Which step is typically not included when gas-freeing a tank?

When gas-freeing a tank, the primary focus is on ensuring a safe atmosphere for entry, which involves removing any hazardous gases and ensuring adequate oxygen levels. Measuring the oxygen content is crucial because a safe oxygen level (typically between 20.8% and 21% for most operations) is necessary for personnel to work in the tank without risk of asphyxiation. Clearing the tank of residues helps eliminate any remaining flammable or toxic materials that could pose a risk. Using a hydrocarbon detector is also vital for identifying any flammable vapors that may still be present after the tank has been cleaned and ventilated.

The application of degreasing solvents, while it may be necessary for cleaning purposes, is generally not considered a standard step in the gas-freeing process. The intent of gas-freeing is primarily to create a safe breathing environment inside the tank, rather than to clean it to a specific standard. Therefore, this step is typically not involved in the gas-freeing procedure itself, which is focused on verifying that the atmosphere is safe for entry.