Dimensions of Non-Metallic Flat Gaskets ASME B16.21
to be used with Raised Face flanges ASME B16.5



 
CLASS 150 TO 900 NPS 1/2 TO 24
NPSd1d2
Class 150Class 300Class 400Class 600Class 900
1/2214854545464
3/4275767676770
1336773737379
427683838389
488695959598
260105111111111143
73124130130130.2165
389137149149149168
102162165162162...
4114175181178194206
5141197216213241248
6168222251248267289
8219279308305321359
10273340362359400435
12324410422419457498
14356451486483492521
16406514540537565575
18457549597594613638
20508606654648683699
24610718775768791838
NPSd1Class 150Class 300Class 400Class 600Class 900
d2
 

 

General notes:

  • Dimensions are in millimeters unless otherwise indicated.
  • d1 = Inside diameter.
  • d2 = Outside diameter.
  • Dimensional tolerances outside diameter NPS 12 and smaller: +0 / -1.5 mm.
  • Dimensional tolerances outside diameter NPS 14 and larger: +0 / -3.0 mm.
  • Dimensional tolerances inside diameter NPS 12 and smaller: ± 1.5 mm.
  • Dimensional tolerances inside diameter NPS 14 and larger: ± 3.0 mm.
  • Thickness (t) specified by customer.