A fundamental component of your reliability programme is a well-structured equipment inspection process. If good design standards (such as the use of mesh safety screens for belts and couplings) have been followed during the construction of your plant, many inspections will be possible during normal plant operation.
A few things to consider when developing your inspection routes.
- Make sure that the scope and frequency of inspections are based on sound reliability principles. The time between inspections for any mode of failure should be about one half of the failure development period (FDP). FDP is the operating or elapsed time from when a failure first becomes apparent when using the inspection technique specified on the route sheet to the time that the equipment will fail to function.
- The route sheet should list all the equipment that is to be inspected in the most logical order, taking into account walking distance, stairs, ladders, etc.
- The time to complete the route should be about the normal time between work breaks. Avoid very long route sheets because the probability of being interrupted is increased.
- Show the estimated time to carry out all the inspections listed, and also show the allowance for making small repairs and adjustments and for self-planning of the repairs required for discovered problems. For example of self-planning, if a gasket is found to be leaking and can not be resolved by tightening the flange bolts, don’t just report the leak, add useful planning information such as “Requires a 6″ 150# Metalflex gasket and 8 4-1/2″ 1/2″ bolts with nuts. Needs the building HVAC system isolated for access”.
- Include a list of tools required for the route – infra-red thermometers, stroboscopes, etc.
- Provide a suitable tool and instrument carrying device – a surveyor’s vest or small tool cart, depending on the quantity and type of tools and instruments required to perform the inspections on the route sheet and to carry out simple adjustments and repairs.
- Make it easy for the inspector to find out if a found problem already has a repair work order in the system.
- Keep the inspection route sheet short and compact by using standards. For example, for a typical process pump with a mechanical seal, the instruction to the inspector could state “Use inspection standard M123, pump with mech seal”. This standard should be used in training and should be easily accessible, but an experienced inspector does not need this detail. Important information unique to the equipment such as important flows and pressures, with acceptable ranges, should be included on the sheet.
- Report problems by exception only, on a separate sheet if paper route sheets are being used. Don’t make it necessary for someone to go through all the completed sheets to find the reported problems.
- When training the inspectors, encourage them to look beyond the equipment on the route sheet. For example, include a bright spotlight in their inspection kit and have them use it to look around at each station for problems such as broken pipe and cable tray hangers, corroded service piping, damaged equipment bases and any other threats to reliability.
- Encourage continuous improvements to inspection route sheets by increasing or decreasing frequencies based on experience, revising the scope and improving inspection techniques.
- Use the best technology available to minimize administrative effort.
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© Veleda Services Ltd
Don Armstrong, P.Eng, President
250-655-8267 Pacific Time