OHS risk prevention: working at heights

Did you know that the CNESST applies a zero-tolerance policy to risks related to work at heights? Consequently, these risks must be considered a priority in your prevention plan.

The objective of this article is to present the main fall risks as well as the obligations arising from Quebec’s occupational health and safety legislation.

Here are some statistics on the subject:

• 64% of fatal falls are less than 9 metres
• 10% of fatal falls are less than 3 metres
• 69% of fall victims state that the accident could have been avoided

• The impact speed on the ground of a worker who falls from 3 metres is 27 km/h
• The most frequent cause of a fall is poorly designed workplaces

– An impact against the ground: this risk is often caused by the absence of personal protective equipment, by a break in protective equipment or by an inadequate choice of equipment.
– Impact with an obstacle during a fall: a muddy work area or poor anchoring can increase this risk.
– Deceleration during a fall (forced stop): the greater the worker’s weight and height, the greater the risk.
– An injury caused by poorly adjusted equipment: the anchoring points of personal protective equipment can cause friction during a fall.
– Trauma due to suspension in a vacuum: harnesses are designed to be comfortable for a period of 20 to 30 minutes. In the event of a fall, it is important to return the worker to the ground as quickly as possible in a horizontal position.

The Regulation respecting occupational health and safety (RROHS) provides for mandatory measures regarding work at height.

Guardrails (art. 12 RROHS)
The National Building Code must be read before installing a guardrail and its installation must be done in accordance with the Code. The RROHS provides for the minimum loads that a temporary guardrail must resist. It also provides for the installation of rails and toe boards at certain locations on the guardrail.

Protection Against Falls (art. 33 RROHS)
This article is divided into five paragraphs and provides for the cases where the worker must be protected against falls as well as the safety measures that the employer must take if such cases occur. Section 33 RROHS also provides for when the guardrail must be installed and when the guardrail can be replaced by a warning line or an anchoring system.

Safety Harness (art. 347 RROHS)
To comply, a harness must meet the Safety Harness standard, CAN/CSA Z259.10 and be connected by a fall arrest connection to an anchoring system. This connection must limit the maximum fall arrest force to 6 kN or the free fall height to a maximum of 1.8 m. Flying scaffolds, worker lifting activities and work in confined spaces also require the wearing of a safety harness.

Fall arrest link (S. 348 RROHS)
This section of the regulation provides for the composition of the fall arrest system and the standards to be used to verify the conformity of each piece of equipment.

Anchoring system (S. 349 and 349.1 RROHS)
An anchorage is a fixed support or attachment point for the connection system of protective equipment. The anchorage must be designed and installed according to an engineer’s plan and inspected by the engineer or a qualified person acting under his or her supervision before testing.

Safety Belt (S. 350 RROHS)
A safety belt cannot be used as equipment to stop a worker’s fall. It must only be used to limit the movement of the worker or to maintain him in his work position. The belt must comply with the standard Work Belts and Saddles for Restraining and Limiting Movement, CAN/CSA-Z259.1.

Safety Net (S. 354 RROHS)
This section of the regulation lists nine safety requirements for nets. In addition to these requirements, nets must be provided with a hole diameter not exceeding six inches. The net must be placed as close as possible to the work area, be free of any object and must not allow a fall of more than six metres. It is important to schedule a weekly check, especially when exposed to the sun. After two years, or if there is any sign of deterioration, it is recommended that the net be replaced.

Warning Line (S. 354.1 RROHS)
A warning line is used to indicate to workers the area in which they can safely perform their work. Section 354.1 RROHS sets out the standards that the line must meet and the manner in which it must be installed. The construction industry is subject to more regulatory obligations regarding mandatory safety measures. For more information, you can consult articles 2.9.1 and following of the Safety Code for Construction Work.

Having an intervention strategy, preparing the equipment and planning the tasks are three elements that help reduce the risks associated with working at heights. To prevent falls, it is necessary to plan the maximum number of operations on the ground. The less time spent working at heights, the lower the risk of falling.

The employer must also adopt safe work at height methods and ensure that these methods are respected in the field. Finally, the collective protections provided for by the regulations must be available and comply with the various standards that are attached to them.

Your organization’s management must keep in mind that a contravention of the Occupational Health and Safety Act (OHSA) and its regulations may support the referral of your prime contractor, supervisors, or managers to trial on a charge of manslaughter under the Criminal Code. Due diligence is therefore required.

If your organization does not have a specialized resource that can ensure that the work environment, equipment and work methods are adequate, outsourcing prevention to an external firm may be a solution. Although it may seem costly in the short term, this solution can increase your productivity in the medium and long term.

Paragraph 9 of section 51 of the OHSA requires employers to train their employees on the risks associated with their work.

To help you educate your employees on the key safety concepts when working at heights, MEDIAL has recently developed a training course on the subject.

>> Find out more about the training now!

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