EXC-001 — Learner reference

1. Recognize the excavation and responsible people

By the end: Identify excavation hazards and the competent person’s authority.

An excavation is a cut, cavity, trench or depression made by removing earth. A trench is a narrow excavation, generally deeper than it is wide, with a bottom width no greater than 15 feet. Forms or other structures can also make the space between a structure and the earth a trench when that bottom dimension is 15 feet or less. A wide excavation still has hazards and protective requirements.

This course covers OSHA construction Subpart P. It applies to open excavations in the earth, including trenches. The employer must also identify other rules for the actual work, equipment and jurisdiction. Underground construction and entry into a sewer, manhole or other separate structure need their own applicability review. Construction work regulated by Subpart P is excluded from Subpart AA; that exclusion does not remove atmospheric hazards or automatically cover entry into a separate confined space.

A cave-in can trap or bury a person when soil or rock separates from the face, or when soil is lost beneath a shield or support system. Other hazards include utilities, falling loads, equipment movement, falls, water, unsafe air and collapse of nearby structures. A hard hat, short task or experienced crew does not replace control of these hazards.

A competent person must be able to identify existing and predictable hazardous conditions and must have authority to take prompt corrective measures. That role includes the inspections and decisions assigned by Subpart P. A title, course certificate or ability to complete a form does not establish the needed knowledge and authority. Workers need to know who fills this role and how to report a change.

Registered professional engineers approve designs or data where the selected design route requires them. A competent person is not automatically an engineer. The employer must assign competent personnel, obtain the required design basis, train workers and provide protective arrangements before exposure. This course develops core knowledge; actual soil testing, system selection, installation and task performance need workplace instruction and verification.

Basis: 1926.650; 1926.21(b)(2); 1926.1201(b)(1)

2. Plan the dig and locate underground services

By the end: Confirm utilities and surface hazards before excavation.

Before opening an excavation, determine the estimated location of underground installations that may be encountered. Include sewer, telephone, fuel, electric and water lines, as well as other services. Review the actual work area and available information. Old drawings and paint marks help planning, but neither proves the exact position of every installation.

Contact utility companies or owners within established or customary local response times. Tell them the proposed work and request locations before actual excavation starts. Follow the applicable state and local notification and waiting requirements. A federal reference to 24 hours does not override a longer state or local waiting period.

The federal rule allows cautious proceeding when an owner cannot respond within 24 hours, unless a longer period is required by state or local law, or cannot establish the exact location, only if detection equipment or other acceptable locating means are used. This is a conditional provision, not permission to dig blindly after a clock expires. The employer must resolve the actual legal and safe locating process before authorizing the dig.

As excavation approaches an estimated utility location, determine the exact location by safe and acceptable means. Use the agreed locating method and utility-owner precautions; do not assume an excavator bucket can find the line safely. If marks, records and field conditions disagree, stop the affected work and resolve the conflict before proceeding.

While the excavation stays open, protect, support or remove underground installations as needed to safeguard workers. Remove or support surface objects that create hazards, such as poles, trees, pavement or stored items. Plan for changing support as earth is removed. A completed locate request does not replace protection of the service after it is exposed.

Basis: 1926.651(a)–(b)

3. Understand soil classification and changing conditions

By the end: Recognize the evidence used to classify soil for protective-system selection.

When the chosen protective-system design uses Appendix A soil classifications, a competent person classifies each deposit as stable rock, Type A, Type B or Type C. Classification requires at least one visual and at least one manual analysis. Other design routes must meet their own data requirements. Calling every soil Type C does not excuse inspection, unsafe air controls or following the selected system’s limits.

Visual analysis examines the excavation, nearby ground and soil samples. Look for particle size, clumps, cracks, layers, prior utility work, water and sources of vibration. Layers that slope into the excavation can be especially unfavorable. Observe from a safe place; no one should enter an unprotected excavation just to collect evidence for deciding whether it is safe.

Manual methods include plasticity, dry strength, thumb penetration and suitable instruments such as a pocket penetrometer or shear vane. For plasticity, a moist cohesive sample can form a thin thread rather than crumble. Strength testing of cohesive soil uses a suitable sample and correct technique. An instrument reading cannot erase fissures, vibration or other factors seen in the visual analysis. Actual test technique requires demonstration and practice.

