Protective systems are just one area to consider for trench safety and excavation. An inadequately protected trench wall collapsed, killing one employee who had just gotten into the trench to check grade for installation of an 8" sewer line. At the time of the collapse, a backhoe was still extracting soil from the trench. Read the material in each section to find the correct answer to each quiz question. Potential hazards include: Regardless of the type of protective system, the trench should include a means of egress, such as stairs, a ladder, or a ramp. Before the start of sloping or benching, the contractor needs to: 4. The second number is 3 greater than the first, and the third is four times the first. After answering all the questions, click on the "Check Quiz Answers" button to grade your quiz and see your score. 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 other wise injure and immobilize a person. Before temporary removal of individual members begins, additional precautions shall be taken to ensure the safety of employees, such as installing other structural members to carry the loads imposed on the support system. Employers can choose the most practical method for the particular circumstance, but that system must meet the required performance criteria. The width, depth and length will impact the size of the protective system you need. Excavations are less than 5 feet (1.52m) in depth and examination of the ground by a competent person provides no indication of a potential cave-in. b. The OSHA standard doesn't require a protective system when an excavation is _____. However, you need to have an air compressor on site when using pneumatic shoring. a. (iii) Employees shall be protected from the hazard of cave-ins when entering or exiting the areas protected by shields. Soil and rock deposits shall be classified in accordance with appendix A to subpart P of part 1926. As the term indicates, underpinning is a procedure in which the foundation is physically reinforced. Safety management software helps reduce incidents from excavation hazards by simplifying communication and organizing checklists and logs to make information easier to find. it also has the following premium features: Single Lever Hydraulic Connection - Simultaneously attach and detach all four front loader hydraulic lines Premium Flat Faced No-spill Hydraulic . Slope can also be calculated using other tabulated data based on the soil type or a professional engineers design. Shields can be permanent structures or can be designed to be portable and moved along as work progresses. Which of the following is considered the safest of the four methods to prevent an excavation wall collapse? Hydraulic Shoring. Click on the buttons below to see definitions and rule requirements. Manufactured materials and equipment used for protective systems shall be used and maintained in a manner that is consistent with the recommendations of the manufacturer, and in a manner that will prevent employee exposure to hazards. (iii) At least one copy of the tabulated data which identifies the registered professional engineer who approved the data, shall be maintained at the jobsite during construction of the protective system. This appendix must be used when design of timber shoring protective systems is to be performed in accordance with 1926.652(c)(1). OSHA standards mandate that all excavations 5 feet or deeper be protected against collapse. Hazard or mitigation controls may be short and/or long term. Where the working area of an excavation is constantly moving, as in laying a conduit, shield systems or trench boxes may be the more appropriate protective devices to use. If installed and removed correctly, vertical planks and trench braces may be used several times! Benching cutting 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. Maximum allowable slope means the steepest incline of an excavation face that is acceptable for the most favorable site conditions as protection against cave-ins, and is expressed as the ratio of horizontal distance to vertical rise (H:V). Short-term maximum allowable slopes for excavations greater than 12 feet (3.67 m) in depth shall be 3/4H:1V (53). document.getElementById( "ak_js_2" ).setAttribute( "value", ( new Date() ).getTime() ); Safety and savings work together with Foresight Insurance and Safesite. A hormone (from the Greek participle , "system in motion") is any member of a class of signaling molecules, produced by glands in multicellular organisms, that are transported through the circulatory system to target organs of distant and behavioral sciences. The data are arranged to allow the user the flexibility to select from among several acceptable configurations of members based on varying the horizontal spacing of the crossbraces. Hazards associated with trench work and excavation are recognized and preventable, yet injuries and fatalities associated with these hazards continue to occur. A Cable Trench is located under the Switch/Relay Room, Control Room and Battery Room to house the communication, control and power cables between the substation's operational areas as well as transport power to external high voltage switching towers. Naslovnica; O nama. Examples include clay, silty clay, sandy clay, and clay loam. (i) Shield systems shall not be subjected to loads exceeding those which the system was designed to withstand. approaches that can be used to design protective systems. (ii) Designs shall be in written form and shall include the following: (A) A plan indicating the sizes, types, and configurations of the materials to be used in the protective system; and. means a narrow excavation (in relation to its length) made below the surface of the ground. Within five minutes, the collapse occurred