Infection Control and Construction

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Infection Control in Construction

• Clark Buttner - Registered Architect
• Senior Staff Engineer
• Design and Construction Department
• The University Hospital
• Cincinnati, Ohio

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Presentation Topics

• Fundamentals of Building Air Distribution
• Using Air Pressure to Isolate Construction Sites

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Heat Transfer

• Conduction is commonly the transfer of energy
  through the interior of a substance. For example,
  if you apply heat to one side of a piece of
  metal, soon the other side will become hot.
  Conduction also happens when two different
  substances come in contact. Consider for example
  your coffee spoon heating up from contact with
  the hot coffee in your cup. Conduction is most
  effective in solids-but it can happen in fluids.
  Have you ever noticed that metals tend to feel
  cold? Believe it or not, they are not colder!
  They only feel colder because they effectively
  conduct heat away from your hand. You perceive
  the heat that is leaving your hand as cold.
• Radiation Electromagnetic waves that directly
  transport heat energy through space. Sunlight is
  a spectrum of electromagnetic waves that radiate
  through space to warm our planet without the aid
  of direct contact as in conduction. Sunlight is
  changed to heat when it contacts the surface of
  our planet. Infrared light is another
  electromagnetic spectrum that generates heat on
  contact with a substance. Consider standing in
  front of a fire on a cold night. The heat you
  feel is radiated directly from the fire.
• Convection is the transfer of heat by the actual
  movement of a heated medium. Heat leaves your
  coffee cup as the mediums of steam and air rise.
  Convection is the transfer of heat energy in a
  gas or liquid by movement of those mediums. The
  heat moves with the medium. Convection is the
  Heat Transfer mode used most frequently to heat
  buildings. The heat is transferred to air and the
  air is moved to a cold space to heat the space.

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HVAC System Configurations

• VAV Systems
• Induction Systems
• Convection Systems
• Dedicated Outdoor Systems
• Split Systems

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Duct Systems - Concept
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VAV Systems

• During the 1970s variable air volume (VAV)
  systems gained their current popularity. They are
  designed to supply only the volume of conditioned
  air to a space that is needed to satisfy the
  load. Fan energy is saved when the volume of air
  handled by the fan is reduced. Air volume control
  is accomplished by installing modulating dampers,
  or in some cases, an air valve, in the supply
  duct to each zone. As the room temperature demand
  becomes satisfied, the thermostat signals the
  damper to move the supply air zone valve toward
  the closed position.
• A key component in the VAV system is the air
  valve. It is commonly installed inside an
  insulated sheet metal box suspended in a ceiling
  plenum. The air valve has a damper that regulates
  the air flow in response to the room's
  thermostat. A multi-port pressure sensing ring
  provides both accurate airflow sensing and
  control in response to duct static pressure.
• When zone valves are throttled, the static
  pressure in the supply duct changes. A static
  pressure sensor located in the supply duct senses
  the static pressure change, and either increases
  or decreases the airflow from the source, using
  variable speed control or dampers on the main air
  supply fan.
• As VAV systems have evolved, so have the
  terminals. There are six popular VAV systems.
  They are
• Shutoff
• VAV Reheat
• Parallel Fan Powered
• Series Fan Powered
• Dual Duct
• Changeover/Bypass

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VAV Reheat Schematic
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Air Handling Unit
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Dual Duct System
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Single Duct System Schematic
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Diffusers
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Air Movement
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FPM vs CFM
FPM Feet per Minute, a rate or speed CFM Cubic
Feet per Minute, a rate of volume CFM must be
divided by the cross sectional area of the duct
in order to find FPM A duct carrying 400 cfm that
has a dimension of 6x8 will have a FPM of 400
x .5 x .66 132
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Pressure Differential
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New Buildings
New building construction presents some risk to
hospital patients. Protective measures during
construction adjacent to existing facilities can
include

• Exterior pre-filters
• Internal pre-filters
• Reduce air infiltration
• Building pressurization
• Building recirculation daytime
• Redefine patient pathways
• Dust Sampling

• Reduce dust generation through wetting
• Monitor demolition and/or excavation
• Monitor wind and weather

