What this lesson covers
Falls are among the leading causes of death in construction, and fall protection (OSHA 29 CFR 1926 Subpart M) is one of the most heavily tested topics in the hazards domain, which is 36.6% of the CHST blueprint. The exam is closed book, so you need the triggers and numbers in your head. This lesson gives you a three-step habit for every fall question: trigger, system, check.
We cite OSHA sections by number and use our own wording. Your reference for the full text is the current 29 CFR 1926.
Step 1: the trigger
The general construction rule is that fall protection is required when a worker is exposed to a fall of 6 feet or more to a lower level (1926.501(b)(1)). Fall protection always means one of the listed systems; a flag or a verbal warning is not one.
| Situation | Rule | Where |
|---|---|---|
| Unprotected side or edge | 6 feet or more | 1926.501(b)(1) |
| Leading edge | 6 feet or more; use a system, or a plan where a system is infeasible | 1926.501(b)(2) |
| Holes, including skylights | Protect at any height | 1926.501(b)(4) |
| Roofing | 6 feet or more, with set choices by roof type and slope | 1926.501(b)(10), (b)(13) |
| Steel erection | 15 feet, with extra rules for connectors | 1926.760 |
| Ladders | Ladder or stairway where there is a break of 19 inches or more | 1926.1051 |
Two points trip people up. First, construction uses 6 feet while general industry uses 4 feet, so the setting decides the number. Second, the trigger is measured to the lower level, and a hole needs protection even if it is only a few feet deep, because a worker can fall through it.
Step 2: choose the system
Guardrails, covers and toeboards
A guardrail system protects every worker who passes by. The top rail sits about 42 inches above the walking surface, plus or minus 3 inches, with a midrail about halfway down. The top rail must withstand a heavy outward push and the system is free of snag points (1926.502(b)). A toeboard is at least 3.5 inches high and stops tools and debris from rolling off an edge (1926.502(j)). A hole cover supports at least twice the weight of the people, equipment and materials that may cross it, is secured, and is marked as a cover (1926.502(i)).
Safety nets and warning lines
Nets are placed as close under the work as practical and not more than 30 feet below it (1926.502(c)). A warning line, set 6 feet back from a roof edge and about 34 to 39 inches high, is allowed for low-slope roofing, usually with a safety monitor or other system near the edge. A warning line alone does not stop a fall.
Personal fall arrest systems
A personal fall arrest system (PFAS) has three parts: an anchorage, a body harness and a connector. It stops a fall that has already begun, so it must limit the forces:
- Maximum arresting force on the worker: 1,800 pounds with a harness (1926.502(d)(16)).
- Free fall limited to 6 feet.
- Anchorage strength of 5,000 pounds for each worker attached, or a design by a qualified person with a safety factor of at least two (1926.502(d)(15)).
Inspect the system before each use (1926.502(d)(21)). If it has stopped a fall, take it out of service until a competent person inspects it and finds it undamaged (1926.502(d)(19)). A harness stops a fall, but it leaves a worker hanging, so the employer must provide for prompt rescue or ensure workers can rescue themselves (1926.502(d)(20)).
Which system fits
| Work | Better choice | Why |
|---|---|---|
| Open floor edge used by many trades | Guardrail system | Protects everyone, no inspection by the user |
| A single worker on a short task at a roof edge | PFAS, or a monitor on a low-slope roof | Guardrails may be impractical |
| Work over a large open area that cannot be railed | Safety net | Catches without a tie-off |
| Hole in a deck | Cover or guardrail | A harness is unnecessary here |
The hierarchy of controls still applies: where you can, eliminate the exposure (build sections on the ground) or engineer the hazard out with a guardrail before choosing a personal system, which depends on every worker using it correctly.
Step 3: check
A competent person inspects the systems and the work area. Workers who might be exposed are trained by a competent person on the fall hazards, how to use the systems and how to recognize falling object hazards, and a written certification is kept (1926.503). Retrain when the employer has reason to believe a worker lacks the understanding or skill, or when the work or equipment changes (1926.503(c)).
Do not forget what falls from above. Toeboards, screens, canopies or barricades protect people below, and hard hats are worn where overhead hazards exist.
Worked scenarios
Scenario 1. A crew works on a floor of a building under construction. The slab edge has no protection and the drop is 9 feet. The drop is above the 6-foot trigger, so the system must be installed before work continues. Best answer: a guardrail system, because several trades use the floor. A harness would protect only the person wearing it.
Scenario 2. A worker on a ladder wants to tie off to the top rail of a guardrail to "be safe". Guardrails are not designed as anchorages, so this connection is not acceptable. The anchor needs 5,000 pounds per worker or a qualified person's design. This is also a retraining signal.
Scenario 3. A skylight sits in the middle of a roof where 3 workers are laying insulation, and the roof edge is guarded. The skylight is a hole at any height, so it needs a cover or a guardrail. A warning line does not satisfy the hole rule.
Check yourself
Try the five questions in the free practice set for this lesson. The same three-step habit works on each one.
Where to look in the regulations
- 29 CFR 1926 Subpart M: 1926.500, 1926.501, 1926.502 and 1926.503
- 29 CFR 1926 Subpart X: 1926.1051 to 1926.1053
- 29 CFR 1926.760 for steel erection