OHS Code Explanation Guide

Published Date: July 01, 2009
Bookmark this page

Part 41 Work Requiring Rope Access

Section 839 Descenders

Descenders are used to attach the worker to the working line and to control descent. Descenders should give the worker control over the speed of descent and should not cause undue shock loads to the working line when braking. If the worker loses control, the descender must stop the worker or allow only a slow, automatically controlled descent in the hands-off position. In addition, descenders should not cause significant abrasion of the rope sheath when suddenly clamped onto the working line. Descenders should be of a type that cannot be accidentally detached from the working line or become detached under any circumstances while supporting the worker’s weight.

For compliance purposes, the descender  must bear the mark or label of a nationally accredited testing organization such as CSA, UL, SEI, etc. as evidence that the descender meets the requirements of at least one of the listed standards. A descender bearing a CE mark is considered acceptable for the purposes of this Code. The CE mark – Conformite Europenne – indicates that the company manufacturing the product has met the requirements of one or more European directives.

Standard EN 341

Standard EN 341: 1997, Personal protective equipment against falls from height – Descender devices, specifies requirements, test methods, marking and instructions for use for descender devices as rescue equipment to be used in conjunction with personal protective equipment against falls from a height e.g. full body harnesses, or rescue equipment, e.g. rescue harnesses. Descender devices are a means by which a worker can, at a limited velocity, descend from a higher to a lower position either on his or her own or assisted by a second person.

For a Class A descent device, the descent velocity must be maintained between 0.5 m/s and 2 m/s. In the case of hand operated devices, the velocity must not exceed 2 m/s after the control device is released. During the descent the descent velocity must be almost constant.

NFPA Standard 1983

Chapter 5 of the NFPA Standard 1983: 2006, Standard on Fire Service Life Safety Rope, Harness, and Hardware, specifies design labelling and performance requirements for descent devices. Descent devices must withstand a tensile test of not less than 1200 lbs-force without permanent distortion and not less than 5000 lbs-force without failure. Both tests must be performed in manner of function.