meet that temperature.

The specific allowable temperature should be based on the rated parameters of the seat, sealing ring, valve body, and other key component materials.

3.3 Pressure and Maximum Differential Pressure

Pressure and maximum operating differential pressure are both very important, but they are not the same parameter.

As operating pressure or shutoff differential pressure increases, higher requirements are placed on:

• Disc
• Stem
• Valve body
• Seat
• Sealing structure

Concentric butterfly valves are commonly used in conventional pressure applications.

If the system has higher requirements for maximum differential pressure, seat wear, or long-term operating reliability, a double offset design can be evaluated.

For applications that simultaneously involve high temperature, metal sealing, or severe differential pressure conditions, a triple offset butterfly valve can be further considered.

However, the following still needs to be confirmed:

Specific product pressure rating + maximum allowable differential pressure.

The valve’s pressure-bearing capability cannot be determined solely by the number of offsets.

3.4 Leakage and Sealing Direction Requirements

Different projects have very different requirements for shutoff leakage.

During selection, the following should be clarified:

• What leakage class is required?
• Is zero visible leakage required?
• Is unidirectional or bidirectional sealing required?
• What is the actual valve installation direction?
• What type of seat structure is used?
• Is soft sealing or metal sealing used?
• What design and testing standards are used?

Concentric butterfly valves usually achieve reliable shutoff through compression of the soft seat.

Double offset butterfly valves can reduce seat friction during opening and closing while maintaining sealing performance.

Triple offset butterfly valves are more suitable for applications requiring metal sealing while also facing higher temperatures or severe operating conditions.

Therefore, “triple offset” does not automatically represent a fixed leakage class. The specific product design and testing requirements still need to be checked.

3.5 Operating Frequency

The higher the operating frequency, the more attention needs to be paid to long-term friction between the disc and seat.

If the butterfly valve operates only infrequently, a concentric butterfly valve is already sufficient for many conventional applications.

However, if the valve needs to open and close frequently, long-term friction may gradually affect the effective service cycle of the soft seat.

In this case, because the disc of a double offset butterfly valve can disengage from the seat more quickly, the design is generally more beneficial for reducing sealing surface wear.

It should be noted:

A structure that can reduce wear does not mean that a fixed service life can be directly guaranteed.

The actual cycle life is still affected by:

• Seat material
• Operating temperature
• Maximum differential pressure
• Medium
• Operating frequency
• Maintenance conditions

and other factors.

3.6 Valve Torque and Actuator

Concentric, double offset, and triple offset butterfly valves can all be equipped with:

• Pneumatic actuators
• Electric actuators
• Manual operators

to achieve different control methods.

However, the actuator cannot simply be selected according to which offset design the butterfly valve uses.

The following factors need to be considered comprehensively:

• Actual valve opening and closing torque
• Maximum differential pressure
• Pipeline pressure
• Medium conditions
• Operating temperature
• Air supply pressure
• Actuator output torque
• Safety factor

Double offset and triple offset designs can indeed reduce sealing surface friction during part of the opening and closing process, but this does not mean that the total valve torque will always be lower than that of a concentric butterfly valve for every size.

Therefore, when selecting an actuator for an automated butterfly valve, the actual torque data provided by the manufacturer should still be used as the basis for actuator sizing.

3.7 Life Cycle Cost

In addition to the purchase price, long-term operating costs should also be considered.

Concentric Butterfly Valve

It has a simple structure and lower initial investment, making it very suitable for general operating conditions.

Double Offset Butterfly Valve

The initial purchase cost is usually higher than that of a conventional concentric butterfly valve. However, in systems with frequent operation or higher requirements for long-term industrial operating performance, reducing sealing surface friction can help reduce seat wear.

Triple Offset Butterfly Valve

The structure and manufacturing requirements are usually higher, so it is mainly used in severe operating conditions where conventional soft-seated butterfly valves cannot operate reliably over the long term.

Therefore, the final cost comparison should not focus only on the purchase price, but should comprehensively consider: purchase cost + sealing component service cycle + maintenance frequency + downtime cost

Quick Selection Table

If Your Operating Conditions Mainly Include…	You Can Prioritize Evaluating…
Water, air, and other general media, with relatively conventional temperature and pressure, and high cost sensitivity	Concentric Butterfly Valve
Frequent operation, with higher requirements for seat friction, long-term operating performance, and industrial adaptability	Double Offset Butterfly Valve
Soft sealing materials cannot meet temperature or media requirements	Triple Offset Butterfly Valve
Metal sealing is required	Focus on Evaluating Triple Offset Butterfly Valves
High temperature, severe media, or critical industrial shutoff applications	Focus on Evaluating Triple Offset Butterfly Valves
Unsure which type to choose	Select comprehensively according to medium, temperature, pressure, maximum differential pressure, leakage requirements, and sealing materials

KST provides concentric butterfly valves, high performance double offset butterfly valves, and triple offset butterfly valves, covering applications ranging from conventional soft-seated fluid control to applications with higher requirements for seat friction, operating frequency, and industrial operating performance, as well as severe operating conditions requiring metal sealing.

