Copper pipes used in fire sprinkler systems are somewhat superior to steel pipes in terms of corrosion resistance. They have been widely used in apartments since 2010, but their firefighting performance has not been firmly established due to leakage caused by pitting. In order to solve this problem, copper pipes need to be replaced by pipes made of other materials such as STS or C-PVC, which, however, would impose an economic burden on the party responsible for maintenance, as well as economic loss to other relevant parties and inconvenience to residents. Although 27 leakages occurred in the E region in 2018, it was found that the number of incidents was reduced to just one case after an application of corrosion inhibitor. Therefore, for 2 months beginning in October 2020, a second project to reduce piping corrosion was conducted with 2,000 households in five regions nationwide. During this period, the standing fire water of five apartment buildings in the A region was measured as having a pH 8.34–9.08, an ORP -94.9–-135.8 mV, and an EC 0.097–0.137 ms/cm, which indicated a need for improvement. Subsequently, a corrosion inhibitor was poured into the fire water, resulting in improved values of pH 11.13–11.26, ORP -257–-265.5 mV, and EC 4.189–5.769 ms/cm, which demonstrated the effect of preventing pipe corrosion. It was evident that water-soluble silicate was adsorbed on the metal pipe of the anode to form a thin monolayer, which induced basicity by increasing the pH and by decreasing the ORP, which eventually minimized corrosion.

The safety of carbon dioxide fire extinguishing facilities is studied through a fundamental case analysis of leakage accidents in carbon dioxide fire extinguishing facilities. In Korea, since 2001, there have been 11 accidents caused by leaks from carbon dioxide fire extinguishing facilities, killing 9 people and injuring more than 60 others. Recently, three subcontractors inhaled CO₂ gas from a transportation passage outside a collection chamber, killing two of them and injuring the other. This incident brought social attention to the CO₂ fire extinguishing facility in the first basement of S Electronics. In this study, we analyze the cause of the accident (e.g., pressure and temperature changes in the carbon dioxide leakage process) using a one-dimensional transient model, the effects of oxygen and CO₂ concentration at the location of the incident, and that these results can be used as basic data to prevent suffocation disaster in carbon dioxide fire extinguishing facilities.

Perilla oil cakes are the residues of oil pressing processes, and used as fertilizers, feedstuff, food, etc. However, according to recent reports, perilla oil cakes often ignite spontaneously due to scorching heat, particularly in rice mills, general mills, and oil mills where large amounts of perilla oil cakes are stored. Thus, in this study, we attempted to elucidate the risk of spontaneous ignition of perilla oil cakes. For this purpose, thermogravimetry/differential thermal analysis (TG-DTA) was performed to identify thermal properties like weight reduction and heat generation, and spontaneous ignition was conducted for sample vessels of different thicknesses. The results showed that the ignition temperature of perilla oil cakes was 115 ℃ for the small (20 cm × 20 cm × 3 cm) vessel. The apparent activation energy associated with the critical ignition temperature was 60.74 kJ/mol. The ignition delay time and the time to reach maximum temperature were both found to increase with increasing vessel thickness. It was concluded that proper protection against heat must be in place because fire risk increases and spontaneous ignition can occur when large amounts of perilla oil cakes are accumulated.