Fall protection

When arresting a fall, a full-body harness spreads the force through the thighs, pelvis and shoulders and keeps the body upright. A belt concentrates force on the abdomen and spine, so under codes such as ANSI/ASSP Z359 it is used only for positioning or restraint, not fall arrest. The arrest attachment is normally the dorsal D-ring.

Required clearance is the lanyard length plus shock absorber deployment, the worker's height to the D-ring, harness stretch and a safety margin. For a 1.8 m lanyard anchored at shoulder level this often comes to roughly 5 to 6 m below the anchor. If there is not enough clearance, use a self-retracting lifeline or switch to a restraint system.

Under OSHA rules, a fall arrest anchorage must support 22.2 kN (5,000 lbf) per person, or be designed with a safety factor of at least two under the supervision of a qualified person. Pipes, guardrails and cable trays usually do not meet this. Anchor above the D-ring where possible to reduce free fall and swing.

The user inspects visually before every use: stitching, webbing, buckles, hooks and the shock absorber indicator. A competent person should also inspect periodically as the manufacturer recommends, typically at least every 12 months. Any equipment that has arrested a fall must be removed from service immediately.

A worker suspended in a harness can suffer blood pooling in the legs and lose consciousness quickly, so a rescue plan must be in place before work at height begins. Do not rely only on calling outside emergency services. Suspension relief straps extend tolerance time but do not replace a rescue plan.

It is needed. A worker suspended in a harness after a fall can suffer suspension trauma if not rescued promptly, often within a few tens of minutes. The rescue plan should name the equipment, the people and the access method before work starts, rather than relying on calling the fire service.

The back D-ring should sit between the shoulder blades, leg straps should be tight enough to fit only a flat hand underneath, and the chest strap should sit across mid-chest. Loose straps can let the wearer slip out or cause injury when the fall is arrested. Choose the harness within the manufacturer's size range and readjust whenever layers of clothing are added or removed.

A self-retracting lifeline keeps the line taut and locks within a short distance during a fall, so it needs less clearance below. A shock-absorbing lanyard has a fixed length and must deploy its energy absorber to stop the fall. Some self-retracting lifelines are rated only for overhead anchorage, with separate models for foot-level anchorage or sharp edges.