Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

Presentación del tema: "Harwood Grant 46F1-HT06 - Texas Engineering Extension Service"— Transcripción de la presentación:

1 Harwood Grant 46F1-HT06 - Texas Engineering Extension Service
EXCAVACIONES Subparte P 1926 Subpart P ‑ Excavations This presentation is designed to assist trainers conducting OSHA 10-hour Construction Industry outreach training for workers. Since workers are the target audience, this presentation emphasizes hazard identification, avoidance, and control – not standards. No attempt has been made to treat the topic exhaustively. It is essential that trainers tailor their presentations to the needs and understanding of their audience. This presentation is not a substitute for any of the provisions of the Occupational Safety and Health Act of 1970 or for any standards issued by the U.S. Department of Labor. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Department of Labor. This material was translated under Susan B. Harwood grant number 46F1-HT06 awarded to the Texas Engineering Extension Service, OSHA Training Institute Southwest Education Center from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. Este material fue traducido bajo número 46F1-HT06 de la concesión de Susan B. Harwood concedido a Texas Engineering Extension Service, OSHA Training Institute Southwest Education Center del Occupational Safety and Health Administration, U.S. Department of Labor. No refleja necesariamente las vistas o las políticas del U.S. Department of Labor, ni menciona los nombres comerciales, productos comerciales, o las organizaciones implican el endoso por el gobierno de Estados Unidos. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

2 Riesgos en Excavaciones
Los derrumbes son el mayor riesgo Otros riesgos son: Asfixia debido a falta de oxígeno Inhalación de sustancias tóxicas Fuego Maquinaria en movimiento cerca del borde de la excavación que puede causar un colapso Corte accidental de cables de energía subterráneos Instructor note: OSHA Standard Exemptions: House foundation/basement excavations (including those that become trenches by definition when formwork, foundations, or walls are constructed) are exempt from the OSHA standard. The specific information regarding the interpretation of this exemption may be found on the OSHA public web site. Reference 29 CFR The exemption specifies height and width for the excavation, impact of water and environmental conditions, soil and equipment factors, and operation of heavy equipment in the vicinity. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Lesiones y muerte La excavación es una de las operaciones más riesgosas de la construcción La mayoría de los accidentes ocurren en zanjas de entre 5 y 15 pies de profundidad Por lo general no hay nada que alerte previamente de un derrumbe Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Definiciones Excavación Corte, cavidad, zanja o depresión hecho por el hombre removiendo tierra Zanja Excavación angosta donde la profundidad es mayor que el ancho, éste no debe ser mayor de 15 pies Escudo Estructura capaz de resistir un derrumbe y proteger a los empleados Apuntalamiento Estructura que soporta los costados de una excavación y la protege de derrumbes Pendiente Técnica que usa un ángulo de inclinación específico en los costados de la excavación (el ángulo varía de acuerdo a la evaluación de los factores que impactan en el lugar) Reference Shield (shield system) -- a structure able to withstand a cave-in and protect employees with the structure. Shields can be permanent structure or can be designed to be portable and moved along as work progresses. Also known as trench box or trench shield. apuntalamiento (apuntalamiento system) -- a structure such as a metal hydraulic, mechanical or timber apuntalamiento system that supports the sides of an excavation and which is designed to prevent cave-ins. ataluzado (ataluzado system) -- protects employees from cave-ins by excavating to form sides of an excavation that are inclined away from the excavation to prevent cave-ins. The angle of incline varies with differences in such factors as the soil type, environmental conditions of exposure, and application of surcharge loads. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Entrenamiento El entrenamiento de los empleados deberá centrarse en: El mayor riesgo en una excavación Cómo proteger a los empleados de derrumbes Factores que representan un riesgo para los empleados que trabajan en una excavación Rol de la Persona Competente en una excavación The discussion of this topic covers four main points. At the conclusion of the training, you should be able to: 1. State the greatest risk that is present at an excavation. 2. Briefly describe the three main methods for protecting employees from cave-ins. 3. Name at least three factors that pose a hazard to employees working in excavations, and at least one way to eliminate or reduce each of the hazards. 4. Describe the role of a competent person at an excavation site. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

