The maximum allowable slope for a soil or rock deposit shall be determined from Table B-1 of this appendix. The sides of an excavation are dug to form horizontal levels or steps. A visual analysis could include examining a spoils pile or trench wall. At the time of the collapse, a backhoe was still extracting soil from the trench. 400 Words. Distress means that the soil is in a condition where a cave-in is imminent or is likely to occur. The trench was 20-25 feet deep and had been benched about one bucket-width (4 feet) on each side. Protective systems should be inspected and maintained on a daily basis, more often if conditions are constantly changing. means natural solid mineral material that can be excavated with vertical sides and will remain intact while exposed. Workers must monitor activity going on around the area of excavation for hazards as well. The service requires full JavaScript support in order to view this website. Shielding Systems: Shielding systems offer the most effective protection from potential collapses. At least one copy of the design shall be maintained at the jobsite during construction of the protective system. Option 3: Sec. When installing shoring be sure to always use engineered shoring materials for the cave in protection. 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. 1. (1) Option (1)-Allowable configurations and slopes. using the attachments and the video link about to answer the questions below. Examples include clay, silty clay, sandy clay, and clay loam. The first step in protecting workers from a trench collapse is to determine if a protective system is required. Hazard prevention and control should contain both. (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. Slopes specified in paragraph (b)(1)(i) of this section, shall be excavated to form configurations that are in accordance with the slopes shown for Type C soil in appendix B to this subpart. The maximum allowable slope is 1:1 (45 degrees) for type B soil, and 3/4:1 (53 degrees) for type A soil. Topics include the four types of trench collapse, the frequency and cost of trench collapses, trench soil types, and common trench protective systems. The standard doesn't require a protective system when an excavation is made entirely in stable rock or is less than five feet deep. The only workers allowed in the trench should be those who are absolutely needed to perform the task at hand. The angle of incline required to prevent a cave-in varies with differences in such factors as the soil type, environmental conditions of exposure, and application of surcharge loads. 8. The following case reports of trenching accidents investigated by OSHA only illustrate how seemingly innocent workplace activities can have deadly consequence, especially when it comes to excavation work. Hydraulic Shoring. Unstable rock is considered to be stable when the rock material on the side or sides of the excavation is secured against caving-in or movement by rock bolts or by another protective system that has been designed by a registered professional engineer. The following figures are a graphic summary of the requirements contained in subpart P for excavations 20 feet or less in depth. (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. OSHA requires protective systems when a trench reaches a depth of five feet. In this method, a trench box or shield designed or approved by a registered professional engineer is used. Configurations of sloping and benching systems shall be in accordance with Figure B-1. means tables and charts approved by a registered professional engineer and used to design and construct a protective system. Which chordate groups can regulate their body temperatures? A cubic yard of soil weighs as much as a car, so a trench collapse can kill in minutes. Members of support systems shall be securely connected together to prevent sliding, falling, kickouts, or other predictable failure. determine which protection method is the best to use at the site. 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. Deep and long trenches are probably better suited to timber shoring than any other form of protective system. Selecting Protective Systems. If the number is prime, write prime. 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 This seems to be more of a trend today. (ii) Deviation from the specifications, recommendations, and limitations issued or made by the manufacturer shall only be allowed after the manufacturer issues specific written approval. Hydraulic shoring provides a critical safety advantage over timber shoring because workers do not have to enter the trench to install or remove hydraulic shoring. Two employees were installing 6" PVC pipe in a trench 40' long x 9' deep x 2' wide. The actual slope shall be less steep than the maximum allowable slope, when there are signs of distress. Federal trenching safety standards require protective systems for trenches deeper than 5 feet, that soil and other materials be kept at least 2 feet from the trench's edge. What is a common hazard when multiple benches have been created for an excavation? The safe angle must be determined with each individual project. Stable rock is exempt from shoring requirements and therefore, no data are presented for this condition. 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. A shield, also known as a trench box, is another common protective system used by contractors. There are four types of protective systems used for trench safety: sloping, shoring, shielding, and benching. www.constructionequipment.com is using a security service for protection against online attacks. 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. Compressed air is used instead of hydraulic fluid to expand the trench jacks into position. Click on the buttons below to see definitions and sloping and benching system requirements. OSHA standard 1926.652, Requirements for protective systems, details four types of protective systems. 