Earth work

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# Trenching and Excavation (cont.) ## What should occur before beginning an excavation? (cont.) - Check areas near the site for potential hazards and sources that can impact the stability of the soil. Be aware that nearby vehicles and equipment can cause the soil to vibrate and then collapse. - Determine if nearby buildings or structures and their foundations may put pressure on the soil and affect the walls of the trench. - Test for hazardous gas, vapours, and dust before entering. Test for oxygen levels in the space before entering, and during the work as required. - Plan appropriate organization of the work site, and good housekeeping practices including moving debris and excavated soil far enough away from the excavation site. - Remove water from the excavation. - Protect workers from falling into the excavation. - Identify appropriate personal protective equipment including high visibility apparel for vehicular traffic and make sure every worker wears them as required. - Have a worker above ground when a worker is working in the trench to warn those in the trench of danger and to provide emergency help. - Determine if the trench is considered a confined space If so, do not allow workers to enter the trench until the requirements of the organization's confined space program are met, including entry permits and training. - Prepare work permits for work in confined spaces, as appropriate. - Have a means of exit provided from the inside of the trench, usually no more than 8m (25 ft) away from any worker in the trench. - Plan for adverse weather conditions (e.g. hot or cold environments, storms, etc.). - Prepare an emergency plan and rescue procedures. - Keep first aid equipment at the site. - Educate and train workers about all existing and potential hazards and risks and appropriate safety measures. ## What factors determine what is the appropriate protective system to use? In general, trenches that are 1.2 metres (4 feet) deep or great…

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SAMPLE-Excavation Checklist # EXCAVATION CHECKLIST (To be completed by a Competent Person) SITE LOCATION: <empty> DATE: <empty> TIME: <empty> COMPETENT PERSON: <empty> SOIL TYPE (See attached form): <empty> SOIL CLASSIFICATION: <empty> EXCAVATION DEPTH: <empty> EXCAVATION WIDTH: <empty> TYPE OF PROTECTIVE SYSTEM USED: <empty> ## Indicate for each item: YES - NO - or N/A for not applicable <table><tr><th>1. General Inspection of Jobsite:</th><th></th></tr><tr><td>A. Excavations, adjacent areas, and protective systems inspected by a competent person daily before the start of work.</td><td></td></tr><tr><td>B. Competent person has the authority to remove employees from the excavation immediately.</td><td></td></tr><tr><td>C. Surface encumbrances removed or supported.</td><td></td></tr><tr><td>D. Employees protected from loose rock or soil that could pose a hazard by falling or rolling into the excavation.</td><td></td></tr><tr><td>E. Hard hats worn by all employees.</td><td></td></tr><tr><td>F. Spoils, materials, and equipment set back at least two feet from the edge of the excavation.</td><td></td></tr><tr><td>G. Barriers provided at all remotely located excavations, wells, pits, shafts, etc.</td><td></td></tr><tr><td>H. Walkways and bridges over excavations four feet or more in depth are equipped with standard guardrails and toeboards.</td><td></td></tr><tr><td>I. Warning vests or other highly visible clothing provided and worn by all employees exposed to public vehicular traffic.</td><td></td></tr><tr><td>J. Employees required to stand away from vehicles being loaded or unloaded.</td><td></td></tr><tr><td>K. Warning system established and utilized when mobile equipment is operating near the edge of the excavation.</td><td></td></tr><tr><td>L. Employees prohibited from going under suspended loads.</td><td></td></tr><tr><td>M. Employees prohibited from working on the faces of slopes or benched excavations above other employees.</td><td></td></tr><tr><td>2. Uti…

