18 inches.
Specifically, the trench shield extends 18 inches (0.45 m) above the vertical part of the walls, but is below the top of the trench. Therefore, where the top of the shield is below grade, it must extend a minimum of 18 inches above the vertical part of the wall.
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When using a trench box it should extend at least?
18 in
Trench boxes are generally used in open areas, but they also may be used in combination with sloping and benching. The box should extend at least 18 in (0.45 m) above the surrounding area if there is sloping toward excavation. This can be accomplished by providing a benched area adjacent to the box.
How tall are trench boxes?
When do you need a trench box? A trench box must be used when a confined space is 5 feet or greater in –depth. It must extend 18 inches above the surface, and it must be no greater than 2 feet from the bottom.
How deep is a trench box?
Trenches 5 feet (1.5 meters) deep or greater require a protective system unless the excavation is made entirely in stable rock. If less than 5 feet deep, a competent person may determine that a protective system is not required.
When a trench is 4 feet or more in depth?
A stairway, ladder, ramp or other safe means of egress shall be located in trench excavations that are 4 feet (1.22 m) or more in depth so as to require no more than 25 feet (7.62 m) of lateral travel for employees.
What are the OSHA requirements for trenches?
OSHA requires employers to provide ladders, steps, ramps, or other safe means of egress for workers working in trench excavations 4 feet (1.22 meters) or deeper. The means of egress must be located so as not to require workers to travel more than 25 feet (7.62 meters) laterally within the trench.
What is the maximum height above a lower level that a jobsite walkway can be before it is required by OSHA to have handrails?
Are guardrails required on all open sides of scaffolding? The standard requires employers to protect each employee on a scaffold more than 10 feet (3.1 m) above a lower level from falling to that lower level.
What is a trench box in construction?
Trench boxes, also called trench shields or trench sheets, are one type of protective system. They aren’t designed to shore or prevent a trench wall from collapsing. Instead, they’re designed to protect workers from the pressure and weight of soil in the event of a cave-in.
Why are trench boxes used?
Trench Boxes are used for rapid shoring of trench runs during construction. These provide a quick and easy way of holding the ground stable in a trench without the need for other shoring equipment.
What is the maximum depth a trench can be dug without support?
The basis of the rule is that, if a trench is under 1.2m deep, then people can enter the trench without the sides of the excavation being supported or battered back. This rule is no longer something that should be considered. 1.2m is no longer the threshold for the need to support an excavation.
Is a trench box the same as a trench shield?
What’s the difference between a trench box, shore box and a trench shield? Nothing. They are all terms used to refer to the same common type of trench protective system. A trench box, or trench shield, protects the workers inside it in the event of a trench wall collapse.
Is a trench a confined space OSHA?
While a trench or other excavation may seem to fit within the definition of a confined space per the Federal OSHA permit-required confined space entry standards, the answer is “No, trenches and other excavations are not regulated by OSHA as permit-required confined spaces”.
Is code for trench excavation?
4.13 No excavation or earthwork below the level of any foundation of building or structure shall be commenced or continued unless adequate steps are taken to prevent danger to any person employed, from collapse of the structure or fall of any part thereof.
At what height must excavations be benched?
Benching and battering should be started at a depth of 1 metre. The rule is one metre up and one metre back.
What is the OSHA definition of a trench?
“Trench (Trench excavation)” means a narrow excavation (in relation to its length) made below the surface of the ground. 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).
Can a trench be wider than 15 feet?
According to OSHA, a trench is a narrow excavation (compared to its length) made beneath the ground’s surface. Usually, a trench’s depth is relatively larger than its width, whereas the width at the bottom is never greater than 4.6 meters or 15 feet.
What is the minimum height of the top guard rail of a scaffold above the edge from which someone is liable to fall?
How high should the guardrails on a scaffold be? For construction work, the top guardrail should be a minimum of 950mm above the working platform and any gap between the top rail and the intermediate rail should not exceed 470mm.
What is the the minimum height of guards in meter from the upper surface of the top rail to the floor or platform level?
1 meter
(2) Standard railings shall be at least 1 meter (3.3 ft.) from the floor level to the upper surface of the top rail.
How high must the top of the guard rail be above the working surface?
42 inches
Top edge height of top rails, or equivalent guardrail system members, shall be 42 inches (1.1 m) plus or minus 3 inches (8 cm) above the walking/working level.
When should you use a trench box?
In rules set for trench box applications, OSHA requires a protective system be used when trench depths reach 5 ft. or more. Protective systems also are required for trenches less than 5 ft. deep if the soil could cave in when the trench is dug, according to United Rentals.
What is the minimum slope required if sloping is used to make the trench safe for occupancy?
1½H:1V
OSHA requires type C soil to be sloped at 1½H:1V and it cannot be benched. This means that the slope must be cut back 1½ ft horizontally for every 1 ft of depth.