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Task-Specific Ventilated Robotic Enclosures for Product
and Worker Protection in High-Throughput Laboratories
Douglas B. Walters,
Ph.D., CSP, KCP, Inc.
Today's laboratories have changed significantly. Synthesis-based
R&D has moved into the new millennium and been replaced with
advanced analysis/discovery processes utilizing sophisticated computer
and high throughput robotic technology. Many automated laboratory
practices produce aerosols and particulates, e.g., weighing, pipetting,
transfer, handling, autoclaving, and incubating. The laboratory
use of high-throughput technology with hazardous solvents (e.g.,
DMSO, methanol), biological agents (e.g., HIV, TB, hepatitis), and
novel compounds of unknown potency (e.g., drugs), is rapidly expanding.
Enclosure, containment, and ventilation are frequently overlooked
when automated and robotic laboratory equipment is used with potentially
hazardous materials. Containment of these operations is further
complicated if clean environments are required for sample and worker
protection because incoming and exhaust air may require HEPA filtering.
Towards this goal we summarize development and testing of a task-specific
ventilated robotic enclosure designed and optimized for operator
and product protection. Computational fluid dynamics (CFD), (i.e.
computer modeling of airflows) was extensively used to analyze airflow
distributions inside the enclosure to optimize equipment and enclosure
layouts and to promote stable containment performance of the entire
airflow system. The final design employs a unique double-filtration
system to deliver unidirectional horizontal airflow distribution
throughout the work area, thus eliminating turbulent recirculation
zones susceptible to work area concentration build-up, ensuring
stable balance reading characteristic of a unidirectional airflow
design, while providing reliable worker and product protection.
Findings:
Recent studies conducted at Bristol-Myers Squibb to investigate
potential for air and surface contamination with compounds of unknown
toxicity during robotic operations indicated detectable model compound
levels present in air samples taken near the balance when the robot
malfunctioned and dropped a vial, spilling its components, thus
clearly emphasizing the need for robotic systems to be contained
within appropriate vented enclosures to minimize the potential for
inhalation exposure. While a variety of vented devices providing
different levels of containment protection during routine laboratory
operations exist today, the need to enclose automated robotic equipment
results in unconventional challenges and requires additional design
considerations. With laminar non-turbulent airflow inside the vented
work area being a crucial factor in providing stable containment
protection, the geometric configuration of the robot together with
the presence of its moving parts creates obstacles along the airflow
pathways resulting in excess turbulence and leading to the loss
of containment. This presentation documents the design of a vented
robotic enclosure aimed at addressing these concerns. Presented
results highlight the advantages of establishing lateral work area
airflow pattern in ensuring efficient contaminant removal and document
the use of a patented double-filtration system to deliver efficient
worker and sample protection. Computer simulated airflow patterns
within the enclosure illustrate the solution strategy employed in
the task specific iterative design process, while presented smoke
test results provide test data necessary to validate the stated
design objectives.
Labs21 Connection:
The changing function of the modern lab environment results in
additional challenges requiring flexible task specific solutions
to minimize environmental impacts, protect operator safety and optimize
overall process efficiency. In particular, the need to identify
new drag components in the pharmaceutical industry has resulted
in the use of advanced concepts of combinatorial chemistry requiring
employment of automated analysis/discovery processes utilizing sophisticated
computer and high throughput robotic technology. Containment of
these automated operations within vented enclosures is important
due to the documented instances of air and surface contamination
during robotic handling of compounds of unknown toxicity. Conventional
containment solutions, i.e. chemical hoods, bio-safety cabinets
and/or glove boxes are ill suited for the task of robotic containment
due to increased turbulence levels and airflow obstructions produced
by the robot geometry, thus requiring enclosure design optimization
to permit adequate contaminant removal and provide efficient operator
and sample protection. CFD-based computer modeling provides unique
insight into the detailed flow field characteristics of the entire
ventilation process. In that, it allows for studying the airflow
patterns within the enclosure/robot system by providing directional
velocity distribution within the enclosure and around the robotic
equipment, hence pointing the areas of potential concentration buildup
Subsequent computer modeling iterations are used to optimize enclosure
geometry and operation to ensure smooth airflow movement within
the robot work area. In addition, the exhaust characteristics of
the enclosure are modified to address the capture velocity and energy
efficiency concerns within the framework of providing operator and
product protection. The paper presents the summary of the iterative
CDF-driven design process and documents the smoke test results validating
enclosure performance, thus addressing the following aspects of
the Labs 21 Approach: minimize overall environmental impacts and
protect occupant safety, by eliminating the potential for air and
surface area contamination during automated robotic operations.
Biographies:
Douglas B. Walters, Ph.D., CSP, CCHO, is on the advisory
board for Flow Sciences, Inc. Dr. Walters is President of KCP Inc.;
a consulting company in Raleigh, North Carolina, specializing in
laboratory health and safety, laboratory ventilation and hoods,
and industrial hygiene. He is the former Head of Laboratory Health
and Safety for the National Toxicology Program (at the National
Institute of Environmental Health Sciences and former adjunct associate
professor in the Program of Public Health at Old Dominion University.
Dr. Walters has been a reviewer and served on the Editorial Board
for several publishers. Dr. Walters is a Certified Safety Professional
(CSP) and a Certified Chemical Hygiene Officer (CCHO). He is the
American Industrial Hygiene Association (AIHA) Liaison to the American
Chemical Society (ACS), a member of ANSI Z 9.5 Laboratory Subcommittee,
a member of numerous AIHA and ACS committees, and is past Chair
of the ACS Division of Chemical Health and Safety and the ACS Northeast
Georgia Section. Dr. Walters has lectured internationally, received
two ACS awards for his contributions to chemical health and safety,
and received three government awards. He has authored more than
100 publications, books, book chapters, electronic databases, journal
articles, one patent, and one video.
Dr. Walters received his Ph.D. in Chemistry at the University of
Georgia, Athens, received his MS and BS in Chemistry from Long Island
University, Brooklyn, NY.
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