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HEPA Fans

• Abatement Technologies HEPA Fan Models
• HEPA-AIRE Model H600V - At just 46 lbs.,
  including filters, the H600V is our most
  lightweight and portable model. It is ideally
  suited for use in confined spaces, where space is
  limited. This mighty mite is designed to
  produce up to 600 cfm, yet draws only about 1.9
  operating amps. Features include two top handles,
  an attached 8 in. outlet collar and plastic feet
  to protect surfaces. Available options include a
  drop-in caster cart and an inlet manifold that
  accepts 8 inlet ducting.
• Variable speed controller (50-600 cfm)
• Filter change indicator light
• Maintenance-free motorized impeller
• Internally protected, 99.97 certified HEPA
  filter
• HEPA-AIRE Model H1000V - The compact,
  full-feature H1000V is a smaller and more mobile
  option to 2,000 cfm machines. It is ideal for
  jobs requiring a higher level of portability and
  maneuverability, such as residential mold
  remediation. Features include a polished aluminum
  cabinet, professional, high-tech appearance and
  all the bells and whistles. The fully variable
  speed controller (100-900 cfm) enables the user
  to "tune in" airflow to meet specific job
  requirements.
• Solid rivet aircraft construction
• Modular, recessed control panel
• Tested certified 99.97 HEPA filter
• Filter change indicator light
• Weighs just 79 lbs.
• HEPA-AIRE Model H1990HP - The H1990HP provides a
  lighter (142 lbs.) and narrower option to
  full-size 2,000 cfm models. It is equipped with
  the same 1.75-hp, 2-speed motor as the full-size
  2000 models, and its peak airflow of 1,800 cfm is
  only 10 less.
• High capacity fiberboard HEPA tested at 1,800 cfm
  
• Deluxe, recessed control panel
• Thermal overload protection

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Pressure and Measurement
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Environment of Care
Standard EC.5.50The hospital develops and
implements activities to protect occupants during
periods when a building does not meet the
applicable provisions of the Life Safety
Code.Note This standard does not apply to
facilities classified as a business occupancy by
the LSC.Rationale for EC.5.50When building code
deficiencies are identified and cannot be
immediately corrected or during renovation or
construction activities, the safety of patients,
staff, and other people coming to the hospitals
facilities is diminished. Hospitals need to
proactively identify administrative actions (for
example, additional training, additional
inspections, additional fire drills, and so on)
to be taken ifthese scenarios arise.Elements of
Performance for EC.5.501. Each hospital develops
a policy for using interim life safety measures
(ILSMs).2. The policy includes written criteria
for evaluating various deficiencies and
construction hazards to determine when and to
what extent one or more of the following measures
apply Ensuring free and unobstructed exits.
Staff receives additional information/communicatio
n when alternative exits are designated.
Buildings or areas under construction must
maintain escape routes for construction workers
at all times, and the means ofexiting
construction areas are inspected daily.
Ensuring free and unobstructed access to
emergency services and for fire, police, and
other emergency forces Ensuring that fire
alarm, detection, and suppression systems are in
good working order. A temporary but equivalent
system must be provided when any fire system is
impaired. Temporary systems must be inspected and
tested monthly. Ensuring that temporary
construction partitions are smoke-tight and built
of noncombustible or limited combustible
materials that will not contribute to the
development or spread of fire Providing
additional fire-fighting equipment and training
staff in its use Prohibiting smoking throughout
the hospitals buildings and in and near
construction areas Developing and enforcing
storage, housekeeping, and debris-removal
practices that reduce the buildings flammable
and combustible fire load to the lowest feasible
level Conducting a minimum of two fire drills
per shift per quarter Increasing surveillance
of buildings, grounds, and equipment, with
special attention to excavations, construction
areas, construction storage, and field offices
Training staff to compensate for impaired
structural or compartmentalization features of
fire safety Conducting hospitalwide safety
education programs to promote awareness of fire
safety building deficiencies, construction
hazards, and ILSMs3. Each hospital implements
ILSMs as defined in its policy.
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HEPA Tent Enclosure
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Construction Barriers
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Barrier Type 1
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Barrier Type 2
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Barrier Type 3
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Barrier Type 4
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Architectural Fire Wall Plan
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Site Details
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Infection Control in Construction