Trenching and Excavation Safety

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# Occupational Safety and Health Administration (cont.) ## 1926.651(g)(2).(i) (cont.) 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. ## 1926.651(h) Protection from hazards associated with water accumulation. ## 1926.651(h)(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. - 1926.651(h)(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. - 1926.651(h)(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. - 1926.651(i) Stability of adjacent structures. ## 1926.651(i)(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 suc…

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# Occupational Safety and Health Administration (cont.) ## Definitions applicable to this subpart. (cont.) Shield (Shield system) means a structure that is able to withstand the forces imposed on it by a cave-in and thereby protect employees within the structure. Shields can be permanent structures or can be designed to be portable and moved along as work progresses. Additionally, shields can be either premanufactured or job-built in accordance with $1926.652(c)(3) or (c)(4). Shields used in trenches are usually referred to as "trench boxes" or "trench shields." Shoring (Shoring system) means a structure such as a metal hydraulic, mechanical or timber shoring system that supports the sides of an excavation and which is designed to prevent cave- ins. Sides. See "Faces." Sloping (Sloping system) means a method of protecting employees from cave-ins by excavating to form sides of an excavation that are inclined away from the excavation so as to prevent cave- ins. The angle of incline required to prevent a cave-in varies with differences in such factors as the soil type, environmental conditions of exposure, and application of surcharge loads. Stable rock means natural solid mineral material that can be excavated with vertical sides and will remain intact while exposed. Unstable rock is considered to be stable when the rock material on the side or sides of the excavation is secured against caving-in or movement by rock bolts or by another protective system that has been designed by a registered professional engineer. Structural ramp means a ramp built of steel or wood, usually used for vehicle access. Ramps made of soil or rock are not considered structural ramps. Support system means a structure such as underpinning, bracing, or shoring, which provides support to an adjacent structure, underground installation, or the sides of an excavation. Tabulated data means tables and charts approved by a registered professional engineer and used to design and construct a …

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# Occupational Safety and Health Administration (cont.) ## 1926.651(i)(1) (cont.) - 1926.651(i)(2) Excavation below the level of the base or footing of any foundation or retaining wall that could be reasonably expected to pose a hazard to employees shall not be permitted except when: - 1926.651(i)(2)(i) A support system, such as underpinning, is provided to ensure the safety of employees and the stability of the structure; or - 1926.651(i)(2)(ii) The excavation is in stable rock; or - 1926.651(i)(2)(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 - 1926.651(i)(2)(iv) A registered professional engineer has approved the determination that such excavation work will not pose a hazard to employees. - 1926.651(i)(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. - 1926.651(j) Protection of employees from loose rock or soil. - 1926.651(j)(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. 1926.651(j).(2) Submit Feedback

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# Occupational Safety and Health Administration (cont.) ## Definitions applicable to this subpart. (cont.) Cave-in means the separation of a mass of soil or rock material from the side of an excavation, or the loss of soil from under a trench shield or support system, and its sudden movement into the excavation, either by falling or sliding, in sufficient quantity so that it could entrap, bury, or otherwise injure and immobilize a person. Competent person means one who is capable of identifying existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them. Cross braces mean the horizontal members of a shoring system installed perpendicular to the sides of the excavation, the ends of which bear against either uprights or wales. Excavation means any man-made cut, cavity, trench, or depression in an earth surface, formed by earth removal. Faces or sides means the vertical or inclined earth surfaces formed as a result of excavation work. Failure means the breakage, displacement, or permanent deformation of a structural member or connection so as to reduce its structural integrity and its supportive capabilities. Hazardous atmosphere means an atmosphere which by reason of being explosive, flammable, poisonous, corrosive, oxidizing, irritating, oxygen deficient, toxic, or otherwise harmful, may cause death, illness, or injury. Kickout means the accidental release or failure of a cross brace. Protective system means a method of protecting employees from cave-ins, from material that could fall or roll from an excavation face or into an excavation, or from the collapse of adjacent structures. Protective systems include support systems, sloping and benching systems, shield systems, and other systems that provide the necessary protection. Ramp means an inclined walking or working surface that is used to gain access …

