Current through Register 2024 Notice Reg. No. 38, September 20, 2024
(a) Design and Operation. The construction,
installation, inspection, testing, and maintenance of exhaust systems shall
conform to all requirements of Article 107. Additional guidance may be obtained
from the American National Standard Fundamentals Governing the Design and
Operation of Local Exhaust Systems, ANSI Z9.2-1971 and the Standard for the
Installation of Blower and Exhaust Systems, NFPA No. 91-1973.
NOTE: Ventilation requirements for control of flammable
vapors are prescribed in Sections
5153(d) and
5416.
(1) The exhaust system shall be so designed,
constructed, maintained and operated as to prevent harmful exposure by
maintaining a volume and velocity of exhaust air sufficient to gather dusts,
fumes, mists, vapors or gases from said equipment or process and to convey them
to suitable points of safe disposal, thereby preventing their dispersion in
harmful quantities into the atmosphere of work rooms or other places where
persons are employed.
(2) Exhaust
ducts, inlet ducts, and fan plenums shall be so designed, constructed, and
supported as to prevent collapse of the ducts and/or failure of the supporting
system.
(3) Exhaust ducts which
convey dusts, fumes, and mists shall be provided with inspection or clean-out
doors at intervals not to exceed 12 feet of horizontal running length for ducts
up to 12 inches in diameter, but the distance may be greater for larger ducts.
A clean-out door or doors shall be provided for servicing the fan and, where
necessary, a drain shall be provided.
(4) Two or more operations shall not be
connected to the same exhaust system where the combination of substances
removed may constitute a fire, explosion, or chemical reaction hazard in the
duct system.
(5) The ventilation
rate of every mechanical ventilation system used to prevent harmful exposure
shall be tested after initial installation, alterations, or maintenance, and at
least annually, by means of a pitot traverse of the exhaust duct or equivalent
measurements. Records of these tests shall be retained for at least five
years.
(b) Duration of
Operations. The exhaust system shall be in operation continually during all
operations for which it is designed. The system shall continue to operate for
some time after the cessation of said operations, the length of time to depend
upon the individual circumstances and effectiveness of the ventilation
system.
(c) Disposal of Exhaust
Materials.
(1) The air outlet from every dust
separator/collector and the dusts, fumes, mists, vapors or gases collected by
an exhaust or ventilating system shall discharge to the outside atmosphere,
provided that the exhaust system shall discharge to the outer air in such a
manner that it will not cause a harmful exposure in any accessible workplace.
Collecting systems which return air to work areas may be used if contaminants
which accumulate in the work area do not result in harmful exposure to
employees.
(2) The air exhausted
from blast-cleaning equipment, grinding, buffing, polishing equipment and all
other equipment requiring exhausting of dust or particulate shall be discharged
through dust-collecting equipment. Dust and refuse discharged from an exhaust
system shall be disposed of in such a manner that it will not result in harmful
exposure to employees.
(d) Make-Up Air. Clean, fresh air, free of
contamination from adjacent industrial exhaust systems, chimneys, stacks, or
vents, shall be supplied.
(1) The outside air
supply shall enter the workroom in a manner which will not reduce the
effectiveness of any local exhaust systems.
(2) All seams and joints shall be sealed if
negative pressure exists within inlet ductwork such that there is a possibility
of infiltration of harmful quantities of gases, fumes, or mists from areas
through which ductwork passes.
(3)
Where the air supply is filtered, the filters shall be replaced or cleaned
regularly to prevent significant reductions in airflow. A pressure gauge shall
be installed to show the pressure drop across the filters. This gauge shall be
marked to show the pressure drop at which filters require cleaning or
replacement.
(4) Where make-up air
is heated by combustion, except gas, the products of combustion shall not be
mixed with the make-up air and shall be vented to a point remote from all
points where make-up air enters the building. For gas heating where combustion
products are mixed with the make-up air, the following must exist:
(A) The gas must be nontoxic and have a
distinctive and strong enough odor to warn workmen of its presence if
unburned.
(B) The maximum rate of
gas supply to the make-up air heater shall not yield in excess of 2000 ppm of
total combustible gas in the mixture upon flame failure.
(C) A fan shall be provided to remove the
mixture of heated air and combustion products from gas burner plenum chambers.
(Title 24, T8-5143)
1.
Amendment filed 7-16-76; effective thirtieth day thereafter (Register 76, No.
29).
2. Amendment of subsection (a)(2) filed 2-20-80; effective
thirtieth day thereafter (Register 80, No. 8).
3. Editorial
correction of subsection (a)(5) (Register 2003, No.
24).
Note: Authority cited: Section
142.3, Labor
Code. Reference: Section
142.3, Labor
Code.