6 Sistemas de Protección
Los empleados deben estar protegidos de derrumbes utilizando un sistema de protección diseñado de modo adecuado Los sistemas de protección deben poder resistir todas las cargas previstas Reference (a) Protective system – 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. Protective systems include support systems, ataluzado and banqueo systems, shield systems, and other systems that provide the necessary protection. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

7 Sistemas de Protección - Requisitos
Un sistema de protección bien diseñado requiere: Diseño correcto de sistemas de pendiente y banqueo Diseño correcto de sistemas de soporte, con escudo y otros sistemas de protección Manejo apropiado de los materiales y el equipo Atención a la instalación y eliminación correcta ¡Todo ésto es necesario para proteger a los trabajadores en excavaciones! Several factors come into play when developing a total “protective system”. The design of of the system itself, how materials and equipment are handled in and around the excavation, and installation and removal of protective system components. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

8 Sistemas de Protección - Diseño
El empleador seleccionará y construirá : Los declives y configuraciones de sistemas de inclinacion y banqueo Sistemas de soporte, sistemas de escudos y otros sistemas de protección Escudo Puede ser permanente o removible (también conocido como caja de zanja o escudo de zanja) Apuntalamiento Sistema hidráulico de metal, mecánico o de madera que sostiene los lados Ataluzado Formar lados que se inclinan hacia fuera de la excavación Reference , (b), (c) banqueo -- 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. apuntalamiento or shielding is used when the location or depth of the cut makes ataluzado back to the maximum allowable slope impractical. There are two basic types of apuntalamiento, timber and aluminum hydraulic. Trench boxes (shielding) are different from apuntalamiento because instead of supporting the trench face, they are mostly serve to protect workers from cave-ins. The excavated area between the outside of the trench box and the face of the trench should be as small as possible. The space between the trench box and the excavation side may be backfilled (or other means may be used) to prevent lateral movement of the box. Shields may not be subjected to loads exceeding those which the system was designed to withstand. Trench boxes may be used in combination with ataluzado and banqueo. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

9 Sistemas de protección - Instalación
Protege a empleados expuestos a posibles derrumbes: Ataluzar o escalonar los costados de la excavación, Apuntalar los costados de la excavación o Colocar un escudo entre los costados de la excavación y el área de trabajo Reference (a) Each employee in an excavation shall be protected from cave-ins by an adequate protective system except when: Excavations are made entirely in stable rock; or Excavations are less than 5 feet in depth and examination of the ground by a competent person provides no indication of a potential cave-in. 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. Reference (b) Design of ataluzado and banqueo systems. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

10 Ejemplo – Insuficiencias
Esta excavación tiene postes de soporte y accesos de salida inadecuados Presenta riesgo de derrumbe Reference (a) and (c)(1) Designs for aluminum hydraulic apuntalamiento shall be in accordance with paragraph (c)(2), but if manufacturer's tabulated data cannot be utilized, designs shall be in accordance with appendix D. Employees exposed to potential cave-ins must be protected by ataluzado or banqueo the sides of the excavation, by supporting the sides of the excavation, or by placing a shield between the side of the excavation and the work area. 1926 Subpart P Appendix D Aluminum Hydraulic apuntalamiento for Trenches Contains information that can be used when aluminum hydraulic apuntalamiento is provided as a method of protection against cave-ins in trenches that are not more than 20 feet deep. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

11 Ejemplo - Insuficiencias
Este trabajador está en una zanja sin sistema de protección No está escalonada ni apuntalada y no tiene vía de egreso Reference (a) and (b) and (c) Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Factores de Diseño Entre los factores que intervienen en el diseño de un sistema de protección se incluyen: La clasificación del suelo La profundidad del corte Contenido de agua del suelo Cambios debidos a factores meteorológicos y clima Otras operaciones en las cercanías (c) The employer or his designee must select and construct designs of support systems, shield systems, and other protective systems Trenches more than 5 feet require apuntalamiento or must have a stabilized slope Trenches less than 5 feet - a competent person must inspect to determine that a protection system is not necessary in soils where there is no indication of a potential cave-in In hazardous soil conditions trenches under 5 feet need protection Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Apuntalamiento General Crea un marco en el cual trabajar Usa puntales, apuntalamiento cruzado y largueros Sostiene las paredes de la excavación Las tablas de OSHA proveen datos de apuntalamiento Se debe conocer el tipo de suelo Se debe saber el ancho y la profundidad de la excavación Se debe estar familiarizado con las Tablas de OSHA Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Escudo de Zanja Se construyó un escudo de zanja alrededor de este área de trabajo Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