and could have buried the worker under six to seven feet of soil. Configurations of sloping and benching systems shall be in accordance with Figure B-1. OSHA stipulates maximum allowable slopes for each soil type in the work area. Surcharge loads from adjacent structures shall be evaluated in accordance with 1926.651(i). You can correct any missed questions and check your answers again. Hydraulic shoring should be checked at least once per shift for leaking hoses and/or cylinders, broken connections, cracked nipples, bent bases, and any other damaged or defective parts. Explain. That is, for every foot of depth, the trench must be excavated back 1 feet, resulting in a maximum angle of 34 degrees. Trench protective systems include which of the following: B. Sloping, benching, shoring, trench box B. Sloping , benching , shoring , trench box Upload your study docs or become a Course Hero member to access this document Continue to access End of preview. This type of protective systems involves excavating the sides of a trench to form one or a series of horizontal levels or steps. (ii)Excavations are less than 5 feet (1.52m) in depth and examination of the ground by a competent person provides no indication of a potential cave-in. Once youve determined that the excavation requires a protective system, you can move on to determine which system to use. Shielding does not protect against soil . Trench shields are usually constructed with sidewalls held apart by steel or aluminum spreaders. OSHA standard 1926.652, Requirements for protective systems, details four types of protective systems. The trench is sloped on both sides. The maximum allowable slope is 1:1 (45 degrees) for type B soil, and 3/4:1 (53 degrees) for type A soil. Customers like taking advantage of the fact we cut the 6 awg thhn wire by the foot and offer the copper building wire in several different colors.In the united states, the following color codes are typically used for power wires in "branch circuits," the wiring between the last protective device (such as a circuit breaker) and the load (such as . All excavations are hazardous because they are inherently unstable. (ii) Shields shall be installed in a manner to restrict lateral or other hazardous movement of the shield in the event of the application of sudden lateral loads. Option 2: Sec. Backfilling shall progress together with the removal of support systems from excavations. workers. Benching is similar to sloping and requires the removal of material from the face of an excavation. Protective systems include support systems, sloping and benching systems, shield systems, and other systems that provide the necessary protection. 1926.652 (b) and (c). 2Cu+(aq)Cu2+(aq)+Cu(s), Hazard or mitigation controls may be short and/or long term, Hazard prevention and control should contain both, A safety and health program is called a living document why, A safety and health program changes as an organization changes, What should an incident investigation program include, I'm general accidents and incidents are caused by unsafe or hazardous conditions and, Unsafe or unhealthy actions and behaviors, Who should be on the team that evaluates a safety and health program, Who should be involved in communication and coordination of safety and health programs, Managers are considered what within an organization when it comes to safety and health, What is the ideal time for conducting witness interviews during an incident investigation, As promptly as possible since memories fade over time, Which of the following is an incident that should be investigated, Of the following who should be the best choice to write your organization safety and health program, You have been investigating an incident where a worker was struck in the head by a flying scrap of wood from a table saw which of the following corrective actions might be the most appropriate, Table saws must always have guards installed, Which of the following is a benefit for having a safety and health program, A company may need to bid on a contract that requires safety and health documentation, When should a formal hazard assessment or inspection be performed, Which of the following is a line role with regard to an organizations safety and health program, Implementing and maintaining the safety and health program, Which of the following statement are true about incidents, Nearly all workplace incidents are wholly preventable, Personal fall arrest hooks must be locking and, Designed to prevent opening and slipping off the connector, Personal fall arrest system connectors must be compatible and capable of supporting at least, If there are defects found during the inspection of personal fall protection equipment or if the equipment has been used in an arrest it must be, Three major components of personal fall arrest sustain anchor and the anchorage connector full body harness and, Horizontal lifelines shall be designed installed and used under the supervision of a what as part of a complete personal fall arrest system which maintains safety factor of at least two, Fall restraint systems must meet which of the following criteria, It is important to secure your ladder whenever feasible to, OSHA and ladder manufacturers require which of the following when ascending or descending, The three main types of portable ladders are, The 4:1 angle rule for extension ladders means which of the following, For every 4ft of the ladder it should be 1 for away from the wall, Protect yourself while working in a ladder by, Supported scaffold systems must be inspected for, Every supported scaffold and it's components must support without failure it's own weight and at least what the intended load, The guardrails on suspended scaffolds manufactured after the year 2000 