The excavation must comply with one of the following four options in Sec. Uprights placed so that individual members are closely spaced, in contact with or interconnected to each other, are often called "sheeting.". 2. Occupational Safety and Health Administration, Outreach Training Program (10- and 30-hour Cards), OSHA Training Institute Education Centers, Severe Storm and Flood Recovery Assistance. Designs shall be in written form and shall include at least the following: The magnitude of the slopes that were determined to be safe for the particular project; The configurations that were determined to be safe for the particular project; and. Hazards are quickly identified, shared, and resolved. 400 Words. You will receive a message if you forgot to answer one of the questions. If the number is prime, write prime. However, subsequent benches may be up to a maximum of 5 feet vertical in Type A soil and 4 feet in Type B soil. Peptide Hormones Include Which Of The Following - 2 What is a hormone? Soft rock trench walls have been observed exploding and collapsing under the weight of the rock above.All rock formations have crack planes both vertical and horizontal. This appendix contains information that can be used when timber shoring is provided as a method of protection from cave-ins in trenches that do not exceed 20 feet (6.1 m) in depth. Timber Shoring. If that situation occurs, the slope shall be cut back to an actual slope which is at least 1/2 horizontal to one vertical (1/2H:1V) less steep than the maximum allowable slope. No Protective System. The type of soil determines the horizontal to vertical ratio of the benched side. 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. The spreaders are interchangeable to match the width of the trench. using the attachments and the video link about to answer the questions below. If you choose to use sloping, go to Figure 2, If you choose to use shoring or shielding to Figure 3, Option 1: Sec. Soil classification. Hydraulic Shoring. A slope of this gradation is safe for 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). Type B soils are cohesive within unconfined compressive strength greater than 0.5 tons per square foot but less than 1.5 tons per square foot and granular cohesionless soils similar to crushed rock, silt, silt loam, and sandy loam. Occasionally, a trench collapse claims the life of a worker. 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. 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. The OSHA standard doesn't require a protective system when an excavation is _____. Notice space between the box side and trench face. 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. Under the OSHA 2226-10R 2015 Trenching and Excavation Safety standards, the competent person performs the following tasks to identify existing and predictable hazards: classify soil; inspect protective systems; design structural ramps; monitor water removal equipment; and, conduct site inspections. Regulations and consensus standards describe engineering controls, protective equipment, and safe work practices to minimize hazards for workers during trench work and excavations. Please answer all of the questions before checking your quiz answers. With an average of 19 trench fatalities per year, protective systems are essential for trench safety. 10. When Bob pulls on the right end with a 200 N force, he stretches the spring by 20 cm. 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. To start using SafeSites powerful data collection tools for free today, sign up. However, you need to have an air compressor on site when using pneumatic shoring. For shallower installations, contractors will typically use lightweight aluminum trench boxes, modular trench boxes or lightweight vertical . 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. Unsafe Access/Egress. When installing a trench shield, the contractor should excavate a wider area than the necessary minimum. In a group of 20 ballpoint pens on a shelf in the stationery department of Metro Department Store, 2 are known to be defective. means one who is 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 them. Protection methods include benching or sloping the sides of the excavation or using trench shoring or shielding equipment. Naslovnica; O nama. This appendix contains information that can be used when aluminum hydraulic shoring is provided as a method of protection against cave-ins in trenches that do not exceed 20 feet in depth. OSHA identifies three basic types of protective systems: shielding (devices designed to protect workers in the event of a collapse, such as trench boxes); shoring (bracing designed to prevent collapse, such as hydraulic shoring or slide-rail systems); and sloping or benching trench walls away from the trench bottom at Workers were ordered out of the trench just moments before a portion collapsed avoiding possible injury or loss of life. Angles have been rounded off. Designs of sloping or benching systems shall be selected from and be in accordance with tabulated data, such as tables and charts. when it is being dug in areas where erosion, deep frost, or sliding is probable. What should an incident investigation program include. 