In recent months we have received numerous inquiries from design professionals about the potential us of our ArmorCore Bullet Resistant Panels for construction of "safe rooms" for protection during hurricanes and tornadoes. We contacted the Wind Engineering Research Center at Texas Tech University who partners together with the Federal Emergency Management Agency (FEMA) to test many different building materials for their suitability to withstand wind damage from hurricanes and tornadoes.
Of particular interest is the ability of a given material to defeat or resist "missiles" which refers to debris and other objects picked up by the wind and moved with enough force to damage and even penetrate windows, doors, walls, and other parts of a building. The stronger the wind, the larger and heavier the missiles it can carry and the greater risk of severe damage.
ArmorCore UL752 Level 3(1/2" thick and 5.0 lbs per sq. ft) panels at 4' x 4' were submitted to the Wind Engineering Research Center at Texas Tech University for testing to see how well they could resist an airborne missile typical of an F5 strength tornado. The results clearly indicated that ArmorCore bullet resistant panels are well suited for safe room construction provided the overall structural system that supports the ArmorCore panels is adequate.
Following is the project report on the Investigation of Wind Projectile Resistance of Waco Composites, Inc. Armorcore UL752 Level 3 Panels. Videos of the actual test are available upon request.
Project Report on:
Investigation of Wind Projectile Resistance of Waco
Composites, Inc.
Armorcore UL752 Level 3 Panels
Submitted to:
Waco Composites, Inc.
481-C Texas Central Parkway
P.O. Box 21223
Waco, Texas 76702-1223
Research and Development Performed by:
The Wind Science and Engineering Research Center
Texas Tech University
Box 41023
Lubbock, Texas 79409-1023
Investigators:
Ernst W. Kiesling, Ph.D, P.E.
Russel R. Carter, E.I.T.
October 3, 1999
Waco Composites initiated contact for testing of ArmorCore UL752 Level 3 by the Wind Science and Engineering (WISE) Research Center at Texas Tech University to assess the missile shielding ability of the composite panels. The panels were 4'x4'x1/2" mounted to wood studs placed at 16" on center. The panels were attached to the studs with 3" x 1/4" dia. self-tapping screws spaced at 6" on center the length of the studs. The panel was placed in front of the reaction frame and impacted with the tornade test missile. The specifics about each test follow.
The missile criterion used for the tests was a 15 point 2x4 in. wood board traveling along the board's longitudinal axis, striking the panel perpendicular to the panel face. The tornade test criterion uses this missile traveling at 100-mph which corresponds to a 250-mph wind and is the criterion used in designing for occupant protection. Additional margins of safety are inherent in the criterion since there is a very small probability that a missile will be traveling along its axis and will strike a wall perpendicular to its surface.
The missile impacted near the center of the panel between the studs. The panel had a permanent deformation 1/4" (0.25 inches) at the point of impact. The panel began to delaminate as indicated by the lines of delamination originating from the point of impact. The non impact surface began so show signs of delamination. This was concentrated from the point of impact to the screw at the bottom of the panel.
The missile impacted the same place as Missile Shot 1 in order to determine the ability of the material to resist the missile after delamination of the panel had occured. The impact propagated the expansion of the delaminated line evident in the resion of the impact surface. Other areas of delamination away from the point of impact also began to be more evident.
The ArmorCore UL752 Level 3 panel is able to resist perforation of the 15 pound 2x4 traveling at 100mph. Further testing would be required to determine the minimum number of layers of weave required to resist the missile. The amount of energy transferred from the panel to the main structural system caused the wood studs to split and break. For a structure clad in ArmorCore to resist the combined effects of debris impact and severe wind load a stronger structural system will be required. Once a structural system is designed, testing would be performed to determine that the system meets debris impact performance criteria.