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I need to dig a 10' deep trench for a large storm water pipe installation. Do I need a trench box?

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In Maryland, OSHA regulations require that all employees in an excavation be protected from cave-ins by an adequate protective system [1]. This typically includes using a trench box (also known as a trench shield), shoring, or sloping the sides of the excavation [2].

For a trench that is 10 feet deep, a protective system is required unless the excavation is made entirely in stable rock, or the excavation is less than 5 feet in depth and a competent person has examined the ground and found no indication of a potential cave-in [1].

Since your trench will be 10 feet deep, you will likely need a protective system. A trench box (shield) is one option [2]. Other options include sloping or shoring the sides of the excavation [2].

Before starting any excavation, you must also identify and locate any underground utilities in the area [3]. Contact utility companies to determine the location of underground installations prior to the start of excavation [3].

Daily inspections of the excavation, adjacent areas, and protective systems must be conducted by a competent person for any evidence of potential cave-ins, failure of protective systems, hazardous atmospheres, or other hazardous conditions [1].

3 source record(s)

Sources used for this answer

[1] Safety and Health Regulations for Construction (OSHA)

Page 92

Open source document

Source excerpt

## 29 CFR 1926 (OSHA) 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 to one point from another, and is constructed from earth or from structural materials such as steel or wood. Registered Professional Engineer means a person who is registered as a professional engineer in the state where the work is to be performed. However, a professional engineer, registered in any state is deemed to be a 'registered professional engineer' within the meaning of this standard when approving designs for 'manufactured protective systems' or 'tabulated data' to be used in interstate commerce. Sheeting means the members of a shoring system that retain the earth in position and in turn are supported by other members of the shoring system. Shield (Shield system) means a structure that is able to withstand the forces imposed on it by a cavein 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

[2] Safety and Health Regulations for Construction (OSHA)

Page 96

Open source document

Source excerpt

- (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 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 sys

[3] Safety and Health Regulations for Construction (OSHA)

Page 93

Open source document

Source excerpt

## 29 CFR 1926 (OSHA) 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 protective system. Trench (Trench excavation) means a narrow excavation (in relation to its length) made below the surface of the ground. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 m). If forms or other structures are installed or constructed in an excavation so as to reduce the dimension measured from the forms or structure to the side of the excavation to 15 feet (4.6 m) or less (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

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