Designed to be welded on site at its end(s) to connect pipe(s) together and allow change in direction or pipe diameter, or branching or ending. Widely utilized oil and gas industries, including upstream (exploration and production), midstream (transportation by ships, pipeline, rail, trucks: storage and wholesale) and downstream (refining into fuels or chemicals: marketing and distribution). Power plants using fossil or nuclear fuels. Geothermal energy for harnessing heat from the earth

KS ( Korean Industrial Standards)
JIS (Japanese Industrial Standards)
ANSI (American National Standards Institute)