|
NIJ Journal No. 254 • July 2006
Body Armor Safety Initiative: To Protect and Serve…Better
by Dan Tompkins
About the Author
Dan Tompkins is a writer/editor at the National Institute
of Justice and Editor of the NIJ Journal.
On December 23, 1975, Seattle Police Department Patrolman
Raymond T. Johnson stood in the checkout line at a local
market when a robbery suspect entered the store and brandished
a weapon. Johnson lunged for the suspect’s gun.
In the violent struggle that ensued, the suspect emptied
his .38 caliber pistol, striking Johnson in the left hand
and twice in the chest before fleeing.1
Johnson survived with severe hand injuries, chest bruises,
and a unique distinction—the first law enforcement
officer saved in a field test of a new generation of soft
body armor being conducted by the National Institute of
Justice (NIJ).
Johnson was wearing body armor made with Kevlar®,
an extraordinarily strong fabric developed by DuPont.
NIJ, in partnership with the U.S. Army, began a program
in the early 1970s to develop lightweight body armor woven
from Kevlar®. Field
testing began in the summer of 1975, with 5,000 armors
provided to 15 urban police departments. Less than 6 months
later, Johnson was the first officer saved by one of the
field test armors. In all, 17 other armor-wearing officers
were saved during the 1-year field test.
About the same time, NIJ developed a performance standard
for body armor in collaboration with the National Institute
of Standards and Technology (NIST, then known as the National
Bureau of Standards),2
followed by a voluntary testing program. The standards
and testing program, which still exists today, enables
body armor manufacturers to certify the performance and
safety of new body armor.3
The NIJ standard establishes minimum performance requirements
for armor, and the testing program evaluates armor against
the standard.
Twenty-eight years later, on the night of June 23, 2003,
Forest Hills, Pennsylvania, Police Officer Edward Limbacher,
wearing body armor constructed primarily of a fiber called
Zylon®, threw open
the side door of an unmarked Econoline van and stepped
out to move in on a drug suspect. The suspect fired, striking
Limbacher in the arm and abdomen with .40 caliber rounds.
The shot to the abdomen penetrated the body armor Limbacher
was wearing. He survived but sustained severe injuries.4
The Forest Hills shooting was the first case ever reported
to NIJ in which body armor compliant with the NIJ standard
failed to prevent penetration from a bullet it was designed
to defeat.
In the 28 years between those two incidents and in the
time since, at least 3,000 officers survived shootings
or other incidents because they were wearing body armor
meeting NIJ performance standards.5
But the Forest Hills incident caused great concern within
the law enforcement community and within the U.S. Department
of Justice: Are we keeping our officers safe?
The Body Armor Safety Initiative
In November 2003, in the aftermath of the Forest Hills
incident, then Attorney General John Ashcroft announced
a Body Armor Safety Initiative to address the reliability
of body armor used by law enforcement and to review the
process by which body armor is certified.6
As part of the initiative, NIJ tested both new and used
ballistic-resistant vests made with Zylon®.7
NIJ also tested upgrade kits distributed by the manufacturer
of the armor in the Forest Hills incident to retrofit
some models of its Zylon®-based
vests. And NIJ began a review of its standards and testing
program for ballistic-resistant vests, which has resulted
in interim changes to the standards and testing process.
Read on for the results of these tests and a summary of
changes to the standards and testing program.
Why Did the Vest Fail?
Even before the announcement of the Attorney General’s
initiative, NIJ staff contacted representatives of the
Forest Hills Police Department and the Allegheny County
Police Department (the agency handling the criminal investigation
of the shooting) to examine the vest, the weapon, and
the ammunition used in the shooting to determine why the
vest failed. The examination found that:
- The bullet velocity from the gun
used in the shooting was not greater than the bullet
velocity NIJ uses in compliance testing for the type
of vest Limbacher was wearing.
- The physical properties of the
bullets used in the shooting were similar to bullets
used in NIJ’s compliance testing of the type of
vest Limbacher was wearing, although there were some
differences in bullet geometry and in how the bullet
deformed on impact.
- The tensile strength of Zylon®
yarns removed from the back panel of Limbacher’s
vest was up to 30 percent lower than Zylon®
yarns from new armor that the manufacturer provided
for this study. (The front panel, which was penetrated
in the incident, was being held as evidence in the criminal
case against the shooter, so it was not available for
testing.)
