How to prepare a JHA for excavation?

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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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# How do I "identify potential hazards"? (cont.) ## 1. Eliminate the hazard (cont.) If the hazard cannot be eliminated, contact might be prevented by using enclosures, machine guards, worker booths or similar devices. These are generally engineering controls. ## 3. Revise work procedures Consideration might be given to modifying steps which are hazardous, changing the sequence of steps, or adding additional steps (such as locking out energy sources). Work procedures and training fall under administrative controls. ## 4. Reduce the exposure These measures are the least effective and should only be used if no other solutions are possible. One way of minimizing exposure is to reduce the number of times the hazard is encountered. An example would be modifying machinery so that less maintenance is necessary. The use of appropriate personal protective equipment may be required. To reduce the severity of an incident, emergency facilities, such as eyewash stations, may need to be provided. This preventive measure is also an administrative control. Reducing the exposure may include using personal protective equipment. It is important to note that personal protective equipment can limit exposure to the harmful effects of a hazard, but only if the personal protective equipment is worn and used correctly. In listing the preventive measures, do not use general statements such as "be careful" or "use caution." Specific statements which describe both what action is to be taken and how it is to be performed are preferable. The recommended measures are listed in the right-hand column of the worksheet, numbered to match the hazard in question. For example: Job Safety Analysis CCOHS

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# What are the benefits of doing a job safety analysis? (cont.) ## How do I break the job into "basic steps"? (cont.) Care must be taken not to make the steps too general. Missing specific steps may make it difficult to identify potential hazards. On the other hand, if the steps are too detailed, the job safety analysis will be too long. A rule of thumb is that most jobs can be described in less than ten steps. If more steps are required, you might want to divide the job into two segments, each with its separate job safety analysis, or combine steps where appropriate. As an example, the job of changing a flat tire will be used throughout this document. An important point to remember is to keep the steps in their correct sequence. Any step that is out of order may cause a team to miss potential hazards or introduce hazards which do not actually exist. Make notes about what is done rather than how it is done. Start each item with an action verb. Appendix A (below) illustrates a format that can be used as a worksheet to prepare a job safety analysis. Job steps are recorded in the left-hand column, as shown here: <table><tr><th>Sequence of Events (Steps)</th><th>Potential Incidents or Hazards</th><th>Preventive Measures</th></tr><tr><td>1. Park vehicle</td><td></td><td></td></tr><tr><td>2. Remove the spare tire and tool kit</td><td></td><td></td></tr><tr><td>3. Pry off the hub cap and loosen lug bolts (nuts)</td><td></td><td></td></tr><tr><td>And so on</td><td></td><td></td></tr></table> This part of the analysis is usually prepared by knowing the basic steps of a job or watching a worker do the job. The observer is normally the immediate supervisor. However, a more thorough analysis often happens by having another person, preferably a member of the health and safety committee, participate in the observation. Key points are less likely to be missed in this way. The job observer should have experience with the task and be capable in all parts of the job. The reason…

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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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# How do I "identify potential hazards"? (cont.) ## 4. Reduce the exposure (cont.) <table><tr><th>Sequence of Events</th><th>Potential Incidents or Hazards</th><th>Preventive Measures</th></tr><tr><td>1. Park vehicle</td><td>a) Vehicle too close to passing traffic b) Vehicle on uneven, soft ground c) Vehicle may roll</td><td>a) Drive to an area clear of traffic. Turn on emergency flashers. b) Choose a firm, level parking area. c) Apply the parking brake; leave the transmission in PARK; place blocks in front and back of the wheel diagonally opposite to the flat.</td></tr><tr><td>2. Remove the spare tire and tool kit</td><td>a) Strain from lifting the spare tire</td><td>a) Turn the spare into an upright position in the wheel well. Using your legs and standing as close as possible, lift the spare out of the trunk and roll it to the flat tire.</td></tr><tr><td>3. Pry off the hub cap and loosen lug bolts (nuts)</td><td>a) Hub cap may pop off and hit you b) Lug wrench may slip</td><td>a) Pry off the hub cap using steady pressure. b) Use a proper lug wrench; apply steady pressure slowly.</td></tr><tr><td>And so on</td><td>a)</td><td>a)</td></tr></table> ## How should I communicate the information to everyone? A job safety analysis is a useful technique for identifying hazards so that workers and supervisors can take measures to eliminate or control hazards. The job safety analysis breaks down the job into steps that can be understood clearly; however, the table format may not always be the best way to communicate the information. Once the analysis is completed, the results must be communicated to all workers who are or will be performing that job. The side-by-side format used in JSA worksheets is not ideal for instructional purposes. Better results can be achieved by using a narrative-style communication format. For example, the work procedure based on the partial job safety analysis developed as an example in this document might start out like this: ## 1. Park vehic…

