Basic Documentation

Table Of Contents
Exhaust Systems
Siemens Industry, Inc. 143
Topic Requirement(s) Commentary
Operational
Reliability
National Sanitation Foundation, NSF 49 -2008, Biosafety Cabinetry: Design,
Construction, Performance and Field Certification
2.3 Roof Exhaust Systems
It is recommended that roof exhaust fans be energized by direct-connected electric
motors to avoid failures caused by slipping and breaking of belts. Another advantage
of direct connected fans is the ability to use the motor non-function to activate an
alarm in the laboratory, whereas when a malfunctioning belted fan is employed, the
motor can be operating when the fan is idle
National Fire Protection Association, Standard NFPA 45, 2011
8.5.8 Controls and dampers when required for balancing or control of the exhaust
system shall be of a type that in event of failure, will fail open to ensure continuous
draft. (See 8.10.3 through 8.10.5)
A-8.2.2.It is not the intent of this Standard to require emergency or standby power for
laboratory ventilation systems
American National Standard for Laboratory Ventilation ANSI/AIHA Z9.5 2003
5.3.2.4 Unless all individual exhausts connected to the centralized exhaust system
can be completely stopped without having a hazardous situation, provision shall be
made for continuous maintenance of adequate negative static pressure (suction) in
all parts of the system.
5.3.2.12 Manifolds shall be maintained under negative pressure at all times and be
provided with at least two exhaust fans for redundant capacity. Emergency power
shall be connected to one or more of the exhaust fans where exhaust system function
must be maintained even under power outage situations.
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.
ASHRAE, 2011 Handbook, HVAC Applications, Laboratories, Pg. 16.9 -16.10
EXHAUST SYSTEMS:
Laboratory exhaust systems should be designed for high reliability and ease of
maintenance. This can be achieved by providing multiple exhaust fans that are not
necessarily redundant or by sectionalizing equipment so that maintenance work may
be performed on an individual exhaust fan while the system is operating.
Another option is to use predictive maintenance procedures to detect problems prior
to failure and to allow for scheduled shutdowns for maintenance.
For reliability, centralized exhaust systems
should always have multiple fans. A reliable
operational arrangement consists of always
having a minimum of two fans running and
also having at least one additional non-
operating standby fan for a total of three fans.
If one of the two operating fans fails, having
another operating fan can ensure that a total
loss of facility exhaust does not occur during
the time required to bring the standby fan into
operation.
When a building is equipped with emergency
power, it is strongly recommended that
laboratory exhaust systems be on the
emergency power system.