Write a toolbox talk on Trench collapse

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# Toolbox Talks Preventing Excavation/Trench Cave-ins - Ask the following questions and give time for answers. ## What are the hazards? Bodily or equipment entrapment in soil. ## What are the results? Broken or crushed limbs and bones, entrapment, suffocation, head injury, internal damage, and death. ## What should we look for? Stable rock and soil type (A, B, C), depth of excavation, cave-ins, water in trench, weather conditions (rain, frost), water table, protective systems, competent person, operation of heavy equipment near excavation, barricades, and falling loads. ## How do we prevent these results? • A competent person must evaluate excavations daily. Excavations should be re-evaluated after events such as rain. • Use shoring equipment, shielding, and/or sloping or benching systems for excavations greater than 5 feet in depth or less when deemed necessary by the competent person. • Examine protective systems in accordance with manufacturers recommendations and remove damaged systems from service. • Excavated material/other objects must be kept at least 2 feet from edge. ## Understanding Soil Types • Type "A" - most stable (clay, hardpan) • Type "B" - next most stable (slit, loam, unstable dry rock) • Type "C" - least stable (gravel, loamy sand) ## Let's talk about this site now How can you prevent cave-ins? Shoring, shielding, sloping, and/or benching. At what depth is cave-in protection required? 5 feet or less depending on the assessment by a competent person. Name some conditions that can increase cave-ins. Rain, heavy equipment, vibration, spoil piles, etc. The unfortunate reality - From 2011 to 2021 there were at least 220 trenching fatalities across the United States. These fatality incidents were preventable with the use of a protective system, proper employee training, and implementation of a safety and health management system. ## AN UNPROTECTED TRENCH IS AN EARLY GRAVE DOLI VIRGINIA DEPARTMENT OF LABOR AND INDUSTRY in li…

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Trenching Safety Preventing Cave-ins Trenching work is risky; cave-ins occur suddenly and bring lasting, tragic consequences. Safety preplanning, oversight, and training are key to ensuring work is set up and performed safely in trenches. ## Protective Systems Protective systems prevent cave-ins and protect workers from falling materials. There are three types: ■ Sloping and benching removes soil to eliminate the chance of cave-ins (benching isn't an option for sand, gravel, and other Type C soils). a ■Shoring uses supports to brace the walls of trench (e.g., aluminum hydraulic supports). ■ Shielding protects workers inside of the shielded area (e.g., trench boxes). Protective systems are required for all trenches four feet or deeper; and for those less than four feet deep if a potential for cave-in exists. Systems for trenches over 20 feet deep must be designed by a registered professional engineer (or designed according to tables, charts, and other tabulated data approved by them). ## Competent Person A competent person is someone who: ■ Conducts daily safety inspections of excavation areas, including protective systems, to identify existing and potential hazards. ■ Has the knowledge and authority to take immediate corrective measures to eliminate hazards and conditions; and has the authority to remove workers promptly if hazardous conditions are found. ## Getting In and Out Safely Workers must be able to easily and safely enter and exit trenches four feet or deeper. A way in or out must be available every 25 feet. The most common method for access is a straight ladder or an extension ladder. If a ladder is used, it must extend at least three feet above the landing. Other means could be a stairway or ramp designed by a registered professional engineer. ## General Safety Tips ■Don't let workers enter or work inside an unprotected trench four feet or more in depth. ■Never work inside a trench if the spoils pile is less than two feet away from the e…

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# WEATHER (cont.) ## RECOMMENDATIONS AND DISCUSSIONS (cont.) Kentucky FACE Program 16KY017 Page 8 Employees working in trenches of five feet or more in depth should be protected from cave-ins by adequate protection systems appropriate for the conditions in the trench, including sloping or benching techniques, shoring, or shields (trench boxes).¹ Sloping involves making sure that the soil is at an angle to prevent the soil from caving into the trench. In this particular incident, sloping was not a viable option due to the proximity of the trench to the adjacent concrete wall. When sloping methods are not feasible, trench shields or aluminum hydraulic shoring systems should be used. In addition to the use of correct protective systems, the spoil pile should also be at least two feet from the edge of the trench. When installing miles of pipeline or cable, the amount of soil that must be moved along with the associated cost of excavator fuel, operator time, backfill, compaction, etc., can make sloping inefficient and time consuming in regard to project deadlines. Rather than foregoing the use of a protective system altogether, it is strongly recommended that employers at least require trench shields or aluminum hydraulic shoring systems, both of which are OSHA-approved protective systems that can be rented, if needed. These protective systems can still adequately protect workers while increasing project expediency and efficiency. Recommendation No. 3: Employers should ensure a competent person conducts soil testing and daily inspections of the excavations, adjacent areas, and protective systems. A competent person is defined by OSHA 1926.650(b) as “a person 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 the hazards".2 Inspections should occur throughout the day and as conditions …