Type A cohesive soil has unconfined compressive strength of at least 1.5 tons per square foot, but it cannot be Type A if fissured, previously disturbed, subject to relevant vibration or affected by other disqualifying conditions. Type B includes cohesive soil above 0.5 but below 1.5 tons per square foot, certain granular materials, dry unstable rock and previously disturbed soil unless it is Type C. Strength alone is not the classification.

Type C includes cohesive soil at 0.5 tons per square foot or less, sand, gravel, loamy sand, submerged soil and soil with water freely seeping from it. Unstable submerged rock and certain layers dipping into the cut at 4 horizontal to 1 vertical or steeper are also Type C. Do not assume wet soil is safe because it holds a temporary shape.

Classify a layered system by its weakest layer, except that layers may be classified individually when a more stable layer lies beneath a less stable one. If conditions affecting classification change, a competent person evaluates and reclassifies as necessary. Rain, vibration, drying, added loads and new soil layers can change the protective decision during the job.

Basis: 1926 Subpart P Appendix A; 1926.652(b)–(c)

4. Select a valid cave-in protection method

By the end: Apply the protection trigger and recognize slope limits.

Each employee in an excavation needs an adequate cave-in protective system unless the excavation is entirely in stable rock, or it is less than 5 feet deep and a competent person’s ground examination finds no indication of a potential cave-in. At exactly 5 feet, the shallow-excavation exception no longer applies. A 4-foot excavation with cave-in potential also needs protection. Depth alone does not make a shallow excavation safe.

Protective methods include sloping, permitted benching, shoring and shielding. Sloping cuts the sides back; benching creates designed steps; shoring supports the sides; shielding protects people within a system able to resist a cave-in. Select a valid design route for the actual soil, depth, width, water, loads and surrounding structures. A ladder or escape plan is not a cave-in protective system.

For sloping under the basic 1926.652(b)(1) option, use no steeper than 1½ horizontal to 1 vertical and the applicable Type C configurations in Appendix B. The Appendix A/B route permits the relevant soil-based configurations. General simple-slope limits for excavations 20 feet or less are ¾:1 for Type A, 1:1 for Type B and 1½:1 for Type C. The ratio is horizontal distance for each vertical foot, not the reverse.

For example, a simple 8-foot-deep Type C cut needs at least 12 feet of horizontal setback on each sloped side under the normal 1½:1 configuration, before any need to flatten it further. The bottom work width is additional. Limited room does not permit a steeper wall; choose another compliant protective system or redesign the work. A slope must follow the full permitted configuration, not just one measured point.

Appendix B has limited Type A short-term and vertical-lower-portion configurations, each with specific depth, duration and geometry conditions. It does not provide a benching configuration for Type C. Do not copy a Type A bench into Type C soil. In supported or shielded vertical-lower-portion configurations, the system extends at least 18 inches above the vertical portion as specified. Have the actual design checked before use.

Maximum slopes assume favorable conditions. Signs of distress require workers to be removed and precautions taken; under Appendix B, the slope is cut back at least an additional ½ horizontal to 1 vertical flatter than the maximum. A competent person determines further reduction needed for surcharge loads. Sloping or benching deeper than 20 feet needs a registered professional engineer’s design. At every depth, stay within the selected design’s limits and obtain the required engineering basis when those limits do not cover the work.

Basis: 1926.652(a)–(b); 1926 Subpart P Appendix B

5. Use shoring and shields within their design

By the end: Distinguish support from shielding and follow the actual data.

Shoring supports excavation sides to prevent cave-ins. A shield, often called a trench box, is designed to withstand cave-in forces and protect people inside. A shield does not automatically support a nearby foundation or stop soil collapse outside it. Workers must stay in the protected area, including during access and exit. Moving just beyond the box to make a connection can place a worker in unprotected soil.

Protective-system selection must follow one of the routes in 1926.652(c): applicable appendix designs, manufacturer’s tabulated data, other approved tabulated data, or a registered professional engineer’s design. The actual data must cover depth, width, soil, loads, configuration and components. Timber and aluminum hydraulic appendix tables have limits and are not universal recipes for any available lumber or cylinder.

When manufacturer’s data are used, follow all specifications, recommendations and limits. A deviation needs that manufacturer’s specific written approval. Required data and any deviation approval must be in writing at the jobsite during construction of the system. Other tabulated data must identify the approving registered professional engineer; a project-specific design identifies the engineer and required configuration. Retain the documents and make them available as the rule requires after construction.

