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Installation and Site Guide for TUPY Brazil Threaded Fittings

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.

Correct wrench tightening for BSP fittings

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 ¾6 inch
1 to 1¼8 inch
10 inch
2212 inch
414 inch
3418 inch
4324 inch
5536 inch
6548 inch
Tightening past the permitted maximum sets up high hoop stress in the body and can crack the fitting. Using a wrench longer than the recommended length carries the same risk.

Make-up length: dimension Z and the C values

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)
¼10224
1027
½13330
¾15436
117540
19640
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

Union tightening torque and tensile strength

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 ⅜65
½ to 1125
1¼ and 1½185
2 to 3245
4300
5700
6800
Size (inch)Tensile strength (kgf)Size (inch)Tensile strength (kgf)
¼1,723213,603
2,40615,877
½3,487318,141
¾4,802422,678
17,026528,347
9,657635,434
11,706
The tensile strength values are the same for unions with a brass seat, an iron seat and a flat seat.

Installation examples: recommended and not recommended

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.

PurposeRecommended solutionNot recommended
Reducing the line diameterReducing 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 offsetLong bend, F/FA nipple with a threaded long bend
Branching a fire protection networkFire protection teeAn ordinary tee with a reducing socket
Mixing hot and cold waterSide outlet elbow (angled branch)90° tee
In particular cases, assemblies that look wrong at first glance — such as using a reducing socket — are acceptable, because manufacturing a special fitting for rare cases is not commercially practical.

Supports and permitted spacing between hangers

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)
¼2.000.6706.0
2.300.9236.0
½2.601.4456.0
¾3.001.9858.0
13.502.9938.0
3.804.1458.0
4.005.1968.0
24.807.36510.0
5.0010.21810.0
35.5013.36810.0
46.5020.16610.0
Outside industrial areas a deflection of up to 25 mm is also acceptable. Valves, gate valves and other heavy components should sit close to a support so the load is spread evenly.

Eleven recommendations for pipework design

  1. Design for temperature, pressure, type of fluid, corrosion, water hammer and fatigue together.
  2. Set the height of the line according to the order of heights of the equipment it has to pass.
  3. Fix the correct spacing between supports and hangers from the outset.
  4. Give priority to the position of branches, valves and air vents.
  5. Never leave out unions and valves; they are essential for maintenance and for isolating the line.
  6. Give the assembly enough flexibility to absorb the stresses of thermal expansion.
  7. Where friction is high, use roller supports.
  8. Control vibration with expansion joints and shock arrestors.
  9. Follow the site procedures that keep the line in alignment.
  10. Set the correct depth for buried pipework, allowing for the weight of soil and asphalt and for vehicle traffic.
  11. Carry out the final assembly carefully and without applying excess force.

Source: TUPY Brazil BSP fittings technical catalogue, pages 21 to 25.

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