29 Cfr 1926.651

Occupational Safety and Health Admin., Labor
(measured at the bottom of the excavation), the excavation is also considered to be a trench.
Trench box. See ‘‘Shield.’’
Trench shield. See ‘‘Shield.’’
Uprights means the vertical members
of a trench shoring system placed in
contact with the earth and usually positioned so that individual members do
not contact each other. Uprights
placed so that individual members are
closely spaced, in contact with or
interconnected to each other, are often
called ‘‘sheeting.’’
Wales means horizontal members of a
shoring system placed parallel to the
excavation face whose sides bear
against the vertical members of the
shoring system or earth.
§ 1926.651 Specific excavation requirements.
(a) Surface encumbrances. All surface
encumbrances that are located so as to
create a hazard to employees shall be
removed or supported, as necessary, to
safeguard employees.
(b) Underground installations. (1) The
estimated location of utility installations, such as sewer, telephone, fuel,
electric, water lines, or any other underground installations that reasonably may be expected to be encountered during excavation work, shall be
determined prior to opening an excavation.
(2) Utility companies or owners shall
be contacted within established or customary local response times, advised of
the proposed work, and asked to establish the location of the utility underground installations prior to the start
of actual excavation. When utility
companies or owners cannot respond to
a request to locate underground utility
installations within 24 hours (unless a
longer period is required by state or
local law), or cannot establish the
exact location of these installations,
the employer may proceed, provided
the employer does so with caution, and
provided detection equipment or other
acceptable means to locate utility installations are used.
(3) When excavation operations approach the estimated location of underground installations, the exact location of the installations shall be determined by safe and acceptable means.

§ 1926.651

(4) While the excavation is open, underground installations shall be protected, supported or removed as necessary to safeguard employees.
(c) Access and egress—(1) Structural
ramps. (i) Structural ramps that are
used solely by employees as a means of
access or egress from excavations shall
be designed by a competent person.
Structural ramps used for access or
egress of equipment shall be designed
by a competent person qualified in
structural design, and shall be constructed in accordance with the design.
(ii) Ramps and runways constructed
of two or more structural members
shall have the structural members connected together to prevent displacement.
(iii) Structural members used for
ramps and runways shall be of uniform
thickness.
(iv) Cleats or other appropriate
means used to connect runway structural members shall be attached to the
bottom of the runway or shall be attached in a manner to prevent tripping.
(v) Structural ramps used in lieu of
steps shall be provided with cleats or
other surface treatments on the top
surface to prevent slipping.
(2) Means of egress from trench excavations. A stairway, ladder, ramp or
other safe means of egress shall be located in trench excavations that are 4
feet (1.22 m) or more in depth so as to
require no more than 25 feet (7.62 m) of
lateral travel for employees.
(d) Exposure to vehicular traffic. Employees exposed to public vehicular
traffic shall be provided with, and shall
wear, warning vests or other suitable
garments marked with or made of
reflectorized or high-visibility material.
(e) Exposure to falling loads. No employee shall be permitted underneath
loads handled by lifting or digging
equipment. Employees shall be required to stand away from any vehicle
being loaded or unloaded to avoid being
struck by any spillage or falling materials. Operators may remain in the
cabs of vehicles being loaded or unloaded when the vehicles are equipped,
in accordance with § 1926.601(b)(6), to
provide adequate protection for the operator during loading and unloading
operations.

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§ 1926.651

29 CFR Ch. XVII (7–1–10 Edition)

(f) Warning system for mobile equipment. When mobile equipment is operated adjacent to an excavation, or
when such equipment is required to approach the edge of an excavation, and
the operator does not have a clear and
direct view of the edge of the excavation, a warning system shall be utilized such as barricades, hand or mechanical signals, or stop logs. If possible, the grade should be away from
the excavation.
(g) Hazardous atmospheres—(1) Testing
and controls. In addition to the requirements set forth in subparts D and E of
this part (29 CFR 1926.50–1926.107) to
prevent exposure to harmful levels of
atmospheric contaminants and to assure acceptable atmospheric conditions, the following requirements shall
apply:
(i)
Where
oxygen
deficiency
(atmospheres containing less than 19.5
percent oxygen) or a hazardous atmosphere exists or could reasonably be expected to exist, such as in excavations
in landfill areas or excavations in areas
where hazardous substances are stored
nearby, the atmospheres in the excavation shall be tested before employees
enter excavations greater than 4 feet
(1.22 m) in depth.
(ii) Adequate precautions shall be
taken to prevent employee exposure to
atmospheres containing less than 19.5
percent oxygen and other hazardous
atmospheres. These precautions include providing proper respiratory protection or ventilation in accordance
with subparts D and E of this part respectively.
(iii) Adequate precaution shall be
taken such as providing ventilation, to
prevent employee exposure to an atmosphere containing a concentration
of a flammable gas in excess of 20 percent of the lower flammable limit of
the gas.
(iv) When controls are used that are
intended to reduce the level of atmospheric contaminants to acceptable levels, testing shall be conducted as often
as necessary to ensure that the atmosphere remains safe.
(2) Emergency rescue equipment. (i)
Emergency rescue equipment, such as
breathing apparatus, a safety harness
and line, or a basket stretcher, shall be
readily available where hazardous at-