When making an actual inquiry or selecting a valve, it is recommended to provide the following parameters:

Medium, operating temperature, normal pressure, maximum pressure, maximum differential pressure, size, connection type, leakage requirements, operating frequency, and actuation method.

This makes it possible to further determine the appropriate butterfly valve design and sealing configuration.

4. What Technical Limits Are Easily Overlooked During Selection?

When comparing the three butterfly valve types, several issues are particularly easy to overlook.

4.1 Offset Design Cannot Directly Determine Actual Operating Torque

Double offset and triple offset designs can reduce some sealing surface friction, but actual valve torque is also affected by valve size, seat structure, differential pressure, medium, and other factors.

Therefore, it cannot simply be assumed that:

Concentric valve torque is high → double offset is lower → triple offset is the lowest.

Actuator selection should still be based on the actual torque data of the specific valve model.

4.2 Temperature Capability Is Mainly Determined Jointly by Materials and Specific Structure

The offset design affects the applicable operating conditions of a butterfly valve, but it cannot independently determine the maximum temperature.

For example, even for the same double offset butterfly valve design, different seat materials may have significantly different allowable operating temperatures.

Therefore, for high-temperature selection, the following should first be confirmed: seat material, sealing structure, valve body material, and product rated temperature.

4.3 Pressure Rating Is Not the Same as Maximum Allowable Differential Pressure

Pipeline pressure and the maximum differential pressure that the valve must withstand when closed are two different concepts.

Even if the nominal pressure rating of the valve meets the requirement, the maximum differential pressure that the disc can withstand in the closed position should still be confirmed.

This is particularly important for large-size and high differential pressure applications.

4.4 Triple Offset Butterfly Valves Are Not Inherently Suitable for All LNG Applications

Cryogenic valves generally require special consideration of:

• Cryogenic materials
• Stem and valve body structure
• Sealing design
• Temperature rating
• Project testing requirements

Therefore, triple offset butterfly valves used in LNG or other cryogenic systems should adopt corresponding special cryogenic designs, rather than being judged suitable solely because they are “triple offset.”

4.5 Unidirectional or Bidirectional Sealing Must Also Be Confirmed

Whether a butterfly valve can meet bidirectional shutoff requirements depends on:

• Seat structure
• Pressure direction
• Sealing pair design
• Valve model

Therefore, for projects with clear bidirectional sealing requirements, it is best to confirm this during the selection stage rather than trying to determine it from the valve type after installation.

5. FAQ

1. What Is the Biggest Difference Between a Concentric Butterfly Valve and a Double Offset Butterfly Valve?

The biggest difference is how the disc contacts the seat after opening begins.

In a concentric butterfly valve, relatively noticeable compression and friction occur between the disc and seat during opening and closing. In a double offset design, the disc can disengage from the seat more quickly after opening begins, thereby reducing sealing surface friction and seat wear.

2. How Should You Choose Between a Double Offset Butterfly Valve and a Triple Offset Butterfly Valve?

If the main requirements are to reduce seat friction, accommodate more frequent operation, and improve industrial operating performance, a double offset butterfly valve can usually be evaluated first.

If soft sealing can no longer meet temperature, media, or sealing requirements, especially when metal sealing is required, a triple offset butterfly valve can be further evaluated.

3. Is a Triple Offset Butterfly Valve Always Better Than Concentric and Double Offset Butterfly Valves?

Not necessarily.

Triple offset butterfly valves are more suitable for certain high-temperature, metal-seated, and severe industrial applications, but their structure and initial cost are usually higher.

For conventional water treatment, HVAC, or general industrial systems, if a concentric or double offset butterfly valve already meets the requirements, there is no need to select a triple offset butterfly valve simply to increase the number of offsets.

4. Which Butterfly Valve Is More Suitable for High-Temperature Applications?

This cannot be determined solely by the offset design.

The temperature capability of concentric and double offset butterfly valves is closely related to the seat and sealing materials. When soft sealing materials cannot meet the operating temperature or long-term stability requirements, a metal-seated triple offset butterfly valve can be further considered.

The final selection should be based on the datasheet of the specific model and the rated temperature of the materials.

5. When Should You Upgrade from a Concentric Butterfly Valve to a Double Offset Butterfly Valve?

When a conventional concentric butterfly valve cannot meet requirements in terms of operating frequency, seat wear, operating temperature, maximum differential pressure, or long-term industrial operating performance, a double offset butterfly valve can be considered.

The core value of the double offset design is not simply that it is a “higher-level” design, but that it changes the movement path of the disc to reduce unnecessary friction between the disc and seat.

6. Is a Double Offset Butterfly Valve the Same as a High Performance Butterfly Valve?

They cannot be considered completely equivalent.

More accurately, the double offset design is a common structural form used in high performance butterfly valves. Different manufacturers may have different product structures, seat materials, and design ranges for “High Performance Butterfly Valves,” so the specific product specifications still need to be checked.