15 Soporte Hidráulico de Zanja
Utilizando gatos hidráulicos el operador puede fácilmente introducir el sistema en el agujero Una vez colocado, se aumenta la presión hidráulica para mantener el encofrado en su lugar Se instalan clavijas por si falla el sistema hidráulico Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Materiales y Equipo El equipo no debe tener daños o defectos que limiten su función Si está dañado debe ser examinado por la persona competente para ver si es apto para seguir en uso Si no es adecuado, debe ser sacado de servicio hasta que un ingeniero profesional apruebe su uso Reference (d) Materials and equipment used for protective systems shall be free from damage or defects that might impair their proper function. Manufactured materials and equipment used for protective systems shall be used and maintained in a manner that is consistent with the recommendations of the manufacturer, and in a manner that will prevent employee exposure to hazards. 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. 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. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Vehículos Para proteger zanjas de los vehículos: Instale barricadas Use señales de mano o mecánicas o troncos de detención Haga una gradiente que se aleje de la excavación Cerque o rodee de barricadas las zanjas que se dejen abiertas por la noche Reference (f) Warning system for mobile equipment When mobile equipment is operated adjacent to an excavation, or when such equipment is required to approach the edge of an excavation, and the operator does not have a clear and direct view of the edge of the excavation, a warning system shall be utilized such as barricades, hand or mechanical signals, or stop logs. If possible, the grade should be away from the excavation. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

18 Condiciones Peligrosas
El peso y las vibraciones de esta grúa crean condiciones muy riesgosas No debe haber empleados trabajando debajo de ella In addition to the unprotected trench, a cave-in hazard is increased by machinery which gets too close. Even normal vehicular traffic, such as that along an adjacent interstate or road through an industrial part may impact an excavation. The vibrations from continuous or heavy traffic may undermine the soil and cause a cave-in. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

19 Tierra Extraída de la Zanja
Colocar la tierra de la zanja bien lejos de la excavación Al menos a 2 pies del borde de la excavación Medir desde el punto más cercano a la tierra sacada de la zanja Coloque tierra de modo que el agua de lluvia corra alejándose de la excavación Reference (j)(2) Protect employees from materials or equipment that could fall or roll into excavations. You may also use retaining devices that are sufficient to prevent materials or equipment from falling or rolling into excavations Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

20 Otros Riesgos en Excavaciones
Acumulación de agua Deficiencia de oxígeno Emanaciones tóxicas Acceso/Egreso Caídas Equipo móvil Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

21 Riesgos Producidos por Agua
Cuando hay agua en una excavación es extremadamente riesgoso entrar (h) Employees shall not work in excavations in which there is accumulated water, or in excavations in which water is accumulating, unless adequate precautions have been taken to protect employees against the hazards posed by water accumulation. The precautions necessary to protect employees adequately vary with each situation, but could include special support or shield systems to protect from cave-ins, water removal to control the level of accumulating water, or use of a safety harness and lifeline. If water is controlled or prevented from accumulating by the use of water removal equipment, the water removal equipment and operations shall be monitored by a competent person to ensure proper operation. If excavation work interrupts the natural drainage of surface water (such as streams), diversion ditches, dikes, or other suitable means shall be used to prevent surface water from entering the excavation and to provide adequate drainage of the area adjacent to the excavation. Note que estos trabajadores no están usando cascos para protegerse de materiales que caigan en la zanja Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

