20 Construction (Focus Four) Practice Questions & Answers
Every Construction (Focus Four) practice question from the OSHA 10 / 30 Practice Test, with the correct answer and a short explanation.
Start practice test →1. A construction worker is on a walking/working surface that has an unprotected side or edge. At what height above the lower level does OSHA require that the worker be protected from falling?
- A.4 feet
- B.15 feet
- C.6 feet✓ Answer
- D.10 feet
In construction (29 CFR 1926 Subpart M), the fall protection trigger height is 6 feet, because OSHA determined that an unprotected fall from that height is likely to cause death or serious injury. The other heights belong to different standards and are the classic distractors: 4 feet is the general industry (Part 1910) trigger, 10 feet applies to scaffolds, and 15 feet applies to steel erection.
Source: 29 CFR 1926.501(b)(1)Report a problem with this question
2. A guardrail system is used as fall protection on a construction site. How high must the top rail be above the walking/working level?
- A.42 inches, plus or minus 3 inches✓ Answer
- B.36 inches, plus or minus 3 inches
- C.30 inches, plus or minus 3 inches
- D.48 inches minimum, with no tolerance
The top edge of a guardrail must be 42 inches plus or minus 3 inches (39 to 45 inches) above the walking/working level. That range places the rail near an average worker's center of gravity, so it stops a body from going over rather than acting as a trip-and-tip point; the midrail then goes at about 21 inches, halfway between the top rail and the walking surface.
Source: 29 CFR 1926.502(b)(1) and (b)(2)Report a problem with this question
3. A guardrail top rail must be able to withstand, without failure, a force applied within 2 inches of the top edge in any outward or downward direction of at least:
- A.5,000 pounds
- B.500 pounds
- C.150 pounds
- D.200 pounds✓ Answer
The top rail must resist at least 200 pounds, a value chosen to approximate the force of a worker stumbling or falling against the rail; a rail that cannot take that load gives the worker a false sense of security. Midrails, screens, and intermediate members need only withstand 150 pounds, and 5,000 pounds is the anchorage requirement for a personal fall arrest system, not a guardrail.
Source: 29 CFR 1926.502(b)(3) and (b)(5)Report a problem with this question
4. Unless it is part of a complete system designed by a qualified person with a safety factor of at least two, an anchorage used for a personal fall arrest system must support at least how much for each employee attached?
- A.1,800 pounds
- B.5,000 pounds✓ Answer
- C.3,000 pounds
- D.10,000 pounds
Anchorages for personal fall arrest must support 5,000 pounds per attached employee, because arresting a falling body generates large, sudden dynamic loads and OSHA requires a wide margin over them. The distractors are real numbers from the same standard used elsewhere: 1,800 pounds is the maximum arresting force allowed on the body when a full body harness is used, and 3,000 pounds is the anchorage strength for a positioning device system.
Source: 29 CFR 1926.502(d)(15)Report a problem with this question
5. A portable ladder is used to reach an upper landing surface. What does OSHA require of the ladder's side rails?
- A.They must extend at least 1 foot above the landing surface
- B.They must extend at least 3 feet above the landing surface, unless the ladder is secured and a grab device is provided✓ Answer
- C.They must stop even with the landing surface so they do not obstruct the walkway
- D.They must extend at least 6 feet above the landing surface
Side rails must extend at least 3 feet above the upper landing so the climber has a handhold during the step-on and step-off transition, which is when most ladder falls happen; if the 3-foot extension is not possible, the ladder must be secured and a grab device provided. The same standard also requires non-self-supporting ladders to be set at a 4-to-1 pitch (base out 1 foot for every 4 feet of working length).
Source: 29 CFR 1926.1053(b)(1) and (b)(5)(i)Report a problem with this question
6. Employees working on a supported scaffold must be protected from falls when the platform is more than what height above a lower level?
- A.4 feet
- B.6 feet
- C.10 feet✓ Answer
- D.15 feet
Scaffolds are governed by Subpart L, which sets the fall protection trigger at more than 10 feet above a lower level, a different number from the 6-foot Subpart M trigger for ordinary walking/working surfaces. Scaffolds also carry their own rules that are commonly tested: erection, moving, altering, and dismantling must be supervised by a competent person, platforms must be fully planked, and cross braces may never be used as a means of access.
