Maximizing User Safety Through Human Factors Design
by Brian Garrett, Product Manager, Labconco Corporation
Abstract
Unlike most industries and professions, the very nature of laboratory science is hazardous. Technicians
and researchers are required to handle and are in close proximity to substances, agents and materials
that are inherently risky. For this reason, greater heed should be taken in selecting equipment that
maximizes safety by reducing the risk of the workstation’s effect on the user. This analysis focuses on
the associated risks of microbiological laboratory procedures and the required equipment that keeps the
researcher safe from the agents being used; with emphasis on the evolution of human factors design in
biosafety cabinets at Labconco Corporation (Kansas City, MO).
Introduction
Though it may not seem obvious, every job has
its own hazards. The majority of these hazards
are due to how we, as humans, interact with
our work. Laboratory science, microbiology
specifically, is no different; many employees do
not associate potential hazards and injuries to
the layout and configuration of their work
centers (EOHSS, 2009).
The field of Human Factors, more commonly
known as Ergonomics (HF/E), is a
multidisciplinary approach to understand how
humans physically interact with their
surroundings. Research in this field strives to
improve how these systems more efficiently
and therefore more safely, integrate with
human users.
Microbiology and HF/E Risk
Factors
The biological agents utilized in microbiological
laboratories inherently come with risk.
However, other risks present include
“…repetitive motion injuries during routine
laboratory procedures such as pipetting,
working at microscopes, operating microtomes,
using cell counters and keyboarding at
computer work stations,” (OSHA, 2011). These
risks are cited to be significant in the onset of
several Repetitive Strain Injuries, or RSIs.
Laboratory acquired RSIs can include:
Tendonitis and tenosynovitis
Rotator Cuff Tendonitis
Thoracic Outlet Syndrome (TOS)
Carpal Tunnel Syndrome (CTS)
Wrist ganglion cysts
Back injuries
2
To combat HF/E risk factors, users and
equipment manufacturers should strive for so-
called ‘neutral posture’ – a position where the
human body is under the least amount of stress
or discomfort. Human Factors Design, simply,
seeks to promote this posture (Mitchell &
Longyear, 2012).
Ergonomic Risk Assessments are performed to
identify the risk factors associated with the
criteria of a specific job or task. Several
resources exist that provide check-lists, gap
analysis, or risk assessment worksheets.
Biosafety Cabinet Risks
Microbiology, the study of microscopic
biological systems, requires tools and
procedures that attempt to put the researcher
in the world of the infinitesimal. The challenge
is to balance comfort with the need for such
precision when designing equipment for
microbiology. Pipetting and microscopy are two
of the worst offenders. When conducting these
activities with biohazards that require a
biosafety cabinet, the HF/E risks are
compounded.
There are exclusive risks that are intrinsically
associated with use of biosafety cabinets (BSCs).
Cumulatively, the risk factors accompanying
these microbiological jobs are:
Poor Working Posture – Head bent
forwards for long periods, raised and/or
outstretched arms, fixed postures held for
prolonged periods.
Upper Limb Disorder Risks – Repetitive
actions, awkward wrist/arm posture,
forceful actions (including pinching grips).
Environment – Space constraints, lighting
temperature, vibration, etc…
Load – Working with sharp, hot, cold or
toxic/hazardous objects.
Other Factors – Personnel Protective
Equipment (PPE) that might make work
more taxing.
Fatigue – An accumulation of multiple risk
factors listed above.
BSC Design Standards
Biosafety Cabinets should be designed, tested
and listed to an approved performance
standard such as the National Sanitation
Foundation’s NSF/ANSI Standard 49 or the
European Union’s standard EN 12469. These
standards and product listings ensure that BSCs
provide a basic safe environment for working
with biohazards, provided the cabinet is
operating properly. A BSC’s human factors
design and end user comfort (features) dictate
how an operator works, thus directly affecting
their productivity and safety. “Designing tasks,
equipment and work stations to suit the user
can reduce human error, accidents and ill-
health. Failure to observe ergonomic principles
can have serious consequences for individuals
and for the whole organisation. Effective use of
ergonomics will make work safer, healthier and
more productive” (HSE, n.d.).
