Various factors and measurements affect an organization’s ability to improve workforce efficiencies.
By Al Poling, RAM Analytics LLC
It’s a given: Maintenance is the largest fixed cost in manufacturing. Maintenance-workforce efficiency has a profound effect on that cost and, in turn, overall business performance. Can that efficiency be improved and, if so, how?
The common metric used to measure this efficiency is wrench time. Research on wrench time has revealed maintenance workforce efficiencies ranging from 18% to 74%. In other words, inefficient maintenance operations will spend exponentially more on maintenance labor than the most efficient operations to complete the same amount of work.
To illustrate the significant financial impact of maintenance workforce efficiency, a highly efficient operation with 74% wrench time spends $100 million/yr. on maintenance labor. A highly inefficient maintenance operation would spend more than four times that amount (or more than $400 million annually) to complete the same volume of work. Translation: The inefficient maintenance operation would waste $300 million a year due to inefficiency.
Numerous factors influence effective use of maintenance labor resources. At the top of any list, however, is a well-defined maintenance-work process. This type of process describes, in detail, each step of maintenance work from identification through execution and closure. Despite claims to the contrary, there is effectively only one universally used maintenance workflow. The five major components are identification, planning, scheduling, execution, and closure:
Identification is the timely pinpointing and prioritization of maintenance work. These activities are performed by equipment operators who use a well-defined work-prioritization matrix or by maintenance coordinators who base priorities on business and related needs.
Planning is formal organization of the work to be done, including scope assessment and identification and procurement of the labor and materials required to complete the job.
Scheduling includes setting the optimum time period in which to complete the planned work. It takes into account the overall resources required at the site and attempts to level the resource load to use normally available maintenance resources.
Execution is the actual hands-on work performed by skilled maintenance craft personnel. This includes company personnel and contract maintenance workers.
Closure involves capturing work history, including critical information on failure modes used to facilitate reliability analysis.
Failure to have or follow a well-defined maintenance-work process results in chaos and, therefore, grossly inefficient resource utilization.
Tools and prep
The next factor that influences maintenance-labor efficiency is the availability of tools and materials required to complete the assigned work. Without that availability, work can’t be completed in a timely manner.
Wrench-time studies consistently reveal that traveling for tools and materials is the most common barrier to maintenance-workforce productivity. If highly skilled (and costly) maintenance-craft personnel have to spend time retrieving tools and materials, it will take significantly longer to complete the work, including possibly delaying completion. It’s troubling why so many organizations depend on highly skilled maintenance resources to perform such mundane work (material and tool transport) rather than assigning those tasks to less costly storeroom and/or delivery personnel.
Next in line as a detrimental impact on maintenance-workforce efficiency is the interface with operations. Equipment must be prepared in advance of maintenance work. Examples include equipment decontamination, lockout/tagout, and work permitting. If these types of tasks aren’t performed in a timely manner, wrench time will suffer. Paying highly skilled maintenance workers to stand around while operators perform such work—that should have been done in advance—is absurd. Yet, as wrench-time studies show, this is a common occurrence in today’s plants.
The culture effect
Empirical evidence suggests that particular work environments, or cultures, are more prone to maintenance workforce inefficiency. At the top of this list is an environment in which unreliable equipment reigns. In this type of reactive environment, it is virtually impossible to achieve high levels of maintenance-workforce efficiency. Unplanned failures, by their very nature, don’t facilitate planning and scheduling, leading to extremely inefficient and expensive reactive corrective work. As if this weren’t bad enough, it is invariably the value of lost production and subsequent lost profit that causes the greatest economic harm to the site and business. Sadly, these costs are often overlooked.
The next environment most prone to maintenance workforce inefficiency is one where maintenance labor costs are low. Southeast Asia, for example, experiences severe inefficiencies—often at appalling levels. In those regions, it’s not unusual to find human labor being utilized instead of equipment. For example, you might find large numbers of maintenance workers with shovels doing the work that a single bulldozer could complete in short order. Sometimes, though, this is by design, i.e., to create more jobs to support a growing middle class. Nonetheless, while it’s an expensive way to operate, the costs can be more easily absorbed due to exponentially lower-skilled maintenance-craft wages.
Surprisingly, highly reliable operations represent yet another, although not necessarily obvious, area where maintenance inefficiencies can be found. In such environments, the business is typically enjoying very high profit margins as a result of achieving maximum production with existing assets.
Of course, it’s human nature for people to focus on what’s important and overlook anything that’s deemed less so. Thus, in a highly reliable production environment, as profits rise, maintenance-cost management can take on a lower sense of urgency. In extreme cases, the inherent inefficiency can lead to anywhere from tens to hundreds of millions of dollars in unnecessary maintenance expense. Interestingly, this situation may also occur in less-reliable operations when the market is tight and profits are high. (It’s not uncommon for managers to remove any maintenance cost controls as long as sales demands are satisfied.)
