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Lightning Risk Assessment Calculator

Results: Strike Frequency:
Tolerable Frequency:
Supporting Structure Construction Type Roof
Area Calculation

Lightning Flash Density 
Relative Structure Location
Structure located within a space containing structures or trees of the same height or taller within a distance of 3H
Structure surrounded by smaller structures within a distance of 3H
Isolated structure, no other structures located within a distance of 3H
Isolated structure on a hilltop
Structure Contents
Structure Occupancy
Lightning Consequence

- Notes on usage -

  1. When the calculator icon appears next to the 'Results' fields, data has changed and you need to click on that icon to recalculate the sheet.
  2. After a recalc, you can bookmark this page and the data you have entered will be saved in the bookmark. This doesn't work if you have changed the data and not done a recalc.
  3. Calculations are based on NFPA-780 [2000] data and requirements.