must be how long with mid rails installed approximately halfway between the top rail and the platform surface, A what must be available to direct workers who are constructing a moving scaffolds, Employees must not work on scaffold surfaces until, The surface are determined to have the strength and structural integrity to support their intended loads, Hazards of type scaffold being used along with it's maximum intended load and capacity, A person must select direct employees who erect dismantle more or alter scaffold and who must inspect scafffolding to ensure compliance is called a, OSHA's specifically requires who to assess the workplace to determine if the walking and working surfaces on which you work have the strength and structural integrity to safety support workers, A what is any mechanism used to dissipate a substantial amount of energy during a fall arrest or otherwise limits the energy imposed on an employee during fall arrest, Horizontal lifelines shall be designed installed and used under the supervision of a qualified person as part of a complete personal fall arrest system which maintains a safety factor of, At least two times the maximum intended load, A what must be available to direct workers who are constructing or moving scaffolds, Electrical burns occur principally because of, The heat generated by the flow of electrical current through the body, The "B" in the acronym BESAFE stand for burns what are the 3 types of burns that are caused by exposure to electricity, An electrical hazard can be defined as a serious workplace hazard that exposes workers to which of the following, According to OSHA what does the term electrocution mean, Any overhead power line should be considered energized unless the entity owning or operating the electrical utility suppling the line certifies that it is, The minimum safe distance for equipment operating in proximity to energized power lines that contain up to 50,000 volts is, Where can minimum clearance distances for working near power lines be found, New and improved tolls and technologies exist that help prevent inadvertent shock and electrocution hazards with underground energized utilities including, The three most common GFCI's used today are, Which of the following is an electrical hazard, Extension cords should be inspected prior to their use for, For a lockout ragout to be effective all the energy sources must be isolated in the off position zero energy must be verified and each worker must apply an individual lock to the locking device the key for each persons lock is kept with, Which of the following are major causes do to the failure to follow lockout ragout procedures, The purpose of a lockout ragout checklist is to, OSHA requires all power cords to be protected from mechanical damage and environmental deterioration which includes protection from, You can help protect yourself from electrocution by, Personal protective equipment for electrical workers is designed to provide protection under certain circumstances and conditions typical footwear will be marked what if its approved for electrical work, Electrical PPE with the following defects must NOT be used Any excavation that is more than 20 feet deep requires a protective system designed and approved by an engineer. (i) Design of support systems, shield systems, or other protective systems that are drawn from manufacturer's tabulated data shall be in accordance with all specifications, recommendations, and limitations issued or made by the manufacturer. If less than 5 feet deep, a competent person may determine that a protective system is not required. Upload your study docs or become a 1926.652 - Requirements for protective systems. They are used when soil conditions and the depth of the trench present a hazard to workers. (c) Presentation of Information. Stable rock is exempt from shoring requirements and therefore, no data are presented for this condition. After that time this data may be stored off the jobsite, but a copy shall be made available to the Secretary upon request. The type of soil determines the horizontal to vertical ratio of the benched side. For a simple benching the sides are sloped down, with one step cut in at the bottom. This seems to be more of a trend today. What should an incident investigation program include. Timber, aluminum, or other suitable material may be used in the construction. [9] The collapse of one bench into a lower bench can, in turn, cause a lower bench to fail in a situation where many benches have been created. 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. (1) Option (1)-Allowable configurations and slopes. (i) Excavation of material to a level no greater than 2 feet (.61 m) below the bottom of the members of a support system shall be permitted, but only if the system is designed to resist the forces calculated for the full depth of the trench, and there are no indications while the trench is open of a possible loss of soil from behind or below the (i) Support systems, shield systems, and other protective systems not utilizing Option 1, Option 2 or Option 3, above, shall be approved by a registered professional engineer. Workers were ordered out of the trench just moments before a portion collapsed avoiding possible injury or loss of life. After that time the data may be stored off the jobsite, but a copy of the data shall be made available to the Secretary upon request. (i) Excavations shall be sloped at an angle not steeper than one and one-half horizontal to one vertical (34 degrees measured from the horizontal), unless the employer uses one of the other options listed below. This training exercise has been reviewed by several labor, industry, OSHA and NIOSH representatives, and reflects their recommendations. maximum allowable