Basic Documentation

Table Of Contents
Laboratory Ventilation Codes and Standards
Siemens Industry, Inc. 148
Topic Requirement(s) Commentary
Materials and
Fire
Protection
(Continued)
8.5.5 Ducts shall be of adequate strength and rigidity to meet the conditions of service
and installation requirements and shall be protected against mechanical damage.
8.5.6 Materials used for vibration insulation connectors shall comply with 8.5.2.
8.5.7 Flexible connectors containing pockets in which conveyed material can collect
shall not be used in any concealed space or where strong oxidizing chemicals (e.g.,
perchloric acid) are used.
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)
8.7.1 Fans shall be selected to meet requirements for fire, explosion and corrosion.
8.7.2 Fans conveying both corrosive and flammable or combustible material shall be
permitted to be lined with or constructed of corrosion-resistant materials having a
flame spread rating of 25 or less when tested in accordance with ASTM E 84,
Standard Test Method for Surface Burning Characteristics of Building Materials, or
ANSI/UL 723, Standard for Test for Surface Burning Characteristics of Building
Materials.
8.7.3 Fans shall be located and arranged so as to afford ready access for repairs,
cleaning, inspection, and maintenance.
8.7.4 Where flammable gases or vapors or combustible dusts are passed through the
fans, the rotating element shall be of nonferrous or spark-resistant construction.
Alternatively, the casing shall be constructed of or lined with such material.
A.8.7.4. For Informative material regarding spark-resistant fan construction, see Air
Movement and Control Association (AMCA) Standards handbook 99-0401-86,
Classifications for Spark Resistant Construction.
8.7.4.1 Where there is the possibility of solid material passing through the fan that
would produce a spark, both the rotating element and the casing shall be constructed
of such material.
8.7.4.2 Nonferrous or spark-resistant materials shall have a flame spread rating of 25
or less when tested in accordance with ASTM E 84, Standard Test Method for Surface
Burning Characteristics of Building Materials, or ANSI/UL 723, Standard for Test for
Surface Burning Characteristics of Building Materials.
8.7.5 Motors and their controls shall be located outside the location where flammable
or combustible vapors or combustible dusts are generated or conveyed unless
specifically approved for the location and use.
8.10.1 Automatic fire protection systems shall not be required in chemical fume hoods
or exhaust systems except in the following cases:
(1) Existing hoods having interiors with a flame spread index greater than 25 in which
flammable liquids are handled.
(2) If a hazard assessment shows that an automatic extinguishing system is required
for the chemical fume hood, then an applicable automatic fire suppression system
standard shall be followed.
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A centralized exhaust system that combines
all laboratory room general exhausts and all
fume hood exhausts will typically provide a
longer service life than a multitude of
individual fume hood exhausts. A
centralized exhaust system also has higher
overall dilution due to the contribution of the
room general exhaust to the fume hood
exhaust.