R 408.15771 Freezing operations.

Rule 5771. (1) A frozen plug shall be allowed to set a minimum of 1 hour per inch of pipe diameter being frozen. (2) When possible, a frozen plug shall be pressure-tested from above for a minimum of 5 minutes to a pressure which is more than the known wellhead pressure. (3) Following the pressure test, all pressure shall be bled off the pipe above the frozen plug and observed for a minimum of 15 minutes before breaking out the pipe and installing a new valve. (4) After installing the new valve, void space between the frozen plug and valve shall be filled with fluid. (5) A frozen plug shall be allowed to thaw at a normal rate. Steam or hot water shall not be used to thaw a frozen plug.