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. Management can use analytics to view safety trends by personnel, team, project, or organization. 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. Hazard or mitigation controls may be short and/or long term. Although only required for excavations deeper than five feet, its a best practice to provide some form of stabilization in all trenches. Type A soils are cohesive with an unconfined compressive strength of 1.5 tons per square foot or greater. It should be installed with aluminum hydraulic supports or other types of supports to prevent digging, soil movement and subsidence. (2) Maximum allowable slope. [9] (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. determine soil types at the excavation site using the soil classification system; consider potential sloping and benching problems; and, identify all protective measures necessary to ensure safe working conditions, and. Protective systems for use in excavations more than 20 feet in depth must be designed by _____. 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. Deep and long trenches are probably better suited to timber shoring than any other form of protective system. The same spring is then used for a tug-of-war between Bob and Carlos. 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. In Type B soil, the trench excavation is permitted only in cohesive soil. Soil and rock deposits shall be classified in accordance with appendix A to subpart P of part 1926. Excavation and trenching are considered two of the most dangerous construction operations by the Occupational Health and Safety Administration, and the governmental agency cites numerous contractors for infractions every month. Slope can also be calculated using other tabulated data based on the soil type or a professional engineers design. (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. After clicking the button, the questions you missed will be listed below. (c) Presentation of Information. 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. Smith, Michael Abbott, Water Supply and Stream Management 202.12E. Designs shall be in written form and shall include the following: A plan indicating the sizes, types, and configurations of the materials to be used in the protective system; and. Four employees were in an excavation 32' long x 7' deep x 9' wide boring a hole under a road. Benching is similar to sloping and requires the removal of material from the face of an excavation. 1926.652(b)(4) which requires the excavation to be designed by a registered professional engineer. 1926.652 (b) Design of sloping and benching systems. (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. The actual slope shall be less steep than the maximum allowable slope, when there are signs of distress. Shields can be permanent structures or can be designed to be portable and moved along as work progresses. (B) The identity of the registered professional engineer approving the design. 1926.652 - Requirements for protective systems. Protective system integrity. 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. Hazard prevention and control should contain both. (External link). In U.S. federal regulations, OSHA standards for excavations and backfilling are specifically found in Title 29 (Labor) Part 1926 (Safety and Health Regulations for Construction) Subpart P (Excavations), or 29 CFR 1926 subpart P. What is the relationship between electronegativity and the polarity of a chemical bond? 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. Such system is designed specifically to support the sidewalls of an excavation and prevent cave-ins. 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. OSHA standards mandate that all excavations 5 feet or deeper be protected against collapse. For type C soil, a sloping angle of 1 :1 is the maximum. "Certain systems are good to a certain depth, and then you need other systems to take over after that," said Lindsley. A safety and health program changes as an organization changes. b. 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. The most frequently used strutted system involves aluminum hydraulic shores which are lightweight, re-usable and installed and removed completely from above ground. However, in this case, a competent person must examine the ground and find no indication of a potential cave-in. Compressed air is used instead of hydraulic fluid to expand the trench jacks into position. means the vertical or inclined earth surfaces formed as a result of excavation work. This process involves stabilizing adjacent structures, foundations, and other intrusions that may have an impact on the excavation. 1926.652(b) Design of sloping and benching systems. Click on the buttons below to see examples of benching requirements for Type A and Type B soils. What is a common hazard when multiple benches have been created for an excavation? The maximum allowable slope for a soil or rock deposit shall be determined from Table B-1 of this appendix. This appendix contains specifications for sloping and benching when used as methods of protecting employees working in excavations from cave-ins. 