PCC-1 Flanges Too Tight?
PCC-1 Flanges Too Tight?
(OP)
We have recently adopted PCC-1 torque figures for bolting B16.5 flanges.
Feedback from the technicians is that the gaskets are now being found with the spiral windings crushed into the pipe bore and the outer rings are tending to cup.
We use Flexitallic spiral wound gaskets with 'flexicarb' filler.
Has anyone else had this problem?
Feedback from the technicians is that the gaskets are now being found with the spiral windings crushed into the pipe bore and the outer rings are tending to cup.
We use Flexitallic spiral wound gaskets with 'flexicarb' filler.
Has anyone else had this problem?





RE: PCC-1 Flanges Too Tight?
Do you use inner ring with your spiral wound gasket?
RE: PCC-1 Flanges Too Tight?
RE: PCC-1 Flanges Too Tight?
RE: PCC-1 Flanges Too Tight?
This statement isn't correct as the spirals create the sealing surface of the gasket. One ring or two the required seating stress is the same. These ring are only for location of the spirals.
RE: PCC-1 Flanges Too Tight?
RE: PCC-1 Flanges Too Tight?
Graphite filler is fairly compressible; however, once it reaches its full compressive state, it causes the spiral wound to buckle inwards.
There are spiral wound gaskets on the market that eliminate inward radial buckling by allowing this buckling phenomenon to occur to the OD of the gasket and not into the pipe stream.
RE: PCC-1 Flanges Too Tight?
GasketBob's comment regarding the stiffness of inner ring spiral wound gaskets is 100% correct. Inner ring spiral wound gaskets require significantly higher bolt loads to compress as the spiral windings are no longer free to deform towards the ID- thus they are also less prone to buckling.
Anti-buckling spiral wound gaskets are indeed a good solution for eliminating buckling WITHOUT the added cost and bolt load penalty of inner rings. Two companies manufacture anti-buckling spiral wound gaskets- Garlock and Teadit.
RE: PCC-1 Flanges Too Tight?