Does LPI have a risk assessment form for calculating lightning risk, and if so, why?
In NFPA 780 (2011 edition), Annex L is titled Lightning Risk Assessment, and should give most of the information you are requiring. This appendix gives a method for calculating the effective area of a structure from a lightning viewpoint, and shows a US map of lightning frequency to rate the locale. Once you have determined mathematically the likelihood of a lightning strike for that particular structure in that area, there are a number of factors related to the potential loss included. Loss concerns include environment, construction type, contents, occupancy, and consequence. You will then have a mathematical value that indicates whether lightning protection should be required or may be optional. NFPA 780 has a copyright, so we make the entire document available at our cost of $40.00 each, if you would like to see the full wording please click here to go to our Store. You may have access to a full set of fire codes through a company membership with NFPA.
