350 QUESTIONS AND ANSWERS
1. Q: What is the minimum distance that excavations must be kept from
underground utilities? ANSWER Call 811 (Nevada One Call) before digging.
Maintain at least 24 inches clearance from marked utilities.
2. Q: What slope ratio is required for excavations in Type A soil over 5 feet
deep? ANSWER 3/4:1 (34-degree angle from horizontal).
3. Q: What is the maximum allowable slope for Type B soil? ANSWER 1:1
(45-degree angle from horizontal).
4. Q: At what depth must excavations be inspected daily by a competent
person? ANSWER All excavations 4 feet or deeper must be inspected daily.
5. Q: What is required before workers enter an excavation 4 feet or deeper?
ANSWER Inspection by a competent person and proper protective systems
(sloping, benching, or shoring).
6. Q: What is the minimum width required for excavation access and egress?
ANSWER 24 inches minimum width for ladders, stairs, or ramps.
7. Q: How far must spoil piles be kept from excavation edges? ANSWER At
least 2 feet from the edge of excavations.
8. Q: What atmospheric testing is required in excavations over 4 feet deep?
ANSWER Test for oxygen deficiency, hazardous gases, and vapors before
entry and continuously during work.
9. Q: What is the OSHA standard for oxygen levels in excavations? ANSWER
Between 19.5% and 23.5% oxygen content.
10. Q: When is trench shoring required? ANSWER When excavations cannot
be sloped to the required angle or when space limitations exist.
11. Q: What is the maximum horizontal distance workers should be from an
exit in a trench? ANSWER No more than 25 feet of lateral travel to a means
of egress.
,12. Q: What protective equipment is required for excavation work? ANSWER
Hard hats, safety glasses, steel-toed boots, and high-visibility clothing.
13. Q: What is a competent person in excavation work? ANSWER Someone
with authority to take corrective action and knowledge to identify hazards and
soil conditions.
14. Q: How often must excavation protective systems be inspected? ANSWER
Daily and after any occurrence that could affect the excavation's stability.
15. Q: What is required when excavations are left unattended? ANSWER
Proper barricading, warning signs, and covers over openings.
16. Q: What is the minimum safe distance for heavy equipment from
excavation edges? ANSWER At least 2 feet, or equivalent to the depth of the
excavation.
17. Q: What type of soil has the greatest risk of cave-ins? ANSWER Type C
soil (soft clay, organic soils, submerged soil).
18. Q: When must a registered professional engineer design protective systems?
ANSWER For excavations over 20 feet deep or when unusual conditions exist.
19. Q: What is required for excavations in public areas? ANSWER Proper
barriers, warning signs, lighting, and traffic control measures.
20. Q: What is the OSHA requirement for fall protection near excavations?
ANSWER Standard guardrails when excavations are left open in areas where
people may walk.
21. Q: What weather conditions can affect excavation safety? ANSWER Rain,
freezing, and thawing can change soil conditions and require re-evaluation.
22. Q: What is the proper procedure when water is present in excavations?
ANSWER Use proper dewatering methods and ensure stable soil conditions
before entry.
23. Q: What training is required for excavation workers? ANSWER
Recognition of hazards, proper use of protective systems, and emergency
procedures.
24. Q: What is required when using mobile equipment near excavations?
ANSWER Warning systems (backup alarms), spotters, and stop logs or
barricades.
25. Q: What is the maximum allowable simple slope for Type C soil?
ANSWER 1.5:1 (approximately 34 degrees from horizontal).
, 26. Q: When are benched excavations allowed? ANSWER Only in Type A
and Type B soils, with proper bench configurations.
27. Q: What is the minimum bench configuration for Type B soil? ANSWER
4-foot vertical cut with 4-foot horizontal step, not to exceed 20 feet total height.
28. Q: What utilities require special precautions during excavation? ANSWER
Gas lines, electrical cables, water mains, and fiber optic cables.
29. Q: What is required for emergency rescue in excavations? ANSWER
Rescue equipment and trained personnel must be readily available.
30. Q: What factors determine soil classification? ANSWER Unconfined
compressive strength, soil type, and condition (wet/dry).
31. Q: What is the definition of Type A soil? ANSWER Clay, silty clay,
sandy clay, or clay loam with unconfined compressive strength ≥ 1.5 tsf.
32. Q: What makes soil Type C classification? ANSWER Unconfined
compressive strength ≤ 0.5 tsf, granular soils, or submerged soil.
33. Q: What safety measures are required for utility line crossings? ANSWER
Hand digging within 24 inches, proper support, and utility company
notification.
34. Q: What is required for confined space entry in excavations? ANSWER
Entry permit, atmospheric testing, ventilation, and attendant if classified as
confined space.
35. Q: What is the proper response to a cave-in emergency? ANSWER Do not
enter to rescue; call 911 and use proper rescue equipment and trained personnel.
36. Q: What maintenance is required for shoring systems? ANSWER Daily
inspection, proper installation, and immediate repair of defects.
37. Q: What is required when excavations intersect sidewalks or roads?
ANSWER Structural support for the pavement and proper traffic control
measures.
38. Q: What protection is required for workers in excavations during equipment
operation? ANSWER Workers must exit the excavation or be protected by an
adequate protective system.
39. Q: What is the requirement for excavation lighting? ANSWER Adequate
illumination for safe working conditions, especially during extended hours.
