... DN500MaterialDuctile ironFinishPaint, Epoxy or Galvanization ApprovalFM/ULUsage1) Automatic sprinkler system for fire protection on commercial, civil and municipal ... oil field, textile, powder plant, etc.3) Pipeline system on subway station, railway station, airport, seaport, bridge, ... as per customers requirement 2:Usage: 1)Automatic sprinkler system for fire protection on commercial ,civil and ...