地处杭州市偏西北近郊,某学院20#学生宿舍,建筑面积2000平方米,屋顶标高18米,五层砖混结构,一九八一年九月建成使用。原防雷设计采取的措施为利用建筑物基础主筋作接地极,引下线为8镀锌圆钢明敷于外墙,利用屋面四周檐口内钢筋作避雷网。接地电阻要求小于10欧。施工时将基础主筋与引下线8圆钢用电 Located in the suburbs of northwestern Hangzhou, a 20# student dormitory of a college has a building area of ​​2,000 square meters, an elevation of 18 meters, and a five-story brick-concrete structure. It was completed in September 1981. The original lightning protection design adopted measures to make use of the main reinforcements of the building foundation as the grounding electrode, and the down conductors were 8 galvanized round steels applied to the exterior walls. The steel bars around the roof were used as lightning protection nets. The ground resistance requirement is less than 10 ohms. During the construction, the basic main ribs and the lead-off wire 8 will be used for electricity