Excavations and Trenching Safety
62 flashcards covering Excavations and Trenching Safety for the OSHA OSHA 10/30 Construction section.
Excavations and trenching safety focuses on protecting workers from hazards like cave-ins, falls, and equipment accidents during digging operations in construction sites. This topic is defined by OSHA regulations in 29 CFR 1926 Subpart P, which outlines requirements for soil classification, protective systems such as shoring and shielding, and procedures for safe access and emergency response.
On OSHA 10/30 Construction certification exams, this material typically appears in multiple-choice or scenario-based questions that test specific rules, like the need for a competent person to inspect trenches daily. A common trap is overlooking the differences in protective measures for various soil types or depths, leading to incorrect answers about slope stability or shoring requirements.
In practice, workers often forget to check for underground utilities before starting excavations, which can cause serious accidents.
Terms (62)
- 01
What is the definition of a competent person in excavations?
A person who is capable of identifying existing and predictable hazards in excavations and who is authorized to take prompt corrective measures to eliminate them (29 CFR 1926.650).
- 02
How deep must an excavation be to require cave-in protection?
Five feet or greater, unless the excavation is made entirely in stable rock (29 CFR 1926.652(a)(1)).
- 03
Under 29 CFR 1926.651, what must be done before workers enter an excavation?
A competent person must inspect the excavation and the adjacent areas for possible cave-in, failure of structures, water accumulation, or other hazards (29 CFR 1926.651(k)(1)).
- 04
What protective systems are required for excavations in unstable soil?
Sloping, benching, shoring, or shielding, as determined by a competent person (29 CFR 1926.652).
- 05
How often must a competent person inspect excavations?
Daily and as needed after every rainstorm or other hazard-increasing event (29 CFR 1926.651(k)(1)).
- 06
What is the maximum allowable slope for excavations in Type C soil?
horizontal to 1 vertical (34 degrees) (29 CFR 1926.652(b) Appendix A).
- 07
In a scenario where water is accumulating in an excavation, what action is required?
Operations must be stopped, and the water must be removed or controlled by a competent person (29 CFR 1926.651(d)).
- 08
What must be done if hazardous atmospheres are detected in an excavation?
Testing and controls must be implemented, and workers must be protected from the hazards (29 CFR 1926.651(g)).
- 09
Under 29 CFR 1926.651, what precautions are needed near structures?
Support systems must be used to prevent damage or cave-ins from nearby structures or activities (29 CFR 1926.651(a)(1)).
- 10
What is required when excavating near underground utilities?
The location of utilities must be determined and protective measures taken before excavation begins (29 CFR 1926.651(b)).
- 11
For excavations deeper than 4 feet, what access and egress is needed?
A stairway, ladder, ramp, or other safe means must be provided within 25 feet of lateral travel for employees (29 CFR 1926.651(c)(2)).
- 12
In a cave-in scenario, what immediate steps should workers take?
Evacuate the excavation and notify a competent person to assess and stabilize the area (29 CFR 1926.651(k)(2)).
- 13
What is the definition of an excavation according to OSHA?
Any man-made cut, cavity, trench, or depression in an earth surface, formed by earth removal (29 CFR 1926.650).
- 14
How must spoil piles be managed in excavations?
They must be kept at least 2 feet from the edge of the excavation (29 CFR 1926.651(j)(2)).
- 15
Under 29 CFR 1926.652, when is benching allowed?
In excavations made in cohesive soil, as part of a protective system designed by a competent person (29 CFR 1926.652(b)).
- 16
What training is required for workers in excavations?
Training on hazards, recognition, and procedures by a competent person (29 CFR 1926.651(a)(1)(iii)).
- 17
If a worker is exposed to falling loads in an excavation, what protection is needed?
Barricades or stop logs must be used to prevent materials from falling into the excavation (29 CFR 1926.651(j)(1)).
- 18
What is required for excavations involving vehicular traffic?
Warning vests, barricades, and other measures to protect workers from being struck (29 CFR 1926.651(a)(3)).
- 19
Under 29 CFR 1926.651, what must be ensured for surface encumbrances?
They must be removed or supported to prevent cave-ins (29 CFR 1926.651(a)(2)).
- 20
What atmospheric testing is needed before entry into excavations?
Testing for oxygen, flammable gases, and toxic contaminants (29 CFR 1926.651(g)(1)).
- 21
What is the procedure for installing shoring in excavations?
It must be designed and installed by a competent person before workers enter (29 CFR 1926.652(c)).
- 22
In a scenario with unstable soil conditions, what should a competent person do?
Evaluate the soil and implement appropriate protective systems (29 CFR 1926.652(a)).
- 23
How must ladders be used in excavations?
They must extend 3 feet above the excavation edge and be secured (29 CFR 1926.651(c)(1)).
- 24
What is required when excavations are left open overnight?
They must be effectively protected with barriers or covers (29 CFR 1926.651(a)(4)).
- 25
Under 29 CFR 1926.650, what defines stable rock?
Natural solid mineral matter not subject to weathering or degradation (29 CFR 1926.650(b)).
- 26
What protective equipment is needed for workers in excavations?
Hard hats, safety glasses, and other PPE as determined by hazards (29 CFR 1926.651(i)).
