MATERIALS / METRIC REFERENCE
Pipe sizes in mm: metal & plastic piping
Copper, steel, stainless, PP-R, PEX, multilayer, PE100 and drainage pipe sizes, typical lengths and common uses.
Outside diameter (OD) is different from nominal diameter (DN). Wall thickness, pressure rating, temperature class and fittings must be specified as a compatible system. These are coordination examples, not hydraulic design tables.
Copper — Metal · copper tube
Hot / cold water; heating
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 15 | — |
| 18 | — |
| 22 | — |
| 28 | — |
| 35 | — |
| 42 | — |
| 54 | — |
Typical supply lengths: Typically 3–5 m straight; soft coils available
Confirm water chemistry, fittings and insulation. Do not mix joint systems.
Outside diameter (OD), not DN
Explore Copper in the handbook →Steel pipe — Metal · threaded steel
Heating, plant and approved fire-service systems
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 21.3 | — |
| 26.9 | — |
| 33.7 | — |
| 42.4 | — |
| 48.3 | — |
| 60.3 | — |
| 76.1 | — |
| 88.9 | — |
Typical supply lengths: Typically 6 m straight
Wall series and coating must be specified. Galvanised steel is not automatically appropriate for every potable-water installation.
DN15/20/25/32/40/50/65/80 → listed OD
Explore Steel pipe in the handbook →Stainless — Metal · stainless press tube
Water services and plant, where system-approved
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 15 | 1 |
| 18 | 1 |
| 22 | 1.2 |
| 28 | 1.2 |
| 35 | 1.5 |
| 42 | 1.5 |
| 54 | 1.5 |
| 76.1 | 2 |
| 88.9 | 2 |
| 108 | 2 |
Typical supply lengths: Typically 6 m straight
Select stainless grade, seals and potable-water approval. Protect from chloride contamination.
Mapress example: outside diameter × wall; not a universal series
Explore Stainless in the handbook →PP-R — Plastic · polypropylene random
Hot / cold water and heating, by pipe class
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 20 | — |
| 25 | — |
| 32 | — |
| 40 | — |
| 50 | — |
| 63 | — |
| 75 | — |
| 90 | — |
| 110 | — |
Typical supply lengths: Typically 4 m straight
Pressure capacity changes with temperature and service life. Allow thermal expansion; protect from UV unless rated.
Outside diameter; wall depends on SDR / series
Explore PP-R in the handbook →PEX — Plastic · cross-linked polyethylene
Domestic distribution and underfloor heating
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 16 | — |
| 20 | — |
| 25 | — |
| 32 | — |
Typical supply lengths: Typically 50 / 100 m coils; varies by diameter
Heating may require an oxygen barrier. Check temperature class and potable-water approval. Keep unapproved pipe out of sunlight.
Outside diameter × wall; system-specific
Explore PEX in the handbook →Multilayer — Composite · PE / aluminium / PE
Hot / cold water and heating
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 16 | 2.25 |
| 20 | 2.5 |
| 26 | 3 |
| 32 | 3 |
| 40 | 3.5 |
| 50 | 4.5 |
| 63 | 4.5 |
| 75 | 4.7 |
Typical supply lengths: Straight lengths / coils by product and diameter
16 × 2.25; 20 × 2.5; 26 × 3; 32 × 3; 40 × 3.5; 50 × 4.5; 63 × 4.5; 75 × 4.7 mm. Do not mix 25 and 26 mm fittings.
Mepla example: OD × wall (not a universal series)
Explore Multilayer in the handbook →PE100 — Plastic · polyethylene pressure
Buried water mains and irrigation, with required approvals
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 20 | — |
| 25 | — |
| 32 | — |
| 40 | — |
| 50 | — |
| 63 | — |
| 75 | — |
| 90 | — |
| 110 | — |
| 160 | — |
Typical supply lengths: Typically 6 / 12 m straight; coils for smaller sizes
Pipe colour alone is not approval for drinking water or gas. Select a certified service-specific system.
Outside diameter; specify SDR and pressure class
Explore PE100 in the handbook →PVC-U — Plastic · gravity drainage
Below-ground foul drainage and sewer branches
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 82 | — |
| 110 | — |
| 160 | — |
Typical supply lengths: Typically 3 / 6 m; product-specific
Wavin OsmaDrain size examples. Gravity sewer pipe is not pressure pipe. Check bedding, falls, loading and access.
Nominal outside diameter; ring stiffness also matters
Explore PVC-U in the handbook →PP waste — Plastic · polypropylene drainage
Internal waste, soil and vent systems
| Outside diameter (mm) | Wall (mm) |
|---|---|
| 32 | — |
| 40 | — |
| 50 | — |
| 75 | — |
| 110 | — |
Typical supply lengths: Typically 0.5–3 m; system-specific
Acoustic grade, hot-discharge rating and fire stopping are separate design requirements.
Outside diameter; verify compatible fittings
Explore PP waste in the handbook →Dimensions are reference examples, not an exhaustive standard or a live stock list. Confirm the exact product with the supplier. No structural capacity or system performance is calculated.