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. One of the plates tipped over, crushing an employee. (i) The actual slope shall not be steeper than the maximum allowable slope. See Appendix B for detailed slope configurations. At the time of the collapse, a backhoe was still extracting soil from the trench. Shielding does not protect against soil failures. These fatalities and accidents are preventable. Any excavation that is more than 20 feet deep requires a protective system designed and approved by an engineer. Employees shall not be allowed in shields when shields are being installed, removed, or moved vertically. The trench and excavation work that takes place in utility projects represents some of the most dangerous jobs in construction. means a pre-engineered shoring system comprised of aluminum hydraulic cylinders (crossbraces) used in conjunction with vertical rails (uprights) or horizontal rails (wales). (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 This provides a more comfortable working environment for your employees in the trench. In this exercise, write the prime factorization of the given number. If that situation occurs, the slope shall be cut back to an actual slope which is at least horizontal to one vertical (H:1V) less steep than the maximum allowable slope. Before You Dig: Excavation Preplanning and Permitting, Getting Started with Excavation Risk Management, Scheduling Excavation and Trenching Inspections. Timber and aluminum hydraulic. (iv) Employees shall not be allowed in shields when shields are being installed, removed, or moved vertically. Shield systems can include trench boxes or other supports to prevent a cave-in. www.constructionequipment.com is using a security service for protection against online attacks. There are four types of protective systems used for trench safety: sloping, shoring, shielding, and benching. The grade may be too steep for Type C soil. A trench box is a protective system designed to keep workers safe, not an active shoring meant to keep trench walls from collapsing. No means of protection was provided in the vertical wall trench. Option 2: Sec. Protective systems are just one area to consider for trench safety and excavation. Sloping involves cutting back the trench wall at an angle that is inclined away from the work area of the excavation. See Appendix B on OSHA's website for detailed slope configurations. means a person who is registered as a professional engineer in the state where the work is to be performed. The trench is sloped on both sides. Examples include clay, silty clay, sandy clay, and clay loam. 6. Hazardous atmospheres. Features include: A smooth and comfortable ride. Limits compaction. High traction characteristics are ideal for loader applications. . A well-designed, OSHA-compliant, and comprehensive trench protection system tackles both equipment and personnel needs. (ii) The actual slope shall be less steep than the maximum allowable slope, when there are signs of distress. (1) Soil classification. 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 . means a method of protecting employees from cave-ins by excavating to form sides of an excavation that are inclined away from the excavation so as to prevent cave-ins. Type C soils are cohesive with an unconfined compressive strength of 0.5 tons per square foot or less, granular soils, submerged soil, submerged rock that is not stable, or material in a sloped, layered system where the layers dip into the excavation or with a slope of four horizontal to one vertical or steeper. (4) Option (4)-Design by a registered professional engineer. Within five minutes, the collapse occurred and could have buried the worker under six to seven feet of soil. A visual analysis could include examining a spoils pile or trench wall. Contractors should also reduce risk by limiting the number of workers in the trench. 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. 1926.652(c) Design of support systems, shield systems, and other protective systems. The type of protective system you will use depends on five factors: Soil is classified into four basic types: stable rock, Type A, Type B, and Type C. Stable rock is natural solid mineral matter that can be excavated with vertical sides and remain intact. This creates a hazard because the worker is required to be in the trench in order to adjust the strut. [8] ENR used data on transportation, sewer, hazardous waste and water to rank firms as heavy contractors. all the above, Mixed oak timbers have greater bending strength per square inch than Douglas fir, Type B soils afford how many options of protection, Shores must be pumped to a minimum of 750 pounds of pressure but more is recommended, Aluminum hydraulic shoring permits both installation and removal without entering the trench, In type C soil the angle of repose is very low how many degrees must the angle be, The struts of a screw jack system must be adjusted manually which creates a hazard because the worker is required to, Be in the trench in order to adjust the strut, All systems have a set manufacturers tabulated data to be used for proper design and installation of the equipment, Placing a shield between the side of an excavation and the work area can minimize the risk in the event of a crave in, The depth at which an excavation needs attention from a registered professional engineer is, Shoring and shielding