Significant Mitigation of Blast Overpressure Exposure During Training by Adjustment of Body Position as Demonstrated With Field Data

Abstract

Introduction: During training and deployment, service members (SMs) experience blast exposure, which may potentially negatively impact brain health in the short and long term. This article explores if blast exposure mitigation can be effectively achieved for four different weapon training scenarios that are being monitored as part of the CONQUER (COmbat and traiNing QUeryable Exposure/event Repository) program. The training scenarios considered here are a detonating cord linear (det linear) breaching charge, a water breaching charge, a shoulder-fired weapon, and a 120-mm mortar.

Materials and methods: This article focuses on the efficacy of modification of position and standoff distance on SMs' exposure to blast overpressure. Blast overpressure exposures were measured using BlackBox Biometrics (B3) Blast Gauge System (BGS) sensors worn by SMs during normal training. The BGS involves the use of three gauges/sensors, which are worn on the head, chest, and nondominant shoulder to record surface pressures at multiple locations on the SM. For the breaching charges, we compared the level of exposure when the SMs were directly in front of the blast with a breaching blanket to a modified standoff position around a corner from the charge without a breaching blanket. For the shoulder-fired weapon training, the modified approach simply increased the standoff distance of the SM. Finally, for mortars, blast overpressure exposures were compared for different levels of their ducking height (body position) below the mortar tube at the time of firing.

Results: Modification of the position of SMs during training with the det linear breaching charge had the highest measured blast exposure percent reduction, at 79%. Both the water breaching charge and shoulder-fired weapon showed lowered peak overpressures on all gauges. The measured percent reduction for the 120-mm mortar was 35%. When the blast gauges did not trigger at the modified standoff distance, the percent reduction was calculated with the assumption that the new overpressures were below ∼3.4 kPa (0.5 psi) (the lowest trigger threshold for the gauges). A figure summarizes the percent reduction for each subject in the training scenarios.

Conclusions: Results show that the modification of the SMs' position effectively mitigated blast exposures for all considered weapon scenarios. There was at least a 50% overpressure reduction from the initial to modified standoff distances and a 35% reduction from the change in SM body posture. Based on these observations, new locations and body positioning of SMs during training have been suggested for blast mitigation.