Chemical Technology February 2015

Equipment failure prevention needs defect elimination strategy by Mike Sondalini, Managing Director, Lifetime Reliability Solutions, Lean Manufacturing, Enterprise Asset Maintenance and Work Quality Management Consultant Services To reduce maintenance costs and

production downtime it is necessary to reduce their causes. Both are effects and not causes which can be traced back to defects and errors: defects lead to future equipment failures, production downtime and lost profits. Thus strategies prevent their occurrence and eliminate them if they do occur.

A ll equipment starts life new. It comes from the manufacturer fresh. If you do nothing about control- ling it, it also comes with future failures built into it. These future failures are the design errors, the materi- als selection errors, the fabrication errors, the assembly errors and any transportation damage. When installed, further causes of future failures arise from incorrect installation, incorrect site assembly, incorrect mount- ing practices, inadequate environmental protection and deficient foundations/supports. Some of these errors, along with commissioning errors and operating errors, cause failures early in the equipment’s operating life and explain early-life or ‘in- fant mortality’ failures. Those defects and errors that do not appear during equipment infant-life, will eventually surface and cause failures sometime later, during its operating life. The preferred terminology is to call the errors ‘defects’, because that is what you see as a consequence of the mistake. But the truth is that a wrong action (or no action) was taken at some point in time and as a consequence a defect resulted. Another truth is that most times, most things go right. Failure is not the normal situation. The problemwith failures is not the failure in itself. It is the consequences resulting

from them. When the consequences of failure are bad, you want to do everything possible to never again let them happen! Defect elimination is the answer Starting fromnew, a part properly built and installed, without any errors, will operate at a particular level of performance. If looked after properly it should, ideally, deliver its design requirements all its operating life. As its operating life progresses, any of those previously hidden manufacturer’s and installer’s errors noted above start to make their effects known. For some reason the equipment starts to fail. Failure causes can be introduced at any time. They can appear during operation frommanage- ment decision errors, operating errors, repair errors, abuse and even acts of Mother Nature. If you want superbly reliable equipment you must prevent the introduction of defects and errors at all stages of the equipment life cycle, and also act to remove the defects and errors already present in it. By getting rid of the defects that generate future failures, you will greatly reduce your future maintenance requirements, and hence guarantee great production performance. An average item of equipment has several dozen direct and consequential failure modes. The best maintenance

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Chemical Technology • February 2015