MTBF stands for Mean Time Between Failures. It is a maintenance metric that provides valuable insights into asset failure, availability, and reliability. We’ve already written about MTBF in comparison to other maintenance metrics and the importance of tracking MTBF. This article will focus on calculating MTBF and understanding your results. Here, you will also learn how to use MTBF results and improve them, and consequently, improve your asset reliability.
What is MTBF?
But first, a short primer on MTBF. Mean Time Between Failures, as the name suggests, is the average operational time of an asset or component from one failure to the next. It is important to note that only the “operational” time is considered in the MTBF. This means that the time spent repairing and restoring the asset or component is not included. The formula for calculating MTBF is thus:
MTBF = the number of operational hours divided by the number of failures
Another essential reminder about Mean Time Between Failures is that the failures involved are emergency or unplanned failures. Thus, the non-operational time due to preventive maintenance or scheduled downtime should be excluded from the number of failures.
Why is MTBF Important?
Why track MTBF? Because any data on the failure of assets helps reduce, if not eliminate, the occurrence of such failure. MTBF values let you predict when an asset or component is likely to fail. From there, you can create a preventive maintenance program that is more precise and focused. This means that you can minimize the costs of maintenance due to reduced preventive inspections, faster failure detection, and reduced repair time.
Steps to Calculate MTBF
Tracking the Mean Time Between Failures of your assets is a helpful practice only if you do it properly. Do so by following the steps below:
1. Define the terms.
Before you start collecting data from your assets or components, you must specify the terms of your calculation. Identify the assets or the parts you will be monitoring, the period within which you will be checking for failures, and the types of failures you will consider. To illustrate, you will calculate the MTBF of your hydraulic drilling machine, its valves, and pressure regulators for one year for broken drill pipe and drill jamming.
2. Collect the data.
Gather detailed information based on your defined terms. Your assets may already come with recommended MTBF values, but these can change with asset age and operating conditions. You can use these recommended MTBF values as a reference point for initial maintenance planning, but the succeeding MTBF values should be based on actual data. Actual data collection should be as detailed as possible and include information on the failure that occurred, the maintenance task done, and the technician who performed the task and their notes if any.
3. Compute the operational hours.
Total the operational hours for each asset. For single assets, simply add the hours it was in operation. For similar assets that operate at the same times and durations, you can simply multiply the operational hours by the number of assets. Remember to include only the operational hours within your set period.
4. Compute the number of failures.
Identify the failures based on your set terms and total them for each asset. Similar to computing the operational hours, consider only the failures within your set period.
5. Calculate the MTBF.
Using the MTBF formula, calculate the MTBF for each asset. Dividing the total operational hours by the number of failures. The result is the average number of hours between failures. If your hydraulic drilling machine operated for 1000 hours in the past year and failed 10 times, its MTBF would be 100 hours.
How to Use MTBF?
The Mean Time Between Failures for an asset may vary depending on the set terms and periods, but it can be a valuable estimate of availability and reliability. The higher the MTBF, the more available an asset is and the more uptime you can expect from it. An increasing MTBF value for a certain period may mean an improved asset maintenance program. A decreasing MTBF value means that more failures are happening and may require more maintenance efforts. Below are several ways of using MTBF values and improving your asset reliability.
Plan and Schedule Targeted Maintenance Tasks
Schedule preventive maintenance tasks on the asset a tolerable amount of operational hours before the expected failure. In case the expected failure does not occur, reduce the maintenance frequency until it occurs.
Prepare for an Efficient Repair and Decrease Asset Downtime
If you have an estimate of when an asset is likely to fail or break down, you can keep the necessary materials, tools, manpower, and other resources on hand. Thus, you can decrease the waiting time for repair and minimize downtime.
Reduce Inventory Costs
By estimating your asset failure time, you can have better inventory management. This means you can minimize inventory costs by buying only what you need, preventing overstocking and freeing a part of your maintenance budget for other areas.
Improve Maintenance Processes
Calculating an asset’s MTBF is not a one-time process. You must gather MTBF data continuously and calculate the results periodically. This way, you can track the changes in MTBF and improve your maintenance processes accordingly.
Accurate MTBF Reporting with Redlist
Any business nowadays relies on data-driven decisions. And the more accurate your data collection and analysis, the more sound your decisions. Thus, a tool like Redlist’s CMMS (Computerized Maintenance Management System) becomes more indispensable. With Redlist’s digitized data recording and storage, the maintenance team can gather detailed information, store them automatically, and access them instantly whenever needed. On top of that, Redlist comes with powerful computing functions that allow fast and accurate data analysis and reporting. With Redlist, MTBF calculation and monitoring are as easy as a few taps of your finger on your mobile device. Experience this and other maintenance benefits by scheduling your free Redlist demo today!