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# Trench and Excavation Safety Trench collapses, or cave-ins, are the leading hazard in excavation work. Safe trenching helps prevent falls, falling loads, hazardous atmospheres, and incidents involving mobile equipment. ## Trench Safety Measures Trenches 5 feet or deeper require a protective system unless dug in stable rock. For trenches less than 5 feet, a competent person must decide if protection is needed. Trenches 20 feet or deeper must have a protective system designed or approved by a registered professional engineer, as required by OSHA 1926.652(b) and (c). ## Competent Person Before workers enter a trench, a competent person must inspect it daily and after any condition changes to ensure safety. This person is trained to identify hazards, determine soil types, select protective systems, and has the authority to correct issues immediately. ## Access and Egress • Keep heavy equipment and spoils at least 2 feet from trench edges - Locate underground utilities before digging • Test for atmospheric hazards in trenches over 4 feet deep • Inspect trenches daily, at the start of each shift, after storms, and after conditions change • Never work under suspended loads - Wear high visibility clothing when near traffic # Protective Systems • Benching: a method of protecting workers from cave-ins by cutting the sides of an excavation into horizontal steps. Benching is not allowed in Type C soil. • Sloping: involves cutting back the trench wall at an angle inclined away from excavation. • Shoring: requires installing aluminum hydraulic or other types of supports to prevent soil movement and cave-ins. • Shielding: protects workers by using trench boxes or supports to prevent cave-ins. Designing these systems can be complex, as factors like soil type, trench depth, moisture, weather, nearby loads, and site activity must all be considered. OSHA standards require that employers provide workplaces free of recognized hazards. The employer must compl…

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# Trenching-Protection ## Explain dangers You risk injury or death if you enter a trench deeper than 1.2 metres (4 feet) that has not been sloped, shored, or protected by a trench box. ## Identify controls ## SLOPING Sloping the walls is one way to keep a trench from collapsing. The angle of the slope depends on soil conditions. • Type 1 and 2 soils: Cut trench walls back at an angle of 1-to-1 or 45°. That's 1 m (3 ft) back for each 1 m up. Walls should be sloped starting at 1.2 m (4 ft) up the wall. - Type 3 soil: Cut walls back at an angle of 1-to-1, but from the bottom of the trench. - Type 4 soil: Slope the walls at 1-to-3. That's 3 m (10 ft) back for every 1 m (3 ft) up from the trench bottom. Type 1 and 2 GOOD SOIL Minimum 1.2m (4 ft.) Maximum Bank Slope Bank Wall Type 3 FAIRLY GOOD SOIL Minimum Bank Slope Type 4 BAD SOIL 3 Minimum Bank Slope ## SHORING Shoring is a system that supports walls to prevent soil movement. It also helps to support underground utilities, roadways, and foundations. The two types of shoring used most commonly are timber and hydraulic. Both consist of posts, wales, struts, and sheathing. One major advantage of hydraulic shoring is that you don't have to enter the trench to install the system. Installation can be done from the top of the trench. Whenever possible, shoring should be installed as excavation proceeds. If there's any delay between digging and shoring, no one should enter the unprotected trench. ## TRENCH BOXES Trench boxes aren't meant to shore up or support trench walls. They're only meant to protect workers in case of a cave-in. The space between the box and the trench wall should be backfilled. Otherwise a cave-in or collapse may cause the trench box to tilt or turn over. It's also easier to enter the box if soil comes right up next to it. Trench boxes are commonly used in open areas away from utilities, roadways, and foundations. If you're in the trench, stay inside the box. ## LADDERS Whether…

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# Excavation Safety (cont.) ## Access/Egress • [Describe means of access/egress, including use of ramps/steps in excavations and ramps/ladders every 25 ft. in trenches more than 4 ft. deep.] ## Inspection • [Provide the name of the competent person] will inspect the trench and protective systems daily, before the start of work and throughout the day as conditions change. These daily inspections include: - 0 Soil conditions and accumulation of water or anything else that would be indicative of a cave-in. - 0 Protective system integrity. ○ Hazardous atmospheres. - 0 [Describe other site-specific hazards and how they are abated.] • Employees are not allowed to enter the excavation unless cleared safe to do so by the competent person. ## Vehicular Traffic and Warning System • [Describe the warning vests/garments used by exposed employees.] • [Describe the warning system (e.g., barricades, hand or mechanical signals, stop logs) for mobile equipment operating adjacent to an excavation.] ## Hazardous Atmospheres [Describe how oxygen deficiency or other hazardous atmospheres will be tested and controlled in excavations greater than 4 ft. in depth.] • [Describe the emergency equipment (e.g., breathing apparatus, safety harness/line, basket stretcher, etc.) to be readily available.] ## Water Accumulation • Employees will not work in excavations where there is accumulated water unless the following precautions have been taken: [Describe precautions (for example, special support or shield systems, water removal pumps, the means of diverting water from entering excavations, use of harness and safety line, etc.).] ## Loose Rock/Soil • [Describe how employees are protected from loose rock/soil that could pose a hazard by falling from an excavation face (for example, scaling, protective barricades, etc.).] • Excavated materials or equipment that could fall into an excavation are kept at least 2 feet from the edge of the excavation unless the following retai…

