... made according and conforming to the following International Standards:1) American standard (ASTM Sch 40 & Sch 80, SDR 21, SDR 26, SDR41 ... K 6741, JIS K 6743, JIS K 6739)6) National standard (GB 10002, GB 5836, GB 14823, GB 13664)7) International ... standard (ISO 4422, ISO 3633, IEC 614, GY 3050)Management: Wholly ...