This standard specifies the ordering content, classification and code, size, shape, weight and allowable deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of hot-dip galvanized square and rectangular pipes for structural use. This standard applies to hot-dip galvanized square tubes and rectangular tubes for structural use (hereinafter referred to as square and rectangular tubes). It is not suitable for square and rectangular pipes formed by cold bending and welding of galvanized steel plates and steel strips.