Full Bore Vs. Reduced Bore Ball Valve

Home Full Bore Vs. Reduced Bore Ball Valve

Although a ball valve is the most commonly used valve as compared to butterfly valves, choosing the right one can be confusing, as ball valves come in all shapes and sizes. A ball valve’s structure consists of a rod, body, seat, and in some cases, a transmission device.

The valve’s actuator causes the ball core to rotate at different angles which either stop or allow the flow of fluids. Ball valves can be divided into two broad categories, a full bore valve, and a reduced bore valve. Understanding the key differences between full bore vs reduced bore valve is important to determine their applications. 

Full Bore Ball Valve

Full Bore Ball Valve
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A full bore valve refers to a ball valve that can open completely when the actuator moves, creating a clear, unobstructed path for the fluid to pass through the pipe where the valve is used. 

Typically, the inner diameter of the valve ball is greater than 95 percent of the inner diameter of the ball valve port, in a full bore valve. The main difference between full bore and reduced bore ball valve is that the former has smaller internal bore dimensions as compared to its end connections. 

In this type of ball valve, the size of the flow channel from the inlet to the outlet remains consistent and does not change. Since the valve has an equal width flow channel, its diameter should not vary greatly from the nominal flow channel diameter mentioned in the specification. For example, if a full bore valve has a specified diameter of DN30, the flow channel diameter should be nearly equal to 30.


When comparing a full bore and reduced bore ball valve, it is important to know the applications of both. Full bore valves have pressure classes between 150 to 600. Based on their pressure class, diameter, and design, these ball valves are typically used in industries and pipelines where viscous mediums that are prone to slagging need to be transported. 

Since full bore valves offer unobstructed flow and have low fluid resistance, heavy fluids can flow easier through pipelines if these valves are used. A good example where these valves are used is in underground oil and gas pipelines.

Reduced Bore Ball Valve

Reduced Bore Floating Ball Valve
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The main difference between a reduced bore and full bore valve is the size of the diameter. A reduced bore valve refers to a ball valve in which the opening is smaller than its end connection. In this type of valve, the inner diameter of the valve ball is less than 85 percent of the inner diameter of the ball valve port.

Since the inlet is wider than the flow path diameter, the actual diameter can be taken as one specification lower than the given parameter. For example, the flow path of a DN50 reduced bore valve will be around 38. 

It is important to note that the opening in this ball valve is typically not greater than 9 mm, although some manufacturers may create custom sizes depending on the application and load expected. 


When a ball valve reduced bore vs full bore is compared, the former has greater flow resistance. This makes it perfect for use with smaller pipes that feed fluids into storage units like tanks, especially in refinery companies. 

Considering a reduced bore valve’s design and flow resistance, it is often used in industrial pipelines that transport gasses or less viscous mediums like water. Since it has a slightly higher flow resistance as compared to a full bore ball valve, it can reduce the pipeline load significantly, as it regulates the flow of lighter mediums. Hence, it promotes cost savings. 

Comparison Between Ball Valve Full Port Vs Reduced Port

Reduced port Ball Valve
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The two distinct ball valve types can be compared based on aspects such as size, cost, and installation, to determine their individual uses.

1. Installation

A reduced ball valve has a smaller volume and is hence lighter in weight as well. As a result, it is easier to install a reduced bore valve as compared to a full bore valve. In fact, a full bore valve is nearly 30 percent heavier as compared to a reduced port valve, and hence, it has a bigger volume.

Since it is easier to install and has a smaller volume, a reduced ball valve is ideal in situations where the load in the pipeline has to be reduced, such as pipes transporting gasses or water-like liquids. 

2. Maintenance 

The ease of maintenance is yet another important factor that can help determine the type of valve to be used. In industries where there are not enough resources to handle regular cleaning of blocks and other maintenance issues, it is best to opt for a ball valve full bore vs reduced bore.

This is because the former allows the unobstructed flow of fluids, and can last longer without regular maintenance. At the same time, if there are a lot of pressure drops in the area where a ball valve is required, it is best to use a full bore valve.

Extreme variations in pressure severely impact how a medium is transported from one end to the other, in a reduced bore valve. Regular pressure drops can lead to the whole system collapsing since reduced bore valves are not built to withstand them. However, a full bore valve can easily handle both extremities without breaking. 

3. Cost

Since it is smaller in size and considerably lighter, the price of a ball valve reduced bore vs full bore is lower. The cost is also determined by the durability and performance of these two valves.

A full bore valve is built with high-quality materials since it has to withstand greater pressure, in comparison to its counterpart. It does not require regular maintenance and does not collapse easily. 

A reduced ball valve, on the other hand, is built for steady pressures and requires regular maintenance. They are easily replaceable and cannot handle the same level of work that a full bore valve can withstand. 

4. Nature Of Work

The size of the piping network plays a key role in determining the type of ball valve used. Bigger pipes are typically used to handle more viscous mediums. Since full bore valves have bigger diameters and low fluid resistance, they can easily transport these viscous mediums, like in an oil refinery plant.

On the other hand, if the pipeline network handles less viscous and lighter mediums like water, paraffin wax, or gasses, reduced ball valves are preferred. This works well with the fact that smaller pipes handle these mediums. Since they offer a little bit more resistance as compared to a full bore valve, it reduces overall operational costs.


To determine the type of ball valve that has to be used, several factors like nature of work, size of the pipes, maintenance resources, and budget have to be considered. Both full bore and reduced bore valves have different applications. Hence, none is better than the other. 

Full bore valves are used with pipes with larger diameters that transport viscous mediums, whereas reduced bore valves are used with small diameter pipes that transport light, fast-flowing fluids. Contact a premier valve manufacturer today to get high-quality valves for industry-specific needs.

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