1. Starting from 0, pressurize to 0.7kPa at 0.07kPa/s loading rate;

2. Load to the specified pressure level and hold the pressure for 60s, check whether the specimen is damaged or failed;

3. Remove the air to remove the pressure back to zero, check whether the specimen damage or failure;

4. Repeat the above steps, with each level of 0.7kPa increments as the next pressure level, each pressure level should be maintained for 60s, and then remove the air pressure to return to zero, and again check whether the test piece damage or failure;

5. Repeat the test procedure until the specimen damage or failure, stop the test and record the value of pressure before the destruction of a level.