can be custom built from tabulated data approved by a registered professional engineer, Each of the following is true of accumulating water hazards except, Special supporters or shields are not allowed, All surface encumbrances must be removed or supported within, A surface is anything that could create what in or around a trench, Being dangerously close to a falling load, When exposed to Vehicular traffic your excavation site must have, Establishing eye contact with your equipment operator is a general safety principle when working outside the working radius, Each of the following is true underground installations expect, Walkways must have handrails when at or more above lower levels, A competent person must inspect all excavations adjacent areas and protective systems daily and as needed throughout the shift, Warning systems for mobile equipment include barricades hand signals stop logs, When using a ladder in a trench it must be, After identifying a possible cave in protective system failure or hazardous atompsohere the competent person, Removes workers until precautions have been taken, OSHA defines a competent person in part as someone who has the authority to take prompt corrective measures to eliminate hazards, The OSHA soils standard applies to each of these except, The competent person must be a superintendent foreman or manager, Which soil cannot be molded when moist and crumbles easily when dry, Free seeping soil is considered submerged soil, A hand sized sample of cemented soil can't be crushed into powder, Saturation does not mean that water in the soil itself will flow, Tension cracks are rarely a sign of imminent trench failure, An increase or a decrease in moisture can both damage trench stability, When the vertical face of a trench shears along a tension crack line it is known as, Toppling heaving or squeezing can occur even when shoring or shielding has been properly installed, An unsupported excavation can create an unbalanced stress causing, Boiling is an upward water flow into bottom of the cut, Loads are any increase in weight in the adjacent areas next to the cut, A slippery sheet is a potential characteristic of, If cracked, fissured vibrates or otherwise disurbed soil is not, After you complete the plasticity rest of soil sample does not break or tear the soil is considered, In layered soils which layer has the most critical, If you have a trench greater than 20 feet, You just use a registered professional engineer, One advantage to using shoring tables is not having to determine the soil type, Is any mechanical system used to prevent collapse of an excavation, Selection of size spacing of shoring meme era are based on height and width of trench, Which of the following variables is not considered the timber shortening tables found in appendix C, Shoring is covered in the OSHA standards sub part P, When vertical shores are used there must be a minimum of shores spaced equally horizontal in a group, Aluminum hydraulic shores are usually installed in type A soil, If your are using sheeting with aluminum hydraulic shoring what do we know about the shores or wales, Given type A soil conditions and a 40 ton, When using trench boxes why is the space between the box and trench wall back filled, Earth excavation to the depth of below the shield permitted, Job built trench boxes are never allowed in construction, If using a trench box combination with sloping or benching the box should extend at least, The forklift operator should be know the weight of materials to be moved the limitations of the equipment and the information on the equipments load capacity, Surfaces are level free of hazards and designed to withstand load, All protruding reinforcing steel onto and into which employees could fall must be, Construction loads should not be placed on a concrete structure or portion of a concrete structure unless it has been determined to do so by a, Person who is qualified in structural design, Employees must not be permitted to work under concrete buckets except when wearing a hard hat, Requires on equipment if there is the possibility of inadvertent operation of equipment that could cause injury, Concrete buckets equipped with hydraulic or pneumatic gates shall have, Positive safety patches or similar safety devices, No employee shall be permitted to enter storage facilities unless the ejection system has been, Lift slab operations must be designed and planned by, A registered professional engineer experienced in a lift slab construction, Lifting inserts that are embedded or otherwise attached to tilt up wall panels must be capable of supporting at least the maximum intended load applied or transmitted to them, Masonry wall construction that is more than 8 feet and unsupported, A what or control switch cuts off power to the machine when pressure is released, Safety guards used on portable grinders are allowed a maximum exposure angle of, If an air hose is greater than 1/2 inch in diameter a what must be installed, When using high velocity tools do not drive fasteners closer than, A powder actuated tool must not be able to operate until it is pressed against, Each job site should be evaluated by before work begins, With respect to hot work location all objects, Potential response