UNIT 2

Text Pipeline Construction

Pipeline planning is a complex procedure. It includes

• marketing research (маркетинговое исследование)

• pipeline design (проектирование трубопровода)

• pipe and components specification (составление техусловий на трубы и комплектующие)

• route selection (выбор маршрута)

• environmental assessment (оценка воздействия на окружающую среду)

• public consultation (общественное обсуждение),

• land acquisition (землеотвод)

• permitting (получение разрешительных документов)

Pipeline Construction is divided into three phases:

• pre-construction (подготовительные работы),

• construction (сооружение)

• and post-construction (послепусковое обслуживание)

Pre-construction Activities

- Surveying (геодезическая подготовка трассы) and staking (разметка)

At this stage the right-of-way (ROW) is surveyed and staked (готовят и размечают полосу отчуждения). The right-of-way is a zone containing pipeline route and construction site. It also provides access to the site. This stage includes localizing and marking other pipelines to be crossed.

- Right-of-way preparation

The right-of-way is cleared of trees. Top soil is removed, the site is leveled and graded to provide equipment access. Ditchers, backhoes (обратная лопата), side boom bulldozers and trucks should easily get to the construction site. Soil is stockpiled (ссыпать в отвал) for future reclamation (восстановления).

- Trenching прокладка траншей The trench centre line (ось) is surveyed, re-staked and dug. The equipment used depends on the soil. It may be bucketwheel trenchers роторные экскаваторы-траншеекопатели or backhoes экскаватор с обратной лопатой. Small-diameter pipes are buried using plough-like machines скребкового типа that cut the earth and install the pipe.

- Stringing the pipe укладка труб Pipes from stock piles (штабель) are laid end to end (встык) and prepared for welding.

Construction

- Pipe bending (гибка)

Pipe bending is necessary to follow the terrain contour and depends on soil type. Special machines bend the pipe without destroying its cross section.

- Pipe joining

Welding machines and manual arc welding are used to weld pipes. A weld is usually performed in several passes (проходов). Welding site is protected by shacks (сварочные заграждения). Weld integrity is tested by X-ray or ultrasonic methods. To protect pipe coating against damage coated pipes are mechanically interfered (механически накладываются): the tapered end of one pipe is fitted into the flared end of another one. Ep'oxy resin is used to lubricate the pipe joints and to seal them afterward.

- Pipe coating

Inside and outside coating protects pipe against corrosion caused by ground water or throughput. Coating composition depends on the nature of transported product. Pipe sections are pre-coated before construction. Care is taken not to damage this coating. But the welded joints must be coated at the construction site.

- Positioning the pipe in the trench

The pipeline is lowered into the trench using bulldozers with special cranes called sidebooms (трубоукладчик).

- Installing valves and fittings (монтаж арматуры)

Valving and fittings are installed after the pipeline is in the trench. The valves are used for pipeline operation. They shut off or isolate блокировать pipeline sections.

- Backfilling the trench (обратная засыпка траншей) After the pipeline is laid in a trench it is carefully backfilled not to damage pipe coating.

Post-construction

- Pressure testing (опрессовка) The pipeline is pressure-tested for about eight hours with air, water or a water-methanol mixture. A pressure-temperature recorder records the test results and saves them for confirmation.

- Final cleanup (окончательное восстановление) The top soil removed from the right-of-way is replaced and reseeded. The right-of-way is restored to its original condition and where necessary, erosion control barriers are constructed. If the right-of-way passes through farmland, it can be seeded with crops (зерновые).

Ex. 5. Agree or disagree with the following statements:

1) The right-of-way contains only the pipeline.

I'm afraid you are wrong. The right-of-way also contains a construction site. It provides access to the site and storage for pipe and equipment.

2) Bucketwheel trenchers (роторный экскаватор) or backhoes (экскаватор с обратной лопатой) are used to dig a trench.

You are right. This equipment is selected depending on the soil, terrain and other factors. Besides bucketwheel trenchers (роторные экскаваторы) or backhoes (экскаватор с обратной лопатой), plough-like machines (скребкового типа) are used for small pipe laying. They make a deep cut in the earth and lay a pipe there.

3) It is impossible to bend a pipe without destroying its circular profile.

I can't agree with you. Special pipe-bending machines bend the pipe without destroying its circular profile.

4) Coating the pipe is a very important process of pipeline construction.

I fully agree with you. Inside and outside coatings prevent pipe corrosion caused by ground water and transported products.

5) Valves and other fittings are installed before the pipeline is in place in the trench.

You are not quite right, I'm afraid. Valves and other fittings are usually installed after the pipeline is in the trench.

6) Welding machines are used to weld individual lengths of pipe.

Yes, you are right, but I'd like to add that pipes are also welded by manual arc welding. Several passes may be required to complete a weld.

7) Some internally coated pipes can’t be joined together by welding.

You are not quite right. Internal coating is damaged by welding. So coated pipes are joined by mechanical interference механическим наложением, when the tapered end of one pipe is fitted into the flared end (раструбный конец) of the next pipe. An ep'oxy resin is used to lubricate and seal the pipes

Ex.6. Answer the following questions: