Safety, Codes, and Environmental Compliance
What the exam tests
Safety and compliance questions cover trench safety, confined spaces, utility locates, fusion hazards, silica dust, electrical safety, and environmental rules for discharge and antifreeze.
Core rules
- OSHA requires a protective system for trenches 5 ft or deeper, and for smaller trenches where hazards exist; keep spoil and equipment back from the edge.
- Treat vaults and deep pits as permit-required confined spaces unless they are proven otherwise.
- Call 811 before digging; wait for markings and respect tolerance zones.
- Fusion equipment causes burns; use PPE, keep the heater guarded, and work in ventilated areas.
- Contain and dispose of antifreeze and flush water according to local rules; do not dump to storm drains.
Worked example
A 6-ft trench in clay is planned for a header line. Because it is deeper than 5 ft, it needs sloping, benching, shoring, or a trench box. Spoil is placed 24 in from the edge. Before digging, the crew calls 811 and marks the gas line. The vault is tested for oxygen before entry and ventilated; if it fails, entry requires a permit and attendant.
Traps
Entering an unprotected 6-ft trench; assuming a vault is not a confined space; digging before locates clear; using air to test; dumping glycol on the ground.