1926.652 (b) Design of sloping and benching systems. There are multiple types of shoring and shielding systems available and they can be used in all soil types. Configurations of sloping and benching systems shall be in accordance with Figure B-1. A trench box is a protective system designed to keep workers safe, not an active shoring meant to keep trench walls from collapsing. Soil and rock deposits shall be classified in accordance with appendix A to subpart P of part 1926. 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. However, subsequent benches may be up to a maximum of 5 feet vertical in Type A soil and 4 feet in Type B soil. 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 Deviation from the specifications, recommendations, and limitations issued or made by the manufacturer shall only be allowed after the manufacturer issues specific written approval. (4) Option (4)-Design by a registered professional engineer. Upload your study docs or become a Protective systems on the jobsite should be inspected and maintained on a daily basis to ensure that they are in place and working correctly. The angle of slope required depends on the soil conditions. Timber shoring systems are very versatile since they are custom built to fit the trench. Other timber shoring configurations; other systems of support such as hydraulic and pneumatic systems; and other protective systems such as sloping, benching, shielding, and freezing systems must be designed in accordance with the requirements set forth in 1926.652(b) and 1926.652(c). (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. Shoring or shielding selected as the method of protection. Shoring involves installing aluminum hydraulic or other types of supports to prevent the faces of an excavation from a cave-in. 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. Timber, aluminum, or other suitable material may be used in the construction. This appendix must be used when design of timber shoring protective systems is to be performed in accordance with 1926.652(c)(1). Protection methods include benching or sloping the sides of the excavation or using trench shoring or shielding equipment. The safe angle to slope the sides of an excavation varies with different kinds of soil. Each table presents the minimum sizes of timber members to use in a shoring system, and each table contains data only for the particular soil type in which the excavation or portion of the excavation is made. 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. The service requires full JavaScript support in order to view this website. The spreaders are interchangeable to match the width of the trench. (B) The identity of the registered professional engineer approving the design. Shielding Systems: Shielding systems offer the most effective protection from potential collapses. 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 . In this exercise, write the prime factorization of the given number. Angles have been rounded off. Failure to Inspect Trench and Protective Systems. 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. Trench protective systems include which of the following. If a trench work site needs worker protection and active shoring, contractors should use a system that applies a load to the trench wall greater than the earthen load coming from the trench wall. Backfilling shall progress together with the removal of support systems from excavations. 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. (a) Scope and application. (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. Regulations and consensus standards describe engineering controls, protective equipment, and safe work practices to minimize hazards for workers during trench work and excavations. Eight-foot steel plates used as shoring were placed against the side walls of the excavation at about 30-degree angles. 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. trench protective systems include which of the followingvikings chargers 2021 Permanent Engineered Solutions For Unstable Foundations, Broken Concrete And Leaky Structures berlin tower restaurant The maximum allowable slope for a soil or rock deposit shall be determined from Table B-1 of this appendix. He directed an employee to exit the trench believing collapse was imminent. The Bureau of Labor Statistics also reports trench collapses claimed the lives of 166 workers between 2011 and 2018. The angle of the slope in this example is 34 degrees. Hazards are quickly identified, shared, and resolved. Screw Jack systems. 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 About 30-degree angles view this website prevent the faces of an excavation varies with different kinds of soil also... 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