Profile: Alstern Technologies Singapore Pte Ltd. offers pipeline related products and services. Our pipe line service includes pipe freezing, hot tapping, line stopping, leak repair, leak sealing, leak detection and corrosion protection/ pipeline reinforcement. Our pipe freezing is a commercial technique for solidifying the liquid in a pipe, with the utilization of cryogen to form a pressure resistant plugs. Our hot tapping is a method of employing an under pressure drilling machine to cut a hole in an operating pipeline or storage vessel which allows for a new branch connection from the existing pipe or vessel without any interruption to the flow.