Before carrying out repair works onsite, we need to undertake several experiments on different types of waterpipe to estimate the liquid nitrogen supply rate to ensure a safe and smooth completion of the ice plug formation process. There are generally two approaches to make sure that the pipe-freezing method is safe, time-sensitive and appropriate: (1) we measure the water pressure at both sides of the jacket; (2) we monitor the external characteristics and the frost growth to accurately predict the completion of ice plug formation inside the pipe. Approach #2 has already been patented ( Patent No. TW201938923A).

The success of the experiments, testing and onsite application confirmed that this innovative freezing method was safe, cost-effective and suitable to be used efficiently in semiconductor factories and modern buildings.