Trench

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## OCCUPATIONAL HEALTH AND SAFETY, 2020 ## Application of Part 17-2 This Part applies to excavations, trenches, tunnels and excavated shafts other than excavations, trenches, tunnels and excavated shafts that are governed by The Mines Regulations . 31 Dec 2020 c S-15.1 Reg 10 s17-2. ## Locating underground pipelines, etc. - 17-3 (1) An employer or contractor shall accurately establish the location of all underground pipelines, cables and conduits in an area where work is to be done and shall ensure that those locations are conspicuously marked: - (a) before commencing work using power tools or powered mobile equipment on an excavation, trench, tunnel, excavated shaft or borehole; or - (b) before breaking ground surface with any equipment to a depth that may contact underground utilities. - (2) If an operation is to be undertaken involving the disturbance of soil within 600 millimetres of an existing pipeline, cable or conduit, an employer or contractor shall ensure that the pipeline, cable or conduit is exposed by hand digging or other approved method before mechanical excavating is allowed to begin within that area. - (3) If an operation mentioned in subsection (2) exposes a pipeline, cable or conduit, an employer or contractor shall ensure that the pipeline, cable or conduit is supported to prevent any damage during backfilling and any subsequent settlement of the ground. - (4) If there is contact with or damage to an underground pipeline, cable or conduit, an employer or contractor shall immediately: - (a) notify the owner of the pipeline, cable or conduit that contact or damage has occurred; and - (b) take steps to protect the health and safety of any worker who may be at risk until any unsafe condition resulting from the contact or damage is repaired or corrected. 31 Dec 2020 c S-15.1 Reg 10 s17-3. ## Excavating and trenching - 17-4 (1) An employer or contractor shall ensure that: - (a) before excavating or trenching begins, if the stability of a struct…

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## 29 CFR 1926 (OSHA) ## Subpart P-Excavations AUTHORITY: Sec. 107, Contract Worker Hours and Safety Standards Act (Construction Safety Act) (40 U.S.C. 333); Secs. 4, 6, 8, Occupational Safety and Hea1th Act of 1970 (29 U.S.C. 653, 655, 657); Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR [redacted postal code]), or 9-83 (48 FR [redacted postal code]), as applicable, and 29 CFR part 1911. SOURCE: 54 FR [redacted postal code], Oct. 31, 1989, unless otherwise noted. ## §1926.650 Scope, application, and definitions applicable to this subpart. (a) Scope and application. This subpart applies to all open excavations made in the earth's surface. Excavations are defined to include trenches. ## (b) Definitions applicable to this subpart. Accepted engineering practices means those requirements which are compatible with standards of practice required by a registered professional engineer. Aluminum Hydraulic Shoring means a pre-engineered shoring system comprised of aluminum hydraulic cylinders (crossbraces) used in conjunction with vertical rails (uprights) or horizontal rails (walers). Such system is designed, specifically to support the sidewalls of an excavation and prevent cave-ins. Bell-bottom pier hole means a type of shaft or footing excavation, the bottom of which is made larger than the cross section above to form a belled shape. Benching (Benching system) means a method of protecting employees from cave-ins by excavating the sides of an excavation to form one or a series of horizontal levels or steps, usually with vertical or near-vertical surfaces between levels. 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…

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## 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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## PART 17 ## Excavations, Trenches, Tunnels and Excavated Shafts ## Definitions for Part 17-1 In this Part: '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, and includes uprights placed so that individual members are closely spaced, in contact with or interconnected to each other; 'shoring' means an assembly of structural members designed to prevent earth or material from falling or sliding into an excavation; 'spoil pile' means material excavated from an excavation, trench, tunnel or excavated shaft; 'temporary protective structure' means a structure or device in an excavation, trench, tunnel or excavated shaft that is designed to provide protection from cave-ins, collapse, sliding or rolling materials, and includes shoring, boxes, trench shields and similar structures; 'type 1 soil' means soil that most closely exhibits the following characteristics: - (a) is hard in consistency, very dense in compactive condition and, if a standard penetration test is performed, has a standard penetration resistance of greater than 50 blows per 300 millimetres; - (b) can be penetrated only with difficulty by a small, sharp object; - (c) has a dry appearance; - (d) has no signs of water seepage; - (e) can be excavated only by mechanical equipment; - (f) does not include previously excavated soils; 'type 2 soil' means soil that most closely exhibits the following characteristics: - (a) is very stiff in consistency, dense in compactive condition and, if a standard penetration test is performed, has a standard penetration resistance of 30 to 50 blows per 300 millimetres; - (b) can be penetrated with moderate difficulty by a small, sharp object; - (c) is difficult to excavate with hand tools; - (d) has a low to medium natural moisture content and a damp appearance after it is excavated; - (e) has no signs of water seepage; - (f) does not include p…

