Attachment 8 - Calculations Replace Fuel Tanks B2096.pdf

This is a technical analysis document for NFPA 780 Simplified Risk Assessment related to lightning protection determination for a fuel tank replacement project (B2096, comm. no. 482503).

The document presents a comprehensive lightning protection risk assessment for a structure with specific dimensional and material specifications. The structure is a metal building with a nonmetallic roof measuring 8 feet in length, 16 feet in width, and 8 feet in height (equivalent to 2.4 meters by 4.9 meters by 2.4 meters). The assessment calculates an equivalent collective area of 3,090 square feet (287 square meters) and applies NFPA 780 reference tables to determine construction and occupancy coefficients. Key coefficients include: construction coefficient (Cc) of 0.5 for metal structure with nonmetallic roof, structure contents coefficient (Cc) of 3 for standard value and noncombustible materials, structure occupancy coefficient (Co) of 0.5 for normally occupied spaces, and lighting consequence coefficient (Ce) of 10 for consequences to the environment. The annual threat of occurrence (No) is calculated at 1.5×10⁻³, resulting in an annual threat tolerance (Nc) of 200.0×10⁻⁶. The determination indicates that No ≤ Nc with Lightning Protection System (LPS) optional status. The analysis includes tolerance analysis ranges and references NFPA tables for location factors, construction coefficients, structure contents coefficients, structure occupancy coefficients, and lighting consequence coefficients to support the risk assessment conclusion.