- 27
If a trench box is used, what additional measures are needed?
It must be installed properly and the excavation inspected daily (29 CFR 1926.652(a)(2)).
- 28
What is the first step when planning an excavation?
Determine the soil type and potential hazards (29 CFR 1926.651(a)).
- 29
In a flooding scenario during excavation, what must be done?
Pumping or other means must be used to remove water (29 CFR 1926.651(d)).
- 30
Under 29 CFR 1926.652, what factors affect sloping requirements?
Soil type, depth of cut, and environmental conditions (29 CFR 1926.652(b)).
- 31
What documentation is required for excavations?
A daily inspection log by a competent person (29 CFR 1926.651(k)).
- 32
What is the definition of a trench according to OSHA?
A narrow excavation deeper than it is wide, not wider than 15 feet (29 CFR 1926.650).
- 33
How must employees be protected from traffic in excavation areas?
With flaggers, barricades, or vehicle exclusion (29 CFR 1926.651(a)(3)).
- 34
In a scenario where vibration is present, what precautions are needed?
Monitor for potential cave-ins and use additional support (29 CFR 1926.651(m)).
- 35
What is required for the removal of protective systems?
They must be removed in a way that protects employees during removal (29 CFR 1926.652(d)).
- 36
Under 29 CFR 1926.651, what must be done with excavated materials?
Place them to avoid hazards, at least 2 feet from the edge (29 CFR 1926.651(j)(2)).
- 37
What warning systems are needed for excavations?
Signs, signals, or barricades to warn of hazards (29 CFR 1926.651(d)).
- 38
If oxygen levels are low in an excavation, what action is required?
Ventilate the area and retest before entry (29 CFR 1926.651(g)(2)).
- 39
What is the procedure for soil classification?
A competent person must classify based on visual and manual tests (29 CFR 1926.651(c)).
- 40
Under 29 CFR 1926.650, what hazards are associated with excavations?
Cave-ins, falls, flooding, and hazardous atmospheres (29 CFR 1926.650).
- 41
How must access points be arranged in long excavations?
With ladders spaced no more than 25 feet apart (29 CFR 1926.651(c)(2)).
- 42
In a scenario with adjacent structures, what must be checked?
Ensure the excavation does not undermine nearby foundations (29 CFR 1926.651(a)(1)).
- 43
What is required for the use of mobile equipment near excavations?
Barricades and operators must be alerted to the edge (29 CFR 1926.651(a)(1)).
- 44
What daily checks must a competent person perform?
Inspect for water accumulation, atmospheric hazards, and structural stability (29 CFR 1926.651(k)).
- 45
Under 29 CFR 1926.652, when can excavations be sloped?
For any excavation, as long as it meets the required angles for the soil type (29 CFR 1926.652(b)).
- 46
What is the definition of Type B soil in excavations?
Cohesive soil with an unconfined compressive strength of 0.5 tsf or greater, but less than 1.5 tsf (29 CFR 1926.652 Appendix A).
- 47
How must workers be rescued from excavations?
Using properly designed and well-rehearsed methods (29 CFR 1926.651(k)(3)).
- 48
In a gas leak scenario during excavation, what should be done?
Evacuate and ventilate the area immediately (29 CFR 1926.651(g)).
- 49
What is required for the stability of excavation walls?
They must be sloped, shored, or shielded based on soil analysis (29 CFR 1926.652(a)).
- 50
Under 29 CFR 1926.651, what protective measures are for falls?
Guardrails or covers for openings (29 CFR 1926.651(l)).
- 51
What is the procedure for handling heavy rain in excavations?
Inspect and slope or drain as necessary (29 CFR 1926.651(k)(1)).
- 52
If a protective system fails, what must happen?
Evacuate workers and repair or replace the system (29 CFR 1926.652(e)).
- 53
What is the maximum distance for ladder placement in excavations?
No more than 25 feet of lateral travel (29 CFR 1926.651(c)(2)).
- 54
In a scenario with confined space risks in excavations, what is needed?
Follow permit-required confined space procedures if applicable (29 CFR 1926.651 and 1910.146).
- 55
Under 29 CFR 1926.650, what employee rights apply?
The right to a safe workplace and to report hazards (OSHA Outreach Training Program Requirements).
- 56
What is required for excavation signage?
Warning signs for hazards like unstable edges (29 CFR 1926.651(a)).
- 57
How must excavations be backfilled?
In a manner that prevents cave-ins during the process (29 CFR 1926.651(n)).
- 58
What personal fall arrest systems are needed near excavation edges?
If working near the edge, as per fall protection standards (29 CFR 1926.501).
- 59
In a multi-level excavation, what additional protections are needed?
Separate protective systems for each level (29 CFR 1926.652(a)).
- 60
What is the definition of a protective system in excavations?
A method of protecting employees from cave-ins, such as sloping or shoring (29 CFR 1926.650).
- 61
Under 29 CFR 1926.651, what must be done with loose rock?
Scale it down or provide a scaling device (29 CFR 1926.651(f)).
- 62
What emergency procedures are required for excavations?
A plan for rescue and medical services (29 CFR 1926.651(k)(3)).