What is an acceptable alternative to installing an audible back up alarm on vehicles quizlet?
flaggers
What engineering control can cause a caught between hazard?
Improperly protected trenches and excavations are another major cause of caught-in or between accidents. Any trench that is deeper than 5 feet needs to have protective systems in place. If the trench or excavation is over 20 feet deep, a professional engineer is required to design the protective system.
What depth is shoring required?
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.
At what depth do you need a trench box?
5 feet
How high should a trench box be above ground?
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.
What are the 5 horizons of soil and their common names?
There are five soil horizons: O, A, E, B, and C. (R is used to denote bedrock.) There is no set order for these horizons within a soil. Some soil profiles have an A-C combination, some have an O-E-B, an O-A-B, or just an O.
What are the five layers of soil?
Soil Horizons
- Organic – The organic layer (also called the humus layer) is a thick layer of plant remains such as leaves and twigs.
- Topsoil – Topsoil is considered the “A” horizon.
- Subsoil – Subsoil is considered the “B” horizon.
- Parent material – The parent material layer is considered the “C” horizon.
What is the most important property of soil?
Two of the most important properties of soils are their texture and structure . By texture, we mean what soils are composed of and how this affects the way they feel and their cultivation. The main components of soil texture are: sand, silt and clay particles and organic matter.
What are the 5 physical properties of soil?
4. PHYSICAL PROPERTIES OF THE SOIL
- 4.1 Texture: Texture refers to the relative proportions of particles of various sizes such as sand, silt and clay in the soil.
- 4.2 Structure:
- 4.3 Consistence:
- 4.4 Partiole density.
- 4.5 Bulk density.
- 4.6 Pore space:
- 4.7 Atterberg limits:
- 4.8 Soil colour:
Is the top of soil layer?
Topsoil is the upper, outermost layer of soil, usually the top 5–10 inches (13–25 cm). It has the highest concentration of organic matter and microorganisms and is where most of the Earth’s biological soil activity occurs….Evaluation.
| Category | Desired Results |
|---|---|
| Copper (Cu-I) | Index > 25 |
What is the darkest layer of soil at the top of the photograph called?
Called the A horizon, the topsoil is usually the darkest layer of the soil because it has the highest proportion of organic material.
What determines the type of soil?
When soil scientists want to precisely determine soil type, they measure the percentage of sand, silt, and clay. They plot this information on a triangular diagram, with each size particle at one corner (figure 2). The soil type can then be determined from the location on the diagram.