Column On The Floor Reliability Safety

Reliability And Safety Inseparable

Klaus M. Blache | January 18, 2019

Q: How much is reliability tied to safety?

A: The quick answer is that a reliable plant is a safe plant. Reduced reactive maintenance (emergency repair) is the best leading indicator of the impact safety will have on an operation.

Leading indicators are those that are forward looking in terms of your maintenance process. They drive the correct practices to attain the desired results. Examples include percentage of work orders requiring rework, scheduled available hours as a percentage of total available hours, and percentage of work orders completely planned.

Lagging indicators are those that measure the results of your process. Examples are maintenance cost/replacement asset value, mean time to repair (MTTR), unscheduled maintenance-related downtime, and OSHA recordable-incident rate. Increasing planned (proactive) maintenance reduces the number of times personnel are potentially put in harm’s way. It also makes the machinery and equipment safer for all personnel. The accompanying chart, from my 2017 study, shows the direct relationship between reactive maintenance and OSHA recordable rate. This is a trend that I have frequently observed when performing similar analytics.

The graph shows the significant drop in OSHA recordable-incident rate that occurs as the percentage of reactive maintenance decreases in an operation.

As I’ve often stated, “it’s all related.” If you don’t plan and schedule your maintenance activities, how can you control reactive maintenance? If maintenance costs are arbitrarily cut, do managers understand that it may have an impact on safety?

Top-quartile North American companies average about 9% reactive maintenance. The North American average for all companies (2017 study, 140 companies, and almost 3,000 facilities) is 31% reactive maintenance. Although a good representation of all types of industries, those numbers are small in relation to all of North America.

Let’s presume I’m within 10% of the actual North American reactive-maintenance percentage, making the range 27.9% to 34.1% reactive. Based on that, I would expect an OSHA recordable rate of between 2.1 and 2.8. Note that the corresponding actual 2017 average value is 2.8. That isn’t great statistics, but the numbers pass the logic test and mean that the thinking is in the correct direction. The value represents nonfatal workplace injuries and illnesses reported by private-industry employers in 2017, which occurred at a rate of 2.8 cases per 100 full-time equivalent (FTE) workers, as reported by the U.S. Bureau of Labor Statistics.

From my studies, top-quartile companies (low in reactive maintenance) spent 23% of their time finding issues with predictive technologies and condition-based monitoring. This does not include preparing the work orders to fix what was found. Top-quartile-company employee engagement (suggestions per employee):

• had a 27% better safety performance (OSHA recordable-incident rate) than the average of the remaining facilities

• recorded a 14% better OSHA recordable-incident rate than the lower 75% of companies.

It’s this instilled process of root-cause analysis that drives ongoing improvement.

Get the basics of reliability and maintainability right, including developing and sustaining a plant-floor continuous-improvement culture, and all of the affected operation items (safety, people/culture, quality, uptime, and cost) will improve. This is your path to top-quartile performance and improved safety. EP

Based in Knoxville, Klaus M. Blache is director of the Reliability & Maintainability Center at the Univ. of Tennessee, and a research professor in the College of Engineering. Contact him at



Klaus M. Blache

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