What must be maintained continuously while people are inside a confined space?

Ventilation is crucial in confined spaces to ensure the safety of individuals by providing a continuous supply of fresh air and preventing the buildup of hazardous gases, vapors, or flammable substances. Proper ventilation helps to maintain breathable air quality and temperature control, reducing the risk of asphyxiation or health-related issues that can arise from stagnation or inadequate oxygen levels.

While other safety measures such as radio contact, safety harnesses, and signage are important in specific situations or for particular safety protocols, they do not address the fundamental need for adequate airflow and oxygen supply, which is essential for the well-being of individuals working in confined environments. Thus, maintaining proper ventilation is paramount for safety during such tasks.