Before entering boiler drums or fireboxes, what must be certified?

Prior to entering boiler drums or fireboxes, it is crucial that the boiler is certified as gas-free. This means that any hazardous gases, such as combustible gases or toxic substances, must be removed or neutralized to ensure the safety of personnel entering these confined spaces. Without this certification, workers could be exposed to lethal environments, posing significant risks to health and safety.

Ensuring that the boiler is gas-free involves thorough checks and procedures, including ventilation and possibly the use of gas detection instruments, to confirm the atmosphere is safe for human entry. This is a critical step in maintaining safety standards and protocols in any industrial setting. The other options, while related to boiler maintenance and operation, do not directly address the immediate health and safety concerns that gas-free certification does.