## 3 Results
### Fire Detection and Extinction Tests  
#### 3.3.1 Internal Fire Test  
The results of the internal fire tests are shown in Figure 9. Figure 9a shows that smoke detection by aspiration is carried out very quickly as it can be seen that the existing thermal gap was slightly lower than 20 K for thermocouple T2, which presents the greatest increase. With the Hi-Fog(r) water mist system, the fire can be stopped approximately in the third minute, but part of the material remains at a high enough temperature to produce a latter ignition, as can be seen after 25 min, once the 50 L water bottle has run out. This causes the propagation of the fire and the ignition of the material contained in the packaging closest to the T2 thermocouple, measuring a maximum temperature of approximately 160 \({}^{\circ}\)C. Possibly, a larger amount of water (100 L water bottles) would have been able to prevent subsequent reignition; however, the price of this system is high if compared to other fire detection and extinction systems. The results of the smoke detection test with explosion extinguishers are shown in Figure 9b. Noted were the existence of a flame in the pyrotechnic material packaging and the spread of the fire before the explosion of the extinguishers. The existing fire extinguisher on the ground and adjacent to the rear packaging extinguished the fire developed in the same packaging approximately 1 min after the start of the fire (see thermocouple T2). The other extinguisher, placed on the packaging of the pyrotechnic material that caused the fire, was unable to extinguish it, which led to the immediate propagation and reignition of the products inside (see thermocouple T1). In addition, the explosion of the extinguishers causes the dispersion of the packages, which affects the temperatures measured in thermocouple T3, as the distance from the thermocouple to the fire increases. After reignition, another explosion extinguisher with a fuse was manually thrown onto the fire, which completely extinguished the fire. This fact suggests the possibility of having extinguished the fire in the event of the existence of a third explosion extinguisher. The price of this system is very low compared to other fire detection and extinction systems. Furthermore, it is very quick and easy to install and maintain. Figure 9c indicates that CO\({}_{2}\) does not act fast enough to extinguish the fire generated by pyrotechnic articles. The pyrotechnic material contained in the first package cools down around minute 3, when the temperature in the thermocouples closest to the fire (thermocoouples T1 and T3) was slightly above 20 \({}^{\circ}\)C. However, it is not possible to completely extinguish the fire, which produces a reactivation and subsequently spread to the second packaging at approximately minute 8. It can be seen that the maximum temperature reached in the T2 thermocouple (the closest to the second packaging) exceeds 150 \({}^{\circ}\)C. The  
price of this system is high compared to other fire detection and extinction systems and requires a complex installation. In addition, it has the disadvantage of the high toxicity of the gas, which is the main reason why it is not indicated in those places where there is a permanent presence of people. For the optical detection system for smoke and water as an extinguishing agent, Figure 9d shows that, after starting the fire, the temperature in the vicinity of the pyrotechnic load rises to approximately 27 \({}^{\circ}\)C at T1 thermocouple (the closest to the source of fire),  
Figure 9: Results of internal fire tests: (**a**) smoke detection with suction system and water mist Hi-Fog®. (**b**) Smoke detector with explosion extinguishers. (**c**) Ionization detector and CO2 extinguishing system. (**d**) Optical smoke detector and water extinguishing system. (**e**) Optical smoke detector and foam extinguishing system. (**f**) Optical smoke detector and dust extinguishing system. moment at which the extinction of the fire begins.