Basic Documentation

Laboratory Ventilation Codes and Standards
Siemens Industry, Inc. 116
Topic Requirement(s) Commentary
Energy
Conservation
Institute of Laboratory Animal Research, Commission on Life Sciences, National
Research Council, Guide for the Care and Use of Laboratory Animals, Eight
Edition, 2011:
Page 46: Modern heating, ventilation, and air conditioning (HVAC) systems (e.g.,
variable air volume, or VAV, systems) allow ventilation rates to be set in accordance
with heat load and other variables. These systems offer considerable advantages with
respect to flexibility and energy conservation, but should always provide a minimum
amount of air exchange, as recommended for general use laboratories.
The use of recycled air to ventilate animal rooms saves considerable amounts of
energy but might entail some risk. Many animal pathogens can be airborne or travel on
fomites, such as dust, so exhaust air to be recycled into heating, ventilation, and air-
conditioning systems that serve multiple rooms presents a risk of cross contamination.
The exhaust air to be recycled should be HEPA filtered (high-efficiency particulate air-
filtered) to remove airborne particles before it is recycled; the extent and efficiency of
filtration should be proportional to the estimated risk.
Air that does not originate from animal use areas but has been used to ventilate other
spaces (e.g., some human-occupancy areas and food, bedding, and supply storage
areas) may be recycled for animal space ventilation and might require less-intensive
filtration or conditioning than air recycled from animal use space.
Toxic or odor-causing gases, such as ammonia, can be kept within acceptable limits if
they are removed by the ventilation system and replaced with air that contains either a
lower concentration or none of these gases. Treatment of recycled air for these
substances by chemical absorption or scrubbing might be effective; however, the use
of nonrecycled air is preferred for ventilation of animal use and holding areas. The use
of HEPA filtered recycled air without gaseous filtration (such as with activated-charcoal
filters) can be used but only that:
• Room air is mixed with at least 50% fresh air (that is, the supply air does not
exceed 50% recycled air).
• Recycled air is returned only to the room or area from which it was generated,
except if it comes from other than animal housing areas.
• Recycled air is appropriately conditioned and mixed with sufficient fresh air to
address the thermal and humidity requirements of animals in that space.
National Fire Protection Association, Standard NFPA 45, 2011
8.3.1 Laboratory ventilation systems shall be designed to ensure that chemical fumes,
vapors or gasses originating from the laboratory shall not be recirculated.
8.4.1 Air exhausted from chemical fume hoods and other special local exhaust
systems shall not be recirculated.
8.4.2 If energy conservation devices are used they shall be designed in accordance
with 8.3.1. and 8.3.2.
(Continued on Next Page)
Also refer to the requirements listed in:
“Exhaust Systems
Recirculated Air and Cross Contamination”
Note that as written, NFPA 8.4.1 specifically
prevents the recirculation of fume hood
exhaust but not laboratory room air.
Recirculation of laboratory room air is
permissible if the specific requirements of
ANSI/AIHA Z9.5 are met.
The cost to install exhaust filtering and
cleaning systems that would adequately
remove hazardous fumes (and the
associated risk of a failure in such systems)
generally makes it an impractical
consideration.