22 Riesgos Producidos por Agua
Los trabajadores deben estar protegidos de derrumbes (h) Employees shall not work in excavations in which there is accumulated water, or in excavations in which water is accumulating, unless adequate precautions have been taken to protect employees against the hazards posed by water accumulation. The precautions necessary to protect employees adequately vary with each situation, but could include special support or shield systems to protect from cave-ins, water removal to control the level of accumulating water, or use of a safety harness and lifeline. If water is controlled or prevented from accumulating by the use of water removal equipment, the water removal equipment and operations shall be monitored by a competent person to ensure proper operation. If excavation work interrupts the natural drainage of surface water (such as streams), diversion ditches, dikes, or other suitable means shall be used to prevent surface water from entering the excavation and to provide adequate drainage of the area adjacent to the excavation. ¡Note el agua en el fondo de la zanja! ¡Esta es una situación muy riesgosa! Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Atmósfera Riesgosa Antes de que un empleado entre a una excavación de más de 4 pies de profundidad se debe verificar si hay: Falta de oxígeno Alta concentración de gas combustible Niveles elevados de otras sustancias peligrosas Must also test where oxygen deficiency or a hazardous atmosphere could reasonably be expected to exist, before an employee enters the excavation. If hazardous conditions exist, controls such as proper respiratory protection or ventilation must be provided. Also, controls used to reduce atmospheric contaminants to acceptable levels must be tested regularly. Where adverse atmospheric conditions may exist or develop in an excavation, the employer also must provide and ensure that emergency rescue equipment, (e.g., breathing apparatus, a safety harness and line, basket stretcher, etc.) is readily available. This equipment must be attended when used. Employees shall not be permitted to work in hazardous and/or toxic atmospheres. Such atmospheres include those with: -- less than 19.5% oxygen, -- a combustible gas concentration greater than 20% of the lower flammable limit, and, -- concentrations of hazardous substance that exceed those specified in the Threshold Limit Values for airborne contaminants established by the ACGIH. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Medios de Egreso En excavaciones de 4 pies o más de profundidad, debe haber una escalera, escala o rampa a no más de 25 pies de los empleados Reference (c(1) Structural ramps - Structural ramps that are used solely by employees as a means of access or egress from excavations shall be designed by a competent person. Structural ramps used for access or egress of equipment shall be designed by a competent person qualified in structural design, and shall be constructed in accordance with the design. - Ramps and runways constructed of two or more structural members shall have the structural members connected together to prevent displacement. - Structural members used for ramps and runways shall be of uniform thickness. - Cleats or other appropriate means used to connect runway structural members shall be attached to the bottom of the runway or shall be attached in a manner to prevent tripping. - Structural ramps used in lieu of steps shall be provided with cleats or other surface treatments o the top surface to prevent slipping. Esta escalera es inadecuada; debería sobresalir 3 pies de la excavación. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Acceso y Egreso Estas dos escalas que están atadas no son un medio adecuado de egreso La escala debe extenderse 3 pies por encima del borde superior de la excavación Reference (c) and (ladder) Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Lo Bueno, lo Malo y lo Feo Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

27 Caídas, Cargas en Caída y Vehículos
Para protegerse de caídas, cargas en caída y equipo móvil: Instale barricadas Use señales de mano o mecánicas Haga un gradiente que se aleje de la excavación Coloque cercas o barricadas en zanjas dejadas abiertas por la noche Cuando las señales, signos y barricadas no son suficiente protección, use un señalero Falls and Equipment To protect employees from these hazards, OSHA requires the employer to take the following precautions: • Keep materials or equipment that might fall or roll into an excavation at least 2 feet from the edge of excavations, or have retaining devices, or both. • Provide warning systems such as mobile equipment, barricades, hand or mechanical signals, or stop logs, to alert operators of the edge of an excavation. If possible, keep the grade away from the excavation. • Provide scaling to remove loose rock or soil or install protective barricades and other equivalent protection to protect employees against falling rock, soil, or materials. • Prohibit employees from working on faces of sloped or benched excavations at levels above other employees unless employees at lower levels are adequately protected from the hazard of falling, rolling, or sliding material or equipment. • Prohibit employees under loads that are handled by lifting or digging equipment. To avoid being struck by any spillage or falling materials, require employees to stand away from vehicles being loaded or unloaded. If cabs of vehicles provide adequate protection from falling loads during loading and unloading operations, the operators may remain in them. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Persona Competente Debe haber tenido entrenamiento específico y conocer: La clasificación de los suelos El uso de sistemas de protección Los requisitos de la norma Debe ser capaz de reconocer riesgos y tener autoridad para eliminarlos inmediatamente Reference (b) "Competent person" 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. Preamble Page – “Competent Person” The term is used throughout existing subpart P, but was not defined within the subpart, and there were no references to the existing definition in subpart C, in the proposal, OSHA added the definition to subpart P to help those using the standard. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

