Every plant contends with troublesome maintenance problems that consume valuable plant resources and contribute to seemingly random failures. But, by being preoccupied with these failures and establishing a prevention mindset, defect elimination can have a profound impact on your plant’s reliability and performance.
In the 1990s, Winston Ledet’s research found that reactive manufacturing plants typically achieved uptimes of around 83.5%. He also found that the best-performing sites achieved uptimes in excess of 98% by focusing on three things:
The table below summarizes his findings.
To our detriment, these results aren’t widely known, and what’s worse, they’re often misunderstood and dismissed.
The biggest discovery was the impact of defect elimination. DE reduces failures and increases uptime by fixing something forever, rather than forever fixing it. Because of DE’s large impact on uptime, it reveals that our plants are full of failure-causing defects.
We introduce defects at every stage of our plant’s life cycle – during the design, construction, and commissioning of our plants, and during the operation and maintenance phases. If these defects aren’t tackled, they eventually lead to failure.
Maintenance doesn’t address defects, and good maintenance only helps achieve your plant’s inherent reliability. You need a DE program to remove defects and achieve high reliability to find the forever fix.
According to Ledet, defects are “anything that erodes value, reduces production, compromises HSE (health, safety, and environment), or creates waste.”
Defects aren’t just physical problems or equipment failures; defects can also come from:
Let’s look at the three main sources of defects.
You may recognize “The ABCs of Failure” from Ledet’s works, such as his book Don’t Just Fix It, Improve It.
What Ledet’s research tells us is that all failures can be traced back to defects. Defects are the basic cause of failures, and Ledet classifies them into three categories: A, B and C.
A – Aging
Generating about 4% of defects that become failures over long periods (25-50 years), aging is the easiest to identify in your plant’s structure and infrastructure (i.e., steel and concrete) and non-operational equipment.
B – Basic Wear and Tear
Affecting equipment in operation, basic wear and tear generates about 12% of all defects and can cause failures in a short period of time (one month to seven years). These defects are easiest to observe in critical equipment; this equipment usually has longer mean times between repairs and is well-monitored and cared for.
C – Careless Work Habits
Careless work habits contribute the remaining 84% of defects, which often become failures over random periods of time.
By “careless,” Ledet means “not providing the care” that the equipment needs to run perfectly.
Examples of careless work habits include:
Instead of focusing on improving work habits and removing defects, most organizations waste time and energy trying to prioritize a long list of failures to repair – failures that shouldn’t have happened in the first place.
Too often, we simply fix the issue and move on rather than ensure it never happens again. We end up forever fixing, rather than fixing forever.
We know we need defect elimination, but why bother with a structured approach? Because without it, we don’t perform DE well enough. It’s that simple.
Common problems that occur without a structured approach include:
It’s easy to look at a problem in terms of its symptoms, but we must remember that the problem’s framework influences the solution.
Is the problem…
…the compressor is vibrating.
… the compressor is vibrating above its trip point, resulting in a machine shutdown and plant upset.
… the compressor has experienced three unplanned downtime events over the last two months resulting in a 5% production loss.
When a problem arises, our natural tendency is to jump to a solution, but we must understand the full problem first.
The maintenance and reliability fields are filled with technical people who like technical solutions. But, evidence shows that at least 50% of failures have human-related causes, such as:
It’s important that we consider the human elements that contribute to failure.
To truly eliminate a defect forever, we must get down to a systemic level. That means we need to understand if there’s a current or underlying system or process within our control that keeps causing an issue.
How deep you go will vary from issue to issue, but the goal will remain the same; we want to ensure a particular defect is permanently eliminated. We can’t just address symptoms and expect our problems to go away.
Without a structured approach, people tend to jump to conclusions.
This can cause several issues:
Simple problems can often be solved with an unstructured approach, but complex problems require a structured approach.
A structured approach allows us to analyze what we’ve observed and clearly define the problem. This is important because it’s often difficult to differentiate between cause and effect.
Don’t eliminate the symptoms – go after the defect that produces the symptoms!
While they both prevent problems from reoccurring, root cause analysis (RCA) focuses on removing the big-ticket items and dealing with bad actors. In a sense, it focuses on the 20% of issues that cause 80% of breakdowns, downtime, corrective maintenance, and repair costs.
But you also need a process for eliminating the smaller, troublesome things; this is where defect elimination comes in. DE empowers your frontline and wider support teams to independently tackle the small issues that cause failures.
When done well, DE drives you towards a reliability culture by engaging a large part of your organization in reliability. Just like safety, reliability is everybody’s responsibility.
Defect elimination stops small, repetitive reactive work from happening again. But for DE to work, you need a structured process that encourages employees to find and remove the source of defects.
An effective DE process will include:
If you’re still unsure of where to start, try implementing Ledet’s “1% Rule,” which proved that turning one out of every 100 work orders into a DE order can reduce total work order counts by nearly 38% over three years.
To successfully start and sustain a DE program, an organization needs everyone’s buy-in, from the C-suite to the frontline maintenance technicians and everyone in between.
Much like safety and reliability, DE is everyone’s responsibility. A culture that supports defect elimination also supports defect prevention and encourages all employees to consider where and how defects are introduced throughout the equipment’s life cycle. This ultimately gives frontline workers the authority and confidence to tackle the small issues that matter not only to them but to the company’s bottom line.
Defect elimination is more than a fancy phrase or strategy of the month. It’s a structured approach to identifying the root cause of troublesome problems that consume valuable plant resources and contribute to seemingly random failures.
Effective defect elimination requires a preoccupation with failures and a prevention mindset. When used in concert with preventive and predictive maintenance, defect elimination can have a profound impact on your plant’s reliability and performance.