Which type of boiler casualty requires the boiler to be purged after securing the boiler?

When a boiler experiences a rupture in a boiler tube, the integrity of the system is compromised. Upon securing the boiler, it is crucial to purge the system to remove any residual steam, water, or potentially harmful gases that may remain due to the rupture. This process ensures the safety of personnel and equipment by eliminating any explosive or hazardous conditions that could arise from the combination of air and any flammable substances within the boiler.

Purging is a safety measure employed specifically in scenarios where there has been a breach in the boiler's structure. It is not only about ensuring the boiler is safe for maintenance; it is also a fundamental step in safeguarding the environment and preventing any hazardous incidents that could occur if the system is not properly cleared before further work is performed.

Low water conditions, bent boiler casings, and faulty pressure relief valves present their own sets of challenges but do not necessitate the same purging measures as a ruptured tube. Each of these situations may require different actions and repairs without the immediate necessity of purging to ensure a safe working environment.