Bolt Tightening Procedure

 
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Torque Procedure

Related

Number the flange bolts to tighten in the correct pattern
Flange tightening
Flange tightening
Flange tightening

Start the tightening procedure by lubricating the nuts and bolts. Then hand tighten till they are snug against the flanges. If an air wrench is used make sure the pressure is set to the minimum. When tightening, always use the correct sequential bolt order for the flange.

4 and 8 Bolt Flanges

  • First round - 30% of final torque (flange sequential order)
  • Second round- 60% of final torque (flange sequential order)
  • Third round - 100% of final torque (flange sequential order)
  • One final time - clockwise or counter clockwise sequentially around the flange.

12 Bolt Flanges and More

  • First round - 20% of final torque (flange sequential order)
  • Second round - 40% of final torque (flange sequential order)
  • Third round - 80% of final torque (flange sequential order)
  • Fourth round - 100% of final torque (sequential order)
  • One final time - clockwise or counter clockwise sequentially around the flange.

Torque Factor

Pipe Size

(NPS)

150#

(ft-lbs)

300#

(ft-lbs)

400#

(ft-lbs)

600#

(ft-lbs)

900#

(ft-lbs)

1500#

(ft-lbs)

2500#

(ft-lbs)

1/2 45 45 45 45 150 150
3/4 45 90 90 90 150 150
1 45 90 90 90 240 240
1 1/4
1 1/2 45 150 150 150 368 368
2 90 90 90 90 240 240
2 1/2 90 150 150 150 368 368
3 90 150 150 150 240 533
3 1/2
4 90 150 240 240 533 750
5 150 150 240 368 750 1200
6 150 150 240 368 533 1020
8 150 240 368 533 1020 1650
10 240 368 533 750 1020 3000
12 240 533 750 750 1020 3300
14 368 533 750 1020 1020 4770 -
16 368 750 1020 1020 1650 6600 -
18 533 750 1020 1650 3000 8800 -
20 533 750 1200 1650 3300 11580 -
22 -
24 750 1200 2250 3000 6600 -

4 Bolt Tightening Sequence

  • Sequential Order: 1-2, 3-4
  • Rotation Order: 1, 3, 2, 4
4 Bolt Flange

8 Bolt Tightening Sequence

  • Sequential Order: 1-2, 3-4, 5-6, 7-8
  • Rotation Order: 1, 5, 3, 7, 2, 6, 4, 8
8 Bolt Flange

12 Bolt Tightening Sequence

  • Sequential Order: 1-2, 3-4, 5-6, 7-8, 9-10, 11-12
  • Rotation Order: 1, 5, 9, 3, 7, 11, 2, 6, 10, 4, 8, 12
12 Bolt Flange

16 Bolt Tightening Sequence

  • Sequential Order: 1-2, 3-4, 5-6, 7-8, 9-10, 11-12, 13-14, 15-16
  • Rotation Order: 1, 9, 5, 13, 3, 11, 7, 15, 2, 10, 6, 14, 4, 12, 8, 16
16 Bolt Flange

20 Bolt Tightening Sequence

  • Sequential Order: 1-2, 3-4, 5-6, 7-8, 9-10, 11-12, 13-14, 15-16, 17-18, 19-20
  • Rotation Order: 1, 9, 5, 13, 3, 11, 7, 15, 2, 10, 6, 14, 4, 12, 8, 16
20 Bolt Flange

24 Bolt Tightening Sequence

  • Sequential Order: 1-2, 3-4, 5-6, 7-8, 9-10, 11-12, 13-14, 15-16, 17-18, 19-20, 21-22, 23-24
  • Rotation Order: 1, 9, 17, 5, 13, 21, 3, 11, 19, 7, 15, 23, 2, 10, 18, 6, 14, 22, 20, 8, 16, 24
24 Bolt Flange


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