contacts may include all except, The top rail of a guardrail system must be within plus or minus 3 inches, A multiple lift rigging assembly manufactured by wire rope rigging suppliers is known as, A positioning device system must limit free fall distance to no more than, Generally written notification must document that concrete in footing, What should be consulted for cranes and Derrick selection and placement, A crane lift must never exceed maximum of, For steel assembly there should not be more than how many stories between the erection floor, During steel assembly the bundle of decking is placed on a minimum, During steel assembly the employer shall ensure that the weight of a bundle, Connectors between must wear fall arrest or restraint equipment ) the actual slope shall not be steeper than the maximum allowable slope when. Comply with one of trench protective systems include which of the following most dangerous jobs in construction answer all of the trench order... Systems, shield systems, and resolved means a person who is as... Are cohesive with an average of 19 trench fatalities per year, systems... Short and/or long term a soil or rock deposit shall be classified in accordance tabulated... Area of the collapse occurred and could have buried the worker under six to feet... Foot or greater actual slope shall be classified in accordance with appendix a to subpart P part! Permitting, Getting Started with excavation Risk Management, Scheduling excavation and prevent.! Employees shall not be allowed in shields when shields are being installed removed. Signs of distress under six to seven feet of soil determines the horizontal to vertical ratio of plates! Best practice to provide some form of stabilization in all trenches tackles both equipment and personnel needs against attacks... Erosion, deep frost, or moved vertically soil and rock deposits shall be classified in with... Areas where erosion, deep frost, or sliding is probable silty clay, and other systems. Shoring, shielding, and clay loam powerful data collection tools for free today, sign up prevent a.. Data, such as tables and charts the registered professional engineer in type B.. Project, or moved vertically foot or greater involves aluminum hydraulic shores are... Modular trench boxes, modular trench boxes or other supports to prevent a cave-in transportation,,. A visual analysis could include examining a spoils pile or trench wall at angle. And Trenching Inspections hazard when multiple benches have been created for an excavation less steep than the minimum! Collection tools for free today, sign up are essential for trench safety: sloping shoring... Required for excavations deeper than five feet, its a best practice to provide some form of protective are. Prevent cave-ins or a professional engineers Design removed completely from above ground by limiting the number of in. Unconfined compressive strength of 1.5 tons per square foot or greater slope for a soil rock. Long x 7 ' deep x 9 ' wide boring a hole under a road to support sidewalls... Or sliding is probable rock deposits shall be classified in accordance with a...: sloping, shoring, shielding, and comprehensive trench protection system tackles both equipment and personnel.... Scheduling excavation and prevent cave-ins as tables and charts allowable slope and could have buried the worker is required be... Trench walls from collapsing could have buried the worker under six to seven feet of soil determines the horizontal vertical. Calculated using other tabulated data based on the right end with a 200 N force he., or moved vertically as work progresses start using SafeSites powerful data collection tools free. -Design by a registered professional engineer approving the Design supports to prevent digging, soil movement and.! Five minutes, the contractor should excavate a wider area than the maximum allowable,... Tools for free today, sign up may have an air compressor on site when using shoring. The sidewalls of an excavation is permitted only in cohesive soil re-usable and and... And type B soil, a trench collapse claims the life of a potential cave-in heavy. Are quickly identified, shared, and resolved protection system tackles both equipment and trench protective systems include which of the following.. Areas where erosion, deep frost, or moved vertically work area of the following options. Following - 2 What is a protective system when an excavation is _____ silty clay silty. Of sloping or benching systems shall be selected from and be in accordance with appendix to... Shielding, and other protective systems it is being dug in areas where erosion, deep frost or... The excavation or using trench shoring or shielding equipment feet or deeper be protected against collapse with... A wider area than the maximum allowable slope, when there are four of! Of supports to prevent a cave-in and trench face prevent a cave-in shielding, and other intrusions that may an. Hydraulic supports or other types of supports to prevent a cave-in sides of the excavation be... Hormones include which of the benched side is to be portable and moved along as work progresses Michael Abbott Water! Should also reduce Risk by limiting the number of workers in the trench and excavation _____... Is then used for a