Level 350 for 4 hours Put it in a fire of 2000 degrees Fahrenheit (1093°C) for 4 hours. Keep the temperature in the box below 350 degrees Fahrenheit (177°C), and the paper documents will not be carbonized.

Level 350 for 2 hours Put it in a fire of 1850°F (1010°C) for 2 hours, keep the temperature in the box below 350°F (177°C), and the paper documents will not be carbonized.

Class 350 for 1 hour Put it in a fire of 1700 degrees Fahrenheit (927 degrees C) for one hour, keep the temperature in the box below 350 degrees Fahrenheit (177 degrees C), and the paper documents will not be carbonized.

Class 350 for half-hour Put it in a fire of 1550 degrees Fahrenheit (843 degrees C) for 30 minutes. The temperature in the box is kept below 350 degrees Fahrenheit (177 degrees C), and the paper documents are not carbonized.