Explanation to Equivalent Length
In order to simplify the calculation of equivalent length of pipe fittings and valves in plumbing engineering, EngineerMate compared different sources and determined the L/D factor for each of them as listed in the following table.
| Fittings/valves | L/D (in/in) in Different Sources | In PlumAL[1] | |||||
|---|---|---|---|---|---|---|---|
| No. 1 | No. 2 | UPC | IPC | L/D[2] | Code[3] | Name[4] | |
| 45°/Ell | 14 | 20 | 25 | 25 | 25 | F | 45°/Ell |
| 90°/Ell | 30 | 30 | 40 | 40 | 40 | E | 90°/Ell |
| long 90Ell | - | - | |||||
| 180” close return bends | 67 | - | |||||
| Tee | 60 | 60 | 60 | 60 | 60 | T | T-turn |
| T-thru/coupling | - | 16 | 12 | 12 | 12 | R | T-line |
| Ball | - | 6 | 8 | G | Ball | ||
| Gate | 7 | 9 | 8 | 8 | 8 | G | Gate |
| Globe | 333 | 275 | 330 | 330 | 330 | L | Globe |
| Angle | 167 | - | 170 | 170 | 170 | A | Angle |
| Swing Check | 83 | - | 133 | 133 | 133 | C | Check |
| Butterfly Va | - | 20 | |||||
| Balancing Valve | - | - | 18 | 18 | B | ||
| Plug-type cock | - | - | 18 | 18 | 18 | B | Plug / Balancing |
Notes:
Sources:
- "PlumAL" is a tool package for calculation in plumbing engineering.
- "L/D" values in this column are used through-out the PlumAL and the EngineerMate site unless otherwise noted.
- "Code" is the letter assigned for each fitting or valve in plumbing system in PlumAL.
- "Name" is the full name or abbreviation assigned for each fitting or valve for better understanding.
- No.1: International Fuel Code and NFPA 54 adapt the data listed in Table XIV in Piping Handbook, written by Crocker, S. in 1945 and published by McGraw-Hill, Inc.
- No.2: Posted by the following websites: http://www.aquatext.com/tables/frict-wat.htm http://www.scribd.com/doc/24752539/Fitting-Equivalent-Length
- UPC: Uniform Plumbing Code
- IPC: International Plumbing Code
The L/D values for pipe fittings and valves are listed in the following table.
| Fit Code | Fitt/Valve Name | L/D (in/in) |
|---|---|---|
| F | 45-degree ell | 25 |
| E | 90-degree ell | 40 |
| T | T-turn | 60 |
| R | T-line | 12 |
| B | Balancing & plug cock | 18 |
| G | gate/ball valve | 8 |
| L | globe valve | 330 |
| A | angle valve | 170 |
| C | swing check valve | 133 |
Example:
For a 2-inch Tee of copper tube type L, equivalent length, Leq = 60 x 1.965 / 12 = 9.8 ft