学习材料

Weight: 20% of the exam

Why This Chapter Matters

Falls are the number-one cause of death in construction — roughly a third to 40% of all fatalities, and consistently the most-cited OSHA standard year after year. If you master one hazard completely, make it this one. This chapter covers when fall protection is required, the three conventional systems and their exact specifications, the personal fall arrest system (PFAS) in detail, and the two everyday sources of falls that kill and injure the most workers: scaffolds and ladders. The numbers here — 6 feet, 10 feet, 42 inches, 200 pounds, 1,800 pounds, 5,000 pounds — are prime exam material. Learn them cold.

When Fall Protection Is Required (Subpart M)

The core fall-protection rules for construction live in 29 CFR Part 1926 Subpart M (1926.500–503).

### Key Standard — The 6-Foot Rule 29 CFR 1926.501(b)(1): Each employee on a walking/working surface with an unprotected side or edge that is 6 feet or more above a lower level must be protected by a guardrail system, safety net system, or personal fall arrest system.

6 feet is the general construction trigger. But watch out — different settings use different numbers:

Setting	Fall Protection Trigger	Standard
Construction (general)	6 feet	1926.501(b)(1)
Scaffolds	10 feet	1926.451(g)(1)
Steel erection	15 feet (with exceptions)	Subpart R (1926.760)
General Industry (for comparison)	4 feet	1910.28

Subpart M also protects specific fall points regardless of the "quick job" excuse:

• Holes (including skylights): protected by covers, guardrails, or PFAS (1926.501(b)(4)). A cover must support at least twice the maximum expected load, be secured, and be marked ("HOLE" or "COVER").
• Leading edges, hoist areas, ramps and runways, and work above dangerous equipment — each has its own provision in 1926.501.
• Wall openings 6 feet or more above a lower level where the bottom edge is less than 39 inches above the walking surface must be guarded.
• Roofing work on low-slope roofs may use a combination of a warning line and a safety monitoring system, or a controlled access zone, under specific conditions.

The employer must also determine that surfaces can support workers before work begins (1926.501(a)(2)). Where conventional systems are infeasible or create a greater hazard, a written, site-specific fall protection plan is allowed under 1926.502(k) — but this is a narrow exception, prepared by a qualified person, not a routine way to skip protection.

Steel Erection (Subpart R)

Steel erection has its own fall-protection rules under 29 CFR Part 1926 Subpart R (1926.750–761) because ironworkers move along beams where guardrails are impractical. The general fall-protection trigger for steel erection is 15 feet (not 6), reflecting the realities of connecting steel, though connectors and workers in a controlled decking zone (CDZ) have specific provisions. Within a CDZ, decking is installed under controlled conditions with trained workers, and access is limited. Even so, steel erectors typically wear a full-body harness and tie off wherever feasible, and perimeter safety cables are installed on multi-story structures. Do not confuse the steel-erection 15-foot trigger with the general 6-foot rule — the exam tests this.

Roofing and Low-Slope Roofs

On low-slope roofs, workers near the edge may be protected by conventional systems or by a combination of a warning line set back from the edge plus a safety monitoring system, or by a controlled access zone. A safety monitor is a competent person who watches workers and warns them when they get too close to the edge — but the monitor must have no other duties that distract from monitoring. On steep roofs, conventional fall protection (guardrails, nets, or PFAS) is generally required.

The Three Conventional Fall Protection Systems

29 CFR 1926.502 sets the exact criteria for each system. The specifications are heavily tested.

1. Guardrail Systems (1926.502(b))

A passive system — once installed, it protects everyone without any action on their part, which is why it is often preferred.

### Key Standard — Guardrail Specs - Top rail height: 42 inches, plus or minus 3 inches (so 39–45 in) above the walking surface. - Must withstand at least 200 pounds of force applied outward or downward within 2 inches of the top edge, without dropping below 39 inches. - Midrail required midway between the top rail and the surface when there is no wall at least 21 inches high; midrails withstand at least 150 pounds. - Surfaces must be smooth to prevent cuts and snagged clothing; ends must not overhang unless they pose no hazard.

2. Safety Net Systems (1926.502(c))

Used where guardrails are impractical, such as bridge and steel work.

### Key Standard — Safety Net Specs - Installed as close as practicable under the surface but never more than 30 feet below it. - Must extend outward a required horizontal distance from the edge (the higher the fall, the farther out). - Must pass a drop test (a 400-pound bag dropped from the height) or be certified. - Mesh openings may not exceed 36 square inches nor be longer than 6 inches on any side.

3. Personal Fall Arrest Systems (1926.502(d))

An active system that stops a worker after a fall begins. Covered in detail in the next section.

Two additional recognized tools: positioning device systems (hold a worker in place on a vertical surface, such as rebar or a wall — limited to a 2-foot free fall), and warning-line / controlled-access-zone / safety-monitoring systems for specific tasks like low-slope roofing.

Personal Fall Arrest Systems (PFAS) in Detail

A PFAS is the system workers wear when guardrails and nets are not used. Remember its three parts as the ABC:

• A — Anchorage: the secure attachment point.
• B — Body support: a full-body harness (never a body belt).
• C — Connectors: the lanyard, snap hooks, and any deceleration device or self-retracting lifeline (SRL) that tie the harness to the anchor.

### Key Standard — PFAS Numbers (memorize) Under 29 CFR 1926.502(d): - Anchorage strength: at least 5,000 pounds per attached worker, or designed with a safety factor of at least two under a qualified person's supervision. (1926.502(d)(15)) - Maximum arresting force: limited to 1,800 pounds when using a full-body harness. (1926.502(d)(16)(ii)) - Free fall: the worker may not free-fall more than 6 feet, nor contact any lower level. (1926.502(d)(16)(iii)) - Deceleration distance: limited to 3.5 feet. (1926.502(d)(16)(iv)) - Body belts are PROHIBITED for fall arrest — not acceptable since January 1, 1998. Only a full-body harness is allowed.