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U.S. DEPARTMENT OF LABOR # Occupational Safety and Health Administration - Part Number: 1926 - Part Number - Title: Safety and Health Regulations for Construction - Subpart: 1926 Subpart P - Subpart Title: Excavations Standard - Number: - 1926.651 - Title: Specific Excavation Requirements. - GPO Source: e-CFR 1926.651(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. 1926.651(b) Underground installations. 1926.651(b)(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. ## 1926.651(b)(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 Submit Feedback

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# Occupational Safety and Health Administration (cont.) ## 1926.651(b)(3). (cont.) 1926.651(c)(1)(v) Structural ramps used in lieu of steps shall be provided with cleats or other surface treatments on the top surface to prevent slipping. ## 1926.651(c)(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. ## 1926.651(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. ## 1926.651(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. Submit Feedback ## 1926.651(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. ## 1926.651(g) Hazardous atmospheres- 1926.651(g)(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

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U.S. DEPARTMENT OF LABOR # Occupational Safety and Health Administration - Part Number: 1926 - Part Number - Title: Safety and Health Regulations for Construction - Subpart: 1926 Subpart P - Subpart Title: Standard - Number: - Title: - Excavations - 1926.652 - Requirements for protective systems. - GPO Source: e-CFR ## 1926.652(a) Protection of employees in excavations. 1926.652(a)(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: 1926.652(a)(1)(i) Excavations are made entirely in stable rock; or 1926.652(a)(1)(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. - 1926.652(a)(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. - 1926.652(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 Submit Feedback

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# Work Area Safety (cont.) ## Overturning Hazards (cont.) First Edition - First Printing September 2016 # Work Area Safety Only use the machine on firm ground capable of supporting the maximum combined load of the machine and payload. If the subsoil collapses, the machine could tip over. To avoid any risk of overturning, the following precautions should be taken: - Ask your employer (site manager or manager assistant) if there may be buried pipes, pits, old tanks, cellar floor, dung yards, etc. under the ground onto which the stabilizers shall be lowered. - Site ground consistency can be roughly estimated using the tables and picture in this page. - The resistance of the subsoil is in relation to the ground type and soil characteristics. Table 1 indicates the superficial pressure which may be allowed under the stabilizers of the machine. <table><tr><th colspan="2">Type of ground, soil characteristics</th><th>Allowable superficial pressure KPa2</th></tr><tr><td colspan="2">loose, non-compact soil</td><td rowspan="3">generally speaking, not solid; special precautions needed</td></tr><tr><td colspan="2">loamy, peaty,pasty soil</td></tr><tr><td colspan="2">rippable, soft ground</td></tr><tr><td colspan="2">non-cohesive, well com- pact soil, sand, gravel</td><td>200</td></tr><tr><td></td><td>solid</td><td>100</td></tr><tr><td>rippable soil</td><td>semi- solid</td><td>200</td></tr><tr><td></td><td>hard</td><td>400</td></tr><tr><td colspan="2">Rocks, concrete, heavy traffic paved roads</td><td>above 1000</td></tr></table> Make sure the machine (wheels and stabilizers) rests on a firm ground to prevent hazardous unstable conditions. If the ground is not firm enough, position some support planks, capable of withstanding the expected loads, under the stabilizers or the wheels. When working near trenches, lower the stabilizers at a safe distance from the trench edge. a h a & h = minimum distances The distance (a) from the foot of the overhang shall be adequate …

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# Occupational Safety and Health Administration (cont.) ## 1926.651(i)(1) (cont.) 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. ## 1926.651(k) Inspections. 1926.651(k)(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 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. ## 1926.651(k)(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. ## 1926.651(I). 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 [redacted postal code], Oct. 31, 1989, as amended at 59 FR [redacted postal code], Aug. 9, 1994] OSHA Standards Enforcement Topics Media Center Contact Us Scroll to Top + Submit Feedback