used to supplement ventilation, particularly in facilities located in areas of high incidence for
TB.
Scheduled areas (clinics): All scheduled areas serving patients who are at high risk of TB
transmission should be designed to reduce the risk of TB transmission. Air from clinics
serving patients at high risk for TB should not be recirculated unless it is first passed
through an effective high-efficiency filtration system (HEPA filters are currently the effective
high-efficiency filtration system available)".
4. HVAC Design Manual for Hospital Projects dated August 1, 1999, paragraphs
A36.4.D, `Return Air systems recommend:
"Unscheduled Ambulatory Care Areas, Emergency Care areas, and associated waiting areas.
Scheduled Ambulatory Care Areas
Air supplied to the ambulatory care areas can be recirculated and returned to the air handling
unit system provided the return air is recirculated through the HEPA (High Efficiency
Particulate Air) filters.
Install HEPA filters at the air handling unit level only. HEPA filters installed in branch return
air ducts will create air-balancing problems. Only qualified personnel should maintain,
decontaminate, and dispose of HEPA filters".
RECOMMENDATIONS/CONCLUSION:
1. It's clear from above, the basic requirements for admitting and waiting rooms
are, that they should be under negative pressure with a minimum number of 6
air changes per hour of supply air, all air should be exhausted to outside, and
where it's not practical in existing systems, the air can be recirculated through
HEPA filters.
2. Follow HVAC Design Manual for Hospital Projects dated August 1, 1999,
which include ASHRAE, CDC, and Program and Facility Planning Guidance
for Tuberculosis Programs recommendations for admitting and waiting rooms.
3. Where the VA Design Criteria exceed the minimum requirements outlined in
the CDC document, follow VA criteria for all-new facilities and major renovation
projects. For existing facilities where compliance with the VA criteria may not
be feasible (or cost effective) due to limitations of the configuration of the
HVAC system, the minimum requirements outlined in the CDC document
should be implemented.
FOR ADDITIONAL INFOR MATION:
Contact Satish Sehgal at 202-565-5032 in Facilities Quality Service (181A).
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