What precaution should experienced welders take when welding on containers?

Filling containers with inert gas or water is crucial when welding, as it helps to mitigate the risks associated with volatile substances that may be present in or on the surfaces of the containers. Inert gases, such as argon or nitrogen, can help displace oxygen and reduce the potential for an explosion or fire due to the presence of flammable vapors. Additionally, filling a container with water can physically prevent the ignition of these vapors by eliminating the space where they could accumulate and ignite. This precaution is particularly important for containers that previously held flammable materials or gases, ensuring a safer working environment for the welder.

Leaving containers empty poses a risk because any residual vapors could ignite during the welding process. Sealing containers tightly can create a dangerous build-up of pressure if vapors or gases are present and, when heated by the welding process, could lead to an explosion. Rushing into welding without additional safety measures ignores these risks, potentially endangering the welder and others in the vicinity. Therefore, filling containers with inert gas or water is the best practice for ensuring safety while welding.