However, the safety standards have not
established requirements for HF/E and user
comfort specifications. Driven by competition,
manufacturers have made great advances by
engineering products to increase safety through
improved comfort. These design features must
be evaluated by researchers, technicians and
safety officers. It is of utmost importance for
these users to completely evaluate a product
for all of the safety, ergonomic and comfort
features, as there are vast differences between
how each manufacturer approaches BSC design
and HF/E engineering
“Designing tasks, equipment and
work stations to suit the user can
reduce human error, accidents and ill-
health.”
3
Evolution of the Human
Experience
For over four decades, Labconco has recognized
the need for BSCs to address these risks and
their resulting effect on end user comfort,
productivity and safety. The history of the
Purifier® Biosafety Cabinet shows how
Labconco has consistently lead the industry in
the evolution of BSC HF/E design, holding the
position as the industry’s premier innovator in
human factors design.
The first Class II Biosafety Cabinets resembled
fume hoods in general appearance. They were
console units with 90° vertical safety glass
sashes. These sashes pivoted and would not
fully close when the BSC was not in use. There
was a flaw in these designs, however, unlike
chemistry applications, microbiological tasks
tend to require significant time to perform, and
work is highly repetitive in nature. Standing at a
BSC, as one would in front of a chemical fume
hood, is not realistic; putting substantial strain
on the back, legs, arms and neck.
The First Purifier
In 1983, Labconco released the first of its
Purifier Series Class II BSCs. This was the first
BSC of its kind, designed for a seated operator.
A reconfiguration of internal systems (the
blower and filters) allowed for these BSCs to be
bench-mounted, and simply tilting the sash 10°
from vertical permitted a researcher to sit with
their legs comfortably below the BSC, placing
them much closer to their work, improving
working posture, reducing fatigue upper limb
and reducing task risk factors. Furthermore, the
angled sash decreased the reflection of light,
eliminating glare. Labconco removed all console
models from their catalog by 1995.
The changes brought on by the Purifier cabinet
addressed the immediate comfort needs of
users, and were quickly adopted by other
industry leaders. Never satisfied, though,
Labconco enlisted the assistance of a Human
Factors Practitioner, and consulted with several
microbiologists to once again create progress in
biosafety.
Delta brings Change
The 2000 release of the Purifier Delta® brought
to the industry a new standard for HF/E design.
The standard risk factors associated with Pipetting involve heavy usage of the hands and lower arms. Such factors
include repetitive movements and thumb usage, static posture, reach and twisting of the arms and wrists in
‘unnatural’ ways. As laboratories have been analyzed for Human Factors, or ergonomics (HF/E), strategies have
been developed to reduce the strain placed on researches due to incessant pipetting. OSHA recommends the
following (OSHA, 2011):
• Position the chair as to eliminate the need to reach up to pipette.
• Do not twist or rotate the wrist while pipetting.
• Hold the pipette with a relaxed grip.
• Select a lightweight pipette, properly sized for the user’s hand.
• Where possible, utilize a multi-channel pipette.
• Use pipettes with finger aspirators and thumb dispensers to reduce thumb strain.
• Take a 1-2 minute break after every 20 minutes of pipetting.
When using a pipette in a biosafety cabinet, extra planning should be performed to be sure that the layout of the
work center allows for directional work, reducing the amount of strain placed on reaching across one’s body.
Er
go
no
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ic
s
&
P
ip
et
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4
The Delta’s preeminent design brought
unprecedented comfort to almost every user.
Unlike previous BSC’s that were designed for
the average sized user, the Delta was optimally
designed around users between the 2.5 and
97.5 percentile for height of both men and
women (Labconco & Erickson-Harper, 2003).
To achieve this optimization, Labconco
attempted to forget everything they had
learned to date and build a cabinet around a
human operator. This meant addressing each
and every risk factor identified by the Human
Factors Practitioner and microbiologists.
To alleviate lower limb discomfort from hard
and sharp angles, the air inlet grille was
elevated and curved, building in an arm/elbow
rest. A second row of slots was added to ensure
continued safe airflow when the user’s arms
were at rest.
