Design to Minimize Ownership Costs in an Energy Guzzling
Large Animal Biocontainment Building
Kenneth Gow, Merrick and Company
Biocontainment laboratories are expensive to build and expensive
to operate. The challenge of incorporating sustainability principles
is to do so in a way that does not compromise the integrity of the
biocontainment system that is essential in protecting occupant and
environmental safety.
The USDA is currently building a BSL-3 Ag large animal housing
facility as part of the modernization of the National Animal Disease
Center in Ames, Iowa. The design of this building involved many
challenges in providing for the needs of the research program in
a structure that meets the exacting requirements laid down by the
USDA for biocontainment integrity.
The containment design of the building was formidable in itself.
The structure not only has to form a stable backing for the impervious
containment barrier, it has to restrain and withstand severe impact
loads from animals up to the size of bison. The electrical systems
have to provide reliability and redundancy while withstanding the
corrosive effects of decontamination. The mechanical systems provide
high ventilation flows while HEPA filtering all supply and exhaust
air.
To minimize the energy consumption and maintenance effort compounded
the design effort. Heat recovery and flexible operating scenarios
were incorporated. CFD analysis was used to maximize ventilation
effectiveness and as much equipment as possible was located outside
of the contained space.
Findings:
The operating costs of a BSL-3 Ag building are highly dependant
on the ventilation rates. Ventilation rates are dictated by the
requirements of AAALAC (Association for Assessment and Accreditation
of Laboratory Animal Care). Although AAALAC requirements allow a
scientific approach to determining ventilation rates, compliance
is most easily demonstrated by a proscriptive air change rate. Our
CFD study showed that ventilation effectiveness is determined by
room layout and air distribution location as much as by air quantities.
Other unusual aspects of the design process included the exceptionally
close coordination required between different design disciplines.
The rugged penning and gating required to restrain large animals
such as bison, required substantial structural embedments in the
poured in place concrete structure. These in turn interfered with
electrical and plumbing services. Coordination required up to ten
professionals working together to solve problems on a clash by clash
basis. On top of this, the close relationship developed by the designers
with the USDA scientific program staff, was essential to ensure
that the scientific needs of the building were carried through into
the design.
The USDA Ames modernization included additions and enhancements
of the co-generation energy plant. This will serve the fully developed
site with an energy efficient source of steam and chilled water.
However, to reduce the energy demand of the all outside air system,
run around coil heat exchangers were incorporated in the design.
Labs21 Connection:
The BSL-3 Large Animal Building at Ames is a state of the art facility
designed to contain dangerous and exotic research pathogens. The
buildings unique features both prevent accidental release and at
the same time protect its occupants.
As the design developed, a "whole building" approach
became essential as the interrelatedness of every building component
became apparent. With the assistance of biocontainment experts,
architects along with structural, electrical, agricultural and mechanical
engineers worked together to integrate each component into the building.
Measures to reduce expected energy use included analysis of the
fundamental ventilation requirements in the animal rooms and use
of a run around energy recovery loop in the all outside air system.
A commissioning plan has been prepared as part of the design and
detailed functional performance check lists will ensure that the
system design intent is met.
Biography:
Ken Gow is a mechanical engineer with Merrick and Company
of Denver. In his five years with Merrick, Ken has designed mechanical
systems for laboratories built throughout the United States. He
is presently working on the design of a number of biocontainment
facilities.
Prior to joining Merrick, Ken gained many years of experience in
Australia and South East Asia. His notable projects in Australia
included mechanical designs of hospitals and laboratories. In Malaysia,
he worked as a project engineer on the chiller plant and retail
complex associated with the Petronas Towers.
Ken holds a bachelor of engineering degree from the University
of Western Australia and a master of engineering management degree
from Curtin University in Australia. He is a registered professional
engineer in Colorado and a member of the American Society of Heating,
Refrigerating and Air Conditioning Engineers and the Institution
of Engineers, Australia.
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