Valve Sizes: Inches vs DN vs MM
Valves play a critical role in various industries, controlling the flow of fluids within piping systems. When specifying valve sizes, three common metrics are frequently used: inches, DN (Diameter Nominal), and millimeters. While these metrics all measure valve sizes, understanding their differences is essential for accurate selection and installation.
Inches, as the name implies, represent valve sizes in inches, indicating the diameter of the valve's opening. This measurement system is predominantly used in regions where imperial units are standard. Conversely, DN is a metric system that standardizes pipe and valve sizes based on their nominal diameter in millimeters. DN sizes are part of the ISO (International Organization for Standardization) metric series, commonly used in Europe and many other parts of the world. Lastly, millimeters provide precise measurements of valve sizes and are widely adopted in industries globally.
To clarify the correspondence between these three sizing systems, the following comparison table outlines valve sizes in inches, DN, and millimeters, helping you navigate the various standards more effectively:
| Valve Size DN (Diameter Nominal) | Valve Size Inches | Valve Size Millimeters |
| DN08 | 0.375" | 9.525mm |
| DN10 | 0.25" | 6.35mm |
| DN15 | 0.5" | 12.7mm |
| DN20 | 0.75" | 19.05mm |
| DN25 | 1" | 25.40mm |
| DN32 | 1.25" | 31.75mm |
| DN40 | 1.5" | 38.10mm |
| DN50 | 2" | 50.80mm |
| DN65 | 2.5" | 63.50mm |
| DN80 | 3" | 76.20mm |
| DN100 | 4" | 101.60mm |
| DN125 | 5" | 127mm |
| DN150 | 6" | 152.40mm |
| DN200 | 8" | 203.20mm |
| DN250 | 10" | 254mm |
| DN300 | 12" | 304.80mm |
| DN350 | 14" | 355.60mm |
| DN400 | 16" | 406.4mm |
| DN450 | 18" | 457.20mm |
| DN500 | 20" | 508mm |
| DN600 | 24" | 609.60mm |
Keep in mind that while these sizes might appear straightforward, variations can occur depending on the valve type and specific industry standards. It's always best to consult professionals or refer to the manufacturer's specifications to ensure compatibility and performance.
Understanding the different valve size standards will not only simplify the selection process but also ensure your systems function optimally.
