Evaluasi Penangkal Petir Dengan Menggunakan Metode Sudut Proteksi Dan Bola Bergulir Pada Gedung Sekolah Dasar Negeri 041 Kota Tarakan
Abstract The purpose of this study was to evaluate the external lightning protection system of the State Elementary School 041 (SDN 041) building in Tarakan City using the protection angle method and the rolling sphere method, in accordance with the General Regulations for Lightning Protection Installations (PUIPP) and SNI 03-7015-2004. The evaluation was conducted to determine the estimated lightning strike hazard level, the extent of the protected area, the effectiveness of the installed protection system, and the adequacy of the grounding resistance value. A quantitative descriptive research method was employed, involving the collection of building dimension data and monthly thunderstorm data, as well as direct soil resistance measurements using an Earth Tester. Calculation results showed that a lightning strike hazard index of 12, indicating that the installation of a lightning protection system was highly recommended. The building's protected area (A_e) was calculated to be 3,958.22 m², with a direct lightning strike frequency (N_d) of 0.052 strikes per year, placing the building in Protection Level IV. Evaluation using the protection angle method with a 45° angle resulted in a protection radius of 31.125 meters for each air terminal, with the entire building structure situated within the safe zone. Analysis using the rolling sphere method with a 60-meter radius showed that the sphere did not touch the building structure but only contacted the air terminals, with an estimated lightning strike current of 234.89 A. Field measurements indicated a grounding resistance value of 209 2; subsequent parallel calculation showed a value of 0.23 2, which met the safety standard of SNI 03-7015-2004 (requiring a value below 52).