[Code of Federal Regulations]
[Title 29, Volume 5]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1910.125]
[Page 413-414]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1910_OCCUPATIONAL SAFETY AND HEALTH STANDARDS--Table of Contents
Subpart H_Hazardous Materials
Sec. 1910.125 Additional requirements for dipping and coating
operations that use flammable or combustible liquids.
If you use flammable or combustible liquids, you must comply with
the requirements of this section as well as the requirements of sections
1910.123, 1910.124, and 1910.126, as applicable.
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You must comply with this section
if: And:
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<bullet<ls-thn-eq>The flashpoint of <bullet<ls-thn-eq>The liquid is heated as part of the operation; or
the flammable or combustible liquid
is 200 [deg]F (93.3 [deg]C) or
above.
<bullet<ls-thn-eq>A heated object is placed in the liquid.
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(a) What type of construction material must be used in making my dip
tank? Your dip tank must be made of noncombustible material.
(b) When must I provide overflow piping? (1) You must provide
properly trapped overflow piping that discharges to a safe location for
any dip tank having:
(i) A capacity greater than 150 gallons (568 L); or
(ii) A liquid surface area greater than 10 feet \2\ (0.95 m\2\).
(2) You must also ensure that:
(i) Any overflow piping is at least 3 inches (7.6 cm) in diameter
and has sufficient capacity to prevent the dip tank from overflowing;
(ii) Piping connections on drains and overflow pipes allow ready
access to the interior of the pipe for inspection and cleaning; and
(iii) The bottom of the overflow connection is at least 6 inches
(15.2 cm) below the top of the dip tank.
(c) When must I provide a bottom drain? (1) You must provide a
bottom drain for dip tanks that contain more than 500 gallons (1893 L)
of liquid, unless:
(i) The dip tank is equipped with an automatic closing cover meeting
the requirements of paragraph (f)(3) of this section; or
(ii) The viscosity of the liquid at normal atmospheric temperature
does not allow the liquid to flow or be pumped easily.
(2) You must ensure that the bottom drain required by this section:
(i) Will empty the dip tank during a fire;
(ii) Is properly trapped;
(iii) Has pipes that permit the dip tank's contents to be removed
within five minutes after a fire begins; and
(iv) Discharges to a safe location.
(3) Any bottom drain you provide must be capable of manual and
automatic operation, and manual operation
[[Page 414]]
must be from a safe and accessible location.
(4) You must ensure that automatic pumps are used when gravity flow
from the bottom drain is impractical.
(d) When must my conveyor system shut down automatically? If your
conveyor system is used with a dip tank, the system must shut down
automatically:
(1) If there is a fire; or
(2) If the ventilation rate drops below what is required by
paragraph (b) of Sec. 1910.124.
(e) What ignition and fuel sources must be controlled? (1) In each
vapor area and any adjacent area, you must ensure that:
(i) All electrical wiring and equipment conform to the applicable
hazardous (classified)-area requirements of subpart S of this part
(except as specifically permitted in paragraph (g) of Sec. 1910.126);
and
(ii) There are no flames, spark-producing devices, or other surfaces
that are hot enough to ignite vapors.
(2) You must ensure that any portable container used to add liquid
to the tank is electrically bonded to the dip tank and positively
grounded to prevent static electrical sparks or arcs.
(3) You must ensure that a heating system that is used in a drying
operation and could cause ignition:
(i) Is installed in accordance with NFPA 86A-1969, Standard for
Ovens and Furnaces (which is incorporated by reference in Sec. 1910.6
of this part);
(ii) Has adequate mechanical ventilation that operates before and
during the drying operation; and
(iii) Shuts down automatically if any ventilating fan fails to
maintain adequate ventilation.
(4) You also must ensure that:
(i) All vapor areas are free of combustible debris and as free as
practicable of combustible stock;
(ii) Rags and other material contaminated with liquids from dipping
or coating operations are placed in approved waste cans immediately
after use; and
(iii) Waste can contents are properly disposed of at the end of each
shift.
(5) You must prohibit smoking in a vapor area and must post a
readily visible ``No Smoking'' sign near each dip tank.
(f) What fire protection must I provide? (1) You must provide the
fire protection required by this paragraph (f) for:
(i) Any dip tank having a capacity of at least 150 gallons (568 L)
or a liquid surface area of at least 4 feet \2\ (0.38 m \1\); and
(ii) Any hardening or tempering tank having a capacity of at least
500 gallons (1893 L) or a liquid surface area of at least 25 feet \2\
(2.37 m \2\).
(2) For every vapor area, you must provide:
(i) Manual fire extinguishers that are suitable for flammable and
combustible liquid fires and that conform to the requirements of Sec.
1910.157; and
(ii) An automatic fire-extinguishing system that conforms to the
requirements of subpart L of this part.
(3) You may substitute a cover that is closed by an approved
automatic device for the automatic fire-extinguishing system if the
cover:
(i) Can also be activated manually;
(ii) Is noncombustible or tin-clad, with the enclosing metal applied
with locked joints; and
(iii) Is kept closed when the dip tank is not in use.
(g) To what temperature may I heat a liquid in a dip tank? You must
maintain the temperature of the liquid in a dip tank:
(1) Below the liquid's boiling point; and
(2) At least 100 [deg]F (37.8 [deg]C) below the liquid's
autoignition temperature.
