Fall Protection Calculator

A fall restraint system stops a worker from ever reaching the edge, so a fall cannot happen. A fall arrest system catches a worker after a fall has already begun, before they hit a lower level. OSHA recognizes both systems but prefers restraint when feasible because it sits higher in the hierarchy of controls. Restraint also eliminates the need for the rescue plan, fall-clearance calculation, and swing-fall analysis required for arrest. (29 CFR 1910.140, 29 CFR 1926.502, OSHA Standard Interpretation 1995-11-02.)

Total fall clearance equals Free Fall Distance plus Deceleration Distance plus Harness Stretch plus D-Ring Slide-Up plus Safety Factor. If you are using a horizontal lifeline, add HLL deflection. A typical 6-ft shock-absorbing lanyard at D-ring height requires about 13.5 ft of clearance below the anchor. A leading-edge SRL with a foot-level anchor needs more. Use Tab 2 of the calculator above to run your specific numbers.

For fall arrest, anchors must support 5,000 lb per attached worker, or be designed and installed under the supervision of a Qualified Person with a safety factor of at least 2 (29 CFR 1926.502(d)(15)). For fall restraint, anchors must support 3,000 lb or twice the maximum expected restraint force, whichever is greater (OSHA Standard Interpretation 1995-11-02).

Yes. 29 CFR 1926.502(d)(20) requires that the employer provide for the prompt rescue of employees in the event of a fall, or that the employees be able to rescue themselves. ANSI Z359.2 calls for a written, practiced plan with a designated rescuer, staged equipment, and documented training. "Call 911" is not a rescue plan. Suspension trauma can incapacitate a suspended worker in 5 to 15 minutes. Trauma straps and relevant training are recommended for all workers at height.

A horizontal lifeline is the right call when a worker needs to move horizontally along an edge or span. The HLL keeps the connection point near-vertical as the worker moves, which significantly reduces the risk of swing falls that a single anchor cannot manage. HLLs are governed by ANSI Z359.6 and require deflection to be added to the fall clearance calculation. The line itself stretches under full load.

The industry-conservative planning rule per ANSI Z359.6 is 1 ft of peak deflection per 5 ft of span (20% of the span length). Actual deflection varies by rope or wire material, span length, number of users, line pre-tension, and manufacturer design. For the most accurate calculation, locate the deflection chart in your HLL manufacturer's user manual. It is usually labeled "Deflection Chart," "Sag Chart," or "Fall Clearance Chart" and is published next to the installation diagram or alongside the inspection log.

No. Self-retracting lifelines pay out as the worker moves and cannot reliably prevent access to an edge. SRLs are arrest devices only. Fall restraint requires a fixed-length, non-shock-absorbing lanyard sized so that the worker cannot physically reach the fall hazard.

When using a single-point anchor, the worker should stay within a roughly 30-degree cone measured from directly below the anchor. Beyond that, a fall causes the worker to swing laterally toward the anchor like a pendulum. Swing-fall pendulum velocity can exceed 20 mph, causing catastrophic injury when the worker strikes a structure. Either reposition the anchor or install a horizontal lifeline.

Use a non-penetrating seam clamp that mechanically grips the standing seam. The SSRA1 from Fall Protection Distributors fits more than 95% of 22- and 24-gauge steel standing-seam profiles and is rated for both restraint and arrest applications. Penetrating the roof voids most manufacturer warranties and creates hidden leaks. Always verify your seam profile against the compatibility chart before purchase.

EN 795 and ANSI Z359 classify anchors by type. Type A is a fixed, permanent anchor installed in the structure. Type B is transportable temporary (parapet anchors, beam clamps, deadweight anchors). Type C is a flexible horizontal anchor line (rope or webbing HLL). Type D is a rigid horizontal rail. Type E is a deadweight or counterweight anchor. The Frontline HLK1004 Horizontal Lifeline is a Type C anchor.

In construction (29 CFR 1926.501), fall protection is required at any walking-working surface with an unprotected side or edge that is 6 feet or more above a lower level. In general industry (29 CFR 1910.28), the trigger height is 4 feet. Steel erection has its own threshold of 15 feet under 29 CFR 1926.760. Always verify the applicable trigger height for your specific work category.

29 CFR 1926.502(d)(16)(iii) caps maximum arresting force at 1,800 lb when used with a full body harness. ANSI Z359.7 caps the average arresting force across the event at roughly 900 lb. The 1,800 lb figure is the absolute peak that the harness and human body can tolerate without serious injury. Body belts have been prohibited for fall arrest since 1998 because they concentrate that force on the abdomen.

Yes, if the anchor is rated for arrest loads. An arrest-rated anchor (5,000 lb per worker, or engineered with a safety factor of 2) automatically exceeds the restraint requirement (3,000 lb or 2 times the expected force). The reverse is not true. A restraint-only anchor cannot be casually upgraded to arrest service without engineering review.

The user must inspect their own equipment before every shift, looking for cuts, burns, frays, deformation, corrosion, missing labels, and proper function of buckles and hardware. A Competent Person other than the user must conduct a documented, thorough inspection at least every 6 months per ANSI Z359.2. Any equipment that arrests a fall is permanently removed from service immediately. Inspection forms can be downloaded from our Fall Protection Resources Page. 

Most manufacturers specify a 10-year service life from the date of manufacture, subject to inspection results. UV exposure, chemical contact, abrasion, and storage conditions can shorten this. A harness involved in a fall arrest event is permanently retired regardless of age. Inspect every harness before each use and document any damage or wear that requires removal from service.