These authors recently surveyed 21 lightning protection installers across the United States to obtain cost estimates of installing lightning protection on three hypothetical buildings: A single-family residence, a low-rise high school, and a five-story office building. The findings provide cost-estimating guidelines for use during the planning and design phases of construction projects.
In nonresidential buildings, the roof area is the most significant factor in determining the work required to install lightning protection. Hence, multistory buildings will generally cost less per square foot of interior floor area. In the hypothetical building, for example, the cost based on the roof area can be divided by five to estimate the cost based on floor area.
Costs will generally be more in buildings with extensive roof top equipment and demanding architectural considerations; less in building with a modicum of rooftop equipment and a simple configuration. Buildings taller than 23 m (75 ft)—Class II—incur additional expenses. These estimates do not apply to buildings that house explosives and other special occupancies.
In typical single-family homes with pitched roofs, air terminals need only be installed at the roof ridge, not the perimeter of the roof. This explains why lightning protection costs for the home in the study is below the trend line shown for non-residential construction.
It is important to remember, features such as dormers, chimneys, balconies, skylights, and rooftop equipment can add to the cost.
An example of a non-proprietary guide specification for a lightning protection assembly, written by these authors, can be downloaded from here.
Jennifer A. Morgan CSI, is an officer of East Coast Lightning Equipment Inc., an UL-Listed manufacturer of lightning protection components. She also teaches continuing education programs for Lightning Safety Alliance. Morgan can be reached at www.ecle.biz.
Michael Chusid, RA, FCSI, CCS, is a frequent contributor to The Construction Specifier and a product innovation and marketing consultant to building product manufacturers.
He can be reached at www.buildingproduct.guru.