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mtbf or Mean Time Between Failure

What is Mean Time Between Failure or MTBF

In the field of reliability engineering, Mean Time Between Failure (MTBF) is an essential metric used to validate the reliability of a system or machine. It provides valuable information regarding the expected time between failures of a particular device or system. Engineers use this information to make informed decisions on maintenance requirements, spare parts management, and system design. This article will look at MTBF, its calculation, applications, and strategies to improve it. IoT enabled Smart CMMS application such as Fogwing Asset+ helps to track the MTBF without any efforts.

Introduction to Meantime Between Failure

MTBF is a crucial factor for manufacturing, production, transportation, aerospace, and defense organizations. Its importance lies in the direct relationship between system reliability and cost-effectiveness. A high MTBF means the system or component is more reliable, requiring less maintenance and reducing overall operational costs. Alternatively, a low MTBF value indicates that the system needs more maintenance or may break down frequently, leading to increased costs and reduced productivity.

For example, a high MTBF value in the manufacturing industry means that the production line will experience fewer breakdowns, resulting in less downtime and increased productivity. This production efficiency translates into cost savings for the organization. The manufacturing process can operate more efficiently without frequent interruptions.

Definition of MTBF

MTBF means the average time duration between the failures of a particular system or component. It is calculated by dividing the total operational time by the total failures. The value does not directly indicate the lifespan of the component or system but its reliability level during its operational time.

For instance, in the aerospace industry, MTBF is used to measure the reliability of aircraft components. A high value for an aircraft engine means that it is less likely to fail during flight, ensuring passenger safety and reducing the risk of costly unplanned downtime due to engine failure.

Importance of MTBF in Reliability Engineering

MTBF is an essential metric used in reliability engineering to measure device or system reliability, predict failures, and determine maintenance requirements. MTBF ensures that systems operate within their expected reliability limits and are less likely to fail. The evaluation of MTBF can lead to forewarning of potential failures, which allows for planned downtime and scheduled maintenance to prevent costly downtime.

For example, in the transportation industry, MTBF is used to measure the reliability of trains and their components. A high value for a train’s braking system means that it is less likely to fail during operation, ensuring passenger safety and reducing the risk of costly unplanned downtime due to brake failure. Scheduled maintenance based on MTBF evaluations can also prevent accidents and ensure the smooth operation of the transportation system.

MTBF vs MTTF (Mean Time To Failure)

MTBF and MTTF are terms often used interchangeably but differ. MTBF is the average time between one failure and the next in a given period. In contrast, MTTF (Mean Time To Failure) is the average time duration between the initial installation of the system or component and its first failure. MTTF is only an appropriate measure for product design that aims to optimize the device’s expected life based on its operation and environmental conditions. On the other hand, MTBF is used to measure the system reliability for in-service devices or systems.

For example, in the electronics industry, MTTF is used to measure the expected lifespan of a product, such as a smartphone. A high value means the smartphone is expected to last longer before its first failure. In contrast, MTBF is used to measure the reliability of the smartphone during its operational time, such as the likelihood of the battery failing or the screen cracking during use.

Calculating Mean Time Between Failure

To calculate MTBF, you must know the total operational time and the number of failures. The general formula for calculating MTBF is:

MTBF = Total Operational Time / Number of Failures

The operational time and failures can be determined through observation, analytical modeling, or laboratory tests. The MTBF result is mainly reported in hours or cycles of operation, depending on the evaluated system or component.

We must note that MTBF value does not guarantee that the system or component will last for that amount of time. It is merely a statistical measure that estimates the expected time between failures.

Basic MTBF Formula

The basic formula for calculating MTBF is straightforward, as shown above. However, in complex systems, the calculation can vary. For instance, when dealing with redundant systems, the calculation is more complicated because the system’s reliability depends on the reliability of each component. In this case, an online reliability modeling tool or software can help to determine the MTBF value.

It is also critical that MTBF value can change over time as the system or component ages. This change can be due to wear and tear, environmental factors, or changes in operating conditions.

Factors Affecting MTBF

Many factors influence the MTBF value. Significant factors include operational conditions, environmental factors, maintenance, and design. For example, an electronic device expected to operate in industrial environments such as high temperatures, humidity, or vibration will likely have a lower MTBF value than those in more controlled environments. Also, a device that requires regular maintenance will likely have a higher MTBF value than one that needs better maintenance. The design of a system or component is critical in determining its value, as some designs inherently have better reliability characteristics than others.
Other factors that can affect the value include the components’ quality, the manufacturing process, and the level of testing and validation performed during the design and development phase.