mospheric conditions exist or may reasonably be expected to develop during
work in an excavation. This equipment
shall be attended when in use.
(ii) Employees entering bell-bottom
pier holes, or other similar deep and
confined footing excavations, shall
wear a harness with a life-line securely
attached to it. The lifeline shall be separate from any line used to handle materials, and shall be individually attended at all times while the employee
wearing the lifeline is in the excavation.
(h) Protection from hazards associated
with water accumulation. (1) Employees
shall not work in excavations in which
there is accumulated water, or in excavations in which water is accumulating, unless adequate precautions
have been taken to protect employees
against the hazards posed by water accumulation. The precautions necessary
to protect employees adequately vary
with each situation, but could include
special support or shield systems to
protect from cave-ins, water removal
to control the level of accumulating
water, or use of a safety harness and
lifeline.
(2) If water is controlled or prevented
from accumulating by the use of water
removal equipment, the water removal
equipment and operations shall be
monitored by a competent person to
ensure proper operation.
(3) If excavation work interrupts the
natural drainage of surface water (such
as streams), diversion ditches, dikes, or
other suitable means shall be used to
prevent surface water from entering
the excavation and to provide adequate
drainage of the area adjacent to the excavation. Excavations subject to runoff
from heavy rains will require an inspection by a competent person and
compliance with paragraphs (h)(1) and
(h)(2) of this section.
(i) Stability of adjacent structures. (1)
Where the stability of adjoining buildings, walls, or other structures is endangered by excavation operations,
support systems such as shoring, bracing, or underpinning shall be provided
to ensure the stability of such structures for the protection of employees.
(2) Excavation below the level of the
base or footing of any foundation or retaining wall that could be reasonably

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Occupational Safety and Health Admin., Labor
expected to pose a hazard to employees
shall not be permitted except when:
(i) A support system, such as underpinning, is provided to ensure the safety of employees and the stability of the
structure; or
(ii) The excavation is in stable rock;
or
(iii) A registered professional engineer has approved the determination
that the structure is sufficently removed from the excavation so as to be
unaffected by the excavation activity;
or
(iv) A registered professional engineer has approved the determination
that such excavation work will not
pose a hazard to employees.
(3) Sidewalks, pavements, and appurtenant structure shall not be undermined unless a support system or another method of protection is provided
to protect employees from the possible
collapse of such structures.
(j) Protection of employees from loose
rock or soil. (1) Adequate protection
shall be provided to protect employees
from loose rock or soil that could pose
a hazard by falling or rolling from an
excavation face. Such protection shall
consist of scaling to remove loose material; installation of protective barricades at intervals as necessary on the
face to stop and contain falling material; or other means that provide equivalent protection.
(2) Employees shall be protected from
excavated or other materials or equipment that could pose a hazard by falling or rolling into excavations. Protection shall be provided by placing and
keeping such materials or equipment
at least 2 feet (.61 m) from the edge of
excavations, or by the use of retaining
devices that are sufficient to prevent
materials or equipment from falling or
rolling into excavations, or by a combination of both if necessary.
(k) Inspections. (1) Daily inspections
of excavations, the adjacent areas, and
protective systems shall be made by a
competent person for evidence of a situation that could result in possible
cave-ins, indications of failure of protective
systems,
hazardous
atmospheres, or other hazardous conditions. An inspection shall be conducted
by the competent person prior to the
start of work and as needed throughout

§ 1926.652

the shift. Inspections shall also be
made after every rainstorm or other
hazard increasing occurrence. These inspections are only required when employee exposure can be reasonably anticipated.
(2) Where the competent person finds
evidence of a situation that could result in a possible cave-in, indications
of failure of protective systems, hazardous atmospheres, or other hazardous conditions, exposed employees
shall be removed from the hazardous
area until the necessary precautions
have been taken to ensure their safety.
(l) Walkways shall be provided where
employees or equipment are required
or permitted to cross over excavations.
Guardrails
which
comply
with
§ 1926.502(b) shall be provided where
walkways are 6 feet (1.8 m) or more
above lower levels.
[54 FR 45959, Oct. 31, 1989, as amended by 59
FR 40730, Aug. 9, 1994]

§ 1926.652 Requirements for protective
systems.
(a) Protection of employees in excavations. (1) Each employee in an excavation shall be protected from cave-ins
by an adequate protective system designed in accordance with paragraph
(b) or (c) of this section except when:
(i) Excavations are made entirely in
stable rock; or
(ii) Excavations are less than 5 feet
(1.52m) in depth and examination of the
ground by a competent person provides
no indication of a potential cave-in.
(2) Protective systems shall have the
capacity to resist without failure all
loads that are intended or could reasonably be expected to be applied or
transmitted to the system.
(b) Design of sloping and benching systems. The slopes and configurations of
sloping and benching systems shall be
selected and constructed by the employer or his designee and shall be in
accordance with the requirements of
paragraph (b)(1); or, in the alternative,
paragraph (b)(2); or, in the alternative,
paragraph (b)(3), or, in the alternative,
paragraph (b)(4), as follows:
(1) Option (1)—Allowable configurations
and slopes. (i) Excavations shall be
sloped at an angle not steeper than one
and one-half horizontal to one vertical

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