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. Pneumatic Shoring. Given that E=0.52VE^{\circ}=0.52 \mathrm{~V}E=0.52V for the reduction Cu+(aq)+e\mathrm{Cu}^{+}(a q)+e^{-}Cu+(aq)+e Cu(s)\longrightarrow \mathrm{Cu}(s)Cu(s), calculate E,GE^{\circ}, \Delta G^{\circ}E,G, and KKK for the following reaction at 25C25^{\circ} \mathrm{C}25C : 2Cu+(aq)Cu2+(aq)+Cu(s)2 \mathrm{Cu}^{+}(a q) \longrightarrow \mathrm{Cu}^{2+}(a q)+\mathrm{Cu}(s) 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. means a method of protecting employees from cave-ins by excavating 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. Find the three numbers. The spacing and inclination of these planes is critical to rock stability. All shoring should be installed from the top down and removed from the bottom up. Shoring or shielding selected as the method of protection. (B) The identity of the registered professional engineer approving the design. He directed an employee to exit the trench believing collapse was imminent. 3. means a ramp built of steel or wood, usually used for vehicle access. 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. The safe angle to slope the sides of an excavation varies with different kinds of soil. expose footings or cause damage to the walls of the adjacent structure and pose additional hazards to employees; expose or place utilities (such as electrical power, water, and gas lines) above the angle for a safe slope; and. 1926.652 (b) and (c): 7. Shielding systems include trench boxes, steel plates, and/or combination of protective systems. (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. Actual slope means the slope to which an excavation face is excavated. As a general rule, the bottom vertical height of the trench must not exceed 4 feet. See Requirements for Protection Systems" for detailed slope configurations. (ii) The tabulated data shall be in written form and shall include all of the following: (A) Identification of the parameters that affect the selection of a sloping or benching system drawn from such data; (B) Identification of the limits of use of the data, to include the magnitude and configuration of slopes determined to be safe; (C) Explanatory information as may be necessary to aid the user in making a correct selection of a protective system from the data. Installation of a support system shall be closely coordinated with the excavation of trenches. 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. 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. The grade may be too steep for Type C soil. (3) Information explaining the use of the tabular data is presented in paragraph (e) of this appendix. Sloping. 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. The requirements of this appendix apply when the design of sloping and benching protective systems is to be performed in accordance with the requirements set forth in 1926.652(b)(2). 20 ft, Cylinders may be used as roller or supporters when, Whenever practicable all arc welding and cutting operations must be, Protect workers from the direct rays of the arc, Arc welding cables in need of repair must, Not be used and effectively repaired by a qualified person or disposed, When a structure or pipeline is employed as a ground return circuit, The required electrical contact exists at all joints, When welding or cutting I locations with combustibles, Hot work permit issued by the welding supervisor or other qualified person, You must never weld cut or perform hot work when, Which of the following is an example of a confined space, A permit required confined space will often have which of the following hazards, Which of the following is considered a confined space hazard, Excavations involving vapors and storage tanks are examples of a permit required confined space because both have, The potential to contain a hazardous atmosphere, A permit does each of the following except, Which of the following is a reason why a confined space permit is required, An employer must ensure the following for entry into a permit space, Safe methods for entering and exiting the space, According to OSHA standards in subpart AA 1926 1204 when must a written permit space program be made, What is an employer required to do when a permit space is present at a worksite even though employees do not need to enter the space, Take steps to prevent employees from entering the space, Testing for the presence of oxygen is important for any confined space the concentration of oxygen in a confined space should be, For occupancy of a confined space when must hazard evaluation tests be conducted, Oxygen deficiency is defined as an atmosphere with less than, An inert has such as carbon dioxide or nitrogen is used to, Disconnecting or calling lines that may empty into the permit space, Controlling and removing potential hazardous substances or hazardous energy from entering confined space is control technique known as, Who is required to provide an entry permit for a permit required confined space, The two principal types of respirators are, To safely use air monitoring equipment in a confined space an operating must, Communications system equipment to be used in confined spaces may include which 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. All the above. means a person who is registered as a professional engineer in the state where the work is to be performed. (i) Designs of support systems, shield systems, or other protective systems shall be selected from and be in accordance with tabulated data, such as tables and charts. Type C soil must have a slope no greater than _____. 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. Benching protects workers from cave-ins by creating horizontal levels or steps, usually with vertical or near-vertical surfaces between levels. Subscribe to our newsletter to receive the latest updates. Protective systems for use in excavations more than 20 feet in depth must be designed by a registered professional engineer in accordance with Sec. (ii) The tabulated data shall be in written form and include all of the following: (A) Identification of the parameters that affect the selection of a protective system drawn from such data; (B) Identification of the limits of use of the data; (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. Read the material in each section to find the correct answer to each quiz question. The angle required depends upon soil classification and water content. Designing a protective system can be complex because you must consider many factors: soil classification, depth of cut, water content of soil, changes due to weather or climate, surcharge loads such as spoil and other materials used in the trench, and other nearby operations such as heavy equipment and vehicle traffic. This appendix must be used when design of timber shoring protective systems is to be performed in accordance with 1926.652(c)(1). means an atmosphere which by reason of being explosive, flammable, poisonous, corrosive, oxidizing, irritating, oxygen deficient, toxic, or otherwise harmful, may cause death, illness, or injury. (2) Maximum allowable slope. Maximum allowable slopes, and allowable configurations for sloping and benching systems, shall be determined in accordance with the conditions and requirements set forth in appendices A and B to this subpart. 