Zero Likelihood Of Component Failure Delivers Zero Operational Risk to Plant and Equipment

Zero operational risk is an outcome that can be intentionally produced

The full risk equation informs us of the three factors we can use to produce zero operational risk


Slide 19 – Zero Operational Risk is Zero Consequences from Parts Failure, or Zero Opportunities to Fail Parts, or Perfect Reliability of Parts


The slide lists four equations related to operational risk. The top one is the standard operational risk equation where the financial consequence of an event is multiplied by the likelihood of the event. It is normally measured in money lost per year due to the event. Though it can be measured by any other period, and even by measures such as throughput, or number of items manufactured, et cetera. But that is not the complete risk equation to use when you want to create zero operational risk to your plant and equipment.

Likelihood consists of two factors: opportunity, and chance. The full risk equation consist of three factors: consequence, opportunity, and chance.

In the slide above, the full risk equation is the second one down. It reads, risk is equal to the TDAF consequences, multiplied by the frequency of the opportunity occurring, multiplied by the chance of failure at that opportunity. The acronym TDAF is Total Defect And Failure cost that results when the risk event actually occurs.

Risk is probabilistic. When an opportunity for a failure event arises, it either goes onto failure or it does not. The outcome is uncertain—we can’t know for sure what will happen until the situation turns either one way to cause a troublesome event, or the other way and is uneventful. The equation below is used to describe this probabilistic situation.

Chance of Failure = 1 – Chance of Success

The Chance of Success is Reliability. This turns the equation into the one below.

Chance of Failure = 1 – Reliability

In the full risk equation, we can now substitute Chance of Failure with (1 – Reliability). This gives the formula below for the full operational risk equation.

Operational Risk = Consequence x [Opportunity x (1 – Reliability)]

This operational risk formula connects reliability directly with the resulting risk. If you want zero operational risk it can be achieved by having zero consequences from failure, or by having zero opportunities to fail, or by having perfect reliability so there is no failure even if the event occurs. Perfect reliability has the probability value of 1. In the full risk equation, when reliability is perfect, 1 – 1 = 0, which proves 100% reliability delivers zero operational risk.

The full risk equation tells us the three options for zero operational risk. We can ensure that a failure event produces no adverse consequences. We can ensure that there is no opportunity for the failure event to arise. We can ensure absolute reliability even if the failure event occurs.

Five examples of opportunities to fail are shown along the bottom of the above slide. Lubricant contaminated with wear particles means every wear particle is an opportunity to fail. On top of the sump plug are tens of thousands of wear particles. Each one can cause a failure.

A distorted and deformed pump-set causes shafts in the motor and pump to bow, bend and be misaligned. The roller bearings in the motor and pump are sure to fail early in their working lives. So, to will the pump shaft seal.

Over-tensioning in fasteners induce high stresses even before the equipment is in service. When the fluctuating equipment service forces add to the over-tension stresses, fasteners snap unexpectedly.

Running parts require the correct fit and tolerance between them at their operating temperature. If parts become oversized they are forced together and get damaged. If the parts are undersized they rattle against each other and again get damaged.

Unbalanced rotors weigh more on one side of centre-of-rotation. It causes off-centre loads to be forced against the bearing and into the equipment structure. Parts get thumped around, they become overloaded and get overstressed and so are failed earlier.

Those five opportunities to fail machinery are just a few from the many opportunities that could cause a failure event. The Plant Wellness Way EAM reliability-creation philosophy is to prevent all opportunities that might go to failure from arising.

In Plant Wellness Way EAM everything humanly possible is done throughout the life-cycle to create zero operational risk by eliminating consequences of parts failure, removing opportunities for a part to fail, and by maximising component reliability so if unfavourable events occur they do not fail the part.


This slide is a companion to the new Industrial and Manufacturing Wellness book. The book has extensive information, all the necessary templates, and useful examples of how to design and build your own Plant Wellness Way enterprise asset life cycle management system-of-reliability. Get the book from its publisher, Industrial Press, and Amazon Books.

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