Construction of oil, gas
and petrochemical industry objects

Design and construction of natural gas pipelines

Design and construction of gas pipelines is performed by our organization with the use of metal pipes, and we are guided by the requirements of SNIP 42-01, as well as SP 42-101. So that the end user could freely use gas qualified personnel perform very difficult and laborious process of designing and laying of the pipeline. However, modern machinery and the latest technology allow performing construction of a gas pipeline in the shortest possible time.

Designing of gas pipeline

Competently composed pipeline project, in compliance with all requirements, standards and technical conditions is the key to further safe operation.  We usually include in the project pipelines of high, medium and low pressure, as well as gas facilities, regulatory stations and points.

Designing is carried out by really well trained professionals who have been working with us for many years. When drafting a project the most important thing is providing a safe and continuous supply of gas, ways to disable certain elements of a pipeline to carry out maintenance and repair, as well as simplicity and ease of use by end users.

Before the construction starts the project drawn up by our organization undergoes an examination of authorized instances, including "Rostehnadzor,"  "Mosgaz", "Mosoblgaz" then specialists or supervisory authorities give permission for the construction of a gas pipeline or reject the project.

Construction of transit gas pipeline

Construction of transit pipelines consists of a number of stages, each of which is strictly controlled for the compliance with state standards, specifications, rules and regulations.

1. Material inspection

Before laying of pipes external control of all pipes (each pipe of the batch), insulation materials, fittings and all other materials is performed. Pipes with cracks, dents and corrosion damage are rejected. In addition to visual inspection of the insulation coating, at the request of the customer or general contractor an instrumental insulation testing method according to GOST 9.602 may be applied as well.

For the construction of above-ground gas pipelines steel pipes are most commonly used; for underground - steel and plastic for interior - steel and copper. Often the preference is given to plastic, which is not only resistant to corrosion, but also more durable, plus it does not require corrosion protection.

2. Transportation of pipes

Transportation of pipes for gas pipeline construction is conducted by our organization with the help of special vehicles with pole trailer, securing devices and turnstile conics. The trailer has a strong coupling with the vehicle and the driver's cab is equipped with a mandatory safety shield to protect the driver from longitudinal movement of the pipe. All safety requirements are met during the transportation.

3. Coupling of pipeline

Gas pipeline coupling is performed by experienced professionals from pre-fabricated sections and factory made fittings including:

  • pipe sections,
  • bends,
  • semi-bends,
  • plugs,
  • swages,
  • sump units.

Such order of coupling provides sealed and fast installation of the whole pipeline structure. All design elements and dimensions of welded joints of steel gas pipelines used comply with GOST 16037.

Gas pipelines welding technology typically includes:

  • pipe preparation,
  • assembling joints
  • welding pipe sections
  • welding of sections in a line.

To couple pipes we use gas and arc welding, butt fusion welding, CO2 welding and soldering. Only experienced welders qualified in accordance with   RD 03-495 are certified to welding work on the construction of pipelines. Only certified solderers with at least 4th or 5th category are allowed to solder internal copper gas pipelines.

Finished welded joints of gas pipelines are not only visually inspected, but also undergo mechanical and physical tests in accordance with the requirements of SNIP 42-01. Joints welded with arc or gas welding meet the requirements of GOST 16037.

4. Installation and laying

Laying of underground pipeline is carried out either by single pipes (sections) with further welding in the trench or by long-length lashes, pre-welded on the berm of the trench.

5. Ballasting of transit gas pipelines

To ensure the desired position of the gas pipeline in the trench we carry out tentative ballasting and binding on special design elevations in the trench.

Ballasting is usually performed by one of the following methods:

  • pipe concreting,
  • landfilling,
  • concrete weighting hitching,
  • polymer-ground container hitching.
  • Our experts carry out the final fixing of gas pipelines with several types of anchors in the supporting soil.

Leak and Pressure tests of the pipeline

After the completion of construction gas pipelines are leak and pressure in accordance with the applicable rules and standards. Before the test of the gas pipeline for leak the interior cavity of the pipes must be cleaned. Cleaning is done in two stages:

  • cleaning of individual pipes or sections immediately before welding in lashes;
  • purging of the gas pipeline at completion.

Our specialists carry out a set of tests of gas pipeline in the presence of technical supervision of the customer, as well as representatives of gas industry.

Corrosion Protection

Gas pipeline protection project is developed by us simultaneously with the construction or reconstruction project. All types of corrosion protection are carried out by us before putting the pipeline in commission.

Putting the pipeline in commission

After carrying out of all tests the transit gas pipeline is put in commission. After that the district operational gas service can let the gas. Before that it is necessary to displace air from the pipeline.