ISO 9001:2015IBR ApprovedEstablished 1971Full Material Traceability
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ASME B16.21GasketsTG-DS-024 · Rev. 0 · October 2026

ASME B16.21 Non-Metallic Flat Gasket Dimensions

Dimensions of ASME B16.21 non-metallic flat ring gaskets for ASME B16.5 raised-face flanges in millimetres: inside diameter and outside diameter for Class 150, 300 and 600.

Ring gaskets sit inside the bolt circle and are cut from compressed non-asbestos fibre, graphite, PTFE or rubber sheet.

Download PDF Request a quoteA4 · Teshi Group document TG-DS-024 · © Teshi Group · controlled document
Flat ring gasket drawing showing inside and outside diameterIDODFlat ring gasket (not to scale)
Flat ring gasket.

ASME B16.21 Non-Metallic Flat Gasket dimensions — tables

Flat ring gaskets for raised-face flanges (mm)

Flat ring gaskets for raised-face flanges (mm)
NPSinIDInside diaODClass 150ODClass 300ODClass 600
½"21485454
¾"27576767
1"33677373
1¼"42768383
1½"48869595
2"60105111111
2½"73124130130
3"89137149149
3½"102162165162
4"114175181194
5"141197216241
6"168222251267
8"219279308321
10"273340362400
12"324410422457
14"356451486492
16"406514540565
18"457549597613
20"508606654683
24"610718775791

Notes

  • Dimensions are in millimetres unless stated otherwise.
  • Values are rounded to the nearest millimetre; some published tables differ by 1 mm.

Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.

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