The Using Alternative Fall Protection on Roofs guidance only applies on a low slope roof (4:12 or less) when traditional fall protection systems cannot be used, such as a 42-inch parapet wall at the roof edge, guardrails, and personal fall restraint and arrest systems. This guidance does not apply to construction work advancing the roof leading edge or installing the roof deck.
Fall protection is required on any walking or working surface, including roofs, when there is a fall hazard of four feet. These alternative systems may only be used under specific circumstances and procedures.
Alternative systems include a warning line, a safety monitor and a safety watch. See Washington Administrative Code 296-880-40040, 296-880-40045, and 296-880-40050 for more information. Work on steep roofs (greater than 4:12) always requires guardrails or personal fall protection systems.