What is a precaution that must be taken before lighting a gas, oil, or pulverized coal fire?

Before lighting a gas, oil, or pulverized coal fire, one of the paramount precautions is to purge all combustibles. This step is crucial because the presence of any combustible materials in the area can pose a significant safety hazard. When initiating a fire, especially in a controlled environment like a boiler or furnace, any accumulated combustible gases or residues can ignite unexpectedly, leading to potentially dangerous explosions or fires.

Purging the system ensures that any unburned fuel or flammable vapors are expelled from the combustion chamber or surrounding areas, creating a safer environment for ignition. This helps to prevent flashbacks, backfires, or other dangerous incidents that could occur if flames come into contact with materials that are not designed to ignite.

In contrast, other precautions like checking fuel quality, adjusting fuel pressure, or monitoring temperature are important for efficient operation and safety but do not directly address the immediate hazard of combustibles present in the ignition area prior to lighting the fire. Prioritizing the purging of combustibles is crucial for ensuring a safe ignition process.