DEPENDING UP ON PREVIOUS PRE SET FACTOR COVERAGE OF THE DEVIC IS DECIDED BASED ON . . .
Height of the Lightning Arrester.
The height of the air terminal above the protected structure directly influences the achievable protection area.
Coverage should be evaluated at the actual installation height, not simply from the arrester's overall length.
Class/Level of Lightning Protection Required.
The required Lightning Protection Level (LPL I, II, III or IV) affects the design parameters.
Higher-risk structures generally require more stringent protection.
Protection Method Used.
Coverage depends on whether the system uses a conventional Franklin-type air terminal, Early Streamer Emission (ESE) air terminal, or another engineered arrangement.
Different methods use different calculation approaches.
Building Dimensions and Geometry.
Building height, length, width, roof shape, parapet walls and projections must be considered.
Complex structures may require multiple air terminals rather than relying on one terminal.
Angle of protection.
For conventional lightning protection, the applicable design method and protection class determine the protected zone depending on the angle of protection.
The rolling sphere method is particularly useful for checking whether exposed points are adequately protected or not .
Relative Height of Nearby Objects
Water tanks, solar panels, chimneys, antennas, HVAC equipment, towers and other rooftop structures can become potential lightning attachment points.
These objects must be incorporated into the protection design.
Location and Exposure of the Structure
An isolated building on open terrain is more exposed than a building surrounded by taller structures.
Local topography and surrounding structures can influence lightning exposure.
Required Risk Level
The consequences of a lightning strike should be assessed, including risks to people, equipment, business continuity and fire safety.
Critical facilities may require a higher level of protection.
Down-Conductor Arrangement
Adequate protection is not determined by the air terminal alone.
The complete system—including air terminals, down conductors, earth termination and equipotential bonding—must be properly designed.
Earthing and Soil Conditions
Soil resistivity, electrode configuration and earth-termination design influence the overall effectiveness of the lightning protection system.
Lightning current needs a low-impedance path to earth.
