Item:

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

Problem:

• 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

Objective:

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

Approach:

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

Results:

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

Benefits:

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