Why no body belts? A belt concentrates the arresting force on the abdomen and can cause fatal internal injuries — or let the worker slip out entirely head-first. A full-body harness distributes the force across the thighs, pelvis, chest, and shoulders.

Calculating Fall Clearance

A falling body needs room to stop. Before you clip in, calculate total fall clearance below the anchor:

Lanyard length + Deceleration distance + Height of the worker (D-ring to feet) + Safety margin (usually 2–3 ft).

Example: a 6-foot lanyard + up to 3.5 feet of deceleration + roughly 5 feet of worker height + a 2-3 foot safety factor can easily require 18 feet or more of clearance below the anchor. Anchor low, and a worker using a 6-foot shock-absorbing lanyard can hit the ground before the system fully engages. This miscalculation is a common fatal error. Whenever possible, anchor at or above the D-ring and use a self-retracting lifeline to minimize free fall.

Inspection and Rescue

• Inspect before every use: check webbing for cuts, burns, fraying, and chemical damage; check hardware for corrosion, deformation, and proper snap-hook function (self-locking snap hooks only).
• Remove from service immediately any system that has arrested a fall.
• Plan for prompt rescue. A worker left hanging in a harness can suffer suspension trauma within minutes as blood pools in the legs. The employer must have a rescue plan — you cannot simply leave someone hanging until the fire department arrives.

Prompt Rescue Planning

OSHA requires the employer to provide for prompt rescue of a fallen worker or to ensure workers can rescue themselves (1926.502(d)(20)). A workable fall-rescue plan answers three questions before work starts: How will we know a fall happened (line of sight, radio, buddy system)? How will we reach the suspended worker (aerial lift, pre-rigged rescue system, ladder)? How fast can we act (minutes matter because of suspension trauma)? Options range from self-rescue devices the worker deploys, to a controlled-descent rescue kit, to using an aerial lift to reach and lower the worker. "Call 911 and wait" is not an adequate plan on its own — by the time an outside team arrives, a suspended worker may already be in danger. Suspension-trauma relief straps that let a hanging worker stand and restore leg circulation are a low-cost addition to a harness.

Scaffold Safety (Subpart L)

Scaffolds let workers reach heights safely — but only when built and used correctly. Scaffold incidents injure thousands of workers a year. Scaffolds are governed by 29 CFR Part 1926 Subpart L (1926.450–454).

### Key Standard — Scaffold Essentials - Fall protection required above 10 feet (1926.451(g)(1)): guardrails, PFAS, or both, depending on scaffold type. - Capacity: every scaffold and component must support its own weight plus at least 4 times the maximum intended load (1926.451(a)(1)). - Competent person must supervise erection, moving, altering, dismantling and must inspect before each work shift and after any event affecting integrity (1926.451(f)(3)). - Platforms fully planked/decked; gaps generally no more than 1 inch around uprights (1926.451(b)). - Guardrail top rail on supported scaffolds built after Jan 2000: 38 to 45 inches (1926.451(g)(4)). - Keep scaffolds at least 10 feet from energized power lines (for lines up to 300 V it is 3 ft; 10 ft for 300 V–50 kV). - Training by a qualified person required (1926.454).

Access: workers must use a ladder, stair tower, or equivalent to reach the platform. Never climb the cross-braces (1926.451(e)). Supported scaffolds must sit on base plates and mud sills on firm footing, be plumb and braced, and be tied to the structure when the height exceeds 4 times the minimum base width.

Tagging: A scaffold that is incomplete or defective must be tagged out of service (often a red tag) and not used until a competent person clears it. Some sites use green (safe), yellow (caution — extra precautions), and red (do not use) tags.

Scaffold Types

The exam may distinguish scaffold families:

• Supported scaffolds — platforms held up from below by rigid members (frame, tube-and-coupler, mobile). Most common. Must sit on firm footing with base plates and mud sills.
• Suspended scaffolds — platforms hung by ropes or cables from an overhead structure (swing stages used on high-rise facades). These require fall protection independent of the scaffold — workers tie off to a separate vertical lifeline anchored above, not to the scaffold, because the suspension system can fail.
• Mobile scaffolds (rolling towers) — must have locked casters before anyone climbs on, and workers must not ride a moving mobile scaffold unless specific conditions are met.

Aerial Lifts (1926.453)

Aerial lifts — boom lifts and bucket trucks — are governed by 29 CFR 1926.453. Workers in the basket must wear a full-body harness with a lanyard attached to the boom or basket (not to an adjacent pole or structure). Workers must stand on the floor of the basket, never climb on or lean over the rails, and the lift must be operated on a level, stable surface with outriggers set as required. Aerial lifts also concentrate power-line contact risk — maintain clearance as in Chapter 4. Scissor lifts are treated somewhat differently (as mobile scaffolds/work platforms) but the principle is the same: guardrails intact, no climbing on the rails, stable ground.

Ladder Types

• Stepladders — self-supporting; never stand on the top cap or top step, and always lock the spreaders fully open.
• Extension (straight) ladders — non-self-supporting; use the 4-to-1 angle, extend 3 feet above the landing, and secure the top or foot against slipping.
• Fixed ladders — permanently attached; longer fixed ladders require fall-protection provisions.
• Job-made ladders — must be built to the same strength and spacing requirements as manufactured ladders.