Full-bore valves have an internal channel diameter that is essentially the same as the pipe's inner diameter, resulting in minimal flow resistance and making them suitable for high-flow-rate transport and pipeline cleaning operations. Reduced-bore valves, on the other hand, have a channel diameter smaller than the pipe's inner diameter, resulting in smaller size and lower cost, making them suitable for routine applications with lower flow requirements.
Full-bore valves (such as full-bore ball valves) employ a constant-width flow channel design, where the diameter of the internal through-hole is roughly equivalent to the nominal diameter of the connected pipe (usually greater than 95% of the port's inner diameter). For example, a DN50 full-bore valve has a flow channel diameter close to 50mm. This design allows for almost unobstructed fluid flow, minimal pressure loss, and a flow capacity approaching that of a straight pipe, making them particularly suitable for systems requiring efficient transport or periodic pipeline cleaning.
In contrast, reduced-bore valves have an actual flow channel diameter one or more sizes smaller than their nominal diameter. For example, a DN50 reduced-bore ball valve has a flow channel diameter of approximately 38mm, roughly equivalent to a DN40 size. While this "reduced-bore" design slightly increases flow resistance, it significantly reduces valve size and weight, saving space and reducing installation load.
Free Download: Full vs. Reduced Port Spec Chart (PDF) including Weight & Torque data.
Attributes Comparison
| Comparison Item | Full Port (Full Bore) | Reduced Port (Reduced Bore) |
| Definition | Valve ID is identical to pipe ID | Valve ID is smaller than pipe ID (typically 1 size smaller) |
| Flow Path Design | Straight-through, zero obstruction | Funnel/Stepped design with a port transition |
| Flow Capacity (Cv/Kv) | Maximized (equivalent to same-length pipe) | Lower (due to throttling effect) |
| Pressure Drop (
ΔPΔP ) |
Minimal (negligible) | Higher (creates local pressure drop) |
| Resistance Coefficient | Minimum | Significant |
Physical & Economic Parameters
| Parameter Category | Full Port (Full Bore) | Reduced Port (Reduced Bore) |
| Size & Weight | Larger and Heavier (larger ball/wedge) | Compact and Lightweight (smaller body/internals) |
| Installation Space | Requires more space (longer Face-to-Face) | Space-saving, ideal for tight installations |
| Manufacturing Cost | Higher (more material, complex machining) | Economical (cost-effective, less material) |
| Operating Torque | Higher (larger sealing surface friction) | Lower (due to reduced internal components) |
| Pigging Capability | Fully Supported (pigs pass freely) | Not Supported (will trap the pig) |
Applications Comparison
| Scenario Requirement | Recommended Choice | Reason |
| Long-distance Pipelines | Full Port | Must meet periodic Pigging requirements. |
| Viscous / Slurry Media | Full Port | Prevents media accumulation, clogging, or erosion at the port. |
| Standard Water/Gas Systems | Reduced Port | Pressure loss is acceptable; significantly reduces costs. |
| Weight-Sensitive (Offshore) | Reduced Port | Reduces total system weight and support requirements. |
| High Turbulence Service | Full Port | Avoids severe downstream erosion caused by turbulence at the port. |
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FAQ
What is a fully ported ball valve?
A full port or sometimes called full bore, ball valve has a straight flow path where there is not a reduction of flow as it travels through the valve.
What is a reduced port ball valve?
A reduced-port ball valve, also known as a standard-port ball valve or reduced-bore ball valve, is a type of valve commonly used to control the flow of fluids through pipes and tubing.