Hot tapping


Hot tapping, or pressure tapping, is the method of making a connection to existing piping or pressure vessels without the interrupting or emptying of that section of pipe or vessel. This means that a pipe or tank can continue to be in operation whilst maintenance or modifications are being done to it. The process is also used to drain off pressurized casing fluids and add test points or various sensors such as temperature and pressure. Hot taps can range from a ½ inch hole designed for something as simple as quality control testing, up to a 48-inch tap for the installation of a variety of ports, valves, t-sections or other pipes.
Hot Tap Procedures:
A. A hot tap saddle, service saddle or welded threadolet, valve installed, assembly is pressure tested and hot tap machine attached.
B. Valve opened, hot tap completed, coupon or cut portion retained by latches on pilot drill. Pressure is contained within the hot tapping machine.
C. Cutter and coupon retracted and valve closed. Fluid is drained and hot tapping machine is removed. The tapped valve is now ready for the contractor's tie-in or IFT's linestop/stopple equipment to be inserted.
Hot tapping is also the first procedure in line stopping, where a hole saw is used to make an opening in the pipe, so a line plugging head can be inserted.
Situations in which welding operations are prohibited on equipment which contains:
Based on the above, welding on equipment or pipe which contains hazardous substances or conditions as listed below shall not be performed unless positive evidence has been obtained that welding/hot tapping can be applied safely.
Substances
Constraints based on general hazard in the event of line puncturing during welding, not the welding process. Conditions:
Note: The above list is not exhaustive, but gives an indication only.