33.3. Installation of guardrails: Guardrails must be placed on open sides of a roof or around any area from which workers may fall:
(1) into a liquid or dangerous substance;
(2) a height of 1,5 m or more in a well, a basin, a tank, a reservoir, a vat, a container for the storing or mixing of substances, or where the workers are handling a load; or
(3) a height greater than 3 m in other cases.
Despite the foregoing, the guardrail may be removed during the time of the work if it prevents the carrying out of a task that could not be reasonably performed otherwise. In such a case, workers must wear a safety harness secured to an anchorage system by a fall arrest connecting device, in accordance with section 347. The work area must then be delimited in particular by a continuous barrier or trestles of a minimum height of 0,7 m, located at a distance varying between 0,9 m and 1,2 m from the place where workers are at risk of falling, or by a warning line complying with the requirements of section 354.1, so as to prevent access thereto by persons not working therein.