1. Six total air changes per hour are likely to reduce the concentration of bacteria the room. For
the purposes of reducing the concentration of droplet nuclei, TB bedrooms and treatment rooms in
existing health care facilities should have an airflow of greater than or equal to six air changes per hour.
Where feasible, this airflow rate should be increased to greater than or equal to 12 air changes per hour.
New construction or renovation of existing health care facilities should be designed so that TB bedrooms
achieve an airflow of greater than or equal to 12 air changes per hour.
2. Air from TB bedrooms and treatment rooms for S@ TB patients should be exhausted to the
outside. The air should be exhausted in a manner and location so that it is not pulled into intake louvers
or windows without significant dilution. At a minimum, the exhaust shall be 25 feet from any air intake.
However, other factors, such as wind direction, wind velocity, stack effect, system sizes, and height of
buildings must be evaluated and location of intake and exhaust outlets adjusted as required. If, in some
instances, recirculation of air into the general ventilation system from such rooms is unavoidable, high-
efficiency particulate air (HEPA) filters should be installed in the exhaust leading from the room to the
general ventilation system. Air from TB bedrooms and treatment rooms in new or renovated facilities
should not be recirculated into the general ventilation system.
3. Exhaust air quantity must be 10% greater than the supply air. It is further recommended that
the exhaust system should serve only the TB rooms and not be part of the general exhaust system. If this
is not practical, then use of the general exhaust system is acceptable provided appropriate precautions are
taken to assure that these systems are adequately designed, installed, balanced and maintained. These
requirements result in providing additional outside air through the air handling system which then impacts
heating and cooling capacities for both air side and primary equipment. In all applications, thermal load
calculations or occupancy of the space may require a higher air change rate.
4. Rooms should be under negative pressure with respect to adjacent areas when occupied by a
patient with SIKI TB.
5. Anterooms are not necessary for SIKI TB patient bedrooms.
6. The direction of the air-flow for TB rooms shall be monitored daily when an S/KI TB patient
is occupying the room. When not in use by S/KI TB patients, the directional allow will be checked
monthly. The method of testing for directional airflow in the S/KI TB rooms is at the discretion of the
facility, but must be of an acceptable standard. This would include such methodologies as smoke tube
testing or an airflow gauge.
7. The number of air changes per hour in these rooms should be checked yearly at a
minimum. This may need to be more frequent based on facility risk assessment and recommendations of
the Environmental and Infection Control Committee. In addition, the number of air chances per hour
should be checked after any maintenance to the airflow system.
8. In rooms where patient turnover is expected, use CDC guidelines ( MMWR, October28,
1994,Vol.43,No.RR-13) for airchanges per hour to determine time required for removal of airborne
contaminants before the next patient occupies the room vacated by a patient with S/KI TB.
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