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# CONSIDERATIONS BEFORE EXCAVATING (cont.) ## SOIL TYPES (cont.) Establish Mean of Exit from the Excavation or Trench When employees are required to be in excavations or trenches 4 feet deep or more, an adequate means of exit, such as a ladder or steps, must be provided and located within 25 feet of lateral travel. An earth ramp is acceptable, providing all the following are met: • The stability of the earth is adequate for sound footing. • The total travel distance does not exceed 25 feet. • Adequate shoring or equivalent protection is provided for the entire escape route. ## PROTECTING FROM HAZARDOUS ATMOSPHERES Atmospheric testing is required before workers enter an excavation or trench greater than 4 feet (1.22 meters) in depth where an oxygen deficiency or a hazardous atmosphere is present or could reasonably be expected, such as in excavations in landfill areas or excavations in areas where dangerous substances are stored nearby. ## CALL BEFORE YOU DIG Utility locates must be completed prior to digging. Calling 811 before you dig is necessary to prevent damage and injuries. ## INSPECTIONS WAC [redacted identifier] requires that a competent person inspect excavations, adjacent areas, and protective systems daily for evidence of a situation that could result in possible cave-ins, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions. The competent person must inspect before the start of work and as needed throughout the shift. Inspections must also be made after every rainstorm or other hazard-increasing occurrence. Specifically, inspections should help to identify the following: Unusual Hazardous Conditions: Daily inspections of excavations, adjacent areas, and protective systems will be made by a designated competent person in situations that might result in a cave-in, failure of a protective system, or other hazardous conditions. A competent person will inspect before the day's work and throughout the …

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# EXCAVATIONS AND TRENCHES WAC [redacted identifier] defines an excavation as "Any person-made cut, cavity, trench, or depression in the earth's surface, formed by earth removal." A trench is "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. 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." One cubic yard of soil can weigh up to 3000 pounds - approximately the weight of a small car. The fatality rate for excavation work is 112% higher than the rate for general construction, according to data from the Occupational Safety and Health Administration (OSHA). The agency lists "employee injury from collapse" as the primary hazard of excavation work and includes "no protective system" among the leading causes of worker injuries. ## EXCAVATION AND TRENCHING HAZARDS Trenching and excavation work presents serious hazards to all workers involved. Cave-ins pose the most significant risk and are more likely than other excavation- related incidents to result in worker fatalities. One cubic yard of soil can weigh as much as a car. • Collapse of soils and materials (cave-in) due to lack of, inadequate, or weak protective systems • The striking or damaging of underground utility services • Persons falling into excavations due to a lack of barriers or inadequate fencing • Asphyxiation from toxic gases which have collected in the excavation/trench • Spoil (soil from excavation/trench) or materials/equipment being placed too close to the sides of the excavation/trench, which then become overloaded and collapse • Failure to check and maintain shoring, particularly after incle…

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California Department of Industrial Relations Division of Occupational Safety and Health Publications Unit STATE OF CALIFORNIA CAL OSHA DEPARTMENT OF INDUSTRIAL RELATIONS # TAILGATE/TOOLBOX TOPIC October 2022 # Excavation Safety Over a 5-year period, 26 California workers died and 207 others were injured in trench cave-ins. In almost every instance, improperly implemented protective measures were the cause of the accident. The following will be implemented at this job site (only cover the issues that are relevant to your scope of work and be sure to review Article 6-Excavations of the Construction Safety Orders to ensure all regulatory requirements are addressed and implemented). Red italics set in brackets indicate where you must customize the content of this tailgate meeting for your job site's equipment and conditions. ## Before Excavation Begins-Checklist - The excavator has: - 0 Determined the approximate locations of subsurface installations that can be reasonably expected to be encountered. - Notified all affected utility Regional Notification Centers at least 2 working days and not more than 14 calendar days from the start date. - Received clearance from all known owner/operators of subsurface installations that might be affected. - Met with the facility owner/operator to determine how to verify the location for high priority installations that come within 10 ft. of the excavation. - The excavation area has been marked. • A qualified person performed subsurface installation locating activities. ⋅ Permits for excavations 5 ft. or deeper that a person might enter have been obtained from Cal/OSHA. Protective systems such as shoring or sloping are used regardless of depth should soil type or condition warrant it. • All employees exposed to excavation hazards have received required training on excavator notification and excavation practices. ## Subsurface Installations (Utilities, Etc.) The following safe means of determining the exact…

