Effects of using NFPA 780 maximum installation distances to configure air-termination systems

In this work, we study the effects of using only the maximum installation distances of air terminals endorsed by NFPA 780 to validate or configure separation distances in air-termination systems. The protected zone of single and multiple air terminals is assessed through a case evaluation example by employing the 3-D Rolling Sphere Method approach along with simplified formulae provided herein for practical analysis. We propose curves for in-field validation of the maximum height of protected structures for NFPA 780 maximum air terminal distances, considering air terminal lengths of 0,30 m and 0,60 m, and their location near the corners, edges and inner rooftop.