Steel Pipeline Systems [Part.2]

Coupling Procedures.
a. For 8-inch Steel Tubing. Procedures for this tubing, because of weight (210-pound tubing), are different than for lighter pipelines. A saddle-type carrying bar (Figure B-2) and one extra person in the crew are required for constructing the 8-inch tubing pipeline. This extra person is a second helper who assists in raising the new section onto the lineup cage and in lowering it. The rest of the coupling operations are the same as those for a 4- or 6-inch line. Except for size, the 8-inch lineup cage and pipe-cleaner swab are identical to those used on the smaller pipe.

Coupling procedures for 8-inch steel tubing are as follows:
■The second helper assists the wrenchman's helper to raise their end of the tubing section and guide it onto the lineup cage, while the stabber and jackman handle the other end.

■The second helper moves to the other end and assists the jackman and stabber in aligning the section, as directed by the wrenchman.

■The second helper assists the jackman and stabber in lowering the new end of the pipeline on the lazy board. Then the second helper assists the wrenchman's helper with the next section.

For 8- and 12-Inch Standard Steel Pipe and 12-Inch Steel Tubing. Do not manually handle pipe sections heavier than the 6-inch (300-pound) standard-weight pipe. Use powered equipment to off-load the pipe and couple one section at a time. You can stockpile the pipe along the pipeline trace. If you do, use a pipelayer (Figure B-3) to handle the pipe. (The pipelayer is a commercial piece of equipment that must be leased.)

Swabbing and Cleaning. The swabber and pipe-end cleaner swab all of the pipe on a load, one row at a time, in a single operation. (They can swab the pipe while it is still on the truck or in a stockpile.) With one man at each end, they insert a snake in either outside pipe of the top row and pass it through to the other end. The man at the end where the snake is coming through pulls it through the first pipe and simultaneously feeds the snake back through the next pipe in the row. The men repeat this operation until they swab all the pipes (Figure B-4).

(2) Moving the Pipe. The pipe is picked in the middle with an automatic clam-type release hook attached to the hoisting line of the stringing boom. The pipe joint is first raised only a few inches from the pipe. The swabber and pipe-end cleaner, working at opposite ends, clean and file the pipe land and groove on each end at the same time. At the same time, the wrenchman and helper (one team) and the jackman and stabber (another team) construct cribbing of 4- by 4-inch by 3-footlong blocks. This cribbing takes the place of the lazy board and pipe jack. Each of the blocks is tied together with rope. Doing so allows the wrenchman's helper to drag one cribbing set at a time when moving it to the next location.

(3) Positioning the Pipe. After the pipe ends are cleaned, the pipe section is swung into approximate alignment on the pipeline. The stabber inserts the lineup-cage snake through it (only one snake is used). The jackman and wrenchman's helper guide the pipe joint into position on the lineup cage protruding from the end of the line. The stringing-boom operator raises or lowers the load and extends or retracts the boom, as directed by the stabber or wrenchman. Once aligned, the jackman keeps the joint aligned by leaning or shoving against the end.

(4) Installing the Coupling. After tightening the coupling, the crew lifts the pipeline high enough so they can pull the cribbing stack out from under the pipeline and drag it forward (about 40 feet) to the far end of where they will install the next section. The jackman lowers the pipeline and guides it onto the cribbing stack. At the same time the stabber places the gasket inside out on the end of the pipeline. As soon as the coupling is tightened, the stabber pulls the lineup cage forward. The stabber erects the cribbing stacks while couplings are installed. As he moves forward, the wrenchman releases the pipe lifting tongs so that the pipe-stringing boom will swing back to the bolster truck for the next pipe section.