Occupational overpressure exposure of breachers and military personnel

Military and law enforcement personnel may be routinely and repetitively exposed to low-level blast (LLB) overpressure during training and in operations. This repeated exposure has been associated with symptoms similar to that reported for sports concussion. This study reports LLB exposure for various military and law enforcement sources in operational training environments. Peak overpressure and impulse data are presented from indoor breaching, outdoor breaching, shotgun door breaching, small arms discharge, and mortar and artillery fire missions. Data were collected using the Black Box Biometrics (B3) Blast Gauge sensors. In all cases, sensors were attached to the operators and, where possible, also statically mounted to walls or other fixed structures. Peak overpressures from below 1 psi (7 kPa) to over 12 psi (83 kPa) were recorded; all values reported are uncorrected for incidence angle to the blast exposure source. The results of these studies indicate that the current minimum safe distance calculations are often inaccurate for both indoor and outdoor breaching scenarios as true environmental exposure can consistently exceed the 4 psi (28 kPa) incident safe threshold prescribed by U.S. Army doctrine. While ballistic (shotgun) door breaching and small arms firing only expose the operator to low peak exposure levels, the sheer number of rounds fired during training may result in an excessive cumulative exposure. Mortar and artillery crew members received significantly different overpressure and impulse exposures based on their position (job) relative to the weapon. As both the artillery and mortar crews commonly fire hundreds of rounds during a single training session they are also likely to receive high cumulative exposures. These studies serve to provide the research community with estimates for typical operator exposure across a range of operational scenarios or in the discharge of various weapons systems.