Safety, Codes and Standards
Domain 5 - Safety, Codes and Standards
This domain tests the legal floor under everything else: fall protection, silica exposure, and the code and ASTM references a slate contractor is expected to name.
Fall protection
OSHA 29 CFR 1926.500 defines a steep roof as one steeper than 4:12. Under 1926.501, workers 6 ft or more above a lower level need fall protection: guardrails, safety nets, personal fall-arrest systems, or a written fall-protection plan with alternate measures where the rules permit. Slide guards alone do not satisfy OSHA for steep-roof work. Ladders extend 3 ft above the landing, sit at a 4:1 angle and are secured. Ridge hooks, roof jacks and staging go in per manufacturer instructions.
Health and load hazards
Cutting and dressing slate releases respirable crystalline silica; OSHA 1926.1153 expects wet cutting or dust controls, and monitoring and respirators where exposure reaches the action level. Slate is heavy: stockpile over bearing points, never on a valley or cantilever, and never exceed what the structure was designed for. Falling slate and dropped tools are the main ground hazard - use toe boards, chutes and a controlled drop zone.
Codes and standards to name
- IRC Chapter 9, R905.7 (slate and slate-type shingles): material conforming to ASTM C406, minimum slope 4:12, underlayment per the code table, corrosion-resistant fasteners.
- ASTM C406 (roofing slate), C120 (flexure), C217 (weather resistance), D226 (organic felt), D1970 (self-adhering membrane), B370 (copper sheet), A153 (galvanized hardware).
- NRCA steep-slope guidance and manufacturer details where code is silent.
Worked example
A 5:12 slate repair on a two-storey house. Slope passes the 4:12 minimum, so slate is permitted with two layers of No. 30 felt and an ice barrier at the eave if the jurisdiction requires one. The work is well over 6 ft above grade, so fall protection - a personal fall-arrest system on an engineered anchor or scaffolding - is mandatory. A plank on roof jacks is staging, not fall protection.
Traps
Treating the 6 ft rule as industrial-only; assuming slide guards satisfy OSHA; dry-cutting slate in an enclosed space; citing ASTM numbers you cannot tie to a material.