ISO 25947-1:2017 pdf download – Fireworks — Categories 1, 2 and 3 — Part 1: Terminology. 3.16 first? principal? effect principal effect (3.32) of a firework (3.15) which is the first to occur during the functioning of the firework 3.17 friction head ignition head (3.18) designed to be ignited by friction 3.18 ignition head initial fuse (3.20) consisting of pyrotechnic composition (3.36) only 3.19 initial fuse burning burning which immediately follows ignition and precedes any effect 3.20 initial fuse component of a firework (3.15) which is ignited in order to start the firework functioning 3.21 invisible burning time time between...