Source: 29 CFR 1926.451(g)(1), 1926.451(f)(7), 1926.451(e)(1)Report a problem with this question
7. A crane is hoisting a load of masonry block over an active work area. How long may a worker stand or work directly under the suspended load?
- A.As long as the crane operator can maintain eye contact with the worker
- B.Up to 30 seconds, as long as a hard hat is worn
- C.Never — workers must stay out from under the load and clear of the load path at all times✓ Answer
- D.Only if the load is less than half the crane's rated capacity
The answer is zero time: rigging, hooks, and slings can fail suddenly and without warning, and no amount of operator attention changes where the load lands. A hard hat is designed for small falling objects, not a dropped load, so the required controls are keeping workers out of the load path and out from under the load, barricading the swing radius, and using tag lines to control the load.
Source: 29 CFR 1926.1425 (keeping clear of loads); OSHA Focus Four Struck-By training moduleReport a problem with this question
8. A dump truck with an obstructed view to the rear needs to back up on a construction site. What does OSHA require?
- A.The driver must simply back up at less than 5 miles per hour
- B.All workers on foot in the area must wear hearing protection
- C.Nothing extra, as long as the driver sounds the horn twice before backing
- D.A reverse-signal alarm audible above the surrounding noise level, or an observer who signals that it is safe to back up✓ Answer
A vehicle with an obstructed rear view may not be used to back up unless it has a reverse-signal alarm audible above the surrounding noise level or an observer signals that backing is safe. The rule exists because backing vehicles are one of the leading struck-by killers in construction: the driver cannot see a worker on foot, so the standard forces either an audible warning to the worker or a set of eyes for the driver.
Source: 29 CFR 1926.601(b)(4)Report a problem with this question
9. Before construction of a masonry wall begins, a limited access zone must be established on the side of the wall that will not be scaffolded. How far must that zone extend from the wall?
- A.10 feet from the wall
- B.A distance equal to the height of the wall to be constructed plus 4 feet✓ Answer
- C.A distance equal to half the height of the wall
- D.6 feet from the wall
The limited access zone must equal the height of the wall to be constructed plus 4 feet, because an unbraced masonry wall that collapses falls roughly its own height, and the extra 4 feet covers scattering block and debris. Only employees actively engaged in constructing the wall may enter the zone, and walls over 8 feet high must stay braced until permanently supported.
Source: 29 CFR 1926.706(a); bracing requirement 1926.706(b)Report a problem with this question
10. A worker is pinned between a concrete truck that is backing up and a stationary wall, and suffers crushing injuries. Under OSHA's Focus Four, how is this hazard classified?
- A.Operator error, which is not one of the Focus Four hazard categories
- B.A struck-by hazard, because a vehicle made contact with the worker
- C.A materials handling hazard
- D.A caught-in or caught-between hazard✓ Answer
OSHA's dividing line is the mechanism of injury: it is struck-by when the injury comes from the impact alone, and caught-in or caught-between when the injury comes from crushing or compression between two objects. Here the worker was compressed between the moving truck and a fixed object, so it is caught-in/between; the controls are barricading the equipment's path and swing radius and never positioning yourself between moving equipment and a fixed object.
Source: OSHA Construction Focus Four Training, Caught-In or -Between Hazards module (Appendix C definitions)Report a problem with this question
11. At what depth must an excavation be protected by sloping, benching, shoring, or shielding, unless the excavation is made entirely in stable rock?
- A.6 feet or deeper
- B.3 feet or deeper
- C.4 feet or deeper
- D.5 feet or deeper✓ Answer
A cave-in protective system is required at 5 feet or deeper unless the excavation is entirely in stable rock, because a single cubic yard of soil can weigh about 3,000 pounds — roughly a small car — and a buried worker is crushed and suffocated within minutes. The nearby numbers are different requirements: 4 feet triggers the egress and atmospheric-testing rules, and 6 feet is the fall protection trigger for walking/working surfaces.
