Pipeline Construction

Pipeline systems should be constructed in accordance with written specifications that are consistent with API RP 111. The lay methods and other construction techniques are acceptable under those RP provides the pipeline meets all the criteria.

Construction Procedures

Construction offshore pipelines requires careful control of the pipe as it is installaed onto the sea floor. The installation system should be carefully designed, implemented and monitored to ensure safe handling to protect the integrity of the pipeline system. A written construction procedure should be prepared. It should identify the allowable limits for the basic installation variables, including the following :

1. Pipe tension
2. Pipe departure angle
3. Water depth during laying operations and temporary abandonment.
4. Retrieval
5. Termination activities

The construction procedure should reflect the allowable limits of continuous lay operations, the limits where correction or temporary abandonment is necessary and the conditions that require supplemental inspection for suspected damage.

Construction workers should be advised of their safety-awareness responsibilities to protect themselves and the pipeline during construction.

Route Marking

The pipeline route should be either physically marked before construction or positioned with the use of an electronic tracking system during construction to ensure that the pipeline is installed on the designated route.

Handling, Hauling, and Storing of Materials

• Onshore

Materials stored onshore before loading for offshore construction should be handled as provided in ASME B31.4, 434.4, for liquid pipelines; or ASME B31.8, 841.251, and A816 for gas pipelines. Pipe transported by railroad enroute to the loading site should be transported in accordance with API RP 5L1.

• Offshore

Materials enroute to the offshore work site should be properly secured to minimize damage or deterioration in offshore transit. When stored at the offshore work location, materials should be secured and protected from damage.

Damage to Materials

Before being moved to the offshore work site, all materials should be inspected. Damage materials should be replaced or repaired in accordance with ASME B31.4, 434.5, for liquid pipelines; or ASME B318, 841, for gas pipelines.

Source :

API RP 1111, third edition “Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines