2.9.4.0. Despite section 2.9.2, a warning line may be installed, during bridging or roofing work, on surfaces with a slope equal to or less than 15 ° (3/12), in order to replace the use of a guard-rail and delimit a work area.
In such a case, another recognized means of protection against falls, such as a safety harness secured to an anchorage system by a fall arrest connecting device, the whole in accordance with sections 2.10.12 and 2.10.15, must be used outside the area delimited by the warning line.