Basic Documentation

Table Of Contents
Exhaust Systems
Siemens Industry, Inc. 149
Topic Requirement(s) Commentary
Materials and
Fire
Protection
(Continued)
8.10.2 Automatic fire protection systems, where provided, shall comply with the
following standards, as applicable:
(1) NFPA 11, Standard for Low, Medium, and High-Expansion Foam
(2) NFPA 12, Standard for Carbon Dioxide Extinguishing Systems
(3) NFPA 12A, Standard for Halon 1301 Fire Extinguishing Systems
(4) NFPA 13, Standard for the installation of Sprinkler Systems
(5) NFPA 15, Standard for Water Spray Fixed Systems for Fire Protection
(6) NFPA 17, Standard for Dry Chemical Extinguishing Systems
(7) NFPA 17A, Standard for Wet Chemical Extinguishing Systems
(8) NFPA 69, Standard on Explosion Prevention Systems
(9) NFPA 750, Standard on Water Mist Fire Protection Systems
(10) NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems
8.10.3.1* Automatic fire dampers shall not be used in chemical fume hood exhaust
systems.
8.10.4 Fire detection and alarm systems shall not be interlocked to automatically shut
down chemical fume hood exhaust fans.
Perchloric Acid Exhaust Systems:
8.11.2 Perchloric acid hoods & exhaust ductwork shall be constructed of materials that
are acid resistant, nonreactive, and impervious to perchloric acid.
8.11.3 The exhaust fan shall be acid resistant and spark resistant.
8.11.4 The exhaust fan motor shall not be located within the ductwork.
8.11.5 Drive belts shall be conductive and shall not be located within the ductwork.
8.11.6 Ductwork for perchloric acid hoods and exhaust systems shall take the shortest
and straightest path to the outside of the building and shall not be manifolded with
other exhaust systems.
8.11.6.1 Horizontal runs shall be as short as possible, with no sharp turns or bends.
8.11.6.2 The ductwork shall provide a positive drainage slope back into the hood.
8.11.6.3 Ductwork shall consist of sealed sections
8.11.6.4 Flexible connectors shall not be used.
8.11.7 Sealants, gaskets, and lubricants used with perchloric acid hoods, ductwork
and exhaust systems shall be acid resistant and nonreactive with perchloric acid.
(Continued on Next Page)
Note that the NFPA 45 requirement of 8-10.3
to not have fire dampers in the exhaust
system and to not automatically shut down
the exhaust may conflict with some local
codes. Be sure to determine if the local code
that has jurisdiction over a particular
laboratory facility is in conflict with this.
Although the safety standards specifically
prohibit fire dampers in fume hood exhaust
systems, individual local codes may still
require their inclusion. The laboratory
ventilation system designer is advised to
seek a variance from such a requirement
with the ‘authority having jurisdiction’ (AHJ).
If a variance is not attainable, the designer
will have to comply with the local code
requirement but it is recommended that they
confirm by letter to the AHJ that although the
exhaust system will have the required fire
dampers, it is contrary to NFPA 45, AIHA
Z9.5 and other laboratory safety references.
If a fire situation should later occur and the
integrity of the system design becomes
subject to investigation or litigation, the
recommended documentation will help
substantiate the designer’s desire to follow
noted safety standards