Can We Better Address the Siting of Hazard Division 1.3 Systems

Abstract : The United States (U.S.) Department of Defense Explosives Safety Board (DDESB) is responsible for siting ammunition and explosives (AE) for Department of Defense (DoD) storage and transport worldwide in times of peace and war. All siting requirements are outlined in DoD 6055.09-STD, "DoD Ammunition and Explosives Safety Standards" (Reference 1). Current methodologies for siting AE allow mixed storage of Hazard Division (HD) 1.1, 1.2.X, 1.3, 1.4, and 1.6 and follow the equation: D = k(Net Explosive Weight)1/3 Generally, if a storage site or an operating building is sited for HD1.1, the only limitation for HD1.3 AE storage is the physical capacity of the facility. However, HD1.3 systems pose a mass fire hazard and are uniquely different when compared to detonable systems (HD1.1). This paper discusses the following: Many of the recorded accidents have been caused by fire. The false impression that HD1.3 materials are safer than HD1.1. For example, HD1.3 material is much easier to ignite than HD1.1. In addition, HD1.3 readily burns at atmospheric pressure, whereas HD1.1 material generally does not. Mixed storage of HD1.3 with HD1.1 may increase the probability of accident. While HD1.3 materials do not project hazardous fragments, burning HD1.3 materials in buildings with heavy confinement can cause catastrophic failure of the structure with projection of lethal fragments. Why D = kW1/3 is inappropriate for determining safe separation distances for mass burning events and may result in excessive safe separation distance requirements. This paper presents a recommendation for an alternate method for determining safe separation distances from mass fire accidents based on human response to fires and radiation from the fires. It is based on preventing second-degree burns caused by heat flux and exposure time.