Pipeline Hot Tap

Hot Taps atau Hot Tapping adalaah kemampuan pengikatan ke pressurized system, dengan pengeboran atau pemotongan, dalam stream atau under pressure.
Kode dan rekomendasi praktis pada pipeline hot tap adalah sebagai berikut:

• Design: ANSI B31.1, B31.3, ANSI B31.4 & B31.8, ASME Sec. VIII Div.1 & 2
• Fabrication: ASME Sec. VIII Div.1
• Welding: ASME Sec. IX
• NDT: ASME Sec. V

 

Werner Solken menjelaskan mengenai pipeline hot tap dalam website resminya (http://www.wermac.org/specials/hottap.html). Artikel disadur dalam bahasa aslinya sebagai berikut.

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.

The Coupon, is the section of pipe that is removed, to establish service. It is very highly desirable to “retain” the coupon, and remove it from the pipe, and in the vast majority of hot taps, this is the case.
Please note, short of not performing the hot tap, there is no way to absolutely guarantee that the coupon will not be “dropped”.

Coupon retention is mostly the “job” of the u-wires. These are wires which run through the pilot bit, and are cut and bent, so that they can fold back against the bit, into a relief area milled into the bit, and then fold out, when the pilot bit has cut through the pipe.
In almost all cases, multiple u-wires are used, to act as insurance against losing the coupon.