Rescue System Rigging and Lowering Device Operation

Why Rescue Rigging Matters

Wind turbine technicians work at heights where a co-worker can be incapacitated by a fall arrest impact, a medical emergency, or equipment failure. Emergency services rarely have the training or equipment to reach a stricken technician inside a tower in time. That means you — the technician on site — may be the only person who can perform a rescue. A correctly rigged lowering system gets an unconscious or injured person to the ground safely. An incorrectly rigged system can cause a second fatality. There is no margin for error.

The Global Wind Organisation (GWO) Working at Heights module and the GWO Basic Safety Training standard both require that technicians demonstrate rescue lowering competence before working at height. This lab puts that requirement into practice at a low-level training frame before you ever set foot in a nacelle.

The Rescue Kit: Know Every Component

A tower rescue kit typically contains the following components. You must know the name, rated capacity, and correct orientation of each before you touch the rigging.

Rescue line. A dedicated rope or kernmantle line rated for rescue use. Do not substitute a work-positioning lanyard. Check the manufacturer's label for rated load and whether the rope has been previously loaded in a fall — a shock-loaded rope must be retired.

Lowering device (descender). A friction-based device that controls the speed of descent under load. Common types include rack descenders and cam-assisted tube devices. The device must be oriented so the load hangs below the friction mechanism and the operator can smoothly pay out rope while maintaining braking force. If you release hand pressure, the device must stop or nearly stop the load — this is the fail-safe braking feature. Know your device: some require the rope threaded in a specific direction; loading it backwards eliminates braking.

Rescue pulley. Used to redirect the rope from the anchor to the lowering device when the geometry of the rescue requires it. Pulleys have a rated working load; confirm the pulley's rating covers the combined weight of the rescue load plus system forces.

Anchor slings. Pre-sewn textile slings or rated steel components used to connect the system to a structural anchor point. Inspect for cuts, abrasion, UV degradation, and heat damage before every use. A damaged sling must not be used.

Load-releasing hitch or device. A component that allows the rescuer to release tension from a loaded line in a controlled way — for example, to reposition the load or switch from a haul to a lower. Common examples include a Münter-mule combination or a purpose-built mechanical load-releasing device. Practice releasing it under a light load before every rescue evolution.

Trauma strap (rescue harness strap or pick-off strap). Used to attach the rescue manikin or a victim to the lowering line when the victim cannot attach themselves. Confirm it is rated for the load and correctly girth-hitched or buckled to the rescue line attachment point.

Rigging the Lowering System: Step by Step

Step 1 — Inspect the anchor. The anchor point must be a rated, fixed structural point. Visually confirm it is undamaged and that the connection hardware (carabiner or shackle) is the correct type, locked, and oriented so the load is applied along the strong axis.

Step 2 — Attach the anchor sling. Wrap or connect the sling to the anchor using the correct method for that sling type (basket, choker, or direct tie-in). Confirm the sling is not twisted and sits fully on the load-bearing surface.

Step 3 — Connect the lowering device to the anchor sling. Thread the rescue line through the lowering device according to the manufacturer's instructions. Orient the device so the braking side faces the load. Lock any retaining gates or covers.

Step 4 — Add a backup. Tie a stopper knot (overhand or figure-eight) in the rope below the lowering device, or rig a separate backup belay. The backup prevents the rope from running through the device and dropping the load if the operator loses control.

Step 5 — Attach the rescue load. Connect the trauma strap or rescue harness to the bottom of the rope system. Confirm the attachment carabiner is locked and loaded on the major axis.

Step 6 — Conduct a pre-load check. Have your rigging partner work through the rigging checklist before any weight is applied. Check every connection in order from anchor to load. Do not skip this step even if you are confident in your work.

Controlling the Descent

A controlled lowering means the load descends smoothly, without sudden acceleration. The operator feeds rope through the lowering device with the brake hand, never fully releasing grip. The non-brake hand steadies the device. If the load accelerates, close the brake hand fully; the device should arrest movement.

Communicate clearly with any ground crew before beginning the lower. Call out when you are starting descent and keep a steady pace. An uncontrolled drop — even a short one — can injure the victim further and may indicate a rigging error that needs immediate correction.

Safety Non-Negotiables

• Lockout/tagout (LOTO): Before any rescue evolution during actual operations, the turbine must be locked out. In this lab, follow all instructor-directed simulation protocols.
• PPE: Full fall-arrest harness, helmet, gloves, and eye protection are required throughout this lab.
• Never load a damaged component. If an inspection reveals any doubt, remove the component and replace it.
• One evolution at a time. The practice frame anchor handles one student system at a time. No simultaneous rigging on the same anchor without explicit instructor authorization.
• Retire any rope that has arrested a real fall or shows core damage, glazing, or stiffness.