Source: 29 CFR 1926.652(a)(1)Report a problem with this question
12. Workers are performing pipe work in a trench 6 feet deep. All of the following are required EXCEPT:
- A.A cave-in protective system such as a trench box, shoring, or proper sloping
- B.A ladder, stairway, or ramp located within 25 feet of lateral travel for every worker in the trench
- C.Inspection of the excavation by a competent person at least once per week✓ Answer
- D.Spoil piles and equipment kept back at least 2 feet from the edge of the excavation
Weekly inspection is far too infrequent: a competent person must inspect the excavation daily before each shift, as needed throughout the shift, and after every rainstorm or other hazard-increasing event, because soil conditions can change within hours. The other three items are genuine requirements — egress within 25 feet of lateral travel in trenches 4 feet or deeper, spoil and equipment set back at least 2 feet from the edge, and a protective system at 5 feet or deeper.
Source: 29 CFR 1926.651(k)(1) (inspections), 1926.651(c)(2) (egress), 1926.651(j)(2) (spoil), 1926.652(a)(1)Report a problem with this question
13. An excavation on a construction project will be 22 feet deep. What does OSHA require of its protective system?
- A.Type C sloping alone is acceptable at any depth
- B.Any manufactured trench box may be used, since manufactured shields have no depth limit
- C.It must be designed by a registered professional engineer✓ Answer
- D.No protective system is needed if the soil is classified as Type A
Once an excavation exceeds 20 feet in depth, the protective system must be designed by a registered professional engineer, because OSHA's tabulated sloping and shoring data stop at 20 feet and the soil pressures beyond that require site-specific engineering. Below 20 feet the employer may use the standard options — sloping or benching by soil type (Type A at 3/4:1, Type B at 1:1, Type C at 1 1/2:1), shoring, or a shield such as a trench box used within its manufacturer's tabulated limits.
Source: 29 CFR 1926.652(b)(4) and Appendix B (maximum allowable slopes)Report a problem with this question
14. On a jobsite, workers plug tools into 120-volt, single-phase 15- and 20-ampere receptacles that are not part of the permanent wiring of the building. What does OSHA require?
- A.Only double-insulated tools may be plugged into them
- B.The cords must be visually inspected once a month
- C.No additional protection, as long as every tool has a grounding prong
- D.Ground-fault circuit interrupter (GFCI) protection on those receptacles, OR an assured equipment grounding conductor program✓ Answer
The employer has two accepted options: GFCI protection on those receptacles, or a written assured equipment grounding conductor program. A GFCI senses the small current leaking to ground and opens the circuit in milliseconds, before the current is fatal; the AEGCP is the alternative and requires daily visual inspection of cords and tools plus continuity and terminal tests before first use, after repair, after suspected damage, and at least every 3 months, documented by color coding or logs.
Source: 29 CFR 1926.404(b)(1)(i)-(iii)Report a problem with this question
15. Unless the lines have been de-energized and visibly grounded, what minimum clearance must be kept between any part of a piece of equipment or its load and an overhead power line rated 50 kV or less?
- A.4 feet
- B.10 feet✓ Answer
- C.15 feet
- D.20 feet
For equipment and loads operating near overhead lines of 50 kV or less, the minimum clearance is 10 feet, and for higher voltages the clearance increases by 0.4 inch for each kV over 50 kV. Contact is not required for a fatality — high voltage can arc across a gap — so workers must assume every line is energized, and the safest control is to have the utility de-energize and visibly ground the line. Cranes under Subpart CC use their own, larger distances (20 feet up to 350 kV, or the Table A distances with an encroachment-prevention measure).
Source: 29 CFR 1926.600(a)(6); crane distances at 1926.1408Report a problem with this question
16. A worker must service a piece of powered equipment. The energy source has been shut off, locked out, and tagged. What must be done BEFORE servicing begins?
- A.Notify the local OSHA area office of the shutdown
- B.Verify de-energization — attempt to start the equipment and test the circuit with a meter to confirm zero energy✓ Answer
- C.Wait exactly 30 minutes for the equipment to cool
- D.Remove the tag so it does not get torn or dirty during the work
Locking and tagging only control the energy source; verification is what proves the equipment is actually at zero energy, catching mis-identified circuits, back-feeds, and stored energy in capacitors, springs, or hydraulics. The sequence is de-energize, lock, tag, then test before touching, and only qualified persons may work on or near exposed energized parts. Tags are never removed while work is in progress, and only the person who applied a lock removes it.
