--Some of the basic information you, as a customer would need to know when requesting freeze work.—
All flow must be stopped in order to obtain a freeze plug. Leaking packing, pump seals, gaskets, or other minor leaks will not affect obtaining an ice plug. Closing valve(s) in the line will make the flow static. Valve(s) can be upstream or downstream from the freeze jacket. Most systems can isolate branch connections without shutting down the entire system. Should there be no valves or they are not holding then pumps must be shut down for a short period of time. Once and ice plug is obtained the system operation can resume.
Jackets should be at least ten pipe diameters away from the nearest tee or branch connection in order to keep system online. When it is necessary to place the jacket(s) closer than this it may require shutting down pumps to obtain the plug. In this situation pumps may need to remain off for the duration of the work.
There must be a gauge port or vent in the section of pipe which is to be isolated. The contractor is to weld in a half-inch thread-o-let or a temporary clamp on tap will be used.
Liquid nitrogen Dewar(s) will be sent to the job site the day prior to the scheduled freeze. The contractor or owner is responsible for receiving the Dewar(s) and placing them near the actual work location. Note: A Dewar weighs approximately six-hundred pounds. Waters Mechanical can provide a cart for your use when we arrive.