Not a building code requirement, but designers should also be aware of OSHA rerequirements
1910.28(b)(13)
Work on low-slope roofs.
1910.28(b)(13)(i)
When work is performed less than 6 feet (1.6 m) from the roof edge, the employer must ensure each employee is protected from falling by a guardrail system, safety net system, travel restraint system, or personal fall arrest system.
1910.28(b)(13)(ii)
When work is performed at least 6 feet (1.6 m) but less than 15 feet (4.6 m) from the roof edge, the employer must ensure each employee is protected from falling by using a guardrail system, safety net system, travel restraint system, or personal fall arrest system. The employer may use a designated area when performing work that is both infrequent and temporary.
1910.28(b)(13)(iii)
When work is performed 15 feet (4.6 m) or more from the roof edge, the employer must:
1910.28(b)(13)(iii)(A)
Protect each employee from falling by a guardrail system, safety net system, travel restraint system, or personal fall arrest system or a designated area. The employer is not required to provide any fall protection, provided the work is both infrequent and temporary; and
1910.28(b)(13)(iii)(B)
Implement and enforce a work rule prohibiting employees from going within 15 feet (4.6 m) of the roof edge without using fall protection in accordance with paragraphs (b)(13)(i) and (ii) of this section.