Mean Time Between Failures MTBF

MTBF is also used as a measure of performance, availability and reliability of systems, and to help with scheduling maintenance, inventory planning and system design. The MTBF value can be used as a system reliability parameter or to compare different systems or designs. This value should only be understood conditionally as the “mean lifetime” , and not as a quantitative identity between working and failed units.

definition of mean time between failures

It can also be used in calculations of operational efficiency and performance and used to identify ways to decrease costs and increase output and profits. These figures are often provided in the instruction manuals for equipment, to give owners, operators and technicians a rough measure of the reliability of the machine. For component or system manufacturers, testing of samples can be done to create an estimate of MTBF for the given asset. Availability is related to reliability and is a measure of how much of the time a system is performing correctly, when it needs to be. MTBF can be used with Mean Time to Repair to calculate availability for a system.

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The MTBF is typically part of a model that assumes the failed system is immediately repaired , as a part of a renewal process. This is in contrast to the mean time to failure , which measures average time to failures with the modeling assumption that the failed system is not repaired . Mean time between failures is a measure of an asset’s reliability. It shows you how long, on average, an asset can run before you need to repair it. On a basic level, you can use MTBF as a maintenance metric to see how well your team maintains assets. Calculating mean time between failures is one way to start conquering unplanned downtime at your facility.

definition of mean time between failures

As a statistic, it’s also important to collect enough data to ensure the accuracy of the calculation, as short time periods or few failures may lead to distorted and inaccurate MTBF figures. Business owners can develop estimates using MTBF figures for the optimal times for preventive maintenance to be carried out to avoid unplanned downtime. This information can be used to measure the decrease in reliability that can occurs as an asset ages and determine when a decision is made to replace a piece of equipment. However, these figures can only ever be rough estimates, because they can’t take into account the actual performance of a specific asset, under real-life operating conditions. MTTF is calculated in a very similar way to MTBF, except that it involves multiple assets that have failed once, in order to calculate an average estimate of how long items of that type of asset will function as expected before failing.

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With the right software solution, most of this process is automatic. Set your current and par levels in the software, and every time you close out an on-demand or preventive maintenance work order with that part or material, the software subtracts it from your current levels. When you hit the par, the software sends you a message letting you know it’s time to reorder. But you can also use MTBF to improve your operations, including tightening inventory control and fine-tuning your preventive maintenance program. Mean Time Between Failuresmeans the average time between failures of an Element or an individual component, system or subsystem of an Element.

Failures which occur that can be left or maintained in an unrepaired condition, and do not place the system out of service, are not considered failures under this definition. In addition, units that are taken down for routine scheduled maintenance or inventory control are not considered within the definition of failure. Mean time between failures is the average time between system breakdowns. MTBF is a crucial maintenance metricto measure performance, safety, and equipment design, especially for critical or complex assets, like generators or airplanes.

definition of mean time between failures

This means there is a maximum uptime of 10 hours a day or 70 hours a week. However, despite the maintenance done to the machine before daily operations, it’s still possible for the equipment to fail during the shift. Inherent and instigated failure – It’s important to understand that mean time between failures is only meant to describe disruptions that arise from the machine’s own operations. Inherent failures are inevitable in any system and usually take many different forms. Instigated failure, which would be any scheduled or deliberate disruption of operations, should not be included in the calculation.

How to Calculate Mean Time Between Failures

Some also believe that it’s a measure of the point in time where the chance of a machine failing is equal to the chance of it not failing, on average, but again this is not true. By tracking how often software fails to perform as expected under normal use, we can calculate an estimate for MTBF, and use this to improve performance. In these cases, it might be more meaningful to express the failure rates in days or even weeks. Failure rate is defined as how often a system or piece of equipment fails unexpectedly during normal operation. Safety is one benefit of MTBF that is best understood in the context of critical systems, for example an aircraft. By measuring MTBF for components, we can reduce the chances of an unexpected failure of a critical system that could endanger the lives of everyone.

Having this information makes it easier to create PMs so reliability can be improved by tackling issues before they cause failure. If a failure does occur, having all the data allows you to improve maintainability. There are many variations of MTBF, such as mean time between system aborts , mean time between critical failures or mean time between unscheduled removal . Such nomenclature is used when it is desirable to differentiate among types of failures, such as critical and non-critical failures.

The higher the MTBF, the longer a system is likely to work before failing. Mean time between failure refers to the average amount of time that a device or product functions before failing. This unit of measurement includes only operational time between failures and does not include repair times, assuming the item is repaired and begins functioning again. MTBF figures are often used to project how likely a single unit is to fail within a certain period of time.

Because MTBF is a basic measure of a system’s reliability, it can be used in a variety of important business decisions. A concept which is closely related to MTBF, and is important in the computations involving MTBF, is the mean down time . MDT can be defined as mean time which the system is down after the failure.

One of the most immediate benefits of monitoring mean time between failures for your physical systems is to manage volatility. The entire basis of Six Sigma is to reduce variability in the results of business processes, leading to a more controlled and efficient workflow. Don’t worry about downtime related to preventive maintenance work.

  • Developing different applications specific to a company has become the norm for every successful business in today’s world.
  • Let’s say you have a very expensive piece of medical equipment – such as an EKG machine – in a large hospital that’s in use 16-hours a day, 7 days a week, measuring patients’ heart signals.
  • MTBF can also be used as a measure of the reliability of software systems.
  • Jonathan has been covering asset management, maintenance software, and SaaS solutions since joining Hippo CMMS. Prior to that, he wrote for textbooks and video games.
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  • For example, an asset may have been operational for 1,000 hours in a year.

