WHY BOLT TORQUING TIGHTENING SEQUENCE MATTERS? WHY SEQUENCE IS IMPORTANT?

#BOLTORQUING, #BOLT TIGHTENING,
BOLT TIGHTENING Sequence: Why it Matters??
There are many different things that determine whether a new flange connection will be secure and leak-free. One of the most important is the bolt tightening sequence.
To a new bolting apprentice, this may seem straightforward enough. But simply applying full torque to your first bolt and then moving onto the adjacent one is the wrong approach! The order in which you tighten the bolts and the load applied has a huge effect on the integrity of the joint.
To complete a flange joint securely, it is essential to control the stress variation in the flange joint components. In the case of the gasket, this needs to be compressed evenly across the flange face. If you were to tighten adjacent bolts when those opposite remain loose the result will be uneven compression and possible damage to the gasket.
The flanges must be brought together slowly and be parallel. In practice, this means starting by using the correct bolt tightening pattern at partial load, and then carrying out several more bolt passes, increasing the load each time.
The ASME (American Society of Mechanical Engineers) PCC-1-2019 standard is the ‘go-to’ document for bolting standards. This gives multiple options for tightening sequences which if followed correctly will help to ensure a leak free flange joint. Showing all patterns for each flange size could be covered in great detail in a separate article. But to act as an overview, some examples are as described below.
Legacy Pattern and Modified Legacy Bolting Patterns
Before they are tightened, bolts can be numbered sequentially (1,2,3,4 etc) in a clockwise direction around the flange (fig 1 below). Or they can be numbered by the order of tightening (fig 2 below). Both methods have their advantages - but it is important that the one chosen is agreed in pre-job briefs and that the tightening crews are suitably trained.

[@naveenvikrampmp7808]

Great sir I am waiting for your video reg painting and Coating systems like HSS, Stopaq, 2LFBE

[@OilandGas-inspection-soumen]

I will do for sure, Busy with work schedule, I want to make it in better way and with proper video. thanks for your interest.

[@Koliha74]

Must follow..or only guideline....

[@OilandGas-inspection-soumen]

You must follow one of the method from Pcc-1 or need to follow the client standard whatever applicable for you- following right sequence and right torque value will ensure that the joint will not leak