Basic Documentation

Figure 4. Infection Isolation Room Ventilation Arrangement for an Immunosuppressed Patient
with a Contagious Disease.
Isolation Room HVAC Design
Considerations
The 2006 edition of the AIA Guidelines for Design
and Construction of Hospital and Health Care
Facilities state that the number of airborne infection
isolation rooms provided shall be based on the ICRA
or by a multidisciplinary group designated for that
purpose
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. This means that the Infection Control
Risk Assessment (ICRA) and the facility location
(urban versus rural) establish the appropriate
isolation room ratio. The AIA Guidelines also require
an airborne infection isolation room for ED, nurseries
and critical care units.
Supply Air
An important component of being able to ensure a
healthy environment is to have a source of good
quality supply air. If outside air intakes are properly
located and the areas in proximity to the intakes are
properly maintained, outside air will be virtually free
of bacteria and viruses in comparison to interior
air.
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The following list describes important design
Page 8 of 12 Siemens Industry, Inc.
Document No. 149-903
14. AIA Guidelines, 2006, Section 2., p. 26
15. Statement: 2003 Application Handbook, Health Care
Facilities
factors that should be applied to all fresh air intakes
to meet these criteria:
 The bottom of all HVAC supply air intakes
should be a minimum of 6 feet above ground
level and preferably as high as practical to
reduce the intake of vehicular exhaust, surface
dust, and mold spores that originate in damp or
wet areas.
 Supply air intakes and the surrounding area
should be designed to lessen the potential
contamination by birds (no pigeon roosting
ledges near the intakes).
 For roof locations, supply air intakes should be a
minimum of 3 feet above the roof and as far as
possible (at least 25 feet) from any exhaust
outlet on the roof, including medical exhausts
and emergency generator exhaust. All roof
areas, and especially the area near a supply air
intake, should have good drainage to prevent
accumulation of standing water and prevent
mold growth.
 Supply air intakes must be at least 10 feet, or
more, from plumbing vents and medical vacuum
exhaust, if these exhausts are discharged above
the supply air intakes. Supply air intakes should
be located as far as possible from cooling
towers where microscopic water droplets could
be entrained into the supply air.