Bomb Blast Mitigation Test

Transcription

1 7 June 2005 Bomb Blast Mitigation Test In this time and day of increased natural disasters and terrorist activities, windows have not been put to the test more. With the cries for safety film getting louder than ever before, Hüper Optik responded promptly by putting its 3 products of the safety film range through the ASTM F Standard Test Method for Glazing and Glazing Systems Subjected to Airblast Loadings and the US GSA Standard Test Method for Windows and Glazing Systems Subject to Dynamic Overpressure Loadings. A hefty sum was expended to have ABS Consulting co-ordinate the test in Suffield, Canada on 13 April With a charge as large as 1000lbs, all Hüper Optik films (4-mil and 8-mil) met the criteria for Bomb Blast Mitigation based on Medium protection level facilities as defined by the Interagency Security Committee (ISC). While all its 8-mil films achieved at least a performance condition of 3B, the Ceramic 50 Shield (Wet Glazed) attained an impressive performance condition of 2 indicating minimum- or no hazard to the occupant behind the window. Reports, videos and pictures will be made available to all distributors selling the safety range of films by the 3rd quarter. Kenneth Tan Technical Support Engineer Hüper Optik International Pte Ltd

2 BLAST TESTING FOR WINDOW SAFETY FILM AT DEFENSE RESEARCH ESTABLISHMENT SUFFIELD BY ABS CONSULTING MAY 19, 2005 ABSG Consulting, Inc San Pedro, Suite 215 San Antonio, TX USA Tel: Fax: I N T E R N A T I O N A L

3 Table of Contents 1. INTRODUCTION CRITERIA TEST SETUP RECORDED INFORMATION Video Information Blast Pressure Data RESULTS CONCLUSIONS...7 Appendix A - Photographs Appendix B - Window Data Sheets Appendix C - Composite Blast History Traces Appendix D - Individual Blast History Traces Appendix E - Summary Tables List of Figures Figure 1. ASTM F Performance Criteria...2 Figure 2. GSA Performance Conditions...2 Figure 3. Window Cubicles...3 Figure 4. Test Site Layout...4 Figure 5. Explosive Plastic Container...5 Figure 6. Pressure Gauge Locations...6 i

4 TEST PROGRAM FOR WINDOW SAFETY FILM SUBJECTED TO BLAST LOADS 1. Introduction Terrorist bombings in recent years have increased the awareness of government, industrial, and commercial interests in the effects of blast loads on buildings. As many of the bombings have shown, glass fragments represent one of the most significant prominent injury hazards to personnel both in the targeted building as well as adjacent facilities. In many cases, glass breakage occurs over a wide area including potentially hundreds of buildings. Window safety film can offer a significant reduction in glass fragment hazards greatly reducing risks to personnel during explosive events. Safety film can be installed in a retrofit application in a number of configurations providing a more cost effective hazard reduction than replacing the window unit. ABS Consulting was contracted to determine the effectiveness of window safety film in mitigating glass fragment hazards when subjected to blast loads. Two commonly used configurations were tested on annealed and thermally tempered glass to determine the response characteristics. The test program was conducted in accordance with the General Services Administration (GSA) and ASTM test protocols for the Interagency Security Committee (ISC) load criteria for Medium protection level buildings. Testing was conducted on April 13, 2005, 3:00 pm at the Defense Research Establishment Suffield (DRES) in Ralston, Alberta by ABS Consulting and its subcontractors the Canadian Explosives Research Laboratory (CERL), and DRES Criteria Testing was conducted in accordance with ASTM F1642, dated March 2004 and the GSA Standard Test Method for Windows and Glazing Systems Subject to Dynamic Overpressure Loadings dated January 1, and 2. The objective of the testing is to show the window and frame system performance and level of protection as defined by the two criteria. Blast loads were selected based on Medium protection level facilities as defined by the ISC, Security Design Criteria. Window response was compared to the hazard level criteria to determine glazing system performance under applied blast loads. Following each test, glass fragments were collected, measured and weighed by zone in the test enclosure. Fragments striking and embedding in the witness panel were collected and 1 US General Services Administration (GSA), GSA-TS , Standard Test Method for Glazing and Glazing Systems Subject to Dynamic Overpressure Loadings, GSA, January, ASTM Standard, F , Standard Test Method for Glazing and Glazing Systems Subject to Airblast Loadings, ASTM Book of ASTM Standards, Vol , March