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# Trenching and Excavation (cont.) ## What are the hazards associated with trenching and excavation? (cont.) - Contact with buried service lines such as electrical, natural gas, water, sewage, telecommunications, etc. - Contact with overhead electrical lines. - Slips, trips and falls as workers climb on and off equipment, or from inappropriate access and egress methods. - Being struck by moving machinery, or by falling or flying objects. - Hazards related to materials handling (e.g., lifting, struck by, crushed between, etc.). ## What is meant by soil types? Definitions of soil types vary by jurisdiction in Canada. In addition, some jurisdictions have not defined soil types, but do require preventative measures when an excavation reaches a certain depth or proportion. When a soil type is defined, the purpose is to try to identify or predict the potential for the soil to move and cause a collapse while the work is being done. Soil types typically use a scale of 1 to 4 where 1 is hard and dense to 4 which is loose, soft, wet or muddy soil, or a scale of A to C where A is hard and solid, and C is soft, sandy, filled or loose. The soil type is determined by the characteristics of the soil's consistency, ease of removal, appearance, ability to excavate with hand tools vs. machine, water seepage, whether the soil has been excavated before, etc. ## What should occur before beginning an excavation? The employer or supervisor is responsible for the work, and must take the necessary steps to identify all the hazards and risks before beginning any work. These steps include to: - Identify the soil type(s) related to the excavation or trench you are going to dig. Soil properties often vary widely within a single trench (e.g., the soil type changes from top to bottom and along the length of a trench). - Look for the legislative requirements that apply in your jurisdiction and the type of protective measures to be taken. - Locate all buried services. Contact t…

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# Trenching and Excavation (cont.) ## Housekeeping (cont.) - Excavated material, pipes etc. are placed 1 metre away from the edge of the excavation or trench wall? - Are pumps available to remove water? - Is the base and foot of the ladder secure, and free of garbage or water? - Are materials placed on the site obstructing the worker's or vehicle's ability to move freely? - Are established traffic controls used, where required, including adequate signage, personnel, and lighting? - Has the excavation been marked to make the workers and others aware of the excavation (e.g., fence, flags, or other safeguards)? - Are sanitary facilities available at the site, as appropriate? ## General - Are proper barriers or guardrails in place to protect anyone or equipment falling into the excavation or trench? - Has the air in the excavation been tested for low oxygen, and hazardous gasses and vapours? - Is a safe means of entry and exit provided such as a sufficiently long and secured ladder placed at appropriate distances (within 25 feet of all workers)? - Are cracks visible in the ground around the trench or excavation that may indicate soil movement? - Are there any signs of water seeping into the trench or excavation? - Are workers wearing appropriate PPE (e.g., hard hats, respirators, , safety boots, hearing protection)? - Are high visibility vests or clothing provided and worn by all exposed to vehicular traffic? - Is first aid equipment available at the site? - Are operators qualified to operate the heavy machinery or equipment? - Does a competent person regularly inspect the excavation (at the start of each shift before work begins or after any event likely to have affected the strength or stability of the excavation)? - Is there a competent person stationed at the surface of the trench to warn workers in the trench of danger and to provide emergency help? - Is the trench a confined space, and are the requirements of the confined space program met?…

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CCOHS CCHST Canadian Centre for Occupational Health and Safety Centre canadien d'hygiène et de sécurité au travail Health and Safety Programs # Trenching and Excavation ## On this page What is meant by a trench and an excavation? What are the hazards associated with trenching and excavation? What is meant by soil types? What should occur before beginning an excavation? What factors determine what is the appropriate protective system to use? What are the different types of protective systems used to protect against cave-ins? What should NOT be done during an excavation? What can be included in a trenching and excavation inspection checklist? ## What is meant by a trench and an excavation? Generally speaking, an excavation is a hole in the ground as the result of removing material. A trench is an excavation in which the depth exceeds (is bigger than) the width. ## What are the hazards associated with trenching and excavation? Working in trenches and excavations is hazardous to both the workers who work inside them, and to workers on the surface. The hazards include: - Cave-ins or collapses that can trap or crush workers. - Equipment or excavated soil falling on workers (e.g., equipment is operated or soil and debris is stored too close to the excavation). - Falling into the trench or excavation. - Flooding or water accumulation. - Exposure to a hazardous atmosphere (e.g., gas, vapour, dust, biological contaminants, or lack of oxygen). Trenching and Excavation CCOHS