Products | Asbestos | CAF Gaskets
 
 
 
     
 
GASKET ASSEMBLY GUILDELINES - FOR GETTING THE MOST :
 
 
FLANGES should be even and parallel and also sufficiently rigid not to be distorted by the bolt load.
 
 
FLANGE FINISH is important. Concentric groove finish is ideal for high pressure. Spiral (gramophone) groove finish give a continuous path for leakage and is not recommended for gases. For flanges with flat surface a finish equivalent to is considered best.
 
 

BOLTS should be tightened with a torque spanner, working at diametrically opposite nuts alternately. First turn all bolts to about half the recommended torque, then follow up to full assembly torque. It is important to follow up the bolts about 4 hours later or 1 hour after the gasket reaches its working temperature.

 
 

PIPELINES undergo longitudinal thermal expansion which generates forces that can crush the gasket. On the other hand, contraction of pipelines can reduce teh gasket surface stress below the minimum required for sealing, Pipe expansions and contractions must therefore be compensated by suitably selecting the gasket material and its thickness.

 
 
Flat Sheet Gaskets - Dimensional Data
 
 
Flat Ring Gasket to ASME B16.21
 
  To Suit ASME / ANSI B16.5 & BS 1560 Flangers  
     
   
     
 
NOMINAL PIPE SIZE INSIDE DIAMETER
OUTSIDE DIAMETER
mm mm mm mm mm mm mm
% 21.4 47.6 54.0 54.0 54.0 63.5 63.5
3/4 27.0 57.2 66.7 66.7 66.7 69.9 69.9
1 33.3 66.7 73.0 730 73.0 79.4 79.4
11/4 42.1 76.2 82.6 82.6 82.6 88.9 88.9
Vh 48.4 85.7 95.3 95.3 95.3 98.4 98.4
2 60.3 104.8 111.1 111.1 111.1 142.9 142.9
2Vz 73.0 123.8 130.2 130.2 130.2 165.1 165.1
3 88.9 136.5 149.2 149.2 149.2 168.3 174.6
31/2 101.6 161.9 165.1 161.9 161.9 - -
4 114.3 174.6 181.0 177.8 193.7 206.4 209.6
5 141.3 196.9 215.9 212.7 241.3 247.7 254.0
6 168.3 222.3 250.8 247.7 266.7 288.9 282.6
8 219.1 279.4 308.0 304.8 320.7 358.8 352.4
10 273.1 339.7 361.9 358.8 400.0 435.0 435.0
12 323.9 409.6 422.3 419.1 457.2 498.5 520.7
14 355.6 450.8 485.8 482.6 492.1 520.7 577.8
16 406.4 514.3 539.7 536.6 565.1 574.7 641.3
18 457.2 549.3 596.9 593.7 612.8 638.2 704.8
20 508.0 606.4 654.0 647.7 682.6 698.5 755.6
24 609.6 717.5 774.7 768.3 790.6 838.2 901.7
 
     
  *Class 1500 rating is no longer specified in ASME B16.21  
  *Gaskets also available in higher Nominal Bore