5 documented. Frame deflections were recorded and performance of frame anchorage was documented. Performance conditions for each test item were assigned and recorded in accordance with ASTM and the GSA criteria as shown in Figure 1 and Figure 2, respectively. Cubicle Cross Section Blast Load Glass No Break/Hazard Minimal Hazard High Hazard Zone High Hazard Threshold 0.5 m Very Low Hazard Zone 1.0 m Low Hazard Threshold 2 m Low Hazard Zone Figure 1. ASTM F Performance Criteria Cubicle Cross Section Blast Load Glass A 3B 4 24 inches 40 inches 10 feet Figure 2. GSA Performance Conditions ABS Consulting, in consultation with members of the Blast Mitigation Action Group (BMAG) also developed a methodology to clarify damage level classification for the GSA criteria when stray fragments strike the witness panel. This methodology permits minor impacts of stray shards in Zone 5 provided they are low hazard fragments with minimal penetration. ABS Consulting also developed a methodology to clarify hazard level classification of glass 2

6 fragment mass in Zone 3A and 3B (as shown in Figure 2 above). A total mass in zone 3B less than or equal to 100 g is included in the zone 3A total glass mass. A light dusting of glass in the zone 3 area is not counted as glass mass for classification. This light dusting is defined as approximately 10 g in this methodology. These methods were employed in the GSA classification. 2. Test Setup An arena style field test was conducted where a bare explosive charge was placed centrally in the test field and test articles located at predetermined standoffs. Two steel construction window cubicles, shown in Figure 3, were placed 260-feet (79.3 m) from the explosive charge. Figure 4 shows a layout of the test area. Each test cubicle contains 6 test articles with gross dimensions of approximately 70-inches (1778 mm) tall by 57-inches (1448 mm) wide. The test cubicles are 10-feet deep (3-m) and completely enclosed with divider walls between each bay. Window locations were numbered as shown in Figure 4, from south to north. Every individual bay of each cubicle has a witness panel comprised of two layers of insulation board totaling 1.5-inches (381- mm). Nitromethane (NM) was used as the explosive for the testing. This liquid explosive material was placed in a plastic container and detonated with a 1.5-lb DM-12 explosive (see Figure 5). The NM provided a TNT equivalence of 1.0 based on review of side-on pressure gauge data. The charge weight used for the testing was 1000-lb NM (453.6-Kg). Figure 3. Window Cubicles 3

7 8 N 8 Explosive Charge 1000-lb (453.6-Kg) P27 P28 P ft (79.3 m) 260 ft (79.3 m) P30 Free Field Pressure Gauges 8 High Speed Video Camera Hi 8 Video Camera P Cubicle B Cubicle A Figure 4. Test Site Layout 4

8 Figure 5. Explosive Plastic Container 2.1. Recorded Information Detailed information was recorded for test articles prior to testing. Photographs were taken of test specimens and the test setup prior to and following each test to document window performance. Appendix A contains all photographs taken of each specimen throughout the testing Video Information Six high-speed video cameras were located behind the test enclosure, recording the response of the test article throughout the test. Two regular speed cameras were located to the south and west of the test arena to record the overall view of the test (see Figure 4 for camera locations). A complete video history for each test is included on the enclosed VHS tape. All of the video records were converted to a digital video files and are included on the attached CD Blast Pressure Data Blast pressure gauges measuring reflected pressure were mounted on front face of both test cubicles facing the oncoming blast wave, with three or four gauges for each test specimen (see Figure 6). No blast gauges were mounted inside the test cubicle to measure internal incident blast pressure. 5