In both of those scenarios, however, maintenance inefficiency will only be tolerated as long as profit objectives are being met. As soon as market conditions change, pressure will once again be applied to maintenance cost and, subsequently, to maintenance-workforce efficiency. The reaction to this often-sudden change can be quite ugly as arbitrary rules with the potential for unintended consequences, e.g., discontinuing proactive maintenance as a way to reduce maintenance labor costs, are put in place.
In an ideal production environment, skilled maintenance resources are used efficiently and effectively. As the father of statistical process control W. Edwards Deming advised, “You can’t manage what you don’t measure.”
To ensure that maintenance resources are being efficiently and effectively utilized, they must be measured. Although not used extensively today, the early 20th century methodology of maintenance-work sampling provides an effective means to measure wrench time. (Despite exaggerated claims by some that this sampling is akin to Frederick Taylor’s infamous time and motion studies of the late 19th century, it is not.)
Maintenance-work sampling is simply a statistical tool that, when used effectively, can measure maintenance-workforce productivity. Identification and elimination of barriers to productivity can significantly increase the value-added contribution of existing maintenance resources. Work sampling is the process of capturing and analyzing a statistically valid number of random observations to determine the amount of time, on average, that workers spend in various activities throughout their normal workdays. Non-value-added activities are then targeted for reduction and/or elimination using root-cause analysis.
The maintenance-work sampling approach is based on the proven theory that the percentage of observations made of workers doing a particular activity is a reliable measure of the percentage of total time actually spent by the same workers on the activity. The accuracy of this technique is, naturally, dependent upon the number of observations. To achieve a 95% confidence level in the results, approximately 3,000 observations must be made and recorded. While this might seem excessive, a single trained observer can collect that number of observations during a week of single 8- or 10-hr.maintenance work shifts.
Keep in mind that maintenance-work sampling makes it possible to measure utilization of work groups and the overall maintenance workforce. Key opportunities that warrant attention can be isolated and examined. A good example is that of travel time involved in obtaining requisite maintenance tools and materials and delivering them to where they will be used. That time can be accurately measured and a cost assigned simply by taking the number of total hours consumed by the activity and multiplying by the hourly rate.
Additionally, with maintenance-work sampling, unique factors that affect maintenance wrench time can often be identified. For instance, if inadequate means of communication exist between a work group and the supervisor, valuable time can be wasted tracking each other down. Radios or mobile phones, can solve this problem.
The accompanying charts (Figs. 1 and 2) are based on a real-world case study where work sampling was leveraged to identify and eliminate maintenance-workforce inefficiencies. Figure 1 depicts a decline in non-value-added activities, while Fig. 2 depicts an increase in value-added activities.
As these charts show, initial measurement of the site’s maintenance-workforce wrench-time revealed a mere 28% value-added work (wrench time). Through the systematic reduction and/or elimination of non-value-added activities over the course of three years, the wrench time rose to 74%. What really matters here, however, is the recovery of the value of time that was being wasted, as shown in Table I. (Efficiency gains can also be measured in terms of full-time-equivalents, as shown in Table II.)
As part of its development and publication of standard reliability and maintenance metrics, the Society for Maintenance and Reliability Professionals (SMRP, Atlanta, smrp.org) published its work-management metric, 5.6.1 Wrench Time, in 2009. The stated objective of this metric is “to identify opportunities to increase productivity by qualifying and quantifying the activities of maintenance craft workers.”
The Society also published the SMRP Guide to Maintenance Work Sampling, in 2012. As one of three co-authors, I can state definitively that the intent of this publication was to educate younger reliability and maintenance professionals who had not been exposed to maintenance-work sampling. Although adoption has been slow, several companies are beginning to include this sampling methodology as a valued component in their reliability and maintenance tool kits. Ironically, sites are often introduced to maintenance-work sampling by maintenance contractors who want to demonstrate the efficiency and effectiveness of the skilled maintenance-craft personnel they provide.
(Editor’s note: SMRP’s Guide to Maintenance Work Sampling is a simple “how to” document that includes statistical tables designed to help users understand the correlation of the confidence level associated with a number of observations. The guide can be purchased for a small fee at SMRP.org. The co-authors donated their time to the development and publication of this document and receive no royalties from its sale.)
While it might be enticing to simply reduce the number of skilled maintenance craft workers on site as wrench time increases, a more prudent path may be to redeploy resources and invest in failure-prevention activities and/or infrastructure.
Increased wrench time may also provide an opportunity to reduce overtime as resources become available and/or to reduce the reliance upon third-party maintenance resources. With today’s critical shortage of skilled maintenance workers, however, displaced workers would likely be able to secure employment elsewhere.
In summary, maintenance wrench time plays a significant role in measuring efficient utilization of skilled maintenance-craft personnel. This valuable metric can be used by any manufacturing operation to ensure that it is realizing the greatest return possible from its investment in human capital. MT
Al Poling, CMRP, has more than 36 years of reliability and maintenance experience in the process industries. He served as technical director for the Society for Maintenance and Reliability Professionals from 2008 to 2010. Contact email@example.com.