Locations covered by this section. The employer shall ensure that manual cleaning and other cold work
are not performed in the following spaces unless the conditions of paragraph (b) of this section have been met:
Spaces containing or having last contained bulk quantities of combustible or flammable liquids or
Spaces containing or having last contained bulk quantities of liquids, gases or solids that are
toxic, corrosive or irritating.
Requirements for performing cleaning or cold work.
Liquid residues of hazardous materials shall be removed from work spaces as thoroughly as
practicable before employees start cleaning operations or cold work in a space. Special care shall be taken to prevent the spilling or the draining of
these materials into the water surrounding the vessel, or for shore-side operations, onto the surrounding work area.
Testing shall be conducted by a competent person to determine the concentration of flammable,
combustible, toxic, corrosive, or irritant vapors within the space prior to the beginning of cleaning or cold work.
Continuous ventilation shall be provided at volumes and flow rates sufficient to ensure that the
Flammable vapor is maintained below 10 percent of the lower explosive limit; and
Note to paragraph (b)(3)(i): Spaces containing highly volatile residues may require additional ventilation to keep the concentration of
flammable vapors below 10 percent of the lower explosive limit and within the permissible exposure limit.
Toxic, corrosive, or irritant vapors are maintained within the permissible exposure limits and
below IDLH levels.
Testing shall be conducted by the competent person as often as necessary during cleaning or cold
work to assure that air concentrations are below 10 percent of the lower explosive limit and within the PELs and below IDLH levels. Factors such as,
but not limited to, temperature, volatility of the residues and other existing conditions in and about the spaces are to be considered in determining
the frequency of testing necessary to assure a safe atmosphere.
Note to paragraph (b)(4): See Appendix A for additional information on frequency of testing.
Spills or other releases of flammable, combustible, toxic, corrosive, and irritant materials shall
be cleaned up as work progresses.
An employee may not enter a confined or enclosed space or other dangerous atmosphere if the
concentration of flammable or combustible vapors in work spaces exceeds 10 percent of the lower explosive limit. Exception: An employee may enter for
emergency rescue or for a short duration for installation of ventilation equipment provided:
No ignition sources are present;
The atmosphere in the space is monitored continuously;
The atmosphere in the space is maintained above the upper explosive limit; and
Respiratory protection, personal protective equipment, and clothing are provided in accordance
with subpart I of this part.
Note to paragraph (b)(6): Other provisions for work in IDLH and other dangerous atmospheres are located in Subpart I of this
A competent person shall test ventilation discharge areas and other areas where discharged vapors
may collect to determine if vapors discharged from the spaces being ventilated are accumulating in concentrations hazardous to employees.
If the tests required in paragraph (b)(7) of this section indicate that concentrations of exhaust
vapors that are hazardous to employees are accumulating, all work in the contaminated area shall be stopped until the vapors have dissipated or been
Only explosion-proof, self-contained portable lamps, or other electric equipment approved by a
National Recognized Testing Laboratory (NRTL) for the hazardous location shall be used in spaces described in paragraph (a) of this section until such
spaces have been certified as "Safe for Workers."
Note to paragraph (b)(9): Battery-fed, portable lamps or other electric equipment bearing the approval of a NRTL for the class, and
division of the location in which they are used are deemed to meet the requirements of this paragraph.
The employer shall prominently post signs that prohibit sources of ignition within or near a space
that has contained flammable or combustible liquids or gases in bulk quantities:
At the entrance to those spaces;
In adjacent spaces; and
In the open area adjacent to those spaces.
All air moving equipment and its component parts, including duct work, capable of generating a
static electric discharge of sufficient energy to create a source of ignition, shall be bonded electrically to the structure of a vessel or vessel
section or, in the case of land-side spaces, grounded to prevent an electric discharge in the space.
Fans shall have non-sparking blades, and portable air ducts shall be of non-sparking
Note to paragraph (b): See 1915.12(c) of this part and applicable requirements of 29 CFR part 1915, subpart Z for other provisions
affecting cleaning and cold work.
[59 FR 37816, July 25, 1994]