(1) Option (1)-Allowable configurations and slopes. This process is automatic. Type C soil must have a slope no greater than _____. Soil classification. Once youve determined that the excavation requires a protective system, you can move on to determine which system to use. Smith, Michael Abbott, Water Supply and Stream Management 202.12E. 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. The left end of a spring is attached to a wall. After clicking the button, the questions you missed will be listed below. The actual slope shall be less steep than the maximum allowable slope, when there are signs of distress. (C) The identity of the registered professional engineer approving the design. (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. means the accidental release or failure of a cross brace. Shield systems can include trench boxes or other supports to prevent a cave-in. Short-term maximum allowable slopes for excavations greater than 12 feet (3.67 m) in depth shall be 3/4H:1V (53). As a general rule, the bottom vertical bench height of a multiple-benched trench must not exceed _____. Protective systems for use in excavations more than 20 feet in depth must be designed by _____. Type C soil is the least stable type of soil . The trench was 20-25 feet deep and had been benched about one bucket-width (4 feet) on each side. A few things to consider when conducting work underground: Contact the underground notification center at, Identify whether the excavation is less than 5 feet deep, Identify whether the excavation is in stable rock, Have a competent person examine the excavation, Undercutting of structures and foundations. in Pearland. Occupational Safety & Health Administration. 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. For shallower installations, contractors will typically use lightweight aluminum trench boxes, modular trench boxes or lightweight vertical . Stable rock is exempt from shoring requirements and therefore, no data are presented for this condition. Which of the following is considered the safest of the four methods to prevent an excavation wall collapse? 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). The Bureau of Labor Statistics also reports trench collapses claimed the lives of 166 workers between 2011 and 2018. Distress means that the soil is in a condition where a cave-in is imminent or is likely to occur. OSHA has cited KCC Group Inc., Pearland, Texas, and proposed penalties totaling $133,000 for failing to protect workers from trenching hazards that led to an employee's death. What is the relationship between electronegativity and the polarity of a chemical bond? 8. 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. All shoring should be installed from the top down and removed from the bottom up. Please enable cookies on your browser and try again. Trench box with ladder. Uprights placed so that individual members are closely spaced, in contact with or interconnected to each other, are often called "sheeting.". There are two basic types of benching: simple and multiple. AUTO STOP - brzi servis; Naini plaanja; Prijava na newsletter; Servis. Always err on the side of caution. There are multiple types of shoring and shielding systems available and they can be used in all soil types. Ramp See Appendix B for detailed slope configurations. Note collapse of the benching. Of the four trenching and excavation protective systems, shield systems are also the most straightforward and simplistic, presenting less of a learning curve. Workers were ordered out of the trench just moments before a portion collapsed avoiding possible injury or loss of life. Food accounts for 17% of the monthly budget and they spend 5% on entertainment. 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. The spreaders are interchangeable to match the width of the trench. 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. 1926.652(b)(4) which requires the excavation to be designed by a registered professional engineer. workers. (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. After that time, the design may be stored off the jobsite, but a copy of the design shall be made available to the Secretary upon request. 15,30, Heavy machinery equipment or parts which are suspended or held aloft by use of (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. 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. For a simple benching the sides are sloped down, with one step cut in at the bottom. The width, depth and length will impact the size of the protective system you need. 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. Two employees were installing 6" PVC pipe in a trench 40' long x 9' deep x 2' wide. In 2014, it split the data into nine market segments: transportation, petroleum, buildings, power, industrial, water, manufacturing, sewer/waste, telecom, hazardous waste, and a tenth category for other projects. 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. Before You Dig: Excavation Preplanning and Permitting, Getting Started with Excavation Risk Management, Scheduling Excavation and Trenching Inspections. 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. using the attachments and the video link about to answer the questions below. 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. After that time this data may be stored off the jobsite, but a copy shall be made available to the Secretary upon request. 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. Timber and aluminum hydraulic. 1. all the above, When working around electricity which class of helmets is designed to reduce the danger of contact with conductors at higher voltage levels, Electrical equipment noticed in an AEGCP must be visually inspected for damage or defects, What is my employer required to do to protect workers from electrocutions, All pull boxes Justin boxes and fittings must be, Provide covers and plastic covers both a and b, When using a utility locate service to identify underground utilities which of the following is true, Locating underground utilities is not an exact science, A competent person must be designated for, When an injury is caused by impact alone it's generally recorded as, What should not be used to support a scaffold because they could collapse sending the structure to the ground, When a person is injured when crushed between two or more objects the incident recorded as this type, Amputations are caused by allowing your hands or limbs to be caught or between, When a trench is 4 feet or more in depth a means of egress from the trench must be within, Trench protective systems include which of the following, A cubic yard of soil can weigh as much as, What is the minimum distance alllowed between a spoils pile and tranches edge, Excavation safety standards have introduced in 1989, A soils are usually clays and cemented soils such as caliche and hard pan, OSHA requires that the competent person perform two visual and two manual tests on a soil sample fresh out of the ground and not impacted by weather conditions at the site, Each of the following is a type B soil except, The definition of type C-60 Spain is provided by manufacturers to allow competent, Which of the following are common soil classifications tests, A defining feature of stable rock is that it will, The most important distinction between stable rock types a and b and type c is, Which of the following statement a is true about kick out [9] means a structure such as underpinning, bracing, or shoring, which provides support to an adjacent structure, underground installation, or the sides of an excavation. Protective systems on the jobsite should be inspected and maintained on a daily basis to ensure that they are in place and working correctly. 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. When surcharge loads from stored material or equipment, operating equipment, or traffic are present, a competent person shall determine the degree to which the actual slope must be reduced below the maximum allowable slope, and shall assure that such reduction is achieved. 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. When installing a trench shield, the contractor should excavate a wider area than the necessary minimum. (ii) Designs shall be in written form and shall include at least the following: (A) The magnitude of the slopes that were determined to be safe for the particular project; (B)The configurations that were determined to be safe for the particular project; and. Click on the buttons to see the selection charts from 1926 Subpart P App F. Sloping is selected as the method of protection. (Click the Appendix B button below to see the Maximum Allowable Slope chart. Hazardous atmospheres. (2) Information concerning the basis of the tabular data and the limitations of the data is presented in paragraph (d) of this appendix, and on the tables themselves. Hydraulic shoring, a pre-fabricated strut and/or wale system made from aluminum or steel. This seems to be more of a trend today. (iv) Employees shall not be allowed in shields when shields are being installed, removed, or moved vertically. The flatter the angle, the more protection the sloping offers. 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 53 ), modular trench boxes or lightweight vertical depth and length will the! 9 ' deep x 2 ' wide an excavation wall collapse when installing a trench 40 ' x. 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