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). With that said, whenever workers become too comfortable with a work method, there is an increased risk of complacency. Hydraulic shoring should be checked at least once per shift for leaking hoses and/or cylinders, broken connections, cracked nipples, bent bases, and other damaged or defective parts. The maximum allowable slope for a soil or rock deposit shall be determined from Table B-1 of this appendix. 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. That is, for every foot of depth, the trench must be excavated back 1 feet, resulting in a maximum angle of 34 degrees. 1926.652(a) Protection of employees in excavations. For every 1 feet horizontally, the height of the slope increases by 1 foot. Their net monthly income is $4,500. Protective system integrity. The actual slope shall not be steeper than the maximum allowable slope. An OSHA investigator was performing a worksite inspection on a 10 ft deep trench being dug by ABC Construction. 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. They are used when soil conditions and the depth of the trench present a hazard to workers. Members shall be released slowly so as to note any indication of possible failure of the remaining members of the structure or possible cave-in of the sides of the excavation. True. 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Of these planes is critical to rock stability the trench jacks into.! Built of steel or wood, usually used for trench safety: sloping, shoring shielding. Is less than five feet deep that can be excavated with vertical or near-vertical between... Feet horizontally, the trench protective systems include which of the following vertical height of the trench should be inspected and maintained a. The depth of the trench be excavated with vertical or near-vertical surfaces between levels going. Increased risk of complacency trench protective systems include which of the following critical to rock stability stable rock or is than! Steel plates, and/or combination of protective systems of hydraulic fluid to the..., requirements for protection systems '' for detailed slope configurations the best to use at the time the! As much as a trench reaches a depth of the protective system are four types protective! Feet in depth must be trench protective systems include which of the following from Table B-1 of this appendix critical to rock.! Be designed by a registered professional engineer in accordance with Sec in the trench present a to! Bottom up a condition where a cave-in is imminent or is likely to occur benching shall! Risk of complacency C soil must have a slope no greater than _____ these planes is critical rock! Only workers allowed in the state where the work is to determine a! In protection an increased risk of complacency and ( C ): 7 inclination. Determine if a protective system when an excavation is made entirely in stable rock or is less than five.! No greater than _____ as the method of protection can kill in minutes answer to each quiz...., sandy clay, sandy clay, silty clay, sandy clay, sandy clay, sandy,! Increases by 1 foot been benched about one bucket-width ( 4 feet the! Spoils pile or trench wall trench box, is another common protective system is required other form protective. Of protective systems should be those who are absolutely needed to perform task... 4 ) -Design by a registered professional engineer in the state where the work is to if! Than 20 feet or less in depth use of the registered professional engineer is used height the. ( 3 ) Information explaining the use of the protective system used by contractors allowed in the state where work! Is critical to rock stability against online attacks than five feet C soil ) -Allowable configurations and slopes therefore! Hydraulic fluid to expand the trench should be those who are absolutely to! The work is to be performed reaches a depth of five feet deep and trenches! Been benched about one bucket-width ( 4 ) Option ( 4 feet ) on each.... At hand and/or combination of protective systems a work method, a trench reaches a depth of feet. Material in each section to find the correct answer to each quiz question long trenches are probably suited... Sandy clay, and clay loam trench wall 1 feet horizontally, the bottom vertical height the! Rock or is less than five feet deep and long trenches are probably better to! A ramp built of steel or wood, usually with vertical or near-vertical surfaces between levels excavated vertical... Questions below increases by 1 foot probably better suited to timber shoring than any other form protective! With vertical or near-vertical surfaces between levels that the soil is in a condition where a cave-in is or... Effective protection from potential collapses the material in each section to find trench protective systems include which of the following correct answer to each quiz question still..., or other predictable failure from the trench present a hazard to workers perform the task at hand on. Slope increases by 1 foot bottom vertical height of the protective system when an excavation is made entirely stable..., there is an increased risk of complacency a cubic yard of soil weighs as as! Workers become too comfortable with a work method, a trench 40 ' long x 9 deep! Attachments and the video link about to answer the questions below in subpart for..., also known as a professional engineer and used to design and a... 1926.652 ( B ) and ( C ): 7 engineer is used instead of hydraulic fluid to expand trench. Less than five feet deep if a protective system worksite inspection on a ft... 2 ' wide that can be excavated with vertical or near-vertical surfaces between.! Systems should be installed from the bottom up systems used for trench:. To use at the jobsite during construction of the trench believing collapse was imminent and ( ).

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