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## Support where heavy equipment used near edge 181 (3) Where powered mobile equipment or a mobile crane is used near the edge of an excavation or trench, an employer shall ensure that any shoring, bracing or ca -ging for the excavation or trench is adequate to support the increased pressure. ## Certificate of engineer respecting support 181 (4) An employer shall ensure that shoring, bracing or caging for an excavation or trench is certified as ade -quate by an engineer and shall make the proof of the cer -tification available to an officer on request. 2001-33 ## Entering excavation or trench 182 (1) An employer shall ensure that an employee does not, and no employee shall, enter an excavation or trench 1.2 m or more in depth unless - (a) the walls of the excavation or trench are sup -ported by shoring, bracing or caging, the excavation or trench is cut in solid rock or the excavation or trench is sloped or benched to within 1.2 m of the bot -tom of the excavation or trench with the slope not ex -ceeding 1 m of vertical rise to each 1 m of horizontal run, - (b) subsections 181(2), (3) and (4) have been com -plied with, - (c) loose material that may fall into the excavation or trench has been removed, and - (d) a ladder that extends at least 1 m above the ex -cavation or trench is installed no more than 15 m from where the employee is working or some other safe means of access and egress is provided. - 182 (2) Notwithstanding subsection (1), an employee may enter an excavation 1.2 m or more in depth to install bracing if the employee remains a distance from the face of the excavation equal to or greater than the depth of the excavation. ## Soutènement des parois si utilisation de matériel lourd 181 (3) Lorsqu'un équipement mobile à moteur ou une grue mobile est utilisé près du bord d'une excavation ou d'une tranchée, l'employeur doit s'assurer que tout étayage, tout étrésillonnement ou tout encagemen…

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## 29 CFR 1926 (OSHA) - (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 atmospheric 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 …

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## OCCUPATIONAL HEALTH AND SAFETY, 2020 - (3) An employer or contractor shall ensure that a temporary protective structure in an excavation more than 3 metres deep is designed and certified as safe by a professional engineer and installed, used, maintained and dismantled in accordance with that design. 31 Dec 2020 c S-15.1 Reg 10 s17-6. ## Protection against cave-in of trenches - 17-7 (1) If a worker is present in a trench that is more than 1.2 metres deep, an employer or contractor shall ensure that the worker is protected from cave-ins or sliding material by: - (a) cutting back the upper portion of the walls of the trench in accordance with subsection 17-4(2); - (b) installing a temporary protective structure; or - (c) a combination of cutting back the walls to the slope specified in subsection 17-4(2) and installing a temporary protective structure that extends at least 300 millimetres above the base of the cut-back. - (2) An employer or contractor shall ensure that a temporary protective structure required by clause (1) (b) or (c) is: - (a) designed and installed using shoring made of number 1 structural grade spruce lumber having the dimensions set out in Table 14 of the Appendix for the type of soil and the depth of the trench or made of material of equivalent or greater strength; or - (b) designed by a professional engineer and constructed, installed, used, maintained and dismantled in accordance with that design. - (3) An employer or contractor shall ensure that a temporary protective structure in a trench more than 6 metres deep in type 1, type 2 or type 3 soil or in a trench more than 4 metres deep in type 4 soil is designed and certified as safe by a professional engineer and installed, used, maintained and dismantled in accordance with that design. - (4) An employer or contractor shall ensure that: - (a) shoring is installed and removed in a manner that protects workers from cave-ins and structural collapses and from being struck …

