Dimensions Spectacle Blinds - ASME B16.48
Spectacle Blinds
General notes:
  • Dimensions are in millimeters unless otherwise indicated.
  • D = Hole size (where required) should be the same as the flange bolt hole. In practice, these dimensions have been rounded round off upwards.
  • Wt = Thickness of the web (or tie bar) should be 6 mm minimum, or equal to Thickness (t) if less than 6 mm.
  • Spectacle Blinds should be made from a plate or forging specification, approved for use by ASME B31.3, of essentially the same chemical composition as the mating flanges and piping involved.
  • Spectacle Blinds according to ASME B16.48 may be used for installation between ASME B16.5 flanges
  • Depending on a customer specification, some dimensions can be different from what on this page is defined.

Remark(s) of the Author...

Spectacle Blind with Raised Face

Raised Face Joint Blanks

  • ASME B16.48 says: The gasket seating surface finish and dimensions for raised face line blanks shall be in accordance with ASME B16.5. A raised face may be specified at the option of the purchaser.
  • A Raised Face would add machining time and complexity so the price would be higher. Call this the Bugatti or Rolls Royce of the line blind world.
  • Personally, I have seen that version once or twice somewhere. The version without Raised Face is the default and is used everywhere.