Basic Documentation

Table Of Contents
Exhaust Systems
Siemens Industry, Inc. 145
Topic Requirement(s) Commentary
Recirculated
Air and Cross
Contamination
(Continued)
American National Standard for Laboratory Ventilation ANSI/AIHA Z9.5-2003
5.3.4 The discharge of potentially contaminated air that contains a concentration
more than the allowable breathing air concentration shall be:
Direct to the atmosphere unless the air is treated to the degree necessary for
recirculation (See Section 9.3);
5.3.6 Nonlaboratory air or air from building areas adjacent to the laboratory may be
used as part of the supply air to the laboratory if its quality is adequate.
5.3.6.1 Air exhausted from the general laboratory space (as distinguished from
laboratory chemical hoods) shall not be recirculated to other areas unless one of the
following sets of criteria is met:
1) Criteria A
There are no extremely dangerous or life-threatening materials used in the
laboratory;
The concentration of air contaminants generated by maximum credible accident
will be lower than short-term exposure limits required by 2.1.1;
The system serving the laboratory chemical hoods is provided with installed
redundancy, emergency power, and other reliability features as necessary.
2) Criteria B
Recirculated air is treated to reduce contaminant concentrations to those
specified in 2.1.1.
Recirculated air is monitored continuously for contaminant concentrations or
provided with a secondary backup air-cleaning device that also serves as a
monitor (via a HEPA filter in a series with a less efficient filter, for particulate
contamination only). Refer to Section 9.3.1;
Provision for 100% outside air, whenever continuous monitoring indicates an
alarm condition.
5.3.6.2 Exhaust air from laboratory hoods shall not be recirculated to other areas.
Hood exhaust air meeting the same criteria as noted in Section 5.3.6.1 shall only be
recirculated to the same work area where the hood operators have control of the
hood work practices and can monitor the status of air cleaning.
American Institute of Architects, GUIDELINES FOR PLANNING AND DESIGN OF
BIOMEDICAL RESEARCH LABORATORY FACILITIES 1999
C.14.4 Hazardous Waste Storage and Handling
h. A separate ventilation system shall be installed for the storage room. Exhaust
shall be directed away from the building and the buildings’ air intakes. This
ventilation system shall be connected to the building’s standby power system and
contain appropriate filtration and monitoring devices.
(Continued on Next Page)
See applicable commentary on the previous
page.