Reference Tables
Local loss, roughness, velocity, ratings.
Local loss coefficients
| Fitting | ζ |
|---|
| Loto 45° | 0.35 |
| Loto 90° | 0.75 |
| 90° square | 1.3 |
| 180° return | 1.5 |
| Union | 0.4 |
| Std. tee | 0.4 / 1.0 / 1.3 / 1.5 |
| Sudden enlarg. | (1−A1/A2)² |
| Sudden contract. | 0.5·(1−A2/A1) |
| Gate valve | 0.17 / 0.9 / 4.5 / 24 |
| Globe (full) | 6.4 |
| Globe (1/2) | 9.5 |
| Butterfly | 0.24 ~ 751 |
| Plug cock | 0.24 ~ 206 |
| Check (swing) | 2 |
| Check (ball) | 70 |
| Angle valve | 5 |
| Foot valve | 1.5 |
| Strainer | 2 |
| Water meter | 7 |
ζ values vary with make and condition — values shown are typical engineering estimates.
Recommended velocities
| Service | Velocity (m/s) |
|---|
| Pump suction | 0.8 – 1.5 |
| Pump discharge | 1.5 – 2.5 |
| General water | 1 – 2.5 |
| Hot water / cond. | 2 – 3 |
| Steam | 25 – 40 |
| Air / gas | 8 – 15 |
Pipe roughness
| Material / condition | ε (mm) |
|---|
| Brass/copper/lead | 0.01 – 0.05 |
| Clean glass | 0.0015 – 0.01 |
| Rubber hose | 0.01 – 0.03 |
| New steel / galvanized | 0.1 – 0.2 |
| Steel, slight corrosion | 0.2 – 0.3 |
| Steel, marked corrosion | ≥ 0.5 |
| New cast iron | 0.3 |
| Old cast iron | ≥ 0.85 |
| Cement (smooth) | 0.33 |
| Asbestos-cement | 0.03 – 0.8 |
| Wood | 0.25 – 1.25 |
| Clay drain | 0.45 – 6.0 |
Enclosure protection (IP)
| 1st digit | Solids | 2nd digit | Water |
|---|
| 0 | None | 0 | — |
| 1 | ≥50mm | 1 | Dripping |
| 2 | ≥12mm | 2 | Dripping 15° |
| 3 | ≥2.5mm | 3 | — |
| 4 | ≥1mm | 4 | Splashing |
| 5 | Dust protected | 5 | Jets |
| 6 | Dust tight | 6 | — |
| | 7 | Immersion |
Common motor ratings: IP54, IP55, IP65.
Explosion protection
| Zone | Gas atmospheres | Dust atmospheres |
|---|
| 0 / 20 | Continuous hazard | Continuous |
| 1 / 21 | Likely during normal operation | Likely |
| 2 / 22 | Unlikely / brief | Unlikely / brief |
Common marking: Ex d IIB T4 (flameproof).