API 5L specification covers seamless and welded steel line pipe. It includes standard-weight and extra-strong threaded line pipe. It includes standard-weight and extra-strong threaded line pipe; and standard-weight plain-end, regular-weight plain-end, special plain-end, extra-strong plain-end, special plain-end, extra-strong plain-end pipe; as as well as bell and spigot and through-the-flow line(TFL) pipe.
The purpose of this specification is to provide standards for pipe suitable for use in conveying gas, water, and oil in both the oil and natural gas industries
