On a steep-slope roof, workers 6 feet or more above a lower level must be protected by:

解析

On a steep roof - slope greater than 4 in 12 - at 6 feet or more above a lower level, the federal rule allows conventional fall protection only: a guardrail system with toeboards, a safety net system, or a personal fall arrest system. What the wrong answers have in common is that all three are low-slope measures. Warning lines and safety monitoring systems are permitted on LOW-slope roofs, and a monitoring system alone only on roofs 50 feet or less in width; neither is available on a steep roof at any height. Slide guards are a roofing-trade device with no standing as conventional fall protection. In California roofing runs under section 1730, with residential-type roofing under section 1731, and those orders set their own methods by slope and by covering type.