A learning experience platform is an AI-driven peer learning experience platform delivered using software as a service (… Cloud radio access network (C-RAN) is a centralized, cloud computing-based architecture for radio access networks. DHCP is a network management protocol used to dynamically assign an IP address to any … For instance, when you analyze longer amounts of time in which several problems happened, that asks for more steps when calculating MTBF.

Logs are the closest we have to an authoritative source of truth to determine the start times of problems in production, which makes them a really powerful asset that needs to be properly handled and managed. You just take the total time the item is running (i.e., availability of uptime) and divide it by the number of failures that happened over that time frame. Inherent failures and maintenance needs are inevitable in any physical system or device, so it’s something companies need to accept, embrace and integrate into their process cycle. Useful in context – Like any kind of business metric, MTBF is not a useful number on its own. Building data about equipment failures can provide amazing insight into your own processes, but only if its supported with further investigation, additional data sources and real action. If a machine suddenly starts spewing smoke and shuts off, it has clearly failed.

Examples of Mean Time Between Failure in a sentence

That one component has failed completely, but the car runs fine, and you might not even notice the failure until you try to turn on the radio. Epidemic Failure means a series of repeating failures or defects resulting in at least a 0.5% failure rate for the same Product or Material during any twelve-month period. And although it’s not sufficient on its own, MTBF provides an effective way to help your team focus on increasing the operational time of your assets. Get clear on your definitions of “failure” and “operating time” and which components are included in the system to ensure your MTBF value is meaningful.

definition of mean time between failures

The AFR shall be calculated based on the Mean Time Between Failure . A low MTBF can also come from operator error and poor maintenance practices. It’s failing because of how the operators are running it and how the technicians are trying to keep it up and running. GEP Failure means Seller’s failure to produce Delivered Energy in an amount equal to or greater than the Guaranteed Energy Production amount for the applicable Performance Measurement Period. The contractor is required to submit a complete analysis of MTBF and MTTR of the system. Some people get confused and think that MTBF is actually a measure of useful life.

MTBF is calculated by dividing the total time a system was running correctly by the number of failures that happened in the same period of time. Reliability is defined as the absence of unplanned downtime, and MTBF measures how often a piece of equipment stops performing as expected, and so is an important measure of reliability. MTBF can also help make tough repair or replace decisions a little easier. It’s never easy to give up on a piece of equipment and buy an expensive new machine.


Under this assumption, any one particular system will survive to its calculated MTBF with a probability of 36.8% (i.e., it will fail before with a probability of 63.2%). The same applies to the MTTF of a system working within this time period. There are many variations of MTBF, such as mean time between system aborts or mean time between critical failures or mean time between unit replacement . By tracking failures and operational time, a more accurate MTBF definition of mean time between failures can be developed for a piece of equipment, based on actual experience and realistic operating conditions. A primary goal for all businesses is to maximize output and minimize downtime and mean time between failures is a useful metric to assess the reliability of the systems that support your operations. This means that the average time between failures of this the machine is around 578 hours, or just over 5 weeks, under typical operating conditions.

How do you calculate MTBF?

The term is used for repairable systems while mean time to failure denotes the expected time to failure for a non-repairable system. MTBF is used to anticipate how likely an asset is to fail within a certain time period or how often a certain type of failure may occur. When paired with other maintenance strategies, like failure codes and root cause analysis, and additional maintenance metrics, like MTTR, it will help you avoid costly breakdowns.

MTBF Calculation

Because MTBF does not include the time taken to repair a piece of equipment after a failure, it is a measure of how long a machine typically runs correctly before failing but doesn’t reflect how long it is out of operation. Total uptime – The total amount of time that the system or components were operating correctly under normal conditions. It is recommended to use Mean time to failure instead of MTBF in cases where a system is replaced after a failure („non-repairable system“), since MTBF denotes time between failures in a system which can be repaired.

Analyzing your work order data can help you pinpoint the root cause of a particularly consistent failure and eliminate it. You can get a toolkit for finding and using work order data here. One of the most critical components of a personal computer is its hard drive, which typically has an MTBF of 250,000/hours. You should always follow basic best practices when collecting or utilizing data in process management to avoid common pitfalls.

Usually, MDT is considered different from MTTR ; in particular, MDT usually includes organizational and logistical factors while MTTR is usually understood as more narrow and more technical. Leverage the cloud to work together, better in the new connected age of maintenance and asset management. DisclaimerAll content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. Here you’ll get most accurate definitions, close synonyms and antonyms, related words, phrases and questions, rhymes, usage index and more. Cybersecurity is the protection of internet-connected systems such as hardware, software and data from cyberthreats.

This means that long Mean Time Between Failures , short Mean Time To Repair , and easy serviceability must be a basic consideration for all the components. In other words, the likelihood that a specific piece of equipment actually runs for the MTBF before failing is just 37%. MTBF can only ever be a statistical measurement, representing an average value of events that occurred in the past. Sure, it might have “just been” a worn out part or a random occurrence, but take the time to look for systemic issues that might have contributed to the failure, that you can address. MTBF can also be used as a measure of the reliability of software systems. They can also use MTBF to “look ahead” and have the necessary parts and skills available for when unexpected failures occur.