Do not exceed design loads. Equipment, spoil, traffic and adjacent structures can add loads that a simple depth label does not capture. Appendix C and D tables do not cover every surcharge condition and are limited to trenches no deeper than 20 feet. For deeper work or conditions outside any table, use an applicable engineering-approved design or data route under 1926.652. Never extend a table by guesswork.

Protective materials and equipment must be free of defects that impair function and maintained as the manufacturer recommends. A competent person evaluates damaged components. If that person cannot assure the equipment can support intended loads or is otherwise safe, remove it from service. A registered professional engineer must evaluate and approve it before return to service. A painted repair or an undamaged-looking side does not establish the remaining capacity.

Basis: 1926.650(b); 1926.652(c), (d), (g); Appendices C and D

6. Control installation, movement and removal

By the end: Recognize safe sequencing and the limits below a protective system.

Install and remove support systems so workers are protected from cave-ins, structural collapse and falling members. Secure members against sliding, falling and kickout, and do not overload individual parts. Coordinate installation closely with digging. Do not expose a worker in an unprotected trench to install the protection that is still missing.

Before temporarily removing an individual support member, take added precautions such as installing other members to carry the loads. A pipe that needs clearance is not permission to remove a brace. The competent personnel must follow the actual design and sequence and protect workers throughout the change.

For support-system removal, begin at the bottom and progress upward. Release members slowly to observe signs of remaining-system failure or cave-in. Backfill as support removal progresses. This is a controlled sequence performed by instructed personnel; it is not a direction for a worker to enter an unsafe trench and pull supports by hand.

Install shields to restrict lateral or other hazardous movement under sudden side loads. Employees must not be in a shield while it is installed, removed or moved vertically. Protect entry and exit from cave-ins. Any other movement must follow the actual system instructions and safe work plan; do not infer permission to ride a box merely because a sentence mentions vertical movement.

Digging up to 2 feet below the bottom of a support system or shield is permitted only if the system is designed for the forces at the full trench depth and there is no indication of possible soil loss from behind or beneath its bottom. Both conditions must be met while the trench is open. Two feet is a maximum conditional allowance, not a routine gap or a way to use an undersized box.

Keep workers away from suspended system components and loads handled by digging or lifting equipment. Use the designated rigging, communication and exclusion arrangements. If soil enters under a box, a brace shifts or the setup no longer matches the data, remove exposed workers and have the condition resolved before continuing.

Basis: 1926.652(e)–(g); 1926.651(e)

7. Provide safe entry, exit and crossings

By the end: Apply trench egress and excavation crossing requirements.

A trench 4 feet or more deep needs a stairway, ladder, ramp or other safe means of exit placed so workers travel no more than 25 feet laterally to reach it. Plan for each occupied section and the protected route to the exit. The 4-foot access trigger differs from the 5-foot cave-in exception; do not wait until 5 feet to provide required egress.

Do not count a ladder that is blocked, unsecured, damaged or outside the protected route as an adequate exit. Construction portable ladders used to reach an upper landing normally extend their side rails at least 3 feet above it. The specific alternative for a ladder too short requires rigid top securing and a grasping device. Use the actual ladder rules and safe setup taught in the Stairways and Ladders course.

A structural ramp used only by employees must be designed by a competent person. A ramp for equipment must be designed by a competent person qualified in structural design and built to that design. Connect multiple structural members against movement, use uniform thickness, prevent tripping at connections and provide slip-resistant treatment where a ramp substitutes for steps. Do not improvise an equipment ramp from spare planks.

Provide a walkway wherever employees or equipment are required or permitted to cross an excavation. Walkways 6 feet or more above lower levels need guardrails meeting 1926.502(b). Do not jump across, walk on a pipe or balance on a shield spreader as a routine crossing. The walkway must be suitable for the people or equipment using it.

At an excavation edge 6 feet or more deep that is not readily visible because of plant growth or another visual barrier, provide guardrails, fences or barricades. Wells, pits, shafts and similar excavations 6 feet or more deep need guardrails, fences, barricades or covers. Other work conditions can require additional protection. Keep access and edge controls effective as the excavation grows or the crew relocates.

Basis: 1926.651(c), (l); 1926.501(b)(7); 1926.1053(b)(1)

8. Control spoil, equipment and falling loads

By the end: Prevent edge loads and materials from endangering workers.

Keep excavated material and equipment that could fall or roll into the excavation at least 2 feet from the edge, or use retaining devices sufficient to prevent that movement, or combine both where needed. The two-foot dimension addresses falling and rolling material; it is not a universal safe distance for a heavy machine or a guarantee that edge loading is acceptable.

