Closeup on Gas Pipe Line System Connection Installed in House Wall and Rain Gutter. Make Gas Line Connections From Steel or Copper Pipes to Ranges, Clothes Dryers Safe and Secure by Using Proper Fittings. 外部气体管道系统连接安装在房屋墙壁上。通过在室外使用适当的配件，使气体管连接从钢管或铜管到范围、干衣机安全可靠 .