An Empirical Study for the Revision of the Domestic Standard for the Storage Room Temperature of the Carbon Dioxide Fire Extinguishing Agent

“National Fire Safety Code of Carbon Dioxide Fire Extinguishing Systems (NFSC 106)” restricts the storage room temperature of the fire extinguishing agent storage container to 40 °C or less. This standard was borrowed from the Japanese standard at the time of enactment of the domestic standard in 1982. This is at least 9 °C or more lower than the currently internationally used temperature standards such as NFPA 12 and ISO 6183. The low temperature standard increases the safety of the storage container; however, it may act as a regulation requiring the installation of an additional air conditioner. In this study, to conduct efficient experiments and to propose a standard for a reasonable storage room temperature, a container with an internal volume of 3.4 L was used, instead of a 68 L container with a filling ratio of 1.5, which is generally used as a storage container for the carbon dioxide extinguishing agent. However, the filling ratio (or filling density), pressure proof test pressure, and maximum filling pressure of the two containers were identical. Then, the ambient temperature of the storage container was increased from 20 °C to 50 °C, and the change in the container pressure was demonstrated. This experiment demonstrated that the safety of the storage container was maintained without abnormal phenomena such as operation (destruction) of the safety valve (rupture plate) or leakage, despite the increase in the internal pressure of the container up to 50 °C. Therefore, the storage room temperature standard of the domestic carbon dioxide fire extinguishing agent storage container was proposed to be 49 °C or less at a filling ratio of 1.47 (filling density of 0.68), same as that of ISO 6183.