CHST - Construction Health and Safety Technician Excavation and Trenching Safety Questions and Answers 1 — Questions and Answers
Question 1: According to 29 CFR 1926 Subpart P, what is the maximum lateral distance a worker may travel within a trench to reach a means of egress?
- 15 feet
- 25 feet (Correct answer)
- 50 feet
- 100 feet
Correct answer: 25 feet
OSHA standard 1926.651(c)(2) requires that a stairway, ladder, ramp, or other safe means of egress be located in trench excavations that are 4 feet or more in depth so as to require no more than 25 feet of lateral travel for employees.
Question 2: A construction site has an 8-foot deep trench dug entirely in Type A soil. The competent person has observed that heavy vehicle traffic is causing vibrations near the trench. Which of the following is the correct action for the competent person to take?
- No action is needed as Type A soil is the most stable.
- Slope the trench at an angle of 53 degrees.
- Reclassify the soil and adjust the protective system accordingly. (Correct answer)
- Install a warning system for the mobile equipment.
Correct answer: Reclassify the soil and adjust the protective system accordingly.
According to OSHA's soil classification system, a soil cannot be classified as Type A if it is subject to vibration. The competent person must re-evaluate and reclassify the soil, which would likely downgrade it to Type B or C, requiring a change in the protective system (e.g., changing the slope angle or using shoring/shielding).
Question 3: A contractor is excavating a trench that will be 22 feet deep. Which of the following is required for the protective system design?
- Approval by the site's competent person.
- Selection from the manufacturer's tabulated data.
- Design by a registered professional engineer. (Correct answer)
- Benching appropriate for Type B soil.
Correct answer: Design by a registered professional engineer.
OSHA standard 1926.652(c) requires that for excavations 20 feet deep or greater, the protective system must be designed by a registered professional engineer or be based on tabulated data prepared and/or approved by a registered professional engineer.
Question 4: During a daily inspection, a competent person notices water accumulating in the bottom of a 6-foot deep trench. Which of the following is a primary and immediate responsibility of the competent person?
- Document the finding in the daily log.
- Monitor the water level to see if it increases.
- Continue work as long as the water is below boot level.
- Remove exposed employees from the hazardous area. (Correct answer)
Correct answer: Remove exposed employees from the hazardous area.
Per 1926.651(k)(2), if a competent person finds evidence of a situation that could result in a possible cave-in, such as water accumulation, exposed employees shall be removed from the hazardous area until the necessary precautions have been taken to ensure their safety.
Question 5: Which of the following is a key requirement for storing excavated soil and other materials relative to the trench?
- They must be placed at least 2 feet from the edge. (Correct answer)
- They must be stored uphill from the excavation.
- They can be placed at the edge if a barricade is used.
- They must be hauled off-site by the end of each shift.
Correct answer: They must be placed at least 2 feet from the edge.
OSHA standard 1926.651(j)(2) requires that employees be protected from excavated or other materials or equipment that could pose a hazard by falling or rolling into excavations. Protection shall be provided by placing and keeping such materials or equipment at least 2 feet from the edge of the excavation.
Question 6: A competent person performs a daily inspection of an excavation, its adjacent areas, and protective systems. When must these inspections be conducted?
- Only at the beginning of the work shift.
- Only after a rainstorm or other hazard-increasing event.
- At the end of the day to prepare for the next shift.
- Prior to the start of work and as needed throughout the shift. (Correct answer)
Correct answer: Prior to the start of work and as needed throughout the shift.
According to OSHA 1926.651(k)(1), a competent person must make daily inspections of excavations, adjacent areas, and protective systems. These inspections must occur prior to the start of work, as needed throughout the shift, and after every rainstorm or other hazard-increasing occurrence.
CHST - Construction Health and Safety Technician Excavation and Trenching Safety Questions and Answers 1
According to 29 CFR 1926 Subpart P, what is the maximum lateral distance a worker may travel within a trench to reach a means of egress?