29 Inspecciones de Excavaciones
Una persona competente debe hacer una inspección diaria de las excavaciones, áreas alrededor de ellas y sistemas de protección: Antes de que comience el trabajo y de acuerdo a las necesidades Después de tormentas de lluvia, vientos fuentes u otros eventos que pueden aumentar los riesgos, y Cuando puede anticiparse razonablemente que un empleado estará expuesto a riesgos. Reference (k) Daily inspections of excavations, the adjacent areas, and protective systems shall be made by a competent person for evidence of a situation that could result in possible cave-ins, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions. An inspection shall be conducted by the competent person prior to the start of work and as needed throughout the shift. Inspections shall also be made after every rainstorm or other hazard increasing occurrence. These inspections are only required when employee exposure can be reasonably anticipated. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

30 Inspecciones de Excavaciones
Si la persona competente encuentra evidencias de un posible derrumbe, indicaciones de fallas de sistemas de protección, ambientes peligrosos u otras condiciones de riesgo: Los empleados expuestos deben ser evacuados del área peligrosa Los empleados no deben volver hasta que las precauciones necesarias se hayan implementado Reference (k) (2) Where the competent person finds evidence of a situation that could result in a possible cave-in, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions, exposed employees shall be removed from the hazardous area until the necessary precautions have been taken to ensure their safety. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

31 Planificación de la Evaluación del Sitio
Antes de comenzar una excavación: Evaluar las condiciones del suelo Construir sistemas de protección Hacer pruebas para verificar si hay falta de oxígeno, emanaciones riesgosas y gases tóxicos Proveer accesos seguros de entrada y salida Contactarse con las empresas de servicios públicos Determine el equipo de seguridad que se necesita The following concerns must be addressed by a competent person: Evaluate soil conditions [1926 Subpart P Appendix A] and select appropriate protective systems [1926 Subpart P Appendix F]. Construct protective systems in accordance with the standard requirements [ ]. Preplan; contact utilities (gas, electric) to locate underground lines, plan for traffic control if necessary, determine proximity to structures that could affect choice of protective system. Test for low oxygen, hazardous fumes and toxic gases, especially when gasoline engine-driven equipment is running, or the dirt has been contaminated by leaking lines or storage tanks. Insure adequate ventilation or respiratory protection if necessary. Provide safe access into and out of the excavation. Provide appropriate protections if water accumulation is a problem. Inspect the site daily at the start of each shift, following a rainstorm, or after any other hazard-increasing event. Keep excavations open the minimum amount of time needed to complete operations. Surface crossing of trenches should not be made unless absolutely necessary. However, if necessary, they are only permitted under the following conditions: -- Vehicle crossings must be designed by and installed under the supervision of a registered professional engineer. -- Walkways or bridges must: -- have a minimum clear width of 20 inches, -- be fitted with standard rails, and -- extend a minimum of 24 inches past the surface edge of the trench. Fisura Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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Síntesis El mayor riesgo en una excavación es el derrumbe Los empleados pueden ser protegidos con pendientes, instalación de escudos y apuntalamiento de la excavación Una persona competente es responsable de inspeccionar la excavación. Otros riesgos de las excavaciones incluyen acumulación de agua, deficiencia de oxígeno, emanaciones tóxicas, caídas y equipo móvil. Harwood Grant 46F1-HT06 - Texas Engineering Extension Service

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EXCAVACIONES (fin) Harwood Grant 46F1-HT06 - Texas Engineering Extension Service