Source: 29 CFR 1926.417 (lockout and tagging of circuits); qualified person requirement 1926.416(a)Report a problem with this question
17. Which statement BEST describes a 'competent person' as OSHA uses the term in construction?
- A.Anyone the employer assigns to perform a specific duty at a specific location
- B.Someone capable of identifying existing and predictable hazards AND who has authorization to take prompt corrective measures to eliminate them✓ Answer
- C.Someone who holds a recognized degree, certificate, or professional standing and can solve problems relating to the work
- D.Any worker who has completed an OSHA 10-hour or 30-hour Outreach course
The defining feature of a competent person is the combination of hazard recognition AND the authority to stop the work or correct the condition immediately — recognition alone is not enough. A qualified person is defined instead by a recognized degree, certificate, or extensive knowledge and demonstrated ability to solve problems in the subject matter, and an authorized person is simply someone assigned by the employer to a specific duty. Completing an Outreach 10- or 30-hour course is voluntary awareness training and by itself makes no one a competent person.
Source: 29 CFR 1926.32(f) (competent person) and 1926.32(m) (qualified person)Report a problem with this question
18. A contractor brings a hazardous chemical onto the jobsite. Under the Hazard Communication standard, where must the Safety Data Sheet (SDS) for that chemical be kept?
- A.Submitted to OSHA before the chemical is brought on site
- B.Readily accessible to employees in their work area during each work shift✓ Answer
- C.Only with the chemical's manufacturer or supplier
- D.On file at the company's main office, available on request within 30 days
SDSs must be readily accessible to employees in their work area during each work shift, because the information is only useful if a worker or a responder can reach it within seconds during a spill, exposure, or fire. Every SDS follows the same 16-section GHS format so that first-aid (Section 4), fire-fighting (Section 5), and exposure controls/PPE (Section 8) are always in the same place, and container labels must carry the 6 required elements: product identifier, signal word, hazard statement, pictogram, precautionary statement, and supplier information.
Source: 29 CFR 1926.59, which adopts 29 CFR 1910.1200(g)(8) and 1910.1200(f)Report a problem with this question
19. According to the hierarchy of controls, which approach to a jobsite hazard is the MOST effective?
- A.Rotating workers through the task so no one exceeds the exposure limit
- B.Posting warning signs and barricade tape around the hazard area
- C.Eliminating the hazard, or substituting a less hazardous material or process✓ Answer
- D.Issuing respirators, hard hats, and other personal protective equipment to exposed workers
Elimination and substitution sit at the top of the hierarchy because they remove the hazard at its source, so protection does not depend on any worker doing the right thing on any given day. Engineering controls come next, then administrative and work-practice controls such as rotation and signage, and PPE is LAST — it does nothing to reduce the hazard itself, and it fails silently when it is the wrong type, poorly fitted, damaged, or simply not worn.
Source: OSHA Recommended Practices for Safety and Health Programs, Hazard Prevention and Control (hierarchy of controls); PPE requirements at 29 CFR 1926 Subpart EReport a problem with this question
20. What is OSHA's permissible exposure limit (PEL) for respirable crystalline silica in construction, as an 8-hour time-weighted average?
- A.50 micrograms per cubic meter of air✓ Answer
- B.25 micrograms per cubic meter of air
- C.100 micrograms per cubic meter of air
- D.0.1 fiber per cubic centimeter of air
The construction PEL for respirable crystalline silica is 50 micrograms per cubic meter as an 8-hour TWA; 25 micrograms per cubic meter is the action level that triggers exposure assessment and periodic monitoring, and 0.1 fiber per cubic centimeter is the asbestos PEL. Silica dust from cutting, grinding, and drilling concrete or masonry causes silicosis, which is incurable and irreversible, so the standard requires water delivery or dust-collection controls (Table 1), a written exposure control plan with a designated competent person, and prohibits dry sweeping or compressed-air cleaning where a feasible alternative exists.
Source: 29 CFR 1926.1153(c) and (d); Table 1 specified exposure control methodsReport a problem with this question
Practice questions based on the OSHA Outreach standards (29 CFR 1926 / 1910). Not affiliated with OSHA and not a substitute for the official course or the DOL card. About OSHA training →