Test Program for Evaluation of Filmed Windows Subjected to Bomb Blast Loads
Comparative tests were performed on plain annealed glass specimens to demonstrate the potential hazard from unprotected windows. Additionally, some tests were performed on glass specimens with a daylight application of safety film. Tests were also performed on 1/4 inch laminated glass in a standard frame to permit comparison of the relative protection