Availability ≠ Maintenance ≠ Reliability

Source: H. Paul Barringer-2008
*Profit-Ability, LLC views are consistent with H. Paul Barringer and the following content is a derivative of his work.

It is common for availability, maintenance and reliability to be discussed interchangeably across industry. In this article, we will share our opinion using simple definitions to explain why they are not the same. We will also dive into deeper dialog to clarify the level of reliability you are seeking when you consider starting a reliability improvement approach. Management must shift from time and maintenance driven paradigms and focus on business reliability efforts with relentless focus for ALL failure elimination and waste reduction to maximize earnings. This allows for characterization for overall ROI.

Business Case for Change

Firstly, Availability will focus on time utilization.

Secondly, Maintenance will focus on repairs.

Lastly, Reliability will focus on failure elimination.

Here are some common facts about Reliability:

• Failures of equipment and processes can vastly jeopardize business profits due to
unreliability problems.
• Unreliability is the costly part of the business economic equation.
• The business issue of unreliability is control and prevention of failures to reduce costs
and improve operations by enhancing business performance with affordable levels of
• Reliability numbers by themselves will not motivate improvements.
• Utilizing actual plant data for costs and failures, monetizing unreliability will cause
reliability numbers to spring into life and justify actions for making cost effective changes.

Next, let’s discuss some of the many definitions for Reliability:

  • As a general sense, reliability is the ability of an item to perform a required function under stated conditions for a stated period of time.
  • As a characteristic, reliability denotes the probability of success or the success ratio.
  • As a measure of quality, reliability exists by design as an objective or a requirement of a product from its inception to the end of its working life.
  • As a probabilistic statement, reliability is concerned with the probability of future events based on past observations.
  • As a basic concept, reliability is durable and high probability of failure-free performance under stated conditions including all item life units, not just mission time and all failure with the item, not just mission critical failures at the time level of assembly.
  • As an overall concept, reliability is a special development of engineering industries for the collective measures of quality that reflect the effect of time in storage or time in use of a product. The concept is distinct from measures that show the state of the product at time of delivery.
  • As a business concept, reliability is concerned with a balanced integration of strategies for procurement, installation and start-up, equipment/process operations, maintenance, and reliability which avoid failures and maintenance interventions by focusing on the long term cost of ownership in financial terms to avoid waste and optimize facility capability. The net result is improved BUSINESS PROFITABILITY & SUSTAINABILITY.

The simplest reliability definition to use is the characteristic. Most I’ve heard relate with basic. The most productive reliability definition relates to the business concept and the natural connection for business leaders.

What is your value concept for reliability?