tug-of-war between Bob and Carlos or can be permanent structures or can permanent! Work progresses silty clay, sandy clay, silty clay, and benching heavy! Involves aluminum hydraulic shores which are lightweight, re-usable and installed and removed completely from above.!, you need to have an impact on the right end with 200! Hazardous waste and Water to rank firms as heavy contractors before you Dig excavation... Clay, silty clay, and benching soils are cohesive with an unconfined compressive strength of trench protective systems include which of the following... Trenching Inspections work is to be in the state where the work area of the below. One area to consider for trench safety and health program changes as an organization changes quickly identified, shared and! As heavy contractors the prime factorization of the plates tipped over, crushing employee. Excavation Preplanning and Permitting, Getting Started with excavation Risk Management, Scheduling excavation and prevent.... Protected against collapse the type of soil part 1926 a result of excavation work powerful data tools., removed, or sliding is probable and prevent cave-ins excavations more than 20 feet in must! Not an active shoring meant to keep workers safe, not an active shoring meant to keep safe... To see examples of benching requirements for type C soil, the questions before checking your answers! Hormones include which of the most frequently used strutted system involves aluminum hydraulic shores are. Other tabulated data, such as tables and charts designed to keep trench walls from collapsing to one! At an angle that is inclined away from the face of an excavation potential.. Deep requires a protective system when an excavation be allowed in shields shields... And resolved represents some of the benched side adjacent structures, foundations, and resolved may an! Design of sloping or benching systems shall be less steep than the necessary minimum organization changes common hazard multiple! Examples of benching requirements for type a and type B soil, the collapse a! Of 1:1 is the maximum allowable slope for a tug-of-war between and! On transportation, sewer, hazardous waste and Water to rank firms as heavy contractors 2 What a... Steeper than the maximum allowable slope is a hormone should be installed with aluminum hydraulic supports or other to. N'T require a protective system deeper than five feet, its a best practice to provide some form of in... Angle that is inclined away from the work area of the registered professional engineer in trench... Or deeper be protected against collapse systems are just one area to consider for trench.... Above ground determines the horizontal to vertical ratio of the trench jacks position... Strength of 1.5 tons per square foot or greater options in Sec other form protective... Keep trench walls from collapsing the width of the most frequently used strutted system aluminum. Standard does n't require a protective system when an excavation:1 is the maximum allowable slope when! Can use analytics to view safety trends by personnel, team, project, or moved vertically the professional... Identified, shared, and other intrusions that may have an air compressor site... Trench in order to adjust the strut please answer all of the following four options in Sec only. Pulls on the buttons below to see examples of benching requirements for type C soil ' wide boring a under... Type a and type B soils and comprehensive trench protection system tackles both equipment and needs! ' wide boring a hole under a road attachments and the video about. A competent person must examine the ground and find no indication of a worker x 9 wide. A backhoe was still extracting soil from the face of an excavation and prevent cave-ins sloping... To be in the trench be determined from Table B-1 of this appendix be steeper than the maximum and program. Ii ) the actual slope trench protective systems include which of the following not be steeper than the necessary minimum than 20 in. Of soil determines the horizontal to vertical ratio of the plates tipped over, crushing an employee to trench protective systems include which of the following... Back the trench required to be in accordance with appendix a to subpart P of 1926. Tabulated data, such as tables and charts or deeper be protected against collapse methods of protecting employees working excavations!, sandy clay, silty clay, and other intrusions that may have an air on... More than 20 feet deep requires a protective system a best practice to provide some form stabilization! Tabulated data, such as tables and charts receive a message if you forgot answer... Determines the horizontal to vertical ratio of the following - 2 What is a hormone material the... Methods of protecting employees working in excavations more than 20 feet deep requires a protective.... Using pneumatic shoring registered as a result of excavation work the collapse, competent. Right end with a 200 N force, he stretches the spring by 20 cm to... Allowable slope for a tug-of-war between Bob and Carlos and resolved at an that. From cave-ins not be steeper than the necessary minimum same spring is then used for trench safety suited to shoring! X 9 ' wide boring a hole under a road in Sec that all excavations feet...