Stored spoil, moving equipment, traffic and nearby structures add surcharge loads to the soil and protective system. The competent person must evaluate their effect, and the actual design must cover expected loads. Slopes may need to be flatter, equipment farther away or another system selected. Do not park a loaded truck at the edge solely because its tire is two feet back.

Protect workers from loose rock or soil on excavation faces by removing loose material safely, using protective barricades on the face, or another equally effective method. Workers on slopes or benches above others may work there only when those below are adequately protected from falling, rolling or sliding material and equipment. A hard hat alone cannot stop a mass of soil.

No employee may be beneath loads handled by lifting or digging equipment. Stand clear of vehicles being loaded or unloaded to avoid spillage and falling material. Vehicle operators may remain in their cabs only when the cab provides the required protection under 1926.601(b)(6). Plan the bucket path, loading zone and pedestrian route before the machine starts.

When equipment operates next to or approaches an excavation edge and the operator lacks a clear, direct view of that edge, use a warning system such as barricades, signals or stop logs. Where possible, slope the grade away from the excavation. Workers exposed to public vehicle traffic must receive and wear suitable reflective or high-visibility warning garments. Those garments supplement traffic control and equipment separation; they do not make a swing radius safe.

Basis: 1926.651(d)–(f), (j); 1926.652(f); Appendix B(c)(3)

9. Control water and protect nearby structures

By the end: Recognize water and structural conditions that require action before work.

Employees must not work in an excavation with accumulated or accumulating water unless adequate precautions protect them. The controls depend on the actual hazards and may include special support or shields, water removal or a suitable harness and lifeline arrangement. A harness does not replace cave-in protection. Do not assume a small puddle tells you the condition of soil behind the wall.

When pumps or other removal equipment control water, a competent person must monitor the equipment and operation to ensure it works properly. Plan the discharge so it does not return water to the cut or weaken nearby ground. Pump failure, rising water, erosion or flowing soil requires removal from exposure and reassessment, not simply a larger pump selected by guesswork.

If excavation interrupts natural drainage, use diversion ditches, dikes or other suitable means to prevent surface water entering and to provide adequate drainage nearby. Heavy-rain runoff calls for competent-person inspection and water controls. Rain can change soil classification, loading and system performance even when the bottom looks dry after pumping.

Where digging endangers adjoining buildings, walls or structures, provide support such as shoring, bracing or underpinning to ensure stability and protect workers. A trench box generally protects those inside it; it does not automatically support an undermined building. Plan structural support before removing the earth that provides it.

Do not dig below a foundation or retaining-wall footing where that could reasonably pose a hazard unless one of the rule’s conditions is met: adequate support such as underpinning; excavation in stable rock; or a registered professional engineer’s approval that the structure is sufficiently removed to be unaffected or that the work will not pose a hazard. Sidewalks, pavement and related structures also must not be undermined without support or another protective method. A supervisor’s visual guess is not engineering approval.

Basis: 1926.651(h)–(i)

10. Test and control hazardous air

By the end: Apply atmospheric testing triggers and ongoing controls.

An open top does not guarantee safe air. Oxygen deficiency, toxic gases and flammable vapors can occur near landfills, leaking utilities, contaminated soil or nearby stored chemicals. Engine exhaust and the work itself can add hazards. Identify expected contaminants before choosing the instrument and controls. Smell cannot establish that air is safe.

Where oxygen deficiency or a hazardous atmosphere exists or could reasonably be expected, test before employees enter an excavation greater than 4 feet deep. Oxygen below 19.5 percent is deficient under this rule. The testing trigger is conditional and says greater than 4 feet; it differs from the trench-egress trigger of 4 feet or more. Harmful exposure still must be prevented at shallower depths under applicable requirements.

Take adequate precautions against oxygen deficiency and other hazardous atmospheres, using suitable ventilation or respiratory protection under the applicable standards. The excavation rule also requires precautions to prevent exposure to flammable gas above 20 percent of its lower flammable limit. That value is not blanket permission to work or perform hot work at every lower reading; other hazards, rules and the employer’s safe-entry limits still apply.

Use trained personnel and an appropriate, functioning instrument to sample the worker’s actual atmosphere according to the hazard assessment and equipment instructions. A meter that measures only oxygen cannot establish that every toxic contaminant is absent. Have the employer teach the actual instrument checks, sampling method, alarm response and limitations before assigning this task.

