Design for Inspection

A document is needed that addresses how to design equipment so that it can be inspected both during manufacture and after it has been in service. The current situation is that some equipment gets built and delivered that is either very difficult to inspect or that is not inspectable at all. Since most equipment used in the CPI requires routine, scheduled inspection, ownership of equipment that is difficult or impossible to inspect and certify for continued use is expensive to own since the inspection may call for the equipment to be cut apart, inspected, re-welded, and tested before it can be returned to service. Some examples where proper Design for Inspection will aid in making equipment inspectable are: 1) Use of open-ended pipe extensions welded to elbows where corrosion of the extrados on the elbow is hidden from view. 2) Routing of piping to eliminate expansion joints. 3) Correct installation of expansion joints. 4) Use of re-pads where detailed inspection of the welds at nozzles are required. 5) Longitudinal and transverse welds hidden under re-pads and saddles. 6) Skip welding of tray support rings and similar internal components welded to the pressure shell. 7) Construction of equipment that requires cutting to remove internals to allow for inspection of the pressure shell - e.g. deaerators. 8) Construction of tall equipment without access to critical welds/nozzles unless expensive scaffolding is erected. 9) Manways installed inside skirts where spillage of products upon opening will occur. 10) Design of column trays to allow easy removal of manways which will allow for rapid internal inspection. 11) Foundation design for flat bottom storage tanks that prevents water collection under the floor. 12) Dike design for storage tank areas to keep tank floors dry so that inspection can be delayed or eliminated. 13) Frangible roof to shell designs on API storage tanks to minimize crevices. 14) Orientation of PSV nozzles to minimize thrust on foundations. 15) Design that allows for inspection and replacement of anchor bolts. 16) Access for inspection under insulation. There are many more areas where identification of design details and the use of optimum construction methods will add value to equipment by making inspection possible, efficient, and less expensive. The premise for this project is that MTI will get a handbook that enumerates or lists these design "tricks" and options so that they can be used by member companies to help in writing their design standards. The goal is to have standards that incorporate these design details so that member companies can maximize the value that they get in purchased equipment. To make this happen, we will need to contract with a knowledgeable piping and vessel designer and have input from members.