Several aspects of the safety glass sash were
addressed. The use of ultraviolet (UV) light in
cabinets was, before 2000, handicapped by the
inability to fully close the sash. The new sash,
still tilted, was fully closing and the
counterbalanced and anti-racking design
ensured easy, smooth movement. The inclined
sash could be operated by any user with a single
finger anywhere along the width of the sash. To
better accommodate different body sizes and
heights, the Purifier Delta came in two different
nominal sash heights, 8” and 10”. The sash
handle extrusion was substantially reduced in
width to maximize sight lines into the BSC
(Labconco & Erickson-Harper, 2003).
The work zone of the BSC underwent changes
as well. The total depth was configured to allow
for comfortable reach distances anywhere in
the cabinet, while not feeling claustrophobic
(the Purifier Delta boasted the largest cubic foot
volume of any Class II). The work surface was
designed for easy cleaning and to be
removable. Today, it continues to be the only
work surface that is a single piece of stamped
stainless steel. This requires no welding;
removing all seams and provides for a dish with
perfectly radiused edges.
The last piece of the puzzle involved changing
how the user and BSC controls interacted. First,
the analog pressure gauge used to indicate safe
cabinet performance was transplanted from its
position in the header panel above the sash and
out of view of the user, and integrated with the
Delta’s interior for easy viewing (at line-of-sight
while seated). The BSCs controls were also
removed from the header panel, placed on the
right hand corner post, removing the need of
the operator to stretch above their head to
control cabinet function. Finally, provisions and
installations of utility service valves (fixtures)
and the internal electrical outlets were moved
forward, toward the operator, and up on each
side wall within close reach, but out of the way
of manipulations at the work surface. With
these changes, all BSC controls and gauges were
compliant with the American with Disabilities
Act (ADA) and accessible by wheel chair bound
users (Equal Employment Opportunity
Commission and the U.S. Department of
Justice., 1991).
It required innovation in the HVAC industry to
cause another punctuated event in the
evolution of HF/E design in biosafety cabinets.
Logical Comfort
To increase the basic safety of BSC design,
Labconco engineers incorporated an
Electronically Commutated Motor (ECM) driven
5
blower into the Purifier Logic®. This motor
technology comes with a host of advantages
over previously used motors (Hunter & Rouse,
2008). These benefits come from two key
features of the ECM.
1. The design of the ECM is much more
efficient than that of other motor systems.
2. The ECM can be paired with a monitoring
system that can be programmed/trained to
provide valuable status information.
The efficiency of the ECM can be experienced
by a user. Long time users complained of two
inescapable characteristics of BSC use: heat and
noise. Traditional motor systems required the
induction of magnetic fields to turn the blower,
a by-product of which is heat. Subsequently, the
air moving through the cabinet would heat,
causing sweating, discomfort and fatigue of the
researcher. The ECM does not require this
magnetic induction and therefore does not heat
up, maintaining ambient temperatures. Also, a
provision of the ECM’s design and efficiency is a
reduction in the noise emitted from the motor
blower. Operators realize a 50% reduction in
noise levels when BSCs utilize an optimally sized
ECM.
The Logic continued to add value to the HF/E
efforts of Labconco when the antiquated analog
gauge was replaced by a Digital LCD display
(mounted at line-of-sight while seated, of
course). Icons were utilized for at-a-glance
monitoring of critical working parameters
including filter loading, airflow disruption, and
cabinet component functions. Furthermore, a
status line gives descriptive feedback on system
conditions using words, replacing the
commonly used but vague red indicator light
and buzzer, the minimum requirements of BSC
safety standards.
The microbiologists Labconco consulted also
expressed the need for a cabinet to clearly
communicate when the HEPA filters require
service. The HEPA Filter Life Remaining gauge
(expressed as a percentage) delivers an
accurate, real-time evaluation of filter life. This
is only made possible by the incorporation of
the ECM (Hunter & Rouse, 2008).
Opportunistic developments have once again
allowed Labconco to stay at the forefront of
BSC design, and, again, a new cabinet
introduction will revitalize human factors design
in microbiology and biosafety.