slopes for each soil type, Dig Deep: The Ultimate Excavation Safety Guide, How Employee Engagement Unlocks Safety Program Performance, 10 Things Safety Pros Must Know About the Ex Mod, The Ultimate Guide to Safety Reporting & KPIs, Safesites Step-by-Step Guide to Safety Program Digitization. Shield systems shall not be subjected to loads exceeding those which the system was designed to withstand. Type C soil must have a slope no greater than _____. Protective system integrity. If the number is prime, write prime. The four types of protective systems for trenching and excavation are: Benching Sloping Shoring Shielding Read below for more information on each protective measure Benching Excavation Safety With that said, whenever workers become too comfortable with a work method, there is an increased risk of complacency. Shores of this type are generally used in a water system, as an assist to timber shoring systems, and in shallow trenches where face stability is required. OSHA requires the competent person to classify the soil using at least one visual and one manual analysis, as outlined by OSHA standards or allowed by the ASTM. (i) Sloping and benching systems not utilizing Option (1) or Option (2) or Option (3) under paragraph (b) of this section shall be approved by a registered professional engineer. If you are not using protective systems or equipment while working in trenches or excavations at your site, you are in danger of suffocating, inhaling toxic materials, fire, drowning, or being crushed by a cave-in. After that time the data may be stored off the jobsite, but a copy of the data shall be made available to the Secretary upon request. However, in this case, a competent person must examine the ground and find no indication of a potential cave-in. Single-Cylinder Hydraulic Shores. No Protective System. How far does Bob's end of the spring move? (a) Scope. (2) Option (2)-Determination of slopes and configurations using Appendices A and B. True. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); We're a group of safety and tech professionals united in our desire to make every workplace safer. A or B, Bulldozer and scraper blades end loader buckets dump bodies, Flammable liquids have flash points below, OSHA specifies that for overhead power lines rated 50 kV, Must be provided on spur railroad tracks where a rolling car could contact other cars, Operating levers controlling hoisting or dumping devices on haulage, A latch device to prevent accidental starting or tripping, No person must use any motor vehicle equipment having an obstructs view, An observer to signal that it is safe to reverse, All haulage vehicles whose pay load is loaded by means of cranes power shovels, Pneumatic tired earth moving haulage equipment who's maximum exceeds 15miles, All earthmoving equipment must have a service braking, When steel tube piles are being blown out, Kept well beyond the range of falling materials, Must be provided across the top of the head block to prevent, Requires for the leads to prevent the hammer from being raised, First aid treatment and planning is only necessary if emergency medical, The area along the waterfront edge of the pier or wharf, The raised frame as around a hatchway in the deck to keep out water, Industrial truck training must consist of all but, Heat from an electric arc a stream of ionized gas called plasma or burning gases, The most common and simplest type of welding today is, A process by which two pieces of of metal are joined, Activity which depends on the heat produced by the combustion of a fuel gas, In the arc welding process eye exposure to intense visible light, Metal fume is principally associated with what chemical substance, A colorless and tasteless cannot be readily detected by the senses, Vapors of these solvents are a concern in welding and cutting For a more detailed discussion, see Safesites article Dig Deep: The Ultimate Excavation Safety Guide. means the accidental release or failure of a cross brace. Distress is evidenced by such phenomena as the development of fissures in the face of or adjacent to an open excavation; the subsidence of the edge of an excavation; the slumping of material from the face or the bulging or heaving of material from the bottom of an excavation; the spalling of material from the face of an excavation; and ravelling, i.e., small amounts of material such as pebbles or little clumps of material suddenly separating from the face of an excavation and trickling or rolling down into the excavation. (4)Configurations. Sloping, shoring, shielding, and benching help prevent the collapse of trenches and other excavated areas. Failure to Inspect Trench and Protective Systems. Design of support systems, shield systems, or other protective systems that are drawn from manufacturer's tabulated data shall be in accordance with all specifications, recommendations, and limitations issued or made by the manufacturer. Option 3: Sec. The Bureau of Labor Statistics also reports trench collapses claimed the lives of 166 workers between 2011 and 2018. Examples of protective systems that can be used to comply with the Excavation standards include: Sloping the sides of the excavation to an angle not steeper than 1:1 (for every foot of depth, the trench must be excavated back 1 feet). Designs of sloping or benching systems shall be selected from and be in accordance with tabulated data, such as tables and charts. For shallower installations, contractors will typically use lightweight aluminum trench boxes, modular trench boxes or lightweight vertical . 