What are the main reasons for nitrogen purging equipment prior to maintenance?

The main reasons for nitrogen purging equipment prior to maintenance are to remove flammable or toxic substances, to prevent the formation of explosive atmospheres, and to protect personnel from exposure to hazardous materials. Nitrogen is an inert gas, meaning it does not readily react with other substances. Purging equipment with nitrogen displaces any residual hydrocarbons, hydrogen sulfide, or other flammable or toxic gases that may be present, creating a safe environment for maintenance personnel. Removing flammable substances prevents the formation of explosive atmospheres within the equipment. If flammable gases are present, even a small spark can ignite them, leading to a fire or explosion. Nitrogen purging reduces the oxygen concentration to a level that cannot support combustion. Protecting personnel from exposure to hazardous materials is another critical reason for nitrogen purging. Many process fluids are toxic or corrosive, and exposure to even small amounts of these substances can cause serious health problems. Nitrogen purging removes these materials from the equipment, minimizing the risk of exposure. Proper nitrogen purging procedures should be followed to ensure that the equipment is thoroughly purged and that the atmosphere inside the equipment is safe for entry. This includes verifying that the oxygen concentration is below a safe level before allowing personnel to enter the equipment. The purging process also ensures that no auto-ignition fuels are inside the equipment.