GB 50057-2010 第3.0.4条
| | In areas where lightning strikes to ground may occur, a building shall be classified as a Class III lightning protection building when any of the following conditions applies:<br>• Provincial-level key cultural relic protection buildings and provincial-level archives;<br>• Ministerial- and provincial-level office buildings and other important or densely occupied public buildings with an expected lightning strike frequency greater than or equal to 0.01 times/a and less than or equal to 0.05 times/a (Note: if a hotel's expected lightning strike frequency falls within this range, it shall be classified as Class III);<br>• General civil buildings such as residential and office buildings with an expected lightning strike frequency greater than or equal to 0.05 times/a and less than or equal to 0.25 times/a (Note: if a hotel is considered a general civil building and its expected lightning strike frequency falls within this range, it shall be classified as Class III);<br>• In areas with an average thunderstorm day greater than 15 d/a, isolated tall structures such as chimneys and water towers with a height of 15 m or more; in areas with an average thunderstorm day less than or equal to 15 d/a, isolated tall structures such as chimneys and water towers with a height of 20 m or more. |