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# Return to Work - Job Demands Analysis (cont.) ## What do you need to conduct a job demands analysis? (cont.) - Self-supervision - Work pressures and deadlines - Interpersonal skills required - Self-regulation and independent work - Reading, writing, and speech Each element should be compared against an established classification of occupational data. For example, the National Occupational Classification Skills and Competencies Taxonomy. established by the Government of Canada. This data provides the descriptor as well as the definition for specific skills that may be required for a job or task. When describing the demands of a task, we often see "frequency categories." These categories may include descriptors such as rare, occasional, frequent, or constant. These categories must be well defined within the job demands analysis. ## How does a Job Demands Analysis compare to a Job Safety Analysis? A Job Safety Analysis (JSA)_ can be used to identify potential risk factors for injury in a job, and to identify ways to modify a job. Job safety analyses can also be used to understand and address the hazards of a job task, and in developing a return to work program. A job safety analysis (JSA) is a procedure which helps integrate accepted safety and health principles and practices into a particular task or job operation. In a JSA, each basic step of the job is to identify potential hazards and to recommend the safest way to do the job. Other terms used to describe this procedure are job hazard analysis (JHA) and job hazard breakdown. A job demands analysis differs from a job safety analysis. The job demands analysis focuses on the demands of the job, not necessarily how to do the job. The job safety analysis can identify hazards throughout the task and suggest controls, whereas the job demands analysis is describing the demands of the task as is. ## How often should you review a job demands analysis? Job demands analyses should be reviewed as often as ne…

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# How do I "identify potential hazards"? (cont.) <table><tr><th>Sequence of Events</th><th>Potential Incidents or Hazards</th><th>Preventive Measures</th></tr><tr><td>1. Park vehicle</td><td>a) Vehicle too close to passing traffic b) Vehicle on uneven, soft ground c) Vehicle may roll</td><td></td></tr><tr><td>2. Remove the spare tire and tool kit</td><td>a) Strain from lifting spare tire</td><td></td></tr><tr><td>3. Pry off the hub cap and loosen lug bolts (nuts)</td><td>a) Hub cap may pop off and hit you b) Lug wrench may slip</td><td></td></tr><tr><td>And so on</td><td>a)</td><td></td></tr></table> Again, all participants should jointly review this part of the analysis. ## How do I "determine preventive measures?" The next step in a job safety analysis is to determine ways to eliminate the hazards or control the risks identified. Hazards should be controlled using the hierarchy of controls. The hierarchy of controls is a step-by-step approach to eliminating or reducing workplace hazards. For more information, please see the OSH Answers on Hierarchy of Controls. Following the same principles as the hierarchy of controls, you would implement preventive measures in the following order of preference: ## 1. Eliminate the hazard Elimination is the most effective measure. These techniques should be used to eliminate the hazards: - Choose a different process - Modify an existing process - Substitute with less hazardous product - Improve environment (e.g., ventilation) - Modify or change equipment or tools In the hierarchy of controls, these would be elimination or substitution controls. 2. Contain the hazard Job Safety Analysis CCOHS

