Explosion mitigation by grids in combination with a water curtain

Abstract

The protection of people and structures against the effects of blast waves from terrorist attacks or industrial hazards is of great interest. Protective barriers are an effective means of reducing blast loads and mitigating the adverse effects. In this paper, solid protective barriers consisting of perforated plates and water film have been investigated. Two types of metal grids were tested, the first being a metal plate with small round holes and the second being a chain mail of steel rings. Open air blast tests were carried out to evaluate the protection solution under real conditions. Explosion tests were carried out with homogeneous spheres of composition B and configurations with two grids were studied. The addition of a water film to the first grid was also tested. A PCB sensor was used to evaluate the effect of the grids, or the grids covered with a film of water, on the reflected pressure on a wall behind the grids. It was observed that the overpressure and the impulse measured on the wall behind the grids with small round holes were reduced. The addition of a water film on the first grid resulted in greater attenuation. When two chains were used, the reflected overpressure on the wall was not reduced. However, the initial overpressure was reduced when a film of water flowed over the first mesh. A numerical simulation model is being developed. This will be a sizing tool to optimize the effectiveness of this explosion protection solution. This will make it possible to study the effects of different parameters (porosity, grid spacing, grid-to-wall distance…) on the reflected overpressure and impulse in a less time-consuming and costly way. Such a barrier could reduce the load on a building behind it in an advantageous and aesthetic way.