1.What to do before removing a gas pipe after shutting off the supply?
1.关闭燃气供应后，拆除燃气管前应做什么？
2.What’s the proper material for a water supply valve?
2.供水阀门用什么材质比较合适？
3.How frequently should a 1/2-inch steel gas pipe be supported?
3.1/2 英寸钢制燃气管应多长距离支撑一次？
4.What is the maximum flow rate in gallons per minute (GPM) allowed for a residential lavatory faucet?
4.住宅洗手盆水龙头的最大流量是多少加仑每分钟（GPM）？
5.What is the recommended support spacing for plastic piping?
5.塑料管道的建议支撑间距是多少？
6.Who enforces lead/copper rules in drinking water systems?
6.谁负责执行饮用水系统中的铅 / 铜规定？
7.What causes piping noise when fixtures are used?
7.使用固定装置时，什么原因导致管道发出噪音？
8.What is the required burial depth for a plastic gas line where it might be damaged?
8.塑料燃气管道埋设多深才有损坏的风险？
9.How close must a gas appliance shut-off valve be?
9.燃气器具截止阀必须安装在多近的地方？
10.Which underground gas line can be bent?
10.哪种地下燃气管可以弯曲？