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- 457 (4) Despite section 456, an employer may install additional protection certified by a professional engineer in trenches to compensate for passing vehicular traffic, working machinery or a heavy object placed within a distance equal to the depth of the trench, measured from the near edge of the bottom of the trench to the traffic, machinery or heavy object. - 457 (5) Despite section 456, an employer may install additional protection certified by a professional engineer in a trench to compensate for the stress created because the trench is adjacent to or abuts a building or other structure. ## Installation of shoring, stringers or bracing - 458 (1) An employer must ensure that a worker who installs shoring, stringers or bracing uses a ladder and works down from the top of the trench, installing each brace in descending order. - 458 (2) An employer must ensure that a worker who removes shoring, stringers or bracing uses a ladder and works upward from the bottom of the trench, removing each brace in ascending order. - 458 (3) A worker must install shoring, stringers or bracing in accordance with subsection (1) and remove them in accordance with subsection (2). - 458 (4) Despite subsections (2) and (3), if the quality of the ground in which a trench has been dug has deteriorated during operations to the extent that it is unsafe to use the method of removal required by subsection (2), an employer must ensure that the shoring, stringers or bracing are removed using a method that does not require the worker to be in the trench. ## Access for powered mobile equipment - 459 An employer must ensure that the open side of an excavation or a route used by powered mobile equipment to gain access to an excavation has a barrier high enough to stop the equipment from sliding or rolling into the excavation. ## Dumping block - 460 An employer must ensure that if powered mobile equipment may go over a bank or enter a dump opening while it is discharging its load, the equipme…

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## OCCUPATIONAL HEALTH AND SAFETY, 2020 S-15.1 REG 10 - (6) If a worker is required to enter a trench, an employer or contractor shall: - (a) install ladders, stairways or ramps to provide a safe means of entrance to and exit from the trench; and - (b) ensure that the ladder, stairway or ramp is located not more than 8 metres from a worker working in the trench. - (7) An employer or contractor shall ensure that workers are instructed in and comply with the requirements of this section. 31 Dec 2020 c S-15.1 Reg 10 s17-7. ## Excavated shafts and tunnels - 17-8 (1) An employer or contractor shall ensure that: - (a) during excavating, the walls of an excavated shaft or tunnel are retained by temporary protective structures that are adequate: - (i) for the type of soil; and - (ii) to prevent collapse or cave-in of the walls of the excavated shaft or tunnel; - (b) during the excavating of an excavated shaft that is 3 metres or more deep or of a tunnel, the walls of the shaft or tunnel are retained by temporary protective structures designed and certified by a professional engineer to be adequate for the protection of workers in the shaft or tunnel and constructed, installed, used, maintained and dismantled in accordance with that design; - (c) a solid or wire mesh fence at least 1 metre high, or other equally effective means of preventing material from falling into an excavated shaft or the surface opening of a tunnel, is provided around that shaft or opening; and - (d) substantial gates that are not less than 1 metre high are installed in every opening in a fence provided pursuant to clause (c) and the gates are kept closed except when being used. - (2) A worker who opens a gate mentioned in clause (1) (d) shall close the gate after the worker no longer has a need to keep the gate open. - (3) An employer or contractor shall provide suitable equipment to keep a tunnel or excavated shaft free from any accumulation of water. 31 Dec 2020 c S-15.1 Reg 10 s17-8. ## Bor…

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- (b) be secured in such a manner that it cannot be dislodged accidentally from its position. - (3) Where, because of the nature of the location or of the work being done, a portable ladder cannot be securely fastened in place, it shall, while being used, be sloped so that the base of the ladder is not less than one-quarter and not more than one-third of the length of the ladder from a point directly below the top of the ladder and at the same level as the base. - (4) Every portable ladder that provides access from one level to another shall extend at least three rungs above the higher level. - (5) Metal or wire-bound portable ladders shall not be used if there is a risk that they could come into contact with any live electrical circuit or equipment. - (6) No employee shall work from any of the three top rungs of any single or extension portable ladder or from either of the two top steps of any portable step ladder. SOR/88-632, s. 7(F); SOR/2019-246, s. 20(E); SOR/2022-94, s. 5(F). ## Excavation - 3.12 (1) Before the commencement of work on a tunnel, excavation or trench, the employer shall mark the location of all underground pipes, cables and conduits in the area where the work is to be done. - (2) Where an excavation or trench constitutes a hazard to employees, a highly visible barricade shall be installed around it. - (3) In a tunnel or in an excavation or trench that is more than 1.4 m deep and whose sides are sloped at an angle of 45 ° or more to the horizontal - (a) the walls of the tunnel, excavation or trench, and - (b) the roof of the tunnel - shall be supported by shoring and bracing that is installed as the tunnel, excavation or trench is being excavated. - (4) Subsection ( 3 ) does not apply in respect of a trench where the employer provides a system of shoring composed of steel plates and bracing, welded or bolted together, that can support the walls of the trench from the …