Nominal Pipe Size (NPS) is not the sole factor that defines gate valve sizes. In fact, face-to-face dimensions and pressure classes are also checked if they fall under international standards.
Every industrial gate valve is evaluated for:
- Bore diameter determines flow coefficient (Cv) and usually matches the internal diameter of the pipe in full-bore designs.
- Face-to-face (L) length confirms how far the inlet and outlet are from each other, ensuring it fits into the spool.
- Pressure class checks that the body and bonnet wall are thick enough for different temperatures and pressures.
This gate valve measurement guide explains what those above parameters mean when choosing the best unit for a specific industrial application.
NPS vs. Bore Size: Design and Capacity
The internal bore diameter dictates how much fluid can pass through the body with acceptable pressure loss. For isolating, gate valves are preferred for being straight-through, since the plate moves vertically to close.
Full Bore Design
Also called full port design, this type is where the internal opening matches the inside diameter of the connected pipe for:
- Maximum flow capacity (Cv or Kv) for higher flow rates.
- Less pressure loss compared to standard bores.
- Lower turbulence for reduced wedge and seat erosion.
- Easier passage of cleaning pigs.
Reduced Bore Design
While not as common when isolating ports, this standard gate valve size has an internal diameter that is smaller than the opening of the connected pipeline for:
- Tight space navigation during the installation.
- Weight reduction in offshore or elevated pipelines.
- Lighter footprint but slightly more pressure drop.
- Greater value for money when the budget is limited.
By picking a bore size based on pipe diameter, the system stays stable since the seats will not erode prematurely. For foundational knowledge on basic valve sizing, learn How to Read Gate Valve Dimension Charts on the blog.
Expanded Gate Valve Dimensions Chart
The American Society of Mechanical Engineers (ASME) establishes the level of structural integrity and physical footprint in different types of valves. For instance, ASME B16.10 checks the face-to-face and end-to-end dimensions of flanged and butt-weld (BW) valves.
Meanwhile, ASME B16.34 stipulates wall thickness, pressure-temperature ratings, and overall design. These standards permit interchanging of components from different global manufacturers without redesigning existing layouts.
Dimensional Matrix of Class 150 Gate Valves
These are ideal for low-to-medium pressure systems, such as HVAC and water treatment. With sizes ranging from 1½ to 64 inches, they feature more compact face-to-face dimensions. Their lighter shell and thinner flanges offer enough strength with relatively low pressure loss.
| NPS(in) | L(RF)(mm) | L(RTJ)(mm) | L(BW)(mm) | Height (Open) (mm) | Weight(RF) (kg) |
| 2” | 178 | 191 | 216 | 397 | 17 |
| 4” | 229 | 241 | 305 | 590 | 47 |
| 8” | 292 | 305 | 419 | 975 | 122 |
| 12” | 356 | 368 | 502 | 1375 | 225 |
| 24” | 508 | 521 | 813 | 2522 | 1135 |
Smaller versions are often operated using a manual handwheel, while larger diameters need gear operators to open and close.
Dimensional Matrix of Class 300 Gate Valves
To accommodate the rising system pressure levels, these gate valve sizes are longer, thicker, and heavier to keep up with pressure-boundary integrity.
| NPS(in) | L(RF)(mm) | L(RTJ)(mm) | L(BW)(mm) | Height (Open) (mm) | Weight(RF) (kg) |
| 2” | 216 | 232 | 216 | 430 | 26 |
| 4” | 305 | 321 | 305 | 650 | 73 |
| 8” | 419 | 435 | 419 | 1040 | 204 |
| 12” | 502 | 518 | 502 | 1440 | 465 |
| 24” | 1143 | 1165 | 1143 | 2587 | 2320 |
It is worth noting that, with a weight of around 2,320 kg, the 24-inch standard gate valve size needs its own structural supports. Additionally, it cannot be installed or replaced quickly and without any heavy equipment. Gear operators are also recommended to achieve the amount of torque for sealing the seats.
Dimensional Matrix of Class 600 Gate Valves
These are preferred for high-pressure steam, oil and gas extraction, power generation, and other demanding applications. They frequently feature Ring Type Joint (RTJ) or butt-weld end connections, making them heavier, longer, and larger in construction, especially the actuator.
| NPS(in) | L(RF)(mm) | L(RTJ)(mm) | L(BW)(mm) | Height (Open) (mm) | Weight(RF) (kg) |
| 2” | 330 | 333 | 330 | 512 | 55 |
| 4” | 559 | 562 | 559 | 890 | 260 |
| 8” | 838 | 841 | 838 | 1458 | 854 |
| 12” | 991 | 994 | 991 | 1825 | 1317 |
| 24” | 1549 | 1562 | 1549 | 3120 | 7450 |
Since different pressure classes and sizes have varying dimensions, it is vital to verify the measurements using the manufacturer’s gate valve dimensions chart before purchase and installation. These are easily accessible for YKY products, like on the API Gate Valve and GB Gate Valve pages.
Impact of Pressure Class on Mass and Wall Thickness
There might be the same NPS across different valve pressure classes, but some components are adjusted to make up for the greater risk of thermal shock and static pressure.
Shell Thickness: A Class 600 valve requires thicker walls to ensure the material will not yield to stress when pressure levels reach their peak. Extra material is added to flanges and the entire bonnet structure and flow path for this reason too.
End Connections: Class 150 and 300 valves usually need raised face flanges. However, Class 600 and higher need RTJ and BW connections so they will seal properly.
Operational Clearance: A Class 600 valve in the open position has a greater height than a Class 150 or Class 300 unit. This is due to a thicker internal wedge that needs a longer stem and taller bonnet.
Gate Valve Measurement Guide: Installation and Conclusion
The GB Gate Valve is engineered for reliable performance in industrial applications, including chemical, petrochemical, and power industries.
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To properly install a gate valve into the piping system, it is crucial to check the changing footprints while it is being operated. This ensures there is enough clearance for taller stems and checks whether it is compatible with the end connection or not.
Choosing the correct gate valve sizes means looking at the bore diameter, pressure class, and standardized dimensions. YKY Valve provides gate valves in different configurations so every buyer and procurement professional is sure to find a design that matches their specific needs.
