OHS Code Explanation Guide

Published Date: February 23, 2012
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Part 9 Fall Protection

Section 142.3 Shock aborbers

Subsection 142.3(1)

The newest edition of CSA Standard Z259.11-05, Energy absorbers and lanyards, creates two categories of shock absorber (re-named as energy absorber by CSA), known as E4 and E6. An E4 shock absorber is equivalent to the type of shock absorber that has been in use for many years i.e. it limits the arresting force to 4 kN under normal conditions and allows the arresting force to increase to 6 kN if the shock absorber is wet and frozen.

An E6 shock absorber limits the arresting force to 6 kN under normal circumstances, allowing it to increase to 8 kN when the shock absorber is wet and frozen. CSA created the two ratings to better protect workers of different body weights. The E4 shock absorber is intended for use by workers weighing 45-115 kg (100-254 lbs) while the E6 shock absorber is intended for use by workers weighting 90-175 kg (200-386 lbs).

In the case of a heavy worker, an E4 shock absorber may be unable to absorb all the energy of a big fall, causing the worker to “bottom out” and be jolted with the residual energy. Heavier workers should be using an E6 shock absorber. In the case of a heavy worker who takes a long free fall, perhaps because the only anchor location was at the worker’s feet, a European shock absorber may be a better choice. Because of its 1.75 metre (5.75 foot) elongation, it should be able to absorb all the energy of the fall.

For compliance purposes, the shock absorber must bear the mark or label of a nationally accredited testing organization such as CSA, UL, SEI, etc. as evidence that the shock absorber has been approved to the requirements of the Standards. Products bearing a CE mark also comply with this section. The CE mark – Conformité Européenne – indicates that the company manufacturing the product has met the requirements of one or more European directives. The product also complies with the listed CEN European standard.

The 2009 edition of the OHS Code marks the first time that Part 9 accepts fall protection equipment approved to standards from the U.S. and Europe. Fall protection equipment approved to any one of these standards is considered to offer an equivalent level of worker protection. Employers and workers in Alberta now have access to a broader range of equipment to safely meet their fall protection needs. Readers are referred to section 3.1 for information about previous editions of the standards.

Subsections 142.3(2) and 142.2(3)

Situations may arise in which a personal fall arrest system must be used without a shock absorber. The most common circumstance encountered is a lack of adequate clearance distance. All else being equal, eliminating a shock absorber reduces the required clearance distance by 1.1 metres (3.5 feet) to 1.75 metres (5.7 feet) depending on the type of shock absorber used (see Figure 9.14).

If the shock absorber is removed from the personal fall protection system, then the worker’s free fall distance is limited to 1.2 metres. Even with this fixed distance, employers and workers need to be aware that, depending on the type of lanyard selected, the maximum arresting force of 6 kN stated in subsection 151(3) can be exceeded.

It is crucial that the employer carefully select the type of lanyard used in such situations and determine the maximum arresting force so that workers are not endangered.

Subsection 142.3(4)

No explanation required.