Maintenance Technology April 2017 - 56

FINAL THOUGHT

Human Reliability:
More Than Half the Answer

Dr. Klaus M. Blache
Univ. of Tennessee
Reliability &
Maintainability
Center

56 |

y prescription for achieving
reliability incorporates
human reliability.
This human element
consists of people, processes
(engineering and machinery/
equipment), and products
that lead to best practices and
customer deliverables. In short,
the better you do things, the more
availability and throughput you get.
Reliability is about dependable
engineering processes that support designingin and sustaining machinery/equipment (M&E),
maintenance practices to enable early detection of
issues, and specifications that guide the purchase of
maintainable M&E. Aspects to consider include:
1. Accessibility
■ easing access in performing maintenance
■ eliminating the need for special
tools to gain access
■ designing out the need to remove components
and other items that haven't failed to get to those
that often do fail.
2. Modularity
■ making each equipment module easy to handle
by one person
■ ensuring that disposable modules are
easy to reach
■ designing out the need to dispose of long-life
parts by using disposable parts.
3. Diagnostics
■ capturing enough data for problem analysis
■ analyzing faults and issues down to the
component level
■ ensuring that performance data is captured
and stored for analysis, supplier feedback, and
internal continuous-improvement teams.
To me, maintainability refers to the "ease and
speed of maintenance to return the system (people,
process, machinery/equipment, and product) back
to its original operating condition." Maintenance is
the repairing or servicing of a product or machinery/
equipment. Maintainability is a design parameter
(like the preceding examples) to minimize or
optimize repair time.
Unfortunately, research shows that human error
is still occurring at a high rate. Failure-rate studies
have found that more than 50% of all equipment

MAINTENANCE TECHNOLOGY

fails prematurely after maintenance work
has been performed on it. This has
been evidenced in many types of
equipment systems and organizations. To better understand how
human performance influences
risk associated with nuclear
power plant operations, the U.S.
Nuclear Regulatory Commission
(NRC) requested a study (INEEL/
EXT-01-01166) that showed the
average human-error contribution
to the increase in risk was 62%. In the same
study, maintenance practices and maintenance-work
control errors were evident in 76% of the events, and
operations errors were present in 54%.
What can be done? For new M&E, there's an
opportunity to design-in numerous maintainability
concepts. More opportunity, however, is in existing
facilities. A good first step would be to perform a PM
Optimization (PMO) to eliminate any unnecessary
tasks and related interventions.
A PMO will pinpoint if the M&E requires further
design review, changes, and frequency in how
those reviews are performed, or if they should be
eliminated. Mature operations have lots of mistakeproofing and visual controls for operations. This
technique should be expanded to include maintenance to support maintainability needs and reduce
availability risk.
Human reliability is related to the field of human
factors (ergonomics), which refers to designing
work areas, work practices, and workflow to
accommodate the capabilities of people (operators
and maintainers). These factors can't be ignored.
This applies to all types of industries. According to
the Occupational Safety & Health Administration
(OSHA), 30% to 50% of your recordable injuries are
somehow related to ergonomics.
Understanding and instilling human reliability, in
turn, is the key in interconnecting the daily functional links to reliability and maintenance that drive
real-world outcomes in availability. And it's more
than half of the answer. MT

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 kblache@utk.edu.
APRIL 2017

Table of Contents for the Digital Edition of Maintenance Technology April 2017