Basic Documentation

Table Of Contents
Exhaust Systems
Siemens Industry, Inc. 137
Topic Requirement(s)
Commentary
Components
(Continued)
American National Standard for Laboratory Ventilation ANSI/AIHA Z9.5-2003
5.3.3
Each fan applied to serve a laboratory exhaust system or to exhaust an individual
piece of laboratory equipment (e.g., a laboratory chemical hood, biosafety cabinet,
chemical storage, etc.) shall be adequately sized to provide the necessary amount of
exhaust airflow in conjunction with the size, amount, and configuration of the
connecting ductwork. In addition, each fan’s rotational speed and motor horsepower
shall be sufficient to maintain the required exhaust airflow and stack exit velocity and
the necessary negative static pressure (suction) in all parts of the exhaust system.
Laboratory exhaust fans shall be located as follows:
Physically outside of the laboratory building and preferably on the highest level roof
of the building served.
In roof penthouse or a roof mechanical equipment room that is always maintained
at a negative static pressure with respect to the rest of the facility, and provides
direct fan discharge into the exhaust stack(s).
All laboratory exhaust fans shall include provisions to allow periodic shutdown for
inspection and maintenance. Such provisions shall include:
Ready access to all fans, motors, belts drives, isolation dampers associated control
equipment and the connecting ductwork.
Isolation dampers on the inlet side of all centralized exhaust system fans that have
individual discharge arrangements or their own individual exhaust stacks.
Isolation dampers on both the inlet and outlet sides of all centralized exhaust
system fans that discharge into a common exhaust stack or plenum.
Sufficient space to allow removal and replacement of a fan, its motor, and all
associated exhaust system components and equipment without affecting other
mechanical equipment or the need to alter the building structure.
ASHRAE, 2011 Handbook, HVAC Applications, Laboratories, Pg. 16.9 EXHAUST
SYSTEMS:
To the extent possible, components of exhaust systems should allow maintenance
without exposing maintenance personnel to the exhaust airstream. Access to filters
and the need for bag-in, bag-out filter housings should be considered during the design
process.