Step-by-Step Instructions for Pipeline Construction

Many homes have a front-row seat to the pipeline construction process because to the current surge in natural gas pipelines. Construction is happening in backyards, farms, pastures, and even at people’s mailboxes across the nation as a result of the haste to get natural gas to markets. This article explains the steps involved in the ongoing construction of a natural gas pipeline.

Beginning: Pipeline construction companies can start once all state and federal licenses are authorized and easement agreements or eminent domain condemnations are finished. Every area where work will occur has its limits marked by crews. The flags indicate the boundaries of the staging and storage facilities, as well as the temporary construction zone encircling the pipeline right-of-way (ROW). The pipe’s diameter (8 to 42 inches) determines the right-of-way’s width, which ranges from 80 to 125 inches. Temporary access roads are built to provide direct routes from staging locations to the pipeline ROW, even if existing roads are utilized wherever feasible.

Step 1: Storage yards and staging areas for construction

Strategically placed along the proposed right-of-way, staging grounds and storage yards are cleared in order to build a pipeline. In addition to fuel tanks, sand bags, silt netting, stakes, and machine parts, these spaces are utilized to store pipe. They offer spaces for office trailers, staff trucks, and construction equipment parking.

After being cleaned, staging grounds are covered with coarse stone gravel and frequently reinforced with big hardwood matting. These places can affect wetlands and streams and can be found in grassland, fields, or wooded regions. Access roads to and from paved roads, as well as to and from the areas to the pipeline ROW, must frequently be built in these regions.

Step 2: Cutting the ROW Clear

Clearing the pipeline right-of-way will start as soon as the equipment is available at the staging area. Landowners may choose to sell the timber individually or delegate the sale or disposal of the timber to the firm. Tree tops and branches are stacked up and burnt, while large trees are either transported off or stored. The remaining tree stumps in the ROW are then removed using a stump grinder.

Step 3: Trench excavation

After the trees in the ROW are removed, the pipeline trench is excavated. The hillsides are so steep, as can be seen in a number of the pictures below, that trench diggers are dropped and tethered to bigger bulldozers. Track hoes with jack hammers are used to dig the trench if rock ledges are found. Sandbags are positioned within the trench to support the pipe and limit water flow.

Step 4: Assembly, Stringing, and Pipe Transport

After the trench is finished, pre-coated pipe segments—typically 40 feet long—are moved from staging area stockpiles to the right-of-way. In hilly terrain, pipes are placed within the trench on top of supporting sandbags, or above ground next to the trench. To enable the pipeline to follow the intended path and the terrain, some pipe sections are bent using a pipe bending tool. After that, the pipe pieces will be joined by welding, sandblasted, and epoxy-coated at the weld joints to stop corrosion. Lastly, an x-ray is used to check the integrity of the weld joints. After that, pipe segments that are connected can be dropped into the trench.

Step 5: Roads and Streams as Obstacles

Existing roads, highways, streams, rivers, and wetlands are all crossed by pipelines. Under these obstructions, pipes are usually built by either horizontal directional drilling (HDD) for deeper placement or boring for shallow depth. Other challenges include karst terrain, heavily inhabited areas, and abandoned mines. Every issue necessitates a different approach and sequence of action.

Step 6: Restoring and Testing

The ditch is filled in once the pipe has been examined. Hydrostatic testing must be used to confirm the pipeline integrity prior to project completion. Permits are granted to pipeline corporations so they can extract millions of gallons of water from rivers and streams along the pipeline’s route. The pressure is raised above the maximum operating level before this water is pushed through the pipeline. The pipeline is considered operational if it passes this test undamaged. Following this, above-ground markers are positioned along the pipeline course and the ROW’s surface is planted and fertilized.

Extra Facilities

A pipeline project involves the construction of several forms of supporting infrastructure, even if the majority of the pipeline is subterranean. Facilities called compressor stations, which keep the pipeline’s pressure constant, are either renovated or constructed to accommodate new pipeline developments. Furthermore, valve stations are erected above the pipeline’s right-of-way, enabling operators to cut off portions of the line for emergencies or maintenance. In order to quantify the gas flow via a pipeline, metering stations are erected along its length.

Welds must be x-rayed and the pipe hydro-tested to guarantee pipeline integrity. Clean water is pumped in during this operation at a pressure higher than the anticipated MAOP, or maximum average operating pressure. After that, all of the water is taken out, and “pigs” are put into the pipe to clear it. The tube will be filled with dry air after the pigs have finally left the far end of the pipe clean. The air is pumped up by air compressors and then sent through a dryer. A sample of the air will be taken, and its moisture content will be determined. The entire pipeline is filled with nitrogen to absorb more of the residual moisture when those values drop sufficiently. The pipeline isn’t prepared to carry natural gas until then.