What Is Equipment Reliability? (And How to Improve It)

In manufacturing, equipment breakdowns are costly. According to Forbes, manufacturers across the U.S. see 800 hours of equipment downtime annually. This equates to $50 billion every year, with 82 percent of failures occurring randomly. Ensuring high reliability in assets minimizes costly disruptions and improves overall efficiency.

Equipment reliability is a key performance indicator (KPI) that determines how reliable a piece of machinery consistently performs its intended function before failure or breakdown occurs. It can help indicate whether or not a piece of equipment requires more proactive maintenance or simply needs to be replaced. Let’s look at its components and how other maintenance metrics can help support it. 

3 Major Components of Equipment Reliability 

The following components of equipment reliability work together to minimize equipment downtime and optimize operational efficiency for continuous improvement.

• Availability: Availability determines the readiness of equipment to be operational and accessible when needed. High equipment availability equals minimal downtime and maximum productivity. Achieving it requires teams to practice robust strategies, including routine inspections, preventive maintenance, routine inspections and sometimes condition-based monitoring.
• Maintainability: Maintainability evaluates how easily and quickly an asset can be serviced or repaired. It takes aspects like equipment design, ease of access to components, availability of parts and the expertise of maintenance technicians into consideration. A structured maintenance program, proper training and a large spare parts inventory are all factors that help improve asset maintainability. As with availability, a high maintainability ensures less equipment downtime and production disruptions.
• Dependability: Dependability is a reflection of equipment performance and its ability to meet operational requirements under expected conditions. It incorporates design quality, proper operation and effective maintenance practices. As with the other components, a high dependability boosts productivity, safety and overall operations.

7 Metrics to Help Calculate Equipment Reliability 

By monitoring failure metrics, repair times and equipment effectiveness, companies can optimize maintenance practices, enhance operational efficiency and extend equipment lifespan. The following metrics will help you calculate and improve your equipment reliability program.

Mean Time Between Failure (MTBF) 

Mean Time Between Failure (MTBF) measures the average time between breakdowns of an asset or system. In other words, it measures the time an asset remains operational. To calculate MTBF, divide the total time of an asset’s operation by the number of failures that occur during that time. 

For example, a manufacturing plant’s conveyor system has a total operating time of 1,000 hours over a month and experiences five failures. To calculate MTBF, divide the total operating time (1,000 hours) by the number of failures (five), and you’ll get an MTBF of 200 hours. This is the approximate time an asset will operate before failure occurs.

Mean Time to Failure (MTTF) 

Mean Time to Failure (MTTF) is the average time an asset operates before it fails and needs replacement. This metric measures the asset’s lifespan and allows teams to anticipate when it might need replacement so that downtime can be lessened or avoided altogether. This calculation is for non-repairable equipment or equipment that will be used only once. 

To calculate an asset’s MTTF, divide its total operational time by its number of failures. For example, if a manufacturer’s conveyor system operates for 1,000 hours and experiences three failures, the MTTF is about 33.3 hours.

Mean Time to Repair (MTTR) 

Mean Time to Repair (MTTR) measures the time it takes to repair an asset or system after failure. It is calculated by dividing the total repair time for failures by the number of repairs during a specific period. 

To continue the example, the conveyor belt system experiences four failures over the course of a month. The total time spent on repairs for these failures is 12 hours. The MTTR for the conveyor belt system is three hours, meaning it takes three hours to repair the system after each failure.

Availability 

Availability measures the amount of time that an asset is operational and accessible when needed. This metric considers planned and unplanned downtime. To calculate an availability percentage, first divide the asset’s operating time by the total time available, and then multiply the result by 100.

For example, a conveyor belt system runs 1,000 hours and experiences 20 hours of downtime. Subtract the downtime from the total time available to get the operating time, which is 980 hours. Next, divide the operating time (980 hours) by the total time available (1,000 hours), and multiply the result by 100. According to this calculation, the conveyor belt system is available and operational 98 percent of the time with only 2 percent of downtime.

Planned Maintenance Percentage (PMP) 

This metric measures the maintenance time in planned maintenance tasks in comparison to total maintenance duties. PMP, like availability, is calculated as a percentage. Planned maintenance hours divided by total maintenance hours and then multiplied by 100 gives you the calculation. 

For example, a team performs 1,000 hours of maintenance on a conveyor belt system; of those hours, 900 are considered planned maintenance. Nine-hundred hours divided by 1,000 hours multiplied by 100 is 90 percent. This means that 90 percent of the maintenance time is planned. 

Overall Equipment Effectiveness (OEE)

OEE measures an asset’s planned production time, excluding planned downtime like breaks, changeovers or scheduled maintenance. This metric determines the asset’s productivity level and is used to better understand an asset’s daily operations and to help address any short-term inefficiencies. It is calculated as Performance multiplied by Quality multiplied by Availability (i.e., Availability = Actual Production Time divided by Scheduled Time).

An OEE score of 100 percent indicates perfect production, meaning an asset manufactures quality parts efficiently with no downtime. A score of 85 percent is considered “world-class” and is what many businesses strive to achieve. A 65 to 85 percent score is average and signals room for improvement. Anything less than 65 percent shows available capacities aren’t being used optimally, and there needs to be significant corrective actions taken to improve the maintenance process. 

Failure Modes & Effects Analysis (FMEA) 

Failure Mode and Effects Analysis (FMEA) measures possible failure modes (how operations can go wrong) and how equipment failure can impact a business’ assets and systems. FMEA prioritizes risks based on a few factors, including criticality, occurrence, likelihood and detectability. 

This metric allows businesses to execute corrective strategies before they become larger issues.

How to Improve Equipment Reliability 

Aside from the metrics mentioned here, you can take other measures to improve the reliability of equipment for your business. These include: 

• Purchasing quality equipment and parts: Well-designed parts and equipment made from quality materials reduce the likelihood of breakdowns and keep emergency maintenance costs at a minimum.
• Creating standardized repair processes: Coast’s app allows you to organize maintenance tasks and store detailed checklists and standard operating procedures within work orders to ensure consistency and accuracy during any project.
• Training equipment operators properly: Proper training for both those who operate the equipment and those who perform maintenance are critical to having reliable equipment. The quicker that maintenance team members can diagnose and resolve issues, the more your asset uptime will increase.
• Improved availability and accessibility of spare parts (better inventory): Ensuring critical parts are available for asset repair and maintenance prevents delays caused by inventory shortages.  
• Using preventive and predictive maintenance strategies: Regularly maintain assets to prevent failures using either preventive or predictive maintenance to detect issues before they become unexpected stoppages. 

Finally, implementing a computerized maintenance management system (CMMS) like Coast streamlines overall equipment maintenance planning. Our CMMS makes it easy for maintenance teams to centralize their data collection and to view maintenance tasks as they progress. Teams can communicate through the app in real-time, track work orders and schedule preventive maintenance to enhance equipment reliability, reduce costs and boost overall operations.