Lightning Protection Design

All Lightning Protection Systems Designed at PowerCom Solutions, LLC are performed in house by a highly trained and experienced team who have been tested and certified by Lightning Protection Institute (LPI) . Roof Plan and Exterior Elevation drawings are required to provide an adequate design of a lightning protection system on new structures. Roof Plan and Exterior Elevation drawings are helpful but not required for a design on an existing structure. The information required for existing structures are dimensions for the roof perimeter, location and size of mechanical units and height of the structure.

Lightning Protection Design begins with an evaluation of the structure and the purpose of the structure, ordinary structure or a structure that handles/stores flammables. Followed by an examination of the physical characteristics of the structure; height, perimeter footage, building materials, steel framing, etc. The height of a structure is significant because it will determine if the structure is classified as "Class I" or "Class II" which determines the size of conductors and lightning rods. Height also determines the type of grounding utilized, NFPA 780 and LPI-175 requires a ground loop conductor to be installed for any structure exceeding 60 ft in height. The perimeter footage determines the number of paths to ground. Building Materials help to determine the material of the Lightning Protection System, copper components or aluminum components. The steel framing, if applicable, can be utilized at the downlead conductors as long as it is minimum 3/16" thick and continuous throughout the structure.

Lightning Protection Designers must also perform calculations to determine "Zones of Protection" from higher roofs / air terminals. The calculations are based on rolling an imaginary 150' radius (300' diameter) ball over the roof considering all possible directions. Any portion of the structure the ball touches requires an air terminal device. The 150' radius is derived from the distance at which a downward lightning leader results in the initiation of an upward leader from the structure. This 150' striking distance represents 91% of all lightning events. Some structures would be more sensitive in the event of a lightning strike (structure storing flammables/explosives). Structures which fall into this category require extra protection and therefore require the use of a 100' radius (200' diameter) ball. This 100' striking distance represents 97% of all lightning events.
Lightning Protection Design / Drawing Example