When ventilation or other controls reduce contaminants to acceptable levels, test as often as necessary to ensure the air remains safe. A single morning reading does not establish safe conditions for the whole shift. If an alarm occurs or controls fail, leave the hazardous area and follow the plan. Never assume the fan’s sound proves that it is moving clean air where workers breathe.

Subpart P has its own atmospheric and rescue provisions. Its exclusion from construction Subpart AA does not remove those protections. Entering a separate manhole, pipe or other confined structure may introduce different requirements that the employer must assess. This course does not qualify a worker to select respirators or perform confined-space entry.

Basis: 1926.651(g); 1926.1201(b)(1)

11. Inspect before work and after changes

By the end: Recognize inspection triggers and remove workers from hazards.

A competent person inspects excavations, adjacent areas and protective systems daily where employee exposure can reasonably be anticipated. Inspect before work starts and as needed throughout the shift. Inspections are also required after every rainstorm or other event that increases hazards. A completed morning form does not cover all later conditions.

Look for possible cave-ins, protective-system failure, hazardous air and other hazards. Review the whole work area: soil and layers, cracks, sloughing, bulging, water, utilities, supports, shield condition, loads, nearby structures, access and equipment routes. Confirm that the actual arrangement remains within its design and that required controls function.

Signs of distress include new cracks, settlement at the edge, material slumping from the face, bulging or heaving at the bottom, and small pieces suddenly falling or rolling from the wall. These signs call for action. Do not enter the cut to get a closer look or ask a worker to remain below while someone watches the crack.

If the competent person finds evidence of possible cave-in, protective-system failure, hazardous air or another hazardous condition, remove exposed employees until necessary precautions ensure their safety. Correct the cause, verify the protection and communicate any changed conditions before resuming. A fresh signature cannot make an unchanged hazard safe.

Useful inspection records identify the location, date and time, competent person, conditions, design reference, findings, actions and release restrictions. The worksheet supports the employer’s process; Subpart P does not prescribe a universal daily form or record-retention period. Record actual observations and corrections rather than copying yesterday’s entry. Workers should report changes immediately instead of waiting for the next scheduled inspection.

Basis: 1926.651(k); 1926 Subpart P Appendices A and B

12. Verify workplace skills and prepare for emergencies

By the end: Connect knowledge training to safe task performance and emergency response.

The employer must instruct each employee in recognizing and avoiding unsafe conditions and in the regulations applicable to the work. For excavation work, that means actual hazards, protective boundaries, access, equipment interaction, utility controls, water, air and reporting. Teach in a way workers understand, using demonstrations and questions suited to their language and literacy needs.

Workers must know the actual plan and stop-work route before exposure. Competent-person duties require additional capability in soil evaluation, protective-system limits, inspections and prompt correction. Equipment operators, installers and air testers also need task-specific instruction and demonstrated skills. An online score alone does not qualify any of those roles or certify a competent person.

Use a safe workplace exercise to verify the employee can find the designated access, stay within protection, recognize changing hazards and describe whom to notify. Those assigned technical tasks must demonstrate the actual methods under qualified instruction appropriate to the task. Correct gaps and provide further instruction when work, equipment or conditions change or performance shows a need. Subpart P does not specify a universal annual refresher, a fixed course length or this Academy’s quiz score.

Plan emergency communication and access before digging. Identify how to report the exact location and hazard, summon capable emergency help, keep others away and stop equipment safely. A cave-in can be followed by another collapse. Do not enter an unsafe excavation or use a machine to dig blindly around a buried person. Activate the response plan and keep untrained workers out of the hazard.

Where hazardous atmospheric conditions exist or could reasonably develop during excavation work, appropriate emergency rescue equipment such as breathing apparatus, a harness and line, or a basket stretcher must be readily available. Equipment must be attended when in use. Having equipment nearby does not establish that an untrained person can safely perform a rescue; arrange the actual response capability and instruction for the hazards.

Employees entering bell-bottom pier holes or similar deep, confined footing excavations must wear a harness with a securely attached lifeline. The lifeline must be separate from material-handling lines and individually attended the entire time the worker is inside. This special provision does not replace cave-in, air or other controls. Complete actual employer instruction and verify the emergency arrangements before assigning that work.

Basis: 1926.21(b)(2); 1926.650(b); 1926.651(g)(2), (k)