Distribution A: Approved for public release
Comparison of Shock Stimuli from Current Hazard Classification Testing and Potential Threats
Paul Braithwaite, Robert Hatch, Robert Wardle
Northrop Grumman, Innovation Systems; Brigham City, Utah, USA
ABSTRACT
The process of determining hazard classification of energetic materials and articles containing energetic
materials in the United States is described and governed in a Joint Technical Bulletin issued by the Army, Navy and
Air Force titled “Department of Defense Ammunition and Explosives Hazard Classification Procedures.” This
document is often referred to simply as TB 700-2. Articles requiring hazard classification range from very small
initiating devices with under a gram of energetic material to extremely large rockets containing over a million pounds
of propellant. It is challenging to require a single protocol to properly address hazard classification for this broad range
of items. This paper summarizes an ongoing effort to improve knowledge regarding the relationship between storage,
handling and transportation related shock hazards larger solid rockets may experience and the tests used to determine
their hazard classification. This paper presents the results of this study and recommends potential modifications to
current protocols used in shock testing for hazard classification determination.
BACKGROUND
Solid rocket propellants are energetic by nature and design. Transportation, storage and handling of these
solid propellant rockets are carefully monitored and their specific hazard classification is governed by the Department
of Defense Ammunition and Explosives Hazard Classification Procedure most commonly referred to as TB 700-2
1
.
Solid rocket propellants are Class 1 Hazard Division materials and are commonly classified into either 1.1 (mass
explosion) or 1.3 (mass fire, minor blast or fragment) categories. To determine if a specific formulation or article is a
Class 1.1 or Class 1.3 composition, specific tests are performed beginning with basic handling tests (impact, friction,
thermal stability and ignition without confinement). Once formulations have passed these tests, additional testing is
required if a 1.3 hazard classification is desired. For propellants targeted for use in large rocket motors, two additional
major tests are called out in TB 700-2, namely a shock test and a liquid fuel/external fire test.
This paper focuses on current shock testing described in TB 700-2 and complements and enhances an
extensive body of work performed by other researchers in the late 1990s and early 2000s. Examples of references on
this topic may be obtained by contacting the authors. The current TB 700-2 protocol offers three different options for
shock testing as summarized below. To be considered for a 1.3 classification, the composition must pass one of these
options.
Option 1: Test and pass the super large-scale gap test (SLSGT) at zero cards
Option 2: Determine the unconfined critical diameter of the subject formulation and then test the composition
in a configuration representing motor confinement at 1.5 times the critical diameter with a shock input of 70
kbar
Option 3: Test and pass a gap test at motor diameter with a shock input of 70 kbar
A top-level evaluation of these three shock testing options for solid rocket propellants planned for use in
larger rocket motors (> 24 inches in diameter) leads to the following observations regarding Options 1 and 3. Option
1 is a very severe test (the SLSGT) that consists of testing propellant cast in a substantial steel tube and being subjected
to the detonation of a large Composition B booster without any attenuation between the booster and acceptor.
Experimental data generated for a wide range of compositions indicates that formulations containing even modest
amounts of classical high explosives (e.g., cyclotetramethylene tetranitramine [HMX], cyclotrimethylenetrinitramine
[RDX], and nitroglycerin) will not pass this test. Option 3 requires production of very large test articles that are costly
to manufacture and test. For example, a 24-inch-diameter article must be 96 inches long, which will weigh more than
2,500 lbs. and require an explosive booster weighing more than a hundred pounds.
The challenges associated with Options 1 and 3 often drive researchers tasked with developing high
performance hazard class 1.3 propellants for large rocket motors to the Option 2 test.
