Transcript Infection Control and Construction

Infection Control in Construction
Clark Buttner - Registered Architect
Senior Staff Engineer
Design and Construction Department
The University Hospital
Cincinnati, Ohio
Presentation Topics
Fundamentals of Building Air
Distribution
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Using Air Pressure to Isolate
Construction Sites
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.
HVAC System Configurations
 VAV Systems
 Induction Systems
 Convection Systems
 Dedicated Outdoor Systems
 Split Systems
Duct Systems - Concept
VAV Systems
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During the 1970’s 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:
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Shutoff
VAV Reheat
Parallel Fan Powered
Series Fan Powered
Dual Duct
Changeover/Bypass
VAV Reheat Schematic
Air Handling Unit
Dual Duct System
Single Duct System Schematic
Diffusers
Performance Data - 24 x 24 / 600 x 600 Face Size
Liste
d
Size
6
8
Neck Velocity (fpm)
Velocity Pressure, in w.g.
400
.010
500
.016
600
.022
700
.031
800
.040
900
.050
1000
.062
1200
.090
1400
.122
1600
.160
Total Pressure
Flow Rate, cfm
NC
Throw 150, 100, 50
.015
78
-1-2-4
.023
98
-1-2-4
.034
118
-2-3-5
.046
137
-2-3-6
.060
157
-2-4-7
.076
176
19
3-4-7
.094
196
22
3-4-7
.135
235
28
4-5-8
.183
274
33
4-6-9
.239
314
37
5-7-9
Total Pressure
Flow Rate, cfm
NC
Throw 150, 100, 50
.016
140
-2-2-5
.025
175
-2-3-6
.037
209
-2-4-7
.050
244
-3-4-8
.065
279
19
3-5-9
.082
314
22
4-6-9
.102
349
26
4-610
.146
419
31
5-7-11
.199
489
36
6-8-12
.260
558
40
7-9-12
Air Movement
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 6”x8”
will have a FPM of: 400 x .5’ x .66’ = 132
Pressure Differential
New Buildings
New building construction presents some risk to hospital patients. Protective measures during
construction adjacent to existing facilities can include:
•Exterior pre-filters
•Reduce dust generation through wetting
•Internal pre-filters
•Monitor demolition and/or excavation
•Reduce air infiltration
•Monitor wind and weather
•Building pressurization
•Building recirculation daytime
•Redefine patient pathways
•Dust Sampling
HEPA Fans
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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.
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High capacity fiberboard HEPA tested at 1,800 cfm
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Deluxe, recessed control panel
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Thermal overload protection
Pressure and Measurement
Environment of Care
Standard EC.5.50
The 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.5.50
When 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 hospital’s 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 if
these scenarios arise.
Elements of Performance for EC.5.50
1. 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/communication when alternative exits are designated. Buildings or areas under
construction must maintain escape routes for construction workers at all times, and the means of
exiting 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 hospital’s buildings and in and near construction areas
* Developing and enforcing storage, housekeeping, and debris-removal practices that reduce the building’s 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 ILSMs
3. Each hospital implements ILSMs as defined in its policy.
HEPA Tent Enclosure
Construction Barriers
Barrier Type 1
Barrier Type 2
Barrier Type 3
Barrier Type 4
Architectural Fire Wall Plan
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Infection Control in
Construction