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This guide brings the site data for TUPY Brazil BSP threaded fittings together on one page: the correct amount of wrench tightening, how to work out the length of pipe between two fittings, union tightening torque, permitted spacing between supports, and pipework design recommendations. All values are taken from the TUPY Brazil BSP fittings technical catalogue.
A threaded fitting seals on thread engagement, so the amount of tightening must be neither below the minimum nor above the maximum. The table below gives the minimum and maximum number of turns of wrench tightening and the recommended wrench length for each size.
| Nominal size (inch) | Minimum tightening (turns) | Maximum tightening (turns) | Recommended pipe wrench length |
|---|---|---|---|
| ¼ to ¾ | 1½ | 2¾ | 6 inch |
| 1 to 1¼ | 1½ | 2¾ | 8 inch |
| 1½ | 1½ | 2¾ | 10 inch |
| 2 | 2 | 3¾ | 12 inch |
| 2½ | 2½ | 4 | 14 inch |
| 3 | 2½ | 4 | 18 inch |
| 4 | 3 | 4½ | 24 inch |
| 5 | 3½ | 5 | 36 inch |
| 6 | 3½ | 5 | 48 inch |
Working out the exact length of pipe between two fittings prevents site errors and, in tight networks such as a plant room, cuts rework and wasted material. The dimension tables for each fitting give two basic dimensions: dimension A (centre to face) and dimension Z (the amount to be deducted from the pipe length).
The second method is to use the "make-up length", or C value. The C value is fixed for each diameter and equals the difference between A and Z. With this method you simply add the C value of each fitting to the distance between the faces of the two fittings (not between their centres).
| Nominal diameter (inch) | C (mm) | Nominal diameter (inch) | C (mm) |
|---|---|---|---|
| ¼ | 10 | 2 | 24 |
| ⅜ | 10 | 2½ | 27 |
| ½ | 13 | 3 | 30 |
| ¾ | 15 | 4 | 36 |
| 1 | 17 | 5 | 40 |
| 1¼ | 19 | 6 | 40 |
| 1½ | 19 | — | — |
Manufacturing dimensions of the fittings carry tolerances, and those tolerances apply to the make-up length calculation as well:
| Nominal diameter (mm) | Tolerance (mm) |
|---|---|
| Up to 30 | ± 1.5 |
| Over 30 to 50 | ± 2.0 |
| Over 50 to 75 | ± 2.5 |
| Over 75 to 100 | ± 3.0 |
| Over 100 to 150 | ± 3.5 |
A union seals on its seat, not on the thread, so its tightening torque matters directly. The first table below gives the minimum torque needed to seal a union with a brass seat or an iron seat; the second gives the tensile strength of the unions.
| Size (inch) | Minimum torque (N·m) |
|---|---|
| ⅛ and ⅜ | 65 |
| ½ to 1 | 125 |
| 1¼ and 1½ | 185 |
| 2 to 3 | 245 |
| 4 | 300 |
| 5 | 700 |
| 6 | 800 |
| Size (inch) | Tensile strength (kgf) | Size (inch) | Tensile strength (kgf) |
|---|---|---|---|
| ¼ | 1,723 | 2 | 13,603 |
| ⅜ | 2,406 | 2½ | 15,877 |
| ½ | 3,487 | 3 | 18,141 |
| ¾ | 4,802 | 4 | 22,678 |
| 1 | 7,026 | 5 | 28,347 |
| 1¼ | 9,657 | 6 | 35,434 |
| 1½ | 11,706 | — | — |
Much of the extra cost on site comes from not knowing the full range of fittings available; an assembly built from several pieces usually has a single-piece equivalent that is both cheaper and more reliable.
| Purpose | Recommended solution | Not recommended |
|---|---|---|
| Reducing the line diameter | Reducing socket (short pipe) | A socket combined with a reducing nipple |
| Return of flow (180°) | Return bend (180°) | Two elbows with a nipple between them |
| Return of flow with an offset | Long bend, F/F | A nipple with a threaded long bend |
| Branching a fire protection network | Fire protection tee | An ordinary tee with a reducing socket |
| Mixing hot and cold water | Side outlet elbow (angled branch) | 90° tee |
The deflection of the pipe between two supports is one of the main factors in the durability of a line. Excessive deflection loads the joints, causes leaks and downtime, creates undrainable liquid pockets and sets the line vibrating. The table below is for medium-class carbon steel pipe, threaded and socketed, in water and gas service in industrial areas.
| Pipe size (inch) | Spacing between supports (m) | Weight of water-filled pipe (kg/m) | Deflection (mm) |
|---|---|---|---|
| ¼ | 2.00 | 0.670 | 6.0 |
| ⅜ | 2.30 | 0.923 | 6.0 |
| ½ | 2.60 | 1.445 | 6.0 |
| ¾ | 3.00 | 1.985 | 8.0 |
| 1 | 3.50 | 2.993 | 8.0 |
| 1¼ | 3.80 | 4.145 | 8.0 |
| 1½ | 4.00 | 5.196 | 8.0 |
| 2 | 4.80 | 7.365 | 10.0 |
| 2½ | 5.00 | 10.218 | 10.0 |
| 3 | 5.50 | 13.368 | 10.0 |
| 4 | 6.50 | 20.166 | 10.0 |
Source: TUPY Brazil BSP fittings technical catalogue, pages 21 to 25.