Excavation collapse barriers

This bowtie frames an excavation collapse as a barrier-management problem. Soil conditions and edge loading are shown as different threats, each with prevention measures that should be planned before workers enter the excavation. The right side recognises that rescue and medical response may be needed even when prevention fails. Use it to guide a pre-job discussion about the controls required on a specific site, the person responsible for checks and the conditions that should stop work. Add local ground conditions, weather, nearby services and regulations to make the diagram useful for the job. It does not replace a competent-person inspection, engineered protective system or legally required excavation plan.