Shielding protects workers by using trench boxes or other types of supports to prevent soil cave-ins. 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. Hydraulic Shoring. Configurations. 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. All excavations are hazardous because they are inherently unstable. The sides of an excavation are dug to form horizontal levels or steps. Occupational Safety & Health Administration. With an average of 19 trench fatalities per year, protective systems are essential for trench safety. Unsafe Spoil-Pile Placement. Pneumatic shoring works in a manner similar to hydraulic shoring. (ii) 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. (B) The identity of the registered professional engineer approving the design. Short-term maximum allowable slopes for excavations greater than 12 feet (3.67 m) in depth shall be 3/4H:1V (53). Trench box with ladder. Use Protective Systems. This appendix contains specifications for sloping and benching when used as methods of protecting employees working in excavations from cave-ins. Process generally follows what sequence, Secure the scene notify people investigate repot, test often conducted to initially identify and evaluate potential, generally the first and best strategy to control the hazard, the general duty clause imposes requirements on, the general duty clause of the occupational safety, why sometimes do construction workers take risks, positive role models who are committed to safety, OSHA 30 Construction Test Answer Key ELECTROC, OSHA 30 Construction Test Answer Key MANAGING, Fundamentals of Engineering Economic Analysis, David Besanko, Mark Shanley, Scott Schaefer, Introduction to Chemical Engineering Thermodynamics, Hendrick Van Ness, J.M. determine which protection method is the best to use at the site. 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. 6. Type C soil is the least stable type of soil . 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. The actual slope shall be less steep than the maximum allowable slope, when there are signs of distress. Please answer all of the questions before checking your quiz answers. A shield, also known as a trench box, is another common protective system used by contractors. Footnote(3) Sloping or benching for excavations greater than 20 feet deep shall be designed by a registered professional engineer. Within five minutes, the collapse occurred and could have buried the worker under six to seven feet of soil. In this exercise, write the prime factorization of the given number. The trench is sloped on both sides. 1926.652(b) Design of sloping and benching systems. Option 3: Sec. To start using SafeSites powerful data collection tools for free today, sign up. 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. As a general rule, the bottom vertical height of the trench must not exceed 4 feet. A shoring system is a structure such as a metal hydraulic, mechanical or timber shoring system that supports the sides of an excavation and which is designed to prevent caveins. Ramp That is, for every foot of depth, the trench must be excavated back 1 feet, resulting in a maximum angle of 34 degrees. 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. Hydraulic shoring, a pre-fabricated strut and/or wale system made from aluminum or steel. 3. You can correct any missed questions and check your answers again. b. (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. [8] ENR used data on transportation, sewer, hazardous waste and water to rank firms as heavy contractors. Actual slope means the slope to which an excavation face is excavated. The left end of a spring is attached to a wall. (iii) Manufacturer's specifications, recommendations, and limitations, and manufacturer's approval to deviate from the specifications, recommendations, and limitations shall be in written form at the jobsite during construction of the protective system. Selecting Protective Systems. Protective systems on the jobsite should be inspected and maintained on a daily basis to ensure that they are in place and working correctly. After that time the design need not be at the jobsite, but a copy shall be made available to the Secretary upon request. means a narrow excavation (in relation to its length) made below the surface of the ground. OSHA began its investigation Dec. 23, 2004, in response to a trench cave-in at a worksite on York Blvd. "Certain systems are good to a certain depth, and then you need other systems to take over after that," said Lindsley. Hazards are quickly identified, shared, and resolved. This appendix must be used when design of the aluminum hydraulic protective system cannot be performed in accordance with Section 1541.1 (c) (2). After that time the design need not be at the jobsite, but a copy shall be made available to the Secretary upon request. 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. Trenches must also be inspected by a knowledgeable . The same spring is then used for a tug-of-war between Bob and Carlos. Before the start of sloping or benching, the contractor needs to: 4. Trench shields are usually constructed with sidewalls held apart by steel or aluminum spreaders. Click on the buttons below to see the rule and appendix requirements. The type of soil determines the horizontal to vertical ratio of the benched side. Distress means that the soil is in a condition where a cave-in is imminent or is likely to occur. Protective system integrity. Slope can also be calculated using other tabulated data based on the soil type or a professional engineers design. 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. Temporary protective structures (e.g., shoring, trench boxes, pre-fabricated systems, hydraulic systems, engineering systems, etc.) Installation of a support system shall be closely coordinated with the excavation of trenches. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 m). The trench was 20-25 feet deep and had been benched about one bucket-width (4 feet) on each side. (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. means a person who is registered as a professional engineer in the state where the work is to be performed. 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. A cubic yard of soil weighs as much as a car, so a trench collapse can kill in minutes. Employers are required to provide support, such as hydraulic shoring, bracing, or underpinning, to ensure that adjacent structures remain stable for the protection of workers. 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trench protective systems include which of the following