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# What are the benefits of doing a job safety analysis? (cont.) ## Who should conduct a job safety analysis? (cont.) The basic steps in conducting a job safety analysis are: - Select the job to be analyzed - Break the job down into a sequence of steps - Identify potential hazards - Determine preventive measures to control these hazards - Communicate the results ## What is important to know when "selecting the job"? Ideally, all jobs should be subjected to a job safety analysis. In some cases, practical constraints are posed by the amount of time and effort required to do a job safety analysis. Another consideration is that each job safety analysis will require revision whenever equipment, raw materials, processes, or the environment changes. For these reasons, it is usually necessary to identify which jobs are to be analyzed. Even if an analysis of all jobs is planned, this step ensures that the most critical jobs are examined first. Factors to be considered in setting a priority for the analysis of jobs include: - Incident frequency and severity: jobs where incidents occur frequently or where they occur infrequently but result in serious injuries. - Potential for severe injuries or illnesses: the consequences of an incident, hazardous condition, or exposure to harmful products are potentially severe. - Newly established jobs: due to lack of experience in these jobs, hazards may not be evident or anticipated. - Modified jobs: new hazards may be associated with changes in job procedures. - Infrequently performed jobs: workers may be at greater risk when undertaking non- routine jobs, and a JSA provides a means of reviewing hazards. ## How do I break the job into "basic steps"? After a job has been chosen for analysis, the next stage is to break the job into steps. A job step is defined as a segment of the operation necessary to advance the work. Job Safety Analysis CCOHS

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# How do I "identify potential hazards"? Once the basic steps have been recorded, actual and potential hazards must be identified at each step. Based on observations of the job, knowledge of incident and injury causes, and personal experience, list the things that could be unsafe at each step. A second observation of the job being performed may be needed. Since the basic steps have already been recorded, more attention can now be focused on each hazard. At this stage, no attempt is made to solve any problems or correct any hazards which may have been detected. To help identify potential hazards, the job analyst may use questions such as these (this is not a complete list): - Can any body part get caught in or between objects? - Do tools, machines, or equipment present any hazards? - Can the worker make harmful contact with moving objects? - Can the worker slip, trip, or fall? - Can the worker suffer strain from lifting, pushing, or pulling? - Is the worker exposed to extreme heat or cold? - Is excessive noise or vibration a problem? - Is there a danger from falling objects? - Is lighting a problem? - Can weather conditions affect safety? - Is harmful radiation a possibility? - Can contact be made with hot, toxic, or caustic products? - Are there dusts, fumes, mists, or vapours in the air? Potential hazards are listed in the middle column of the worksheet, numbered to match the corresponding job step. For example: Job Safety Analysis CCOHS

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# Trenching and Excavation (cont.) ## Temporary protective structure (cont.) - Trench Boxes are commonly used in open areas that are away from utilities, roadways, and foundations. Trench boxes can be used to protect workers in cases of cave-ins, but not to shore up or support trench walls. They can support trench walls if the space between the box and the trench wall is backfilled with soil and compacted properly. Otherwise, a cave-in or collapse may cause the trench box to tilt or turn over. Workers should not be present in the box when it has to be moved. - Other: In some cases, the trench or excavation walls are made of rock but are not entirely stable. Support the walls by using rock bolts, wire mesh, or a method that provides equivalent support. ## What should NOT be done during an excavation? - Do not enter an unprotected trench deeper than 1.2 metres (4 feet), or as specified in the legislation. - Do not start digging before locating and de-energizing the buried services. - Do not enter a trench before testing the air for hazardous gasses and vapours, or the lack of oxygen. - Do not place the sections of pipes, piles of spoil, unused tools, and timber, and other materials within 1 metre from the trench's edge. - Do not rely on natural freezing to act as a method of soil stabilization. - Do not work under suspended or raised loads and materials. - Do not stand behind a backing vehicle. ## What can be included in a trenching and excavation inspection checklist? The following are some points to consider. Each circumstance will be different, so be sure to adapt the questions to suit your situation. ## Underground or Utility Services - Know the contact numbers? - Located, identified and informed respective parties? - Grounded, isolated, de-energized, or protected from unplanned release? ## Housekeeping Trenching and Excavation CCOHS

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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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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