Slips, Trips, and Falls

Physics-based training on Tribology (friction science), ANSI A1264.1 stair geometry, and Fall Arrest Systems (PFAS). Reduces the #1 cause of general liability claims and lost workdays.

To prevent falls, we must understand the science of Tribology—the study of friction, lubrication, and wear. A slip occurs when the Required Coefficient of Friction (RCOF) (the friction needed to keep your foot planted during a stride) exceeds the Available Coefficient of Friction (ACOF) (the actual friction provided by the floor/shoe interface).
The Gait Cycle:
1. Heel Strike: The most dangerous moment. Your heel hits the floor at an angle, creating a forward force. If the floor is slippery, your heel slides forward (the "Slip").
2. Mid-Stance: Your weight is fully over the foot. The risk here is low unless the surface collapses.
3. Toe-Off: You push off to step forward. If friction is low, your foot slips backward.
Most slips occur at Heel Strike. Factors like stride length, walking speed, and load carrying all increase the RCOF. The "Platinum" standard is to reduce the RCOF by adopting a "Safety Walk"—shorter strides, slower pace, and keeping the center of gravity directly over the feet.

Key Takeaways:
  • Most slips occur at "Heel Strike" when the forward force exceeds available friction.
  • Shortening your stride reduces the required friction (RCOF), making a slip less likely.

The Static Coefficient of Friction (SCOF) is the force required to start an object moving. The Dynamic Coefficient of Friction (DCOF) is the force required to keep it moving. For decades, a SCOF of 0.5 was the OSHA guideline for a safe walkway. However, the 2026 ANSI/NFSI B101.3 standard focuses on DCOF, requiring a minimum of 0.42 for wet, level floors.
Surface Roughness: Micro-roughness (measured in micrometers) creates the "teeth" that grip the shoe sole. Over time, aggressive cleaning pads or high traffic can "polish" a floor, reducing its DCOF below safe levels.
The Hydrodynamic Squeeze Film: When a liquid (water, oil) gets trapped between the shoe and floor, it prevents contact. If the shoe tread cannot channel this liquid away (like a car tire hydroplaning), friction drops to near zero. This is why smooth-soled shoes are lethal on wet floors.

Key Takeaways:
  • A DCOF of 0.42 is the modern safety standard for wet, level floors.
  • "Polishing" from foot traffic can dangerously lower a floor's slip resistance over time.

OSHA requires employers to protect employees from fall hazards using the Hierarchy of Controls. This is a prioritized list of strategies:
1. Elimination (Most Effective): Removing the hazard entirely. (e.g., Moving a high storage shelf to ground level so ladders aren't needed).
2. Substitution: Replacing the hazard. (e.g., Replacing a slippery tile floor with high-traction rubber matting).
3. Engineering Controls: Isolating people from the hazard. (e.g., Installing guardrails, handrails, or covers over floor holes).
4. Administrative Controls: Changing the way people work. (e.g., Implementing a "Clean-as-you-go" policy, requiring "Wet Floor" signs).
5. PPE (Least Effective): Protective equipment. (e.g., Slip-resistant footwear, fall arrest harnesses).
You must always attempt the higher-level controls first. Relying solely on "Watch your step" (Administrative) or "Wear better shoes" (PPE) is a failure of safety management.

Key Takeaways:
  • Elimination (removing the hazard) is the most effective control.
  • PPE (shoes/harnesses) is the last line of defense, used only when other controls fail.

29 CFR 1910 Subpart D governs all general industry walking-working surfaces. The employer must ensure:
1. Surface Conditions: All places of employment must be kept clean, orderly, and sanitary. Workroom floors must be maintained in a clean and, to the extent feasible, dry condition.
2. Load Ratings: Employees must not exceed the load rating of any floor or roof.
3. Access and Egress: Safe means of access and egress must be provided and maintained.
4. Inspection: Walking-working surfaces must be inspected regularly and as necessary. If a hazard is identified, it must be corrected or repaired before an employee uses the surface again. If repair cannot be made immediately, the hazard must be guarded or barricaded.
This standard eliminates the "We'll get to it later" excuse. If a tile is loose or a carpet is torn, it is an immediate violation.

Key Takeaways:
  • Floors must be kept dry; if wet processes are used, drainage and dry standing places (mats) are required.
  • Identified hazards must be repaired immediately or guarded until repair is possible.

Poor housekeeping causes over 50% of trip accidents. The 2026 standard is "Continuous Housekeeping."
Trip Hazards:
- Cables/Cords: Must be taped down, run through bridges, or routed along walls.
- Debris: Pallet fragments, packing straps, and tools must be cleared immediately.
- Rug Bunching: Entry mats must have beveled edges and rubber backing to prevent curling or sliding.
Spill Containment:
- The 3-Zone Strategy: 1. Mark the hazard (Wet Floor Sign). 2. Isolate the hazard (Cones/Barricade). 3. Clean the hazard (Absorbents/Mop).
- Transition Zones: Areas where flooring changes (e.g., tile to carpet) are high-risk. Ensure the transition strip is flush (less than 1/4 inch vertical change) and visually distinct.

Key Takeaways:
  • Cords and cables are the #1 office trip hazard; use bridges or wall routing.
  • Mats must be flat and backed with rubber; curled edges are a major trip risk.

Stair safety relies on consistent geometry. ANSI A1264.1 dictates:
1. Uniformity: Riser height and tread depth must be uniform within a flight of stairs. A variation of just 1/4 inch disrupts the brain's "proprioceptive map," leading to a trip.
2. Tread Depth: Must be sufficient to support the ball of the foot (typically min. 11 inches).
3. Nosings: The leading edge of the stair tread (nosing) should be distinguishable (e.g., yellow high-contrast tape) and non-slip.
4. Handrails: Must be provided on both sides if possible, capable of withstanding 200 lbs of force. The "Power Grip" (wrapping fingers fully around the rail) is required, not just a "Pinch Grip."
Ramps: Slope should not exceed 1:12 (4.8 degrees). Ramps require significantly higher friction surfaces than level floors.