1. Q: What is the minimum distance that excavations must be kept from
underground utilities? ANSWER Call 811 (Nevada One Call) before digging.
Maintain at least 24 inches clearance from marked utilities.
2. Q: What slope ratio is required for excavations in Type A soil over 5 feet
deep? ANSWER 3/4:1 (34-degree angle from horizontal).
3. Q: What is the maximum allowable slope for Type B soil? ANSWER 1:1
(45-degree angle from horizontal).
4. Q: At what depth must excavations be inspected daily by a competent
person? ANSWER All excavations 4 feet or deeper must be inspected daily.
5. Q: What is required before workers enter an excavation 4 feet or deeper?
ANSWER Inspection by a competent person and proper protective systems
(sloping, benching, or shoring).
6. Q: What is the minimum width required for excavation access and egress?
ANSWER 24 inches minimum width for ladders, stairs, or ramps.
7. Q: How far must spoil piles be kept from excavation edges? ANSWER At
least 2 feet from the edge of excavations.
8. Q: What atmospheric testing is required in excavations over 4 feet deep?
ANSWER Test for oxygen deficiency, hazardous gases, and vapors before
entry and continuously during work.
9. Q: What is the OSHA standard for oxygen levels in excavations? ANSWER
Between 19.5% and 23.5% oxygen content.
10. Q: When is trench shoring required? ANSWER When excavations cannot
be sloped to the required angle or when space limitations exist.
11. Q: What is the maximum horizontal distance workers should be from an
exit in a trench? ANSWER No more than 25 feet of lateral travel to a means
of egress.
,12. Q: What protective equipment is required for excavation work? ANSWER
Hard hats, safety glasses, steel-toed boots, and high-visibility clothing.
13. Q: What is a competent person in excavation work? ANSWER Someone
with authority to take corrective action and knowledge to identify hazards and
soil conditions.
14. Q: How often must excavation protective systems be inspected? ANSWER
Daily and after any occurrence that could affect the excavation's stability.
15. Q: What is required when excavations are left unattended? ANSWER
Proper barricading, warning signs, and covers over openings.
16. Q: What is the minimum safe distance for heavy equipment from
excavation edges? ANSWER At least 2 feet, or equivalent to the depth of the
excavation.
17. Q: What type of soil has the greatest risk of cave-ins? ANSWER Type C
soil (soft clay, organic soils, submerged soil).
18. Q: When must a registered professional engineer design protective systems?
ANSWER For excavations over 20 feet deep or when unusual conditions exist.
19. Q: What is required for excavations in public areas? ANSWER Proper
barriers, warning signs, lighting, and traffic control measures.
20. Q: What is the OSHA requirement for fall protection near excavations?
ANSWER Standard guardrails when excavations are left open in areas where
people may walk.
21. Q: What weather conditions can affect excavation safety? ANSWER Rain,
freezing, and thawing can change soil conditions and require re-evaluation.
22. Q: What is the proper procedure when water is present in excavations?
ANSWER Use proper dewatering methods and ensure stable soil conditions
before entry.
23. Q: What training is required for excavation workers? ANSWER
Recognition of hazards, proper use of protective systems, and emergency
procedures.
24. Q: What is required when using mobile equipment near excavations?
ANSWER Warning systems (backup alarms), spotters, and stop logs or
barricades.
25. Q: What is the maximum allowable simple slope for Type C soil?
ANSWER 1.5:1 (approximately 34 degrees from horizontal).
, 26. Q: When are benched excavations allowed? ANSWER Only in Type A
and Type B soils, with proper bench configurations.
27. Q: What is the minimum bench configuration for Type B soil? ANSWER
4-foot vertical cut with 4-foot horizontal step, not to exceed 20 feet total height.
28. Q: What utilities require special precautions during excavation? ANSWER
Gas lines, electrical cables, water mains, and fiber optic cables.
29. Q: What is required for emergency rescue in excavations? ANSWER
Rescue equipment and trained personnel must be readily available.
30. Q: What factors determine soil classification? ANSWER Unconfined
compressive strength, soil type, and condition (wet/dry).
31. Q: What is the definition of Type A soil? ANSWER Clay, silty clay,
sandy clay, or clay loam with unconfined compressive strength ≥ 1.5 tsf.
32. Q: What makes soil Type C classification? ANSWER Unconfined
compressive strength ≤ 0.5 tsf, granular soils, or submerged soil.
33. Q: What safety measures are required for utility line crossings? ANSWER
Hand digging within 24 inches, proper support, and utility company
notification.
34. Q: What is required for confined space entry in excavations? ANSWER
Entry permit, atmospheric testing, ventilation, and attendant if classified as
confined space.
35. Q: What is the proper response to a cave-in emergency? ANSWER Do not
enter to rescue; call 911 and use proper rescue equipment and trained personnel.
36. Q: What maintenance is required for shoring systems? ANSWER Daily
inspection, proper installation, and immediate repair of defects.
37. Q: What is required when excavations intersect sidewalks or roads?
ANSWER Structural support for the pavement and proper traffic control
measures.
38. Q: What protection is required for workers in excavations during equipment
operation? ANSWER Workers must exit the excavation or be protected by an
adequate protective system.
39. Q: What is the requirement for excavation lighting? ANSWER Adequate
illumination for safe working conditions, especially during extended hours.
