How do we perform a hot tap ?
How do we perform a hot tap? A. Hot Tap Setup For a simple hot tap, there are three major components necessary to safely tap into a pipe, the fitting, the valve, and the hot tap machine (which includes the cutter, and housing). The fitting is attached to the pipe, normally by welding. In many cases, the fitting is a full encirclement split tee, with a flanged outlet (See Figure 6). Onto this fitting, a valve is attached, and the hot tap machine is attached to the valve (see FIGURE 1). For hot taps, new studs, nuts, and a new valve should always be used, as the studs, nuts, and valve will become part of the permanent facilities and equipment. The fitting/valve combination, is attached to the pipe, and is normally pressure tested by the site owner. The pressure test is very important, so as to make sure that there are no structural problems with the fitting, and so that there are no leaks in the welds (it makes no sense to cut a hole in a perfectly good pipe, and to create a “new” leak in the system). The hot tap cutter, is a specialized type of hole saw, with a pilot bit in the middle, mounted inside of a hot tap adapter housing. The hot tap cutter is attached to a cutter holder, with the pilot bit, and is attached to the working end of the hot tap machine, so that it fits into the inside of the tapping adapter. The tapping adapter will contain the pressure of the pipe system, while the pipe is being cut, it houses the cutter, and cutter holder, and bolts to the valve. Key Points Hot Taps: • Client/Owner supplied valve • Primarily to establish new service • Can be size on size, or smaller hole cut into larger pipe • New studs and nuts should be used to bolt on the valve, as it becomes part of the permanent installation B. Hot Tap Operation The Hot Tap is made in one continuous process, the machine is started, and the cut continues, until the cutter passes through the pipe wall, resulting in the removal of a section of pipe, known as the coupon. The coupon is normally retained on one or more u-wires, which are attached to the pilot bit. Once the cutter has cut through the pipe, the hot tap machine is stopped, the cutter is retracted into the hot tap adapter, and the valve is closed. Pressure is bled off from the inside of the Tapping Adapter, so that the hot tap machine can be removed from the line. The machine is removed from the line, and the new service is established. (Figure 5 shows a detail of the cutter having cut through the pipe, on a size on size hot tap or line stop tap.)