The Complete Guide to ANSI/ASSP Z359 Certified Height Safety Equipment

Z359.11 specifies the design and performance requirements for harnesses meant to distribute fall forces across the body – specifically the shoulders, chest, pelvis and thighs. A compliant harness must feature a Visual Impact Indicator (often a folded stitch or tag) that deploys when a fall occurs, signaling the unit must be removed from service.

Used for fall arrest, positioning, travel restraint, suspension and/or rescue applications, full body harnesses are designed for users within the capacity range of 130 – 310 lbs.

Z359.3 governs equipment used for work positioning and travel restraint. Unlike fall arrest gear, these lanyards are “static” and do not include shock absorbers. As these lanyards cannot dissipate energy, the standard strictly limits their use to applications where a potential free fall is less than 2 feet. All hardware and webbing in this standard must meet a minimum static strength of 5,000 lbs.

Z359.13 is the standard for “shock absorbing” lanyards used in fall arrest. It mandates that the Maximum Arresting Force (MAF) remains below 1,800 lbs, protecting the user from internal injury. There are two classifications of energy absorbers:

EZ359.12 sets the safety requirements for connectors including carabiners, snap hooks and other attachment hardware used in fall protection systems. The most rigorous part of this standard is the Gate Strength requirement. While the body of the connector must hold 5,000 lbs, the gate (the moving part) must be able to withstand a 3,600 lb load from the front and the side. This is a significantly higher safety threshold than many international standards and is designed to prevent "roll-out," where the connector accidentally forced open during a fall.

Z359.9 is the standard for devices used for controlled descent or evacuation. It covers both Manual (lever-operated) and Automatic (centrifugal brake) units. A key safety requirement is the "Dead-man’s handle" or "Panic-lock", if the user pulls the handle too hard or lets go entirely, the device must automatically stop the descent. These are tested for multiple descents to ensure the friction heat doesn't degrade the rope or the internal braking mechanism.

Z359.15 addresses the combination of vertical lifelines (ropes) and fall arresters (rope grabs). A standout requirement is the "Panic Test." The device must be designed so that if a worker instinctively "death grips" the rope grab during a fall, the device still locks onto the rope rather than sliding down. It also ensures the rope and the grab are tested as a matched system to ensure the teeth of the grab provide the correct "bite" on the specific rope diameter.

Z359.14 covers self-retracting devices (SRDs) and categorizes devices into:

Class 2 devices are subjected to rigorous testing over a 0.005-inch radius steel edge to ensure the lifeline can withstand being pulled over a sharp, abrasive corner without snapping. As these falls involve greater free-fall distances, Class 2 devices must also include an integrated or external shock absorber to keep arrest forces within safe limits.