## 3 Results
### Fire Detection and Extinction Tests
#### 3.3.2 External Fire Test  
The results of the external fire test are plotted in Figure 10. Figure 10a indicates that the aspirating smoke detector registers the fire approximately 20 s from the start and when the temperature slightly exceeded 20 \({}^{\circ}\)C. The nebulized water is capable of extinguishing the fire before it penetrates the interior and causes the initiation of the existing pyrotechnic articles inside. In the case of the smoke detection system and explosion extinguishers, Figure 10b shows that, once the fire is generated, the temperature in the surrounding area of the pyrotechnic load rises slightly to approximately 42 \({}^{\circ}\)C. At this moment, the detection and explosion of the extinguisher initiates, completely extinguishing the fire. For the system with an ionic detector and HFC-227 ea gas as extinguishing agent, Figure 10c shows that, after approximately one minute has elapsed since the start of the fire and having reached temperatures between 30 and 45 \({}^{\circ}\)C in all three thermocouples, the system extinguishes the fire and prevents its spread to adjacent packages. The system has the advantage of the non-existent toxicity of the gas, unlike in the case of CO\({}_{2}\), but the cost of the system is still high compared to other systems. Figure 10d shows the results for the water extinguishing system. Once the fire is generated, the agent is detected and discharged after approximately 10 s, but the flame  
cannot be extinguished. However, thanks to the fact that the extinguishing system does not stop acting at any time, the fire is completely extinguished after approximately five minutes. In the tests carried out, it is verified how, in the first moments, a certain amount of smoke is produced prior to the generation of flame or fire. It is observed that a rapid response of the detectors is important to achieve timely action, with ionic and aspiration detectors being the most sensitive and fastest, although they also have a higher cost. It is observed that all the fire detection and extinction systems evaluated are effective for extinguishing the fire produced outside the packaging of pyrotechnic products as they all produce the fire extinction before the fire has penetrated the existing pyrotechnic articles inside the packaging. In the case of a fire caused by the pyrotechnic material itself, the recommended extinguishing system must have a very high cooling capacity, such as water or foam. Fountains generate a large amount of flame and/or fire, increasing the probability of spreading to the rest of the surrounding pyrotechnic articles and packaging inside the warehouse. For this reason, the extinguishing agent must act on the entire material as otherwise the reignition of the device does not find any difficulty. Therefore, the location of the extinguishing systems and the stacking during storage of the packages should be carefully considered. These systems are usually located in the ceiling of the warehouses; however, if the ceiling is significantly high or the packages are stacked to a high height, it is possible that, in case of fire, the extinguishing agents do not reach the pyrotechnic articles located at the bottom of the packages. If systems are compared, the only system that has managed to extinguish the fire caused by the pyrotechnic products has been the water network due to its continuity and  
Figure 10: Results of external fire tests: (**a**) smoke detection with suction system and water mist Hi-Fog®. (**b**) Smoke detector with explosion extinguishers. (**c**) Ionization detector and HFC-227 ea gas extinguishing system. (**d**) Optical smoke detector and water extinguishing system. high cooling capacity. The low economic cost of installation and maintenance is important, although it is necessary to have a network socket and ensure a supply 24 h a day. For water mist systems and explosion extinguishers, a greater number of tests should be carried out considering the different possibilities that these two fire detection and extinction systems admit.