Embracing Human Inclination
Building on four decades of ergonomic
innovation, the Purifier Logic®+ design team
scrutinized every BSC, looking to find, design
and utilize the best features found throughout
the industry. Their work resulted in the
development of the most extensive human
factors package, Inclination™ Technology, and
the MyLogic™ Operating System.
Anyone who has performed even the most simple of tasks in a microscope has realized that these devices are not
without their drawbacks. The arch of the oculars, bright lights and control knobs place extra strain on the eyes,
neck, shoulders, lower back and wrists. Human Factors Design has come a long way in microscopy to address each
of these risk factors. Articulating ocular heads and telescoping eye pieces have helped to reduce strain on the neck
and shoulders. Many microscopes now have accessories such as digital displays with optical and digital zoom that
are easier on the eyes, and pads to support the arms while controlling the focus and stage of the microscope.
Some of the biggest improvements in safety and performance when working with microscope cannot be
purchased, but are practiced by the operator. These include (OSHA, 2011):
• Sit close to the work surface or microscope.
• Avoid leaning on hard edges.
• Adjust the chair, workbench, or microscope as needed to maintain upright head posture.
• Take short breaks every 15 minutes, close the eyes or focus on something in the distance.
• Every 30-60 minutes, get up, stretch and move around. E
rg
on
om
ic
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&
M
ic
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op
y
6
Keeping the ergonomically sound design of the
Delta and Logic as the foundation, the goal of
Inclination Technology is to maximize safety
through observing and understanding human
habits. Modifications that evoke the essence of
the human experience were added to the
counter balanced, anti-racking, inclined sash,
line-of-sight digital display, ADA compliant
cabinet controls, electrical outlets and utility
service fixtures. For safe entry of cords, cables
and tubing connecting two devices, one outside
of the BSC the other in the BSC’s work zone, a
portal was designed that remained within easy
reach of a seated user, keeps such connections
out of the way of a busy work station, and
protects both the lab and the BSC interior from
loss of containment through a vacuum lock
system. The Vacu-Pass™ Cord & Cable Portal
was first submitted for NSF/ANSI Standard 49
approval in 2012; only after ensuring the design
met all three of the above requirements, was it
formally adopted into BSC design.
Another feature commonly cited as a safety
feature only intrigued and confounded the
design team, the internal electrical outlet. Their
presence and location in the BSC is designed for
HF/E; outlet covers that protrude into the
interior of the BSCs work zone and utilize
loaded springs are anything but ergonomic. The
self-closing mechanisms, required by laboratory
design codes, utilize loaded springs that exert
significant force on the doors; turning them into
high velocity finger traps. To counter this bear-
trap like operation, the stainless steel covers’
hinges have been dampened for slow closing
execution. Furthermore, the stainless steel
electrical outlet covers, of the Logic+, are flush
mounted increasing cabinet access and are easy
to clean during surface decontamination of the
cabinet’s interior.
In today’s fast paced world, it is expected that a
device be ‘plug-and-play’ or turnkey. In
consumer products, this typically means that
the set-up of a device is launched at initial start-
up and is a ‘self-guided’ procedure. This fact
was not lost on the design team. Building from
the digital display employed in the Logic,
MyLogic OS utilizes an optimized, multifunction,
color display with intuitive programming
designed to guide an operator through cabinet
set-up, calibration and diagnostic assistance.
Using full sentences, MyLogic OS leads a new
user through Smart-Start™ set-up, allowing for
control of the cabinet’s entire operation with
simple sash movement. Cabinet status is
displayed on the digital display, and utilizing
system feedback, a diagram of a BSC highlights
areas of the cabinet affected by or causing an
alert or alarm condition. This graphic is
accompanied by a status message that
describes the condition and provides
correctional walk-through instructions. Though
not recommended, the Logic+ could easily be
set-up and operated without ever consulting
the Operator’s Manual.
“…the goal of Inclination Technology
is to maximize safety through
observing and understanding human
habits.”
