Approved for Public Release; Distribution is Unlimited
Approved for Public Release; Distribution is Unlimited
Protective Construction Design Criteria for HD 1.3
Arturo Luna, PE; Naval Facilities Engineering and Expeditionary Warfare Center; Port Hueneme, CA USA
Keywords: Protective Construction, HD 1.3, Explosion, Deflagration, Choked Flow
Abstract
United Facilities Criteria (UFC) 3-340-02 is the governing document that prescribes criteria for the design of
protective construction to resist the effects of accidental explosions. It provides design criteria for the effects of
Hazard Class/Division (HD) 1.1 explosives materials. It does not consider the effects of HD 1.3 explosives systems.
Some protective construction design guidance exists outside of UFC 3-340-02 but has significant limitations. This
paper discusses a number of existing gaps and necessary developments for HD 1.3 protective construction design
criteria. Global HD 1.3 protective construction design considerations are presented. NFPA’s fire protection rating
system and its applicability and limitations to HD 1.3 protective construction is discussed.
Introduction
Within the Department of Defense, protective construction is used to protect personnel and assets from the effects of
intentional or accidental explosions, or to delay the propagation of explosions. For accidental explosions, governing
protective construction design criteria is provided by Unified Facilities Criteria (UFC) 3-340-02, “Structures to
Resist the Effects of Accidental Explosions” [1]. UFC 3-340-02 design and analysis procedures address the effects
of Hazard Division (HD) 1.1 mass-detonating explosives. It presents methods to determine the energetic output and
explosion effects of HD 1.1 materials. It also presents procedures to design protective construction to resist these
effects. These methods are accessible to designers on the basis of equivalent weight of TNT, and determining TNT
equivalencies for HD 1.1 materials is generally feasible.
Currently, UFC 3-340-02 does not provide guidance for the design of protection construction to resist the reaction
effects from HD 1.3 systems. Although some simplified protective construction design guidance exists outside of
UFC 3-340-02, limitations inherent to some of these procedures may make them undesirable to use by designers.
This paper discusses a number of existing gaps and necessary developments for HD 1.3 protective construction
design criteria. Global HD 1.3 protective construction design considerations are presented. Additionally, the NFPA’s
fire protection rating system and its applicability and limitations to HD 1.3 protective construction is discussed.
Reaction Effects of HD 1.3 Energetic Materials
Department of Defense (DoD) Manual 6055.09-M, “DoD Ammunition and Explosives Safety Standards” [2],
provides governing explosives safety standards to manage risks with DoD-titled ammunitions and explosives (AE)
by providing protection criteria to minimize serious injury, loss of life, and damage to property. It states that hazards
associated with HD 1.3 systems include fireball and thermal flux effects, gas pressures, fragments and debris.
A more detailed consideration of the hazards of HD 1.3 materials is likely to be reflected in future explosives safety
standards. The Department of Defense Explosives Safety Board (DDESB) has recognized that that current HD 1.3
criteria does not represent the hazards associated with fire initiated (combustion) reactions [3, 4, 5]. Boggs et al. [3]
conducted a review of mishaps occurring from the beginning of the 20
th
century to March 2012. The results of this
review indicate that over 75% of the mishaps had fire as the primary initiation hazard, which can be present all
throughout an AE’s lifecycle.