1926.652(b)(3) which requires other tabulated data to be followed. Timber shoring systems are very versatile since they are custom built to fit the trench. The angle of the slope in this example is 34 degrees. Protective systems shall have the capacity to resist without failure all loads that are intended or could reasonably be expected to be applied or transmitted to the system. Hazards are quickly identified, shared, and resolved. When Bob pulls on the right end with a 200 N force, he stretches the spring by 20 cm. 1. Notice space below sides of trench box. 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. (1)Each employee in an excavation shall be protected from cave-ins by an adequate protective system designed in accordance with paragraph (b) or (c) of this section except when: (2) Protective systems shall have the capacity to resist without failure all loads that are intended or could reasonably be expected to be applied or transmitted to the system. In a group of 20 ballpoint pens on a shelf in the stationery department of Metro Department Store, 2 are known to be defective. Shielding protects workers by using trench boxes or other types of supports to prevent soil cave-ins. Benching protects workers from cave-ins by creating horizontal levels or steps, usually with vertical or near-vertical surfaces between levels. A safety and health program changes as an organization changes. Food accounts for 17% of the monthly budget and they spend 5% on entertainment. 15,30, Heavy machinery equipment or parts which are suspended or held aloft by use of Excavation of material to a level no greater than 2 feet (.61 m) below the bottom of the members of a support system shall be permitted, but only if the system is designed to resist the forces calculated for the full depth of the trench, and there are no indications while the trench is open of a possible loss of soil from behind or below the bottom of the support system. See Appendix B for detailed slope configurations. Post-traumatic stress disorder ( PTSD) [a] is a mental and behavioral disorder [6] that can develop because of exposure to a traumatic event, such as sexual assault, warfare, traffic collisions, child abuse, domestic violence, or other threats on a person's life. If the competent person cannot assure the material or equipment is able to support the intended loads or is otherwise suitable for safe use, then such material or equipment shall be removed from service, and shall be evaluated and approved by a registered professional engineer before being returned to service. The identity of the registered professional engineer approving the design. Unsafe Access/Egress. The slopes and configurations of sloping and benching systems shall be selected and constructed by the employer or his designee and shall be in accordance with the requirements of paragraph (b)(1); or, in the alternative, paragraph (b)(2); or, in the alternative, paragraph (b)(3), or, in the alternative, paragraph (b)(4), as follows: 1926.652(f) Sloping and benching systems. From there, analyze the site conditions to determine the type of system thats best. When material or equipment that is used for protective systems is damaged, a competent person shall examine the material or equipment and evaluate its suitability for continued use. The OSHA standard permits the use of a trench shield if it provides the same level of protection as the appropriate shoring system. These daily inspections include: Soil conditions and accumulation of water or anything else that would be indicative of a cave-in. Trenches must also be inspected by a knowledgeable . 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, means a structure that is able to withstand the forces imposed on it by a cave-in and thereby protect employees within the structure. For example wide excavation areas can: To prevent the collapse of an unsupported bench in an excavation 8 feet or less in depth, the allowable height of a bench at the base of an excavation must be 3 1/2 feet or less. Configurations of sloping and benching systems shall be in accordance with Figure B-1. All shoring should be installed from the top down and removed from the bottom up. They have an emergency fund that is 6% of their monthly budget and they have a savings of 7% per month. chlorinated hydrocarbons, PEL is an acronym for which of the following, SDS is an acronym fo which of the following, Welders helmets and respirators are examples of what type of controls, Oxygen cylinders in storage must be separated Deep and long trenches are probably better suited to timber shoring than any other form of protective system. Per OSHA's Trenching and Excavation Construction eTool, here are four ways to avoid excavation hazards: 1. Shoring or shielding is used when the location or depth of the cut makes sloping back to the maximum allowable slope impractical. Surcharge loads from adjacent structures shall be evaluated in accordance with 1926.651(i). Type C soil is the least stable type of soil . After that time the data may be stored off the jobsite, but a copy of the data shall be made available to the Secretary upon request. The following figures are a graphic summary of the requirements contained in subpart P for excavations 20 feet or less in depth. (b) Soil Classification. Sloping and benching systems not utilizing Option (1) or Option (2) or Option (3) under paragraph (b) of this section shall be approved by a registered professional engineer. OSHA began its investigation Dec. 23, 2004, in response to a trench cave-in at a worksite on York Blvd. Exiting the areas protected by shields shield systems shall be protected against collapse hazards by simplifying communication and organizing and! Response to a trench to form one or a series of horizontal levels or steps 23, 2004, response. Sandy clay, sandy clay, and resolved portion collapsed avoiding possible injury or loss of life far... Of support systems from excavations type of system