Effect of blocking state on the fire-extinguishing efficiency of liquid nitrogen in a long and narrow space

Abstract

The team's previous research found that liquid nitrogen can effectively extinguish fires in long and narrow spaces, and internal blocking can accelerate the process of fire asphyxia. In order to study the effect of blocking on the fire extinguishing efficiency of liquid nitrogen in long and narrow space, this paper takes the utility tunnel as an example to carry out an experimental study on the effect of blocking state on the fire extinguishing efficiency of liquid nitrogen. The study shows that the fire extinguishing process of utility tunnel is the result of the combined action of liquid nitrogen and blocking, in which the oxygen insulation and suffocation of liquid nitrogen plays a dominant role, and the presence of blocking accelerates the asphyxiation process. The closer the blocking is to the fire source and the greater the blocking rate, the more significant blocking promotes the oxygen-isolating suffocation effect of liquid nitrogen. However, it should be noted that the upper blocking may cause the temperature of local space to be higher. If control measures cannot be taken in time, the excessively high temperature may cause damage to the structure. Therefore, selecting reasonable blocking measures and optimizing sealing methods can maximize the effect of liquid nitrogen fire extinguishing. Relevant research has important reference value for guiding the development and application of liquid nitrogen fire extinguishing technology.