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CPWR TOOLBOX THE CENTER FOR CONSTRUCTION RESEARCH AND TRAINING TALK # Trench Safety When a trench caves in, the weight of the dirt can trap and kill workers. One cubic yard of dirt can weigh 3,000 pounds or more. Each year, trench collapses seriously injure or kill construction workers. In 2016, for example, 23 workers were killed in trench collapses. ## Jim, Nico, and Jose's Story Three laborers were working in an 8-foot-high wall trench. The walls were not shored-up. One side caved in, burying Nico and partially burying Jim. Jose managed to escape unharmed. Jim was pulled out. Nico suffocated and died. - How could this incident have been prevented? - Have you ever been in a trench cave-in? If so, what happened? : ## Remember This ➤ Never enter an unprotected or uninspected trench, even for a short task. A trained, competent person must inspect the trench and surroundings first. ➤Make sure you understand your employer's trench emergency program. ➤ Make sure rocks and dirt are kept at least 2 feet away from the top of the trench. - Never work alone in a trench and never without a lookout standing by. ➤ Make sure trench protection is provided by your employer. OSHA allows benching or sloping ground, shoring, or shielding with supports or trench boxes. How can we stay safe today? What will we do at the worksite to promote trench safety? 1. 2. OSHA Regulation: 1926.651(k)(1) ©2017, CPWR-The Center for Construction Research and Training. All rights reserved. CPWR is the research and training arm of NABTU. Production of this document was supported by cooperative agreement OH 009762 from the National Institute for Occupational Safety and Health (NIOSH). The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH. CPWR 【● THE CENTER FOR CONSTRUCTION RESEARCH AND TRAINING

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# EXCAVATIONS AND TRENCHES (cont.) ## PROTECTIVE METHODS (cont.) Shoring: The process of installing aluminum hydraulic or other types of supports to prevent soil movement and cave-ins. This is often necessary when excavating trench or working where the ground may give way. Shoring can also stabilize a structure damaged by an earthquake or other disaster. a Shoring is a critical part of construction and should only be done by trained professionals. Improper shoring can lead to severe injuries or even death. Shielding: This method is the most common system and protects workers with trench boxes or other supports to prevent soil cave-ins. This method uses a trench box or shield designed or approved by a registered professional engineer (RPE). Note: Excavations that are less than 4 feet in depth may still require protection for workers to enter if the competent person believes that a cave-in may occur. ## INSPECTIONS WAC [redacted identifier] requires that a competent person inspect excavations, adjacent areas, and protective systems daily for evidence of a situation that could result in possible cave-ins, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions. The competent person must inspect before the start of work and as needed throughout the shift. Inspections must also be made after every rainstorm or other hazard-increasing occurrence. ## RESOURCES WAC [redacted identifier] - Excavation and Trenching NIOSH Trench Safety Graphic FSPO-912-000 An Unprotected Trench is an Early Grave (wa.gov) Trenching and Excavation - Overview | Occupational Safety and Health Administration (osha.gov)

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# Tennessee OSHA's Special Emphasis Program on Trenching & Excavation Because trenching and excavation collapse is deadly and often involves multiple victims, Tennessee OSHA has established a special emphasis program to focus attention and resources on these hazards. It is impossible to predict when an excavation or trench will collapse. The sudden collapse of the walls makes escape almost impossible. The only way to prevent collapse is to slope or shore the walls or install a trench shield and follow the TOSHA trenching and excavation standards contained in 29 CFR 1926 Subpart P. Under this special emphasis program, all TOSHA compliance and consultative services personnel will be on the lookout for trenching or excavation work sites. Personal observation, reports of imminent danger, fatality/catastrophe reports, safety and health agency referrals, employee complaints, and media reports are also used to locate trenching and excavation work. Each occurrence is handled with an appropriate intervention by TOSHA. ## Hazards on the Excavation Site Excavation workers are exposed to many hazards, but the chief hazard is cave-in. TOSHA requires that all employees exposed to potential cave-ins be protected by sloping or benching the sides of the excavation, shoring the sides of the excavation, or placing a shield between the sides and the work area. In addition to cave-in hazards, workers must also be protected from adjacent utility lines, exposure to vehicular traffic, falling loads, hazardous atmospheres, and fall hazards. Utility lines such as gas, electrical, sewer, and water must be located and supported prior to placing employees in an excavation. Employees working in, or near, roadways must wear high visibility vests. Workers are not to work beneath suspended loads, and walkways crossing excavations must be equipped with guardrails. Precautions, including atmospheric testing and emergency rescue procedures and equipment, must be taken when workers enter excavat…