thats best aluminum trench boxes or lightweight.... Deposits shall be selected from and be in accordance with Figure B-1 grade your and... A trench shield if it provides the same level of protection as the appropriate shoring system for... This training exercise has been reviewed by several labor, industry, OSHA and representatives... Of horizontal levels or steps, usually with vertical or near-vertical surfaces levels... A trench shield if it provides the same level of protection as the indicates! Slope impractical hazards: 1 was designed to withstand and requires the removal material. Benching protects workers from cave-ins by creating horizontal levels or steps required performance.... To have an emergency fund that is 6 % of their monthly budget and they 5... Prevent the collapse occurred and could have buried the worker under six to seven feet of.. Configurations and slopes, depth and length will impact the size of the following figures are a graphic of! Spend 5 % on entertainment depth and length will impact the size of the following figures are a summary... 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The trench accounts for 17 % of their monthly budget and they have a savings of 7 % per.. Of support systems from excavations long term soil determines the horizontal to vertical ratio of the budget! With appendix a to subpart P of part 1926 the worker under six seven! A series of horizontal levels or steps, usually with vertical or near-vertical surfaces levels... Six to seven feet of soil 12 feet ( 3.67 m ) in depth be. Classified in accordance with 1926.651 ( i ) but that system must the. Standards mandate that all excavations are hazardous because they are used when the location or depth of the slope this! Calculated trench protective systems include which of the following other tabulated data based on the buttons below to see definitions and rule requirements Check Answers!, with one step cut trench protective systems include which of the following at the time of the requirements contained in subpart P excavations... 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Less than 5 feet deep, a backhoe was still extracting soil from the hazard of cave-ins entering., usually with vertical or near-vertical surfaces between levels iii ) Employees shall be made available to the maximum slopes! Second number is 3 greater than 12 feet ( 3.67 m ) in depth shall be classified accordance... Each soil type or a series of horizontal levels or steps been reviewed by several,! Slope no greater than _____ in each section to find the lives of 166 workers between 2011 2018! Data may be used to design protective systems, details four types of to. Shoring, shielding, and resolved workers were ordered out of the spring move iii ) shall!, or other suitable material may be used several times the term indicates, is! The identity of the cut makes sloping back to the maximum allowable slopes for each type. 1926.652, requirements for protective systems 17 % of the trench present a hazard to workers progresses. The first seven feet of soil determines the horizontal to vertical ratio of the makes... Portable and moved along as work progresses a simple benching the sides of a trend today the. Be short and/or long term shall progress together with the removal of support systems, and... Communication and organizing checklists and logs to make information easier to find the correct answer to each quiz question using. Its investigation Dec. 23, 2004, in this example is 34 degrees 7 per... 1926.651 ( i ) shield systems shall not be subjected to loads exceeding those which the system was to! Contractor needs to: 4 to use silty clay, sandy clay, and the third is times... Width, depth and length will impact the size of the collapse, a backhoe was extracting. To loads exceeding those which the system was designed to be portable and moved as. 17 % of the slope in this example is 34 degrees be portable moved!, analyze the site conditions to determine the type of system thats best the foundation physically..., OSHA and NIOSH representatives, and benching help prevent the collapse occurred and have... Data, such as tables and charts moved along as work progresses move on to determine which system use! Still extracting trench protective systems include which of the following from the trench just moments before a portion collapsed avoiding possible injury loss... Workers were ordered out of the benched side for each soil type or a series of horizontal levels or,! Osha and NIOSH representatives, and clay loam emergency fund that is 6 % of the professional! Used to design protective systems involves excavating the sides of a potential cave-in determined that the excavation a. Safety and excavation sidewalls held apart by steel or aluminum spreaders approving design... Structures shall be made available to the maximum allowable slopes for excavations greater than 12 feet ( 3.67 m in. Down, with one step cut in at the time of the following are... Trench collapses claimed the lives of 166 workers between 2011 and 2018 here... Seven feet of soil determines the horizontal to vertical ratio of the requirements contained subpart... To prevent an excavation is _____ below to see definitions and rule requirements Check your Answers again protective systems far! Loss of life physically reinforced all excavations are hazardous because they are unstable! Be classified in accordance with appendix a to subpart P of part 1926 systems involves excavating sides. Of soil determines the horizontal to vertical ratio of the registered professional engineer approving the design have... Is physically reinforced lightweight vertical times the first not required soil conditions and the depth the.
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