NIJ also developed a detailed test plan simulating the
Forest Hills incident to isolate the factors deemed most
likely responsible for the vest failure. Test designers
identified five potential causal factors: ballistic material
tensile strength, bullet type, the gun barrel twist, the
shot angle, and the location of the shot on the armor.
NIJ obtained and tested 32 ballistic panels of the type
worn in the Forest Hills incident. Half of the panels
were tested new, and the other half were artificially
aged for 5 months in a chamber exposing the panels to
controlled temperature and humidity conditions until the
tensile strength of fibers in the vests matched those
of fibers from the rear panel of the Forest Hills vest.
Each of the 32 panels was shot six times. None of the
192 shots penetrated the panels. NIJ is continuing efforts
to determine the cause of the Forest Hills failure but
is still unable to draw a definitive conclusion.
Testing the Upgrade Kits
As part of the Attorney General’s initiative, NIJ
was directed to test any upgrade kits offered by body
armor manufacturers to retrofit existing vests. The tests
would determine if the upgrade kits met the NIJ performance
standard when used with the original vest they were designed
to supplement. One manufacturer, Second Chance Body Armor,
Inc. (the manufacturer of the body armor worn in the Forest
Hills incident), offered an upgrade kit to users of some
models of Zylon®-based
body armor—an additional ballistic panel to be inserted
into the armor. At NIJ’s request, Second Chance
provided 50 sets of armors and matching upgrade kits for
three soft armor protection levels—Level IIA, Level
II, and Level IIIA.8
The samples included both new and used upgrade kits, and
the majority of the armors had been previously worn.
NIJ’s testing found that the Second Chance upgrade
kits added protection when used with the existing used
body armor. However, the level of protection did not meet
existing NIJ performance standards for new body armor.
Also, the vest/upgrade kit combinations in all three
protection levels experienced excessive “backface
signatures.” This means that the bullets didn’t
penetrate the vest, but the impact of one or more bullets
created a “dent” of more than 44 mm (almost
2 inches) into the clay in back of the vests during testing,
a depth that may cause serious injury. Six of eight Level
IIA armors, two of eight Level II armors, and five of
eight Level IIIA armors ultimately tested experienced
excessive backface signatures during testing.
Further, two of the eight Level IIIA vest/upgrade kits
(designed to offer protection against high velocity 9
mm and 44 magnum bullets) experienced penetrations.
Despite the safety questions raised by these test results,
it is important to note that the upgrade kits did add
some measure of protection. Officers who have received
these upgrade kits should wear them.
Testing Used Armor
Heat, moisture, ultraviolet and visible light, detergents,
friction, and stretching may all contribute to the degradation
of fibers used in the manufacture of body armor. Body
armor manufacturers design their armor and provide care
instructions to minimize the effects of these degrading
properties.
Because the evidence showed an unexpected degradation
rate in Zylon®-based
armor, NIJ conducted ballistic and mechanical properties
testing on 103 additional used body armors containing
Zylon®. Law enforcement
agencies across the United States provided these vests
to NIJ. Sixty of these used armors (58 percent) were penetrated
by at least one round during a six-shot test series. Of
the armors that were not penetrated, 91 percent had backface
deformations in excess of that allowed by the NIJ standard
for new armor. Only four of the used Zylon®-containing
armors met all performance criteria expected under the
NIJ standard for new body armor compliance. Although these
results do not conclusively prove that all Zylon®-containing
body armor models have performance problems, the results
show that used Zylon®-containing
body armor may not provide the intended level of ballistic
resistance.
In addition, armors were visually inspected and given
one of four condition ratings from “no visible signs
of wear” to “extreme wear and abuse.”
Testers found no correlation between the level of visible
wear of the body armor panels and the ballistic performance
of those panels. This finding is important because even
used Zylon® body
armor that appears to be in good condition may not provide
an acceptable level of performance.
Exploring Fiber Degradation
With funding provided by NIJ, polymer scientists at NIST
are probing down to the molecular level to learn more
about how Zylon®
degrades. They are examining the chemical changes that
occur as the fibers degrade, the trace contaminants on
fibers that may contribute to degradation, the moisture
content of fibers, and mechanical strength differences
among individual fibers and what causes those differences.
