N-UNCOUNT （覆盖水管、水箱或屋顶内部的）绝热材料，保温材料 Lagging is special material which is used to cover pipes, water tanks, or the inside of a roof so that heat does not escape from them or so they do not freeze. （覆盖水管、水箱或屋顶内部的）绝热材料，保温材料 [mainly British]