Protected range is published in PANS-OPS. 2.5nm from DME ARC centreline gives full clearance (Primary Area). For the next 2.5nm, terrain clearance linearly tapers to zero (Secondary area).
Speed limits are subject to procedure limit speeds (or more stringent if published). Generally 240kts for initial approach and reducing for final approach. Limiting speeds for each flight phase are published in PANS-OPS.