Is Lightning protection always needed?

[Gavin]

I've got a new office building being constructed in Arkansas. All wood construction and shingled roof, no metal materials on roof except eve spouts and down spouts. Should lightning protection always be installed? Seems to me that I maybe designing a building to get struck with lightning? What is the rule for when lightning protection is needed?

Gavin

 

[bphgravity]

First, get yourself a copy of the NFPA 780. Next, perform a risk and hazard analysis using the guidelines provided in the NFPA 780. If the probability of strike occuring at the structure, resulting in loss of property and other financial interests, exceeds the cost of designing, installing, and maintaining the system, you likely need an LPS.

Also check your local building codes and state statutes. Several occupanices types may automatically require an LPS regardless of risk.