Most geodesic dome internal floating roof tanks do not meet the basic requirements for lightning protection contained in National Fire Protection Association NFPA 780, the US lightning protection standard.
The main problem is that they do not meet the minimum thickness requirements specified in the standards to prevent burn through from a direct lightning attachment. Therefore, air terminals (lightning rods) are required to protect the dome and tank.
After recent lightning strike incidents involving geodesic domes, a leading dome manufacturer asked Lightning Master to develop a system for geodesic domes that can be easily installed and maintained. This system consists of air terminals and bonding jumpers, and employs the tank structure as the conductor and grounding system. For certain types of domes it also includes a network of conductors to convey lightning current to the tank shell.
The Lightning Master system meets the requirements of NFPA 780 for air terminal placement and American Petroleum Institute API 545 and 2003 for grounding.
Lightning Master uses its streamer-delaying air terminals (SRAT) in place of Franklin lightning rods. The SRAT’s are designed to help delay the formation of lightning completing streamers from a protected structure. They do this by dissipating the ground charge to atmosphere that would otherwise constitute a streamer through a multiplicity of small radius electrodes attached to the tip of the air terminal. In the event they become saturated and are unable to dissipate sufficient charge, they reliably revert to the mode of a conventional lightning rod and attract the strike. The lightning energy is then conveyed to ground through the tank structure, inherent self-grounding of flat-bottom steel tanks, and any supplemental conductors, jumpers or grounding.