Basic Documentation

Laboratory Ventilation Codes and Standards
Siemens Industry, Inc. 68
Topic Requirement(s) Commentary
Ventilation
for Biosafety
Level 4, Suit
Laboratory
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:
An automatically activated emergency power source must be provided, at a minimum,
for the laboratory exhaust system, life support systems, alarms, lighting, entry and
exit controls, BSCs, and door gaskets.
Monitoring and control systems for air supply, exhaust, life support, alarms, entry and
exit controls, and security systems should be on a UPS.
BSCs and other primary containment barrier systems must be installed so that
fluctuations of the room air supply and exhaust do not interfere with proper
operations. BSCs should be located away from doors, heavily traveled laboratory
areas, and other possible airflow disruptions.
A dedicated, non-recirculating ventilation system is provided. Only laboratories with
the same HVAC requirements (i.e., other BSL-4 labs, ABSL-4, BSL-3 Ag labs) may
share ventilation systems if gas-tight dampers and HEPA filters isolate each
individual laboratory system.
The supply and exhaust components of the ventilation system must be designed to
maintain the laboratory at negative pressure to surrounding areas and provide
differential pressure or directional airflow as appropriate between adjacent areas
within the laboratory. Redundant supply fans are recommended. Redundant exhaust
fans are required. Supply and exhaust fans must be interlocked to prevent positive
pressurization of the laboratory.
The ventilation system must be monitored and alarmed to indicate malfunction or
deviation from design parameters. A visual monitoring device must be installed near
the clean change room so proper differential pressures within the laboratory may be
verified prior to entry.
Supply air to the laboratory, including the decontamination shower, must pass
through a HEPA filter. All exhaust air from the suit laboratory, decontamination
shower and fumigation or decontamination chambers must pass through two HEPA
filters, in series, before discharge to the outside. The exhaust air discharge must be
located away from occupied spaces and air intakes.
All HEPA filters must be located as near as practicable to the laboratory in order to
minimize the length of potentially contaminated ductwork. All HEPA filters must be
tested and certified annually. The HEPA filter housings must be designed to allow for
in situ decontamination and validation of the filter prior to removal. The design of the
HEPA filter housing must have gas-tight isolation dampers, decontamination ports,
and ability to scan each filter assembly for leaks.
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As a practical matter, it is helpful if the facility
operators using the Building Automation
System, get the same pressurization
information that the laboratory workers see at
the entry.