MTBF vs MTTF vs. MTTR: Defining IT Failure BMC Software Blogs

MTBF is used in manufacturing to measure the reliability of pieces of equipment. Calculating mean time between failures is one way to start conquering unplanned downtime at your facility. Taking stock of the symptoms is the first step toward diagnosing and curing the issue.

We’re talking about the difference between spending a few hundred dollars in maintenance-related expenses versus hundreds of thousands of dollars in costly downtime! Aberdeen Strategy & Research reports the average cost of downtime across all businesses is a whopping $260K per hour. To improve the maintenance of systems, we have to measure their reliability via metrics, such as MTTR definition of mean time between failures and MTBF. There are many arenas where MTBF can be a useful tool to calculate the number of failures across a given period of time. 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.

Industry solutions

It’s often paired with other maintenance strategies and key performance indicators like root cause analysis to remedy original causes of repetitive equipment failures. MTBF is critical in the aerospace and defense industry, where the breakdown of a component can have serious safety implications. When human lives are on the line, it is essential to maximize total uptime of critical systems like fuel and oxygen supply systems. MTBF is used to ensure that components and systems meet reliability requirements and to identify potential issues before they become safety risks. The technologies discussed above can help industries automate machine tracking and create maintenance schedules to maximize MTBF. Operators can complete proactive maintenance tasks, checklists, and inspections continually.

Like MTBF, MTTF measures time, but it measures how much life equipment has before it completely breaks down or has maintenance issues. •For the designer, it gives an indication of where reliability improvements can most usefully be made. You need not waste effort on optimizing those components which have little effect overall.

The problem of mean time to failure

Common examples of these products range from items such as fan belts in automobiles to light bulbs in our homes and offices. MTTF is calculated as the total number of hours of operation, divided by the total number of items tracked. So while MTTR measures availability; MTBF measures availability and reliability. The higher the MTBF number, the longer the system is likely to operate before it fails.

  • The Mean Time Between Failure is a measure of how likely an asset is to fail within a given time frame or how frequently a specific form of failure is expected to occur.
  • There is some opposition to the use of MTBF as a reliability indicator.
  • Mean time to failure is an arithmetic average, so you calculate it by adding up the total operating time of the products you’re assessing and dividing that total by the number of devices.
  • When paired with mean time between failures and mean time to repair , MTTF is more useful to enterprises.

Sometimes, short breakdowns may happen because of an operator’s mistake but not due to the machine itself. Engineers use MTBF in electronic manufacture to compare the effect of using different components in an electronic product. There may be one component that lowers the MTBF of the product as a whole, and a single change could make a significant impact on design reliability. Electronic manufacturers choose components that meet their overall MTBF objective. Over-specifying components adds to the cost of the product, but under-specifying could lead to premature failures and customer dissatisfaction.

4.4 The value of MTBF figures

Fan belts should have an MTTF that is higher than the MTBF of the equipment into which it fits. Otherwise, the whole equipment may fail when the fan belt fails. This correlation provides a key for improving an engineering design. The way to improve MTBF of a complex system may be to purchase better quality parts that have a higher MTTF performance. Nevertheless, one must always bear in mind that MTTF and MTBF are probability related and do not guarantee the life of a piece of equipment up to that duration. During normal operating conditions, the chance of failure is random.

definition of mean time between failures

Whether it is the size of the chicken in the poultry processing system or the thickness of the foil used for product packaging, every machine is designed to work within specific parameters. For breakdowns, enabling the quick and effective repairs that minimize the fallout from downtime. They are mean time between system aborts , mean time between critical failures and mean time between unscheduled removal . You’ll most likely see these variations when differentiating between critical and non-critical failures. 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. MTBF tells you when the asset or equipment tends to fail, and a quick review of your data can tell you why it tends to fail.

What is MTBF (Mean Time Between Failures)?

Total uptime is the result of subtracting downtime from total possible uptime. Mean time between failures is closely related to mean time to repair , but they aren’t technically the same. MTTR describes the average interval between repair work done on a machine. There are several ways to collect MTBF data, but the leading recording tools are CMMS software.

definition of mean time between failures

Instigated failure, which would be any scheduled or deliberate disruption of operations, should not be included in the calculation. People commonly mistake MTBF as an expected life of a piece of equipment before failure. The first part of the indicator – “Mean Time” give the impression that on average, each equipment should last at least this long.

Improve Reliability

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. Reliability engineers are responsible for identifying and managing asset reliability risks and then working to reduce those risks.

definition of mean time between failures

During the service life of a piece of equipment, it can be used to compare performance against other similar equipment in similar service. This comparison helps maintenance and reliability practitioners to make wise decisions about where to use their time and energy. Lastly, it can be used as a lagging indicator to evaluate the effectiveness of reliability programs like condition monitoring and risk-based inspection.

What Does Mean Time Between Failures (MTBF) Mean?

You should always follow basic best practices when collecting or utilizing data in process management to avoid common pitfalls. The easiest-to-use facilities and maintenance management solution on the market. In particular, for similar elements, the mean time is extended by 50%. However, this is unrealistic in taking no account of testing or replacement/repair. Similarly, a 10-drive configuration MTTF is one-tenth the MTTF of a single drive, or 1,000hours, and a 100-drive configuration is reduced to just 100hours.

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