Common Mistakes in MTBF Calculation

MTBF calculation can be prone to errors, mainly if not correctly evaluated. Some common mistakes include incorrect measurement of time, underestimation of the failure rate, and misunderstanding of the system or component design. These errors can lead to inaccurate MTBF values and, consequently, lousy decision-making in maintenance and system design. It is always essential to pay attention to the details and clearly understand the system or component’s operational characteristics before calculating MTBF.

In conclusion, MTBF is a critical metric in evaluating the reliability of a system or component. By understanding the factors that affect MTBF and avoiding common mistakes in its calculation, engineers and maintenance professionals can make informed decisions about system design, maintenance, and replacement.

Applications of MTBF in Various Industries

MTBF is a critical metric in various sectors where reliability is essential. Its applications are widespread and play a significant role in system maintenance and design. Some significant industries that use MTBF include electronics and electrical systems, manufacturing and production, transportation and automotive, and aerospace and defense.

Electronics and Electrical Systems

MTBF plays a crucial role in the design of electronic and electrical systems. These systems have a high possibility of failure due to nature and exposure to environmental factors such as temperature, humidity, and electromagnetic interference. Designers use MTBF to optimize the reliability of these systems, especially in high-stress environments such as aerospace, aviation, and defense.

For example, MTBF is used to design aircraft avionics systems to withstand extreme flight conditions. MTBF is also used in medical equipment design, where reliability is critical to patient safety.

Manufacturing and Production

MTBF is widely used in manufacturing and production environments where machine downtime can lead to significant losses. Manufacturers use MTBF to identify potential sources of machine failure and plan regular maintenance schedules to prevent or reduce downtime.

For example, MTBF is followed in manufacturing to ensure the production process runs efficiently. MTBF is also used in producing consumer electronics such as smartphones and laptops to ensure they are reliable and have a long lifespan.

Transportation and Automotive

The transportation and automotive sectors rely heavily on MTBF to ensure the safety and reliability of their systems. MTBF plays a critical role in vehicle design and maintenance, especially in aviation and aerospace, where safety is critical.

For example, MTBF is used to design aircraft engines to ensure that they can operate safely for extended periods without failure. MTBF is also used to design automotive components such as brakes and suspension systems to ensure they are reliable and safe for use on the road.

Aerospace and Defense

MTBF is essential in aerospace and defense applications where systems must operate for extended periods without failure in harsh environments. The military relies heavily on MTBF for maintenance planning, spare parts management, and system design.

For example, MTBF is used in designing military aircraft and weapons systems to ensure they can operate reliably in combat situations. MTBF is also used in the design of spacecraft and satellites to ensure that they can withstand the harsh conditions of space and operate for extended periods without failure.

Improving Mean Time Between Failure

Improving MTBF is critical to increase system reliability and reduce costs associated with downtime and maintenance. Various strategies to improve MTBF include preventive maintenance, root cause analysis, and continuous improvement and monitoring.

Preventive Maintenance Strategies

Preventive maintenance involves regularly scheduled maintenance to prevent potential system failures. Preventive maintenance aims to identify and address potential issues before they become significant problems. It includes activities such as regular cleaning, lubrication, and component replacement. Preventive maintenance is proactive and helps to identify upcoming issues before they occur, so reducing downtime and costs associated with system failure.

Root Cause Analysis

Root cause analysis is a systematic approach to identifying the underlying factors that cause system failures. It involves a thorough investigation to determine the root cause of the failure and then implementing corrective actions to prevent future occurrences. Root cause analysis is essential to improve MTBF, especially in complex systems and critical applications such as aerospace and defense.

Continuous Improvement and Monitoring

Continuous improvement and monitoring involve an ongoing review and evaluation process to identify potential improvement areas. It includes collecting data, analyzing system performance, and implementing corrective actions to optimize performance and increase MTBF. Continuous improvement and monitoring are essential in any industry, especially those where system reliability is critical.

Fogwing Asset+ for Reliability Monitoring

MTBF and MTTF are critical reliability management KPIs that must be monitored continuously for efficiency. However, monitoring and tracking each asset’s MTBF and MTTF is highly impractical in a highly demanding manufacturing environment. Fogwing Asset+ is the smart CMMS software empowered by IoT and AI technologies. The connected asset module within Asset+ allows real-time monitoring of the asset health parameters and tracking the failure. The automation engine within Asset+ helps to closely track, calculate and predict the MTBF and MTTF metrics uniformly. Digitalizing the maintenance operations with Fogwing Asset+ simplifies the overall maintenance operations with actionable insights.

If you are exploring best CMMS software for your organization then you must read this article as well.


In conclusion, MTBF is a valuable metric used to measure the reliability of systems and components. It enables engineers and decision-makers to identify potential issues, plan maintenance schedules, and optimize system design. Understanding and calculating MTBF is critical for any organization that values reliability and productivity. By implementing strategies to improve MTBF, a company can reduce downtime, increase productivity, and, ultimately, reduce operational costs.


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