Initial findings have isolated the ballistic performance
degradation to the breakage of a small part of the Zylon®
fiber molecule. Breakage of this part of the molecule,
called the oxazole ring, occurs as a result of exposure
to both moisture and light. When there was no potential
for external moisture to contact Zylon®
yarns, there was no significant change in the tensile
strength of these yarns. Therefore, it appears that external
moisture is necessary to facilitate the degradation of
Zylon® fibers.
In addition to this work, NIJ is also funding research
on other personal protective equipment to better understand
how and why ballistic-resistant materials degrade over
time.9
Improving the NIJ Standard and Compliance Testing Program
NIJ has undertaken a complete review of its performance
standard for ballistic-resistant armor and the compliance
testing program. It solicited input from law enforcement
and corrections agencies, fiber and armor manufacturers,
and standards and testing organizations.
NIJ’s 2005 Interim Requirements for Bullet-Resistant
Body Armor, issued in August 2005, take into account the
possibility of ballistic performance degradation over
time. These interim requirements will help ensure that
officers are protected by body armor that maintains its
ballistic performance during its entire warranty period.
Under the 2005 interim requirements, NIJ will not deem
armor models containing PBO (the chemical basis of Zylon®)
to be compliant unless their manufacturers provide satisfactory
evidence to NIJ that the models will maintain their ballistic
performance over their declared warranty period.
NIJ recommends that agencies that purchase new ballistic-resistant
body armor select body armor models that comply with the
NIJ 2005 Interim Requirements. A list of models that comply
with the requirements is maintained at www.justnet.org/BatPro.
NIJ is also encouraging manufacturers to adopt a quality
management system to ensure the consistent construction
and performance of NIJ-compliant armor over its warranty
period. In the future, NIJ will issue advisories regarding
body armor materials that appear to create a risk of death
or serious injury as a result of degraded ballistic performance.
Any body armor model that contains any material listed
in such an advisory will be deemed no longer compliant
with the NIJ standard unless the manufacturer satisfies
NIJ that the model will maintain ballistic performance
over the declared warranty period.
Life Vests
There are at least 3,000 other stories like that of Seattle
Police Officer Raymond T. Johnson. That’s 3,000
families spared the anguish of death or debilitating injury
to a loved one in the line of duty. And cases like that
of Forest Hills Officer Limbacher’s are rare—a
testament to the reliability of soft body armor. Even
so, that single failure prompted NIJ to review its body
armor program and to conduct an intensive examination
of why that failure occurred. Through this review and
research, NIJ remains committed to working for the safety
of law enforcement officers.
The evidence is clear: An officer not wearing armor is
14 times more likely to suffer a fatal injury than an
officer who is. Therefore, the most important message
for the law enforcement community is that officers should
continue to wear their body armor.
At least 3,000 officers would second that advice.
NCJ 214112
For More Information
Notes
- The suspect was arrested 6 weeks
later and charged with first-degree assault and attempted
robbery. He was convicted and sentenced to 15 to 30
years’ imprisonment.
- Commercial body armor was being
manufactured and sold even as NIJ’s field test
began, accelerating the need for a standards program.
In fact, the first documented “save” unrelated
to NIJ’s field test occurred in May 1973 in Detroit,
Michigan.
- More information about NIJ’s
body armor standards and testing program can be found
at NIJ’s National Law Enforcement and Corrections
Technology Center Web site, JUSTNET.
- The suspect fled but was arrested
later that night. In April 2004, he was convicted of
2 counts of attempted homicide, 11 counts of aggravated
assault, and 9 counts of reckless endangerment related
to the June 23, 2003, incident.
- In 1987, DuPont and the International
Association of Chiefs of Police (IACP) created the Kevlar
Survivor’s Club, which recognizes law enforcement
and corrections officers who survive life-threatening
or disabling events because they were wearing personal
protective body armor. In March 2006, IACP commemorated
Atlanta Police Department Officer Corey B. Grogan as
the 3,000th documented save. A Web
site keeps a tally of survivors, maintains a database
of survivor stories, and provides criteria and instructions
for membership.
- A Web site supporting the Body
Armor Safety Initiative is located at www.ojp.usdoj.gov/bvpbasi.
- Zylon fiber is manufactured by
Toyobo Co., Ltd., of Japan.
- For a description of the protection
levels, see NIJ’s
Ballistic Resistance of Personal Body Armor, NIJ Standard-0101.04.
- The most recent NIJ solicitation for concept papers,
“Officer Safety Equipment,” is available
at www.ncjrs.org/pdffiles1/nij/sl000720.pdf.
|
