Basic Documentation

Biological Laboratories
Siemens Industry, Inc. 59
Topic Requirement(s) Commentary
Biosafety
Level 3
ASHRAE, 2011 Handbook - HVAC Applications, Laboratories, Pg. 16.17,
Containment Laboratories:
Biosafety Level 3 applies to facilities in which work is done with indigenous or
exotic agents that may cause serious or potentially lethal disease as a result of
exposure by inhalation. The Biosafety Level 3 laboratory uses a physical barrier of
two sets of self-closing doors to separate the laboratory work area from areas with
unrestricted personnel access. This barrier enhances biological containment to
within the laboratory work area.
All procedures involving the manipulation of infectious materials are conducted
inside biological safety cabinets. The engineer must ensure that the connection of
the cabinets to the exhaust system does not adversely affect the performance of the
biological safety cabinets or the exhaust system.
U.S. Dept. of Health and Human Services, Centers for Disease Control and
Prevention publication: Biosafety in Microbiology and Biomedical Laboratories,
(BMBL) 5th edition 2009:
Biosafety Level 3 is applicable to clinical, diagnostic, teaching, research, or
production facilities where work is performed with indigenous or exotic agents that
may cause serious or potentially lethal disease through the inhalation route of
exposure. Laboratory personnel must receive specific training in handling
pathogenic and potentially lethal agents, and must be supervised by scientists
competent in handling infectious agents and associated procedures.
A BSL-3 laboratory has special engineering and design features
All procedures involving the manipulation of infectious materials must be conducted
within BSCs or other physical containment devices.
Laboratory doors must be self-closing and have locks in accordance with the
institutional policies. The laboratory must be separated from areas that are open to
unrestricted traffic flow within the building. Laboratory access is restricted. Access to
the laboratory is through two self-closing doors. A clothing change room (anteroom)
may be included in the passageway between the two self-closing doors.
All windows in the laboratory must be sealed.
A ducted air ventilation system is required. This system must provide sustained
directional airflow by drawing air into the laboratory from “clean” areas toward
“potentially contaminated” areas. The laboratory shall be designed such that under
failure conditions the airflow will not be reversed.
a. Laboratory personnel must be able to verify directional airflow. A visual monitoring
device, which confirms directional airflow, must be provided at the laboratory entry.
Audible alarms should be considered to notify personnel of air flow disruption.
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BSL-3 laboratories are not very common, but it
is not unusual to find a few of them on the
campus of a major university.
Note that the authors of the 2009 edition of
BMBL may not have realized that their
statement “under failure conditions the airflow
will not be reversed” can be (and apparently
has been) interpreted by the industry to mean
that no reverse airflow can take place even for
a second regardless of the situation. Such an
interpretation would require extremely
expensive power backup systems and perhaps
redundant HVAC to handle a seemingly very
short transient period. This may not be the
consensus opinion of the BMBL committee.
Also refer to the requirements of NFPA 45
(page 115 ) for insight into this situation.