Page 58 - JSOM Winter 2022

An Exploratory Comparison of Water-Tamped
and -Untamped Explosive Breaches

Practical Applications for the Tactical Community via a Pilot Study

Gary H. Kamimori, PhD; William McQuiggan; Alejandro M. Ramos, MA;
Christina R. LaValle, MS; Anthony Misistia, MS; Jonathan Salib, MS; Michael J. Egnoto, PhD*

ABSTRACT
Background: Tamping explosive charges used by breachers is allowing for the redirection of what would otherwise be
an increasingly common technique. The ability to increase the wasted energy when the explosives are detonated. Through-
directional effectiveness of the charge used, combined with out explosive breaching history, a variety of tamping materials
the potential to reduce experienced overpressure on breach- have been used, such as wood, rubber, plastic, and water. How-
ers, makes tamping a desirable tool not only from an efficacy ever, the obvious downside to the use of a rigid tamping ma-
standpoint for breachers but also from a safety standpoint for terial is the potential for fragmentation, which could lead to
operational personnel. The long-term consequences of blast critical injuries. The high risk of rigid tamping materials makes
exposure are an open question and may be associated with non-rigid alternatives such as water a preferable alternative.
temporary performance deficits and negative health symp-
tomatology. Purpose: This work evaluates breaches of varying A growing body of literature has noted short-term performance
charge weight, material breached, and tamping device used to deficits after exposure to mild/moderate blasts, and subjects
determine the value of tamping during various scenarios by with repeated blast exposure report symptomatology often re-
measuring actual breaches conducted during military and law ferred to as breachers’ brain. Breachers’ brain is character-
1,2
enforcement training for efficacy and blast overpressure on ized by irritability, trouble sleeping, and cognitive task issues
Operators. Methods: Three data collections across 18 charges such as slow-think. We investigated tamping not only to better
3
of various construction were evaluated with blast overpres- understand the mechanisms of making charges more effective
sure sensors at various distances and locations where breach- and efficient, but also for a secondary benefit of lowering blast
ers would be located, to assess explosive forces on human overpressure, which may affect breacher efficacy and long-term
personnel engaged in breaching activities. Results and Con- health by means of an exploratory pilot study.
clusions: Findings indicate that water tamping in general is a
benefit on moderate and heavy charges but offers less benefit The breaching community has been using water as a tamp-
at a low charge with regard to mitigating blast overpressure ing medium for years because water can increase breaching
on breachers. Reduced overpressure allows Operators to stage charge efficiency by redirecting toward the target the poten-
closer to explosives and lowers the potential for compromised tially lost energy on the backside. By enhancing the blast effect
reaction time. It also reduces the likelihood of negative conse- in this way, breachers can lower the net explosive weight of
quences that can result from excessive overpressure exposure a charge and still gain the same results in breaching. Another
and allow Operators to “do more with less” in complex envi- notable point of interest is that water tamping may mitigate
ronments, where resource access may be limited by logistic or blast overpressure experienced by Operators. Understanding
other limitations. However, tamping in all instances improved whether water tamping can mitigate blast overpressure during
blast efficacy in creating successful breaches. Future studies breaching events is critical because breachers with repeated
are planned to investigate tamping mediums beyond water overpressure exposure have tentative links to negative health
and environment changes, whether tamping can be used to outcomes that may not only have long-term negative conse-
3,4
mitigate acoustic insult, and other explosive types. quence but also short-term performance concerns. Addition-
ally, individuals with chronic low-level blast exposure, such as
Keywords: breachers; blast; overpressure; tamping; water tamp instructors, seem to be more at risk for possible detriments in
neurologic function on high-memory-demand tasks, such as
those assessed by the Defense Automated Neurobehavioral As-
sessment rapid procedural reaction time assessment tool and
Introduction
the Go/No-Go test. Individuals with chronic low-level blast
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Charge construction is the bedrock of a successful breaching exposure also seem to be more at risk for reporting symptoms
program. Variations on charge construction, and specifically of memory issues, sleep disturbance, and irritability. Col-
6
the application of properly executed tamping, can greatly en- lectively, these symptoms present a profile similar to that of
hance breaching success and safety. post-concussive symptoms, with a complex profile of injury
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from the various facets of blast (i.e., pressure, heat, shrapnel,
Tamping is a technique that adds a dense medium to the environmental). Moreover, blast exposure was positively cor-
8
charge “backside” (i.e., the side not facing the target), thereby related to increased symptom profiles. 7
*Correspondence to Michael.j.egnoto.ctr@mail.mil
All authors are affiliated with the Walter Reed Army Institute of Research, Forest Glen Annex, Silver Spring, MD.
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