Method for determining steam leakage

A method for determining steam leakage, comprising:

• obtaining a dummy furnace tube by mechanically cutting a sample of an entire furnace tube;
• simulating an operation of an actual furnace tube by pressurizing an inside of the dummy furnace tube to a plurality of different steam pressures and heating an outer wall of the dummy furnace tube to a plurality of different operating temperatures, wherein a water pressure test with a water pressure higher than a said steam pressure is performed on the dummy furnace tube before the inside of the dummy furnace tube is pressurized to the steam pressure;
• installing at least one thermocouple and at least one strain gauge in an upper section, a middle section and a lower section of the dummy furnace tube to record strain values of the dummy furnace tube corresponding to the steam pressures and the operating temperatures;
• providing a steam pressure graph plotted according to the steam pressures, the operating temperatures and the strain values;
• and
• determining whether a steam leakage occurs in the actual furnace tube according to the strain values by looking up the steam pressure graph.