Technical centre
Pipe and fitting size standards.
How metric UPVC sizes relate to DN, with fitting tolerances and thread dimensions from our catalogue.
Two ways to size a pipe
DN is the nominal size, close to the inner diameter, and is generally used for steel and iron pipes. The plastics industry uses the outside diameter, d.
A UPVC pipe and its fittings are therefore named by the outside diameter in millimetres. The table below links each metric size to its DN and gives the mean diameters of our solvent cement fittings.
d ↔ DN
Choose a size, see its DN.
Pick an outside diameter to see its DN and the tolerances of our fittings. Point at a value to find its column.
- DN
- –
- Outside Ø min
- –mm
- Outside Ø max
- –mm
- Socket Ø min
- –mm
- Socket Ø max
- –mm
| d (mm) | DN | Outside Ø min | Outside Ø max | Socket Ø min | Socket Ø max |
|---|---|---|---|---|---|
| 16 | 10 | 16 | 16.2 | 16.1 | 16.3 |
| 20 | 15 | 20 | 20.2 | 20.1 | 20.3 |
| 25 | 20 | 25 | 25.2 | 25.1 | 25.3 |
| 32 | 25 | 32 | 32.3 | 32.1 | 32.3 |
| 40 | 32 | 40 | 40.3 | 40.1 | 40.3 |
| 50 | 40 | 50 | 50.3 | 50.1 | 50.3 |
| 63 | 50 | 63 | 63.3 | 63.1 | 63.3 |
| 75 | 65 | 75 | 75.3 | 75.1 | 75.3 |
| 90 | 80 | 90 | 90.4 | 90.1 | 90.3 |
| 110 | 100 | 110 | 110.4 | 110.1 | 110.4 |
| 125 | 110 | 125 | 125.4 | 125.1 | 125.4 |
| 140 | 125 | 140 | 140.5 | 140.2 | 140.5 |
| 160 | 150 | 160 | 160.5 | 160.2 | 160.5 |
| 200 | 175 | 200 | 200.6 | 200.2 | 200.6 |
| 225 | 200 | 225 | 225.7 | 225.3 | 225.7 |
| 250 | 225 | 250 | 250.8 | 250.3 | 250.8 |
| 280 | 250 | 280 | 280.9 | 280.3 | 280.9 |
| 315 | 280 | 315 | 316 | 315.4 | 316 |
Threads
Threading dimensions.
Pipe threads according to ISO 7/1, BS 21 and DIN 2999.
| Size (G) | Thread Ø (mm) | Threads per inch | Pitch (mm) | Thread depth (mm) | Thread length (mm) |
|---|---|---|---|---|---|
| 3/8″ | 16.66 | 19 | 1.337 | 0.856 | 11.04 |
| 1/2″ | 20.95 | 14 | 1.814 | 1.162 | 15 |
| 3/4″ | 26.44 | 14 | 1.814 | 1.162 | 16.3 |
| 1″ | 33.25 | 11 | 2.309 | 1.479 | 19.1 |
| 1¼″ | 41.91 | 11 | 2.309 | 1.479 | 21.4 |
| 1½″ | 47.8 | 11 | 2.309 | 1.479 | 21.4 |
| 2″ | 59.61 | 11 | 2.309 | 1.479 | 25.7 |
| 2¼″ | 65.71 | 11 | 2.309 | 1.479 | – |
| 2½″ | 75.18 | 11 | 2.309 | 1.479 | 30.2 |
| 2¾″ | 81.53 | 11 | 2.309 | 1.479 | – |
| 3″ | 87.88 | 11 | 2.309 | 1.479 | 33.3 |
| 4″ | 113.03 | 11 | 2.309 | 1.479 | 39.9 |
| 5″ | 138.43 | 11 | 2.309 | 1.479 | 43.6 |
| 6″ | 163.83 | 11 | 2.309 | 1.479 | 43.6 |
Technical centre
More from the technical centre.
- Solvent bondingPrinciples, seven steps, curing times and safety, with photos from real installations.→
- Information about UPVCWhy UPVC, technical characteristics and how our pressure fittings are engineered.→
- General properties of UPVC at 20 °CPhysical, mechanical and electrical values, and working pressure against temperature.→
- Storage and transportLoading, unloading, stacking heights and long-term storage of pipes.→
- Installation guidesSolvent-welded, flanged and threaded connections, and thermal expansion.→
- Frequently asked questionsPressure classes, drinking water, chemicals, seals and curing times.→
A question we did not cover?
Our technical team helps with product selection, installation and chemical compatibility.