9 Cubicle A P1 P3 P5 P7 P9 P11 P13 P2 12 P4 11 P6 10 P8 9 P10 8 P12 7 Cubicle B P14 P15 P17 P19 P21 P23 P25 6 P16 5 P18 4 P20 3 P22 2 P24 1 P26 Figure 6. Pressure Gauge Locations 3. Results Appendix B contains a data sheet for each test specimen. The data sheets contain the following information: Detailed description of the unit including the frame, glazing, and anchorage into the cubicle. Description of the test conditions. Summary of peak pressure and impulse applied to test specimen Detailed description of the performance condition for both ASTM and GSA criteria. A pretest and post test photograph. A graph of the applied blast history. Sketches of the window. 6

10 Appendix C contains a summary of the blast pressure gauge data and a composite blast history graph for each test showing all pressure gauges. Appendix D contains a blast pressure history for each individual gauge for each test. 4. Conclusions This report contains the test conditions and results for the window film testing performed on April 13, Detailed specimen response information, blast pressure data, and test photographs are included in the appendices. 7

11 Blast Testing for Window safety Film at Defense Research Establishment Suffield on April 13, 2005 APPENDIX E

12 Blast Testing for Window Safety Film at Defense Research Establishment Suffield on April 13, 2005 Client: Hüper Optik WINDOW DESCRIPTION AND RESPONSE Peak Pressure and Impulse Information Test Date Specimen Number 1 4/13/2005 NM1 2 4/13/2005 NM2 3 4/13/2005 NM3 4 4/13/2005 NM4 5 4/13/2005 NM5 Client Window Number Ceramic 50 Shield (C50S) Klar 800 Shield (K800S) Ceramic 50 Shield (C50S) Klar 800 Shield (K800S) Ceramic 50 Shield (C50S) Glazing Description Glazing Thickness TTG 1/4" TTG 1/4" AG 1/4" AG 1/4" TTG 1/4" Upgrade Description Frame Width Frame Height GSA Damage Level ASTM F1642 Response LT LB RT RB Avg LT LB RT RB Avg Notes in in in psi psi psi psi psi psi-ms psi-ms psi-ms psi-ms psi-ms 8-mil film with 3/4" silicone glaze all around 8-mil film with 3/8" to 1/2" silicone glaze all around 8-mil film with 1/2" to 3/4" silicone glaze all around 8-mil film with 1/2" silicone glaze all around 8-mil film with 1/2" silicone glaze all around No Hazard N/A N/A N/A N/A A * Very Low Hazard Minimal Hazard* Glass released in upper right corner; glass loose but still in place in upper left and right bottom corners. No tear in film or silicone N/A N/A N/A N/A 36.1 Glazing stop is outside at 24.5" from cubicle B Low Hazard Minimal Hazard PEAK PRESSURE PEAK IMPULSE One small bracket from interior of framing located inside the cubicle after testing at 21.5" from window (dimension: 6.5" x 4" x 0.5", weight: 124 g), not part of glazing or film system. Glass fragment strike in witness panel without penetration. N/A N/A N/A N/A Diagonal tears in all four corners of film. 7 4/13/2005 NM7 Klar 800 Shield (K800S) TTG 1/4" 8-mil film - daylight applied B Very Low Hazard N/A N/A 26.4 Full sheet of glass was torn out of frame and located outside cubicle. 8 4/13/2005 NM8 Klar 800 Shield (K800S) AG 1/4" 8-mil film - daylight applied B Low Hazard 4.0 N/A N/A Full sheet of glass was torn out of frame and located inside cubicle. 10 4/13/2005 NM10 Ceramic 50 Shield (C50S) AG 1/4" 8-mil film with 3/4" silicone glaze all around Minimal Hazard Diagonal tears from all four corners of film/ 11 4/13/2005 NM11 Klar 400 Shield (K400S) AG 1/4" 4-mil film - daylight applied Low Hazard Full sheet of glass was torn out of frame and located inside cubicle, Glazing struck the witness panel in Zone /13/2005 NM12 Klar 400 Shield (K400S) TTG 1/4" 4-mil film - daylight applied B Low Hazard Full sheet of glass was torn out of frame and located outside cubicle. * Only thing in cubicle is small flat aluminum support for frame (this was not part of the film upgrade, nor would it have entered the structure if the sides had been secured. LT - Left Top gauge LB - Left Bottom gauge RT - Right Top gauge RB - Right Bottom gauge AVG - Average of four gauges