| 摘要 |
PROBLEM TO BE SOLVED: To judge properly to stop supply of gas in earthquake blocks where a gas supplier stops gas supply for preventing secondary hazard immediately after a large scale of earthquake. SOLUTION: In earthquake blocks 1, 2, 3,... wherein a lead pipe network 10 is separated, automatic earthquake sensing interrupters are provided in governors 13, 14, 15 and 16. A Vi index corresponding to the ground amplification factor is obtained by usual small motion observation in an earthquake block 1 and the Vi index is corrected in accordance with the ground kind so as to correspond to SI index (indicating an index shown by an earthquake meter). In an earthquake block 1, at least one of earthquake meters 17 and 18 is placed in a position representing the amplification characteristic of the ground. The SI indexes of each governor 13, 14, 15 and 16 when the earthquake meter 17 placed in a representative position shows 60 kines which is the SI index of interruption for preventing secondary hazard are calculated based on the corrected Vi index ratio. Interruption SI indexes are set based on the calculated values.
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