In The Trenches: Excavation And Trenching

The statement is true because it is a safety requirement to keep spoils and stockpile materials at least two feet away from the top edge of an excavation. This is important to prevent any potential collapse or cave-in of the excavation, as the weight or pressure from the materials could destabilize the walls. By keeping a safe distance, the risk of accidents or injuries can be significantly reduced.

A trench box should extend 18 inches above the point where proper slope begins in order to ensure the safety of workers. By extending the trench box above this point, it provides additional protection against cave-ins and helps to maintain the stability of the trench. This is important because proper slope is necessary to prevent soil collapse and maintain the integrity of the trench. Therefore, it is correct to say that a trench box should extend 18 inches above the point where proper slope begins.

Entering an unsafe excavation in the event of an emergency is not advisable. Excavations can be hazardous due to unstable soil, cave-ins, or the presence of harmful gases. Entering such an excavation without proper safety measures can put one's life at risk. It is important to prioritize personal safety and wait for professional help or rescue teams to handle the situation in a controlled and safe manner.

A competent person is someone who possesses the skills, knowledge, and experience to effectively identify existing and predictable hazards, authorize prompt corrective measures, and recognize excavation emergencies. In addition to these abilities, a competent person may also have a wide range of other skills and expertise related to the specific field or industry they are working in. This term encompasses a comprehensive set of competencies that go beyond the mentioned tasks, making the answer "all of the above plus a lot more" accurate.

The correct answer is "all of the above" because all of the mentioned options can pose dangerous atmospheric conditions. Confined spaces can have limited oxygen levels or hazardous gases, which can lead to asphyxiation or poisoning. Hazardous waste sites may release toxic fumes or gases into the air, causing harm to anyone in the vicinity. Working with adhesives or solvents can release volatile organic compounds (VOCs) that can be harmful if inhaled in high concentrations. Therefore, all of these situations can present dangerous atmospheric conditions.

Water in an excavation can significantly change the properties of soil. Type A soil is considered stable and cohesive, but the presence of water can make it unstable and less cohesive, thereby changing its classification. Hence, if water is present in an excavation with type A soil, it is no longer considered type A soil. Therefore, the correct answer is false.

Thumb penetration is a valid soil test that can be used to assess the compaction and moisture content of the soil. By pressing the thumb into the soil, one can determine its firmness and evaluate whether it is too dry or too wet. This test is commonly used in gardening and agriculture to ensure that the soil is suitable for planting and to determine the need for irrigation or drainage.

The egress should be located within 25 feet of travel to employees at all times. This means that employees should have access to a safe exit route that is no more than 25 feet away from their location. This ensures that in case of an emergency, employees can quickly and easily evacuate the premises without facing any significant obstacles or delays. Having the egress within a close proximity minimizes the risk of injuries or fatalities during an evacuation.