Which of the following is NOT a method to weld on a tank that contained flammable materials?

Which of the following is NOT a method to weld on a tank that contained flammable materials?

• A. Purge With Inert Gas
• B. Boil in Caustic Soda
• C. Steam and Weld While Full of Hot Steam
• D. Grinding Weld Seams

Answer: (D)

When welding on a tank that previously held flammable materials, the priority is to remove or neutralize any vapors and eliminate ignition sources so a spark or heat from welding can’t ignite residual vapors. Purging the interior with inert gas is a standard way to do this: it replaces the air inside the tank with an inert atmosphere, dramatically reducing the chance of ignition during welding. Cleaning steps like boiling in caustic soda can help remove residues from the surfaces, which is part of making the weld area safe, but by itself it doesn’t reliably address the ignition risk inside a closed space. Welding with hot steam inside the tank isn’t a dependable or safe method either; steam doesn’t guarantee complete vapor removal and introduces other hazards like pressure and scalding. Grinding weld seams, however, is the one activity that inherently creates sparks and heat right in the potentially flammable environment, making it an ignition source and something that must be avoided inside a tank that stored flammable materials.

When welding on a tank that previously held flammable materials, the priority is to remove or neutralize any vapors and eliminate ignition sources so a spark or heat from welding can’t ignite residual vapors. Purging the interior with inert gas is a standard way to do this: it replaces the air inside the tank with an inert atmosphere, dramatically reducing the chance of ignition during welding. Cleaning steps like boiling in caustic soda can help remove residues from the surfaces, which is part of making the weld area safe, but by itself it doesn’t reliably address the ignition risk inside a closed space. Welding with hot steam inside the tank isn’t a dependable or safe method either; steam doesn’t guarantee complete vapor removal and introduces other hazards like pressure and scalding. Grinding weld seams, however, is the one activity that inherently creates sparks and heat right in the potentially flammable environment, making it an ignition source and something that must be avoided inside a tank that stored flammable materials.