Key Takeaways:
  • Stair riser height must not vary by more than 1/4 inch.
  • Use the "Power Grip" on handrails; touch-contact is not enough to arrest a fall.

Ladders are tools, not workspaces.
The 4:1 Rule: For every 4 feet of height, the base of the extension ladder should be 1 foot away from the wall. (e.g., A 20ft ladder needs a 5ft base). This ensures the optimal 75.5-degree angle.
The 3 Points of Contact Rule: At all times, you must have either two hands and one foot, or two feet and one hand, in contact with the ladder.
- The "Belt Buckle" Rule: Keep your belt buckle (center of gravity) between the side rails. Leaning out ("Overreaching") shifts your COG outside the base of support, causing the ladder to tip sideways.
- Tie-Off: Whenever possible, secure the top of the ladder to the structure to prevent sliding.
- Extension: The ladder must extend 3 feet above the landing surface to provide a handhold for transition.

[Image illustrating the 4-to-1 rule for ladder placement]
Key Takeaways:
  • Extension ladders must be set at a 4:1 ratio (75 degrees).
  • The ladder must extend 3 feet past the roofline for safe access/egress.

Illumination: ANSI standards recommend minimum lighting levels (measured in foot-candles or lux) for different areas: 5 fc for hallways, 10 fc for stairs, 50 fc for detailed work.
Shadows and Glare: Shadows can hide obstacles; glare can blind a worker to a change in elevation. Lighting must be diffuse and uniform.
Visual Contrast: The human eye detects hazards by contrast.
- Curb Cuts: Must be painted yellow to distinguish the slope from the flat road.
- Step Edges: Must have high-contrast stripping.
- Floor Openings: Must be guarded or covered with a cover marked "HOLE" or "COVER" in high-visibility paint.
In 2026, "Photoluminescent" (Glow-in-the-dark) markings on stair nosings and handrails are standard for emergency egress.

Key Takeaways:
  • Minimum lighting levels (5-10 foot-candles) are required for walkways and stairs.
  • High-contrast markings (yellow) are essential for identifying changes in elevation.

Footwear is a critical component of the friction equation.
Tread Pattern: The pattern must be designed for the specific contaminant.
- Water/Liquid: Requires wide channels ("sipes") to evacuate liquid and prevent hydroplaning.
- Grease/Oil: Requires a tighter, more geometric pattern to bite through the film.
- Outdoor/Mud: Requires deep lugs (cleats) for soft-surface traction.
Material: The outsole rubber must be compatible. "Oil-Resistant" soles won't dissolve in petroleum products.
Wear Indicator: Inspect the tread weekly. Once the tread depth is worn down (smooth spots), the shoe has lost 90% of its wet-traction capability. Employers should mandate "Slip-Resistant" (SR) rated footwear for hospitality and industrial roles.

Key Takeaways:
  • Shoe tread acts like a car tire; it must channel liquid away to maintain contact.
  • Smooth soles on wet floors create a "hydrodynamic film" with near-zero friction.

In General Industry (1910), OSHA requires fall protection for any worker exposed to a fall of 4 feet or more to a lower level. (Note: Construction is 6 feet).
The 3 Options:
1. Guardrails: Top rail at 42 inches (+/- 3 inches), Midrail at 21 inches, Toe-board to prevent falling objects. Must withstand 200 lbs of force.
2. Safety Nets: Installed beneath the work area.
3. Personal Fall Arrest System (PFAS): A harness, lanyard, and anchor point.
Holes: Any floor hole (including skylights) into which a person can accidentally walk must be guarded by a standard railing and toe-board or a floor hole cover.

Key Takeaways:
  • General Industry trigger height is 4 feet. (Construction is 6 feet).
  • Guardrails must have a top rail, midrail, and toe-board.

When using a PFAS, you must understand the ABCD components:
A - Anchorage: The secure point of attachment. It must be capable of supporting 5,000 lbs per worker attached. (Never anchor to a conduit or PVC pipe).
B - Body Wear: The Full Body Harness. Body belts are prohibited for fall arrest as they cause internal organ damage. The D-ring must be located in the center of the back between the shoulder blades.
C - Connector: The device linking the harness to the anchor (Lanyard or Self-Retracting Lifeline). It must have double-locking snap hooks.
D - Deceleration Device: The shock absorber. It limits the arresting force on the body to under 1,800 lbs.
Rescue Plan: You must have a plan to rescue a suspended worker within 15 minutes to prevent "Suspension Trauma" (blood pooling in legs leading to cardiac arrest).

Key Takeaways:
  • Anchors must support 5,000 lbs per person.
  • Suspension trauma can kill in under 30 minutes; a rapid rescue plan is mandatory.

Even with the best equipment, falls happen due to human error.
Psychological Factors:
- "Hurry Sickness": Rushing increases gait speed, reducing friction and attention.
- Distraction: Texting while walking ("Distracted Walking") creates "Inattentional Blindness" to hazards.
- Fatigue: Reduces reaction time and core stability.
Cultural Safety: We must move from "Compliance" to "Commitment." A Platinum safety culture encourages reporting near-misses. "I almost slipped there" is a gift—it tells you where the next accident will happen. Fix the rug, dry the floor, change the lightbulb. Safety is active, not passive.

Key Takeaways:
  • "Hurry Sickness" and Distraction are the leading behavioral causes of falls.
  • Report every near-miss to identify and fix latent hazards before they cause injury.
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