Steel pipe is required in the majority of oil and gas production and pipeline applications. ASME A53 and A106 and API 5L seamless, electric resistance welding (ERW), and submerged arc welding (SAW) steel pipe are commercially available and most commonly used in pipeline systems. PVC, fiberglass, polypropylene, and other materials may be used in low-pressure and utility applications. ASME B31.4 and B31.8 allow the use of alternate materials in very restricted applications. Seamless pipe is seldom used in pipeline applications because of the higher cost and limited availability. From a design and regulatory perspective, pipe made with ERW and SAW seams is equivalent to seamless pipe and is less costly. Note: This is not true for piping systems designed in accordance with ASME B31.3.
For high-pressure pipeline, high-grade pipe, such as API 5L grades X42, X52, X60, and X65, is selected because much thinner wall pipe can be used, which significantly reduces pipe costs. Construction cost savings also are realized, as the welding time is reduced and material shipping/handling costs are reduced.