Niagara 6600 Series, Installation, Operation & Maintenance Manual

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NIAGARA Installation, Operation & Maintenance Manual M600
Rev. E 20
Bolt Tightening Sequence
Do not completely torque one side and then the other. Alternate tightening on up and down stream flanges.
Bolts should be tightened in the correct sequence and repeated several times to ensure that the specified bolt
torques are achieved as shown. It must be noted on flange joints that some relaxation will be experienced and it
should be ascertained that the bolt torques required to effect a seal at the appropriate pressure, as shown in the
charts, are effective at the time of pressure testing. Bolt torques do not have to be restricted to those applicable to a
specific test pressure and higher torques can be applied up to the maximum rated test pressure for the appropriate
flange.
Notes: Use only undamaged rust free bolts.
Lubricate bolt threads and all mating surfaces of nuts and washers.
Tighten bolts in the sequence shown until torque is achieved.
Check, and if necessary, retighten bolts immediately before pressure testing.
For sizes having 12 bolts or more it is recommended that two joiners work simultaneously on diametrically opposite
bolts. Each joiner tightens the first nut in the first quadrant, then the first nut in the second quadrant, returns to the
second nut in the first quadrant and so on.
1
2
4
3
4 Bolts
1
2
4
3
5
7
6
8
8 Bolts
1
1
1 1
2
2
2
2
3
3
3
3
1
2 1
2
First Quadrant
Second Quadrant
First Quadrant
Second Quadrant
12 Bolts or M ore
1
2
4
3
4 Bolts
1
2
4 3
5
7
6
8
8 Bolts
1
1
1 1
2
2
2
2
3
3
3
3
1
2 1
2
First Quadrant
Second Quadrant
First Quadrant
Second Quadrant
12 Bolts or M ore