A spectacle blind – also known as a figure-8 blind – is generally a piece of metal that is cut to fit between two pipe flanges and usually sandwiched between two gaskets. A spectacle blind is often made from two metal discs that are attached to each other by a small section of steel.
The whole idea of a spectacle blind is so that one can be absolutely sure that an item of equipment is properly and securely blanked off with no possibility of any flow or leakage through a valve during maintenance. The flow can be diverted to other items of equipment but not just bypassed around the blank as this would compromise the safety function of the spectacle blind. The flow has to valved off and pressure relieved prior to loosening flange bolts and swinging the blind.
All Dims Per ASME B16.48
- For use with Flat or Raised Face Flanges
- Specify Surface in Microinch ASA 500, 250, 125, 63 or 32. If Not Specified Mill Finish Supplied.
- Available with Phonographic Serrated Surface or Ground Finish. Available with Ring Type Joint
- Normally Supplied in A285 Gr. C, A515 Gr 70, A516 Gr. 70, 304SS, 316SS. Other Materials Available