An excavation in stable hard clay (Type 1 soil) is planned to be 6.0 metres deep. What is the maximum allowable vertical side for this excavation before shoring or sloping is required, according to common provincial regulations?

Question: An excavation in stable hard clay (Type 1 soil) is planned to be 6.0 metres deep. What is the maximum allowable vertical side for this excavation before shoring or sloping is required, according to common provincial regulations?

Answer options: ✅ 1.2 metres

• More than 1.5 metres (shored or sloped)
• Up to 3.0 metres (if inspected daily)
• No limit for Type 1 soil.

Correct answer: 1.2 metres

Explanation: Even in Type 1 soil (hard and compact), most provincial OH&S regulations, including Ontario Reg. 213/91, stipulate that any excavation exceeding 1.2 metres (4 feet) in depth requires shoring, sloping, or another protective system.