Under what conditions can welding and cutting occur without mechanical ventilation?

Welding and cutting can occur without mechanical ventilation primarily when involving non-hazardous materials. This is significant because when non-hazardous materials are being worked on, they typically do not produce harmful fumes or gases that could pose health risks to workers.

In a safe working environment, the absence of hazardous materials reduces the need for additional ventilation systems, as there is a minimal risk of exposure to toxic substances. It is important to ensure that materials being used do not emit harmful byproducts when subjected to heat, as this is essential for safeguarding the health of the personnel involved in the tasks.

While other conditions mentioned may affect ventilation needs or practices, they do not universally ensure safety when welding and cutting, partnering non-hazardous materials with an effective safety protocol helps maintain a compliant and safe working environment.