7
Conclusion
The first Class II biosafety cabinets were
developed with the advent of laminar airflow in
the 1960’s (CDC, 2009). Even though comfort is
paramount to the safety of the operator, it took
nearly 40 years before industry manufacturers
began taking ergonomics seriously. In the time
since then, BSC design has taken on its own look
and feel, with thoughtful regard toward how
form should meet function. However, there
exists a paradox in HF/E engineering, it has
become expected that there be greater
advances made in a shortened period of time
between product releases.
For Labconco, this paradox has been met in
different ways, but always with the same goals
– to provide total comfort, effortless operation
& maximum safety. To this end, there is only
one road to take; collaboration with laboratory
users leading to innovation in design. Invention
in BSC human factors design will continue to
develop, and will have positive impact on safety
performance. How each BSC manufacturer
approaches this concept is the underlying
reason why biosafety cabinets, when designed
to meet just a safety standard, are not created
equally.
References
Hunter, J., Meinders, M. & Garrett, B., 2010.
Controlling Airflow in Class II Biosafety Cabinets.
Kansas City: Labconco Corp.
Mitchell, T. & Longyear, S., 2012. Laboratory
Ergonomics: Pipetting, microscope use, and
hood work, s.l.: Working Well.
ORS, n.d. Office of Research Services (NIH)
Ergonomics at Work: Laboratories. [Online]
Available at: http://www.ors.od.nih.gov
[Accessed 21 January 2013].
UCLA, 2012. UCLA Ergonomics: Laboratory
Workstation Evaluation Checklist. [Online]
Available at:
http://ergonomics.ucla.edu/homepage/laborat
ory-ergonomics/
[Accessed 21 January 2013].
UHS Tang Center at UC Berkeley, 2013.
Laboratory Ergonomics. [Online]
Available at:
www.uhs.berkeley.edu/facstaff/ergonomics/
[Accessed 22 January 2013].
Works Cited
CDC, 2009. Biosafety in Microbiological and
Biomedical Laboratories. 5th ed. Washington,
D.C.: National Instute of Health.
EOHSS, 2009. Laboratory Ergonomics: a guide to
proper work practices and design of your work
Environment. [Online]
Available at:
http://www.umdnj.edu/eohssweb/publications
/LabErgonomics.pdf
[Accessed 23 January 2013].
Equal Employment Opportunity Commission
and the U.S. Department of Justice., 1991.
American with Disabilities Act Handbook.
Wasingint, D.C.: U.S. Government Printing
Office, Superintendent of Documents..
HSE, n.d. Health and Safety Executive: Human
Factors Design. [Online]
Available at: www.hse.gov.uk/humanfactors
[Accessed 22 January 2013].
Hunter, J. & Rouse, M., 2008. The Advantages of
Using an Electronically Commutated Motor
(ECM) in Biosafety Cabinets. Kansas City:
Labconco Corp..
8
Labconco & Erickson-Harper, T., 2003.
Designing a biosafety cabinet to optimize user
ergonomics and safety: a review of the
Labconco Purifier(R) Delta(R) Series Biological
Safety Cabinet.. Kansas City(Missouri): s.n.
Mitchell, T. & Longyear, S., 2012. Laboratory
Ergonomics: Risk factors and workbench
assessment, s.l.: Working-Well.
OSHA, 2011. Laboratory Safety: Ergonomics for
the Prevention of Musculoskeletal Disorders.
Washington, D.C.: OSHA.
About the Author: Brian Garrett is a Product
Specialist and LEED Green Associate at
Labconco Corporation supporting Life Science
applications and Class II Biological Safety
Cabinets. Prior to joining Labconco he was a
Microbiologist, QA/QC Supervisor and
Laboratory Manager over microbiological food
testing labs at the Institute for Environmental
Health (IEH-MEI).
©2013 Labconco Corporation
8811 Prospect Avenue
Kansas City, MO 64132
(800) 821-5525
www.labconco.com
Maximizing User Safety Through Human Factors Design
Unlike most industries and professions, the very nature of laboratory science is hazardous. Technicians and researchers are required to handle and are in close proximity to substances, agents and materials that are inherently risky. For this reason, greater heed should be taken in selecting equipment that maximizes safety by reducing the risk of the workstation's effect on the user.
Dec 28, 2018
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