Blind flange design modification


  • Blind flange located between a pump discharge manifold and a 16" valve.


  • The existing blind is bolted up through both flanges and is 57mm thick, as required by the standard for the current duty
  • Present maintenance practice is to remove the valve and then fit a blank to the discharge pump flange. As this is only bolted to the discharge pump the standard requires a thickness of 76mm
  • Proposed new procedure is to use the 57mm blind flange as a blank. Urgent response required prior to implementation of procedure


  • To determine whether the current 57mm blind flange could be used as a blank that will safely sustain the current operating pressure


  • Inverse design calculations show that the minimum blank thickness would need to be 65mm, using the material of the current blind


  • Current 57mm blind flange not suitable as a blank
  • Possible design of 57mm blank using alternative material identified


  • Client provided with information to make correct decision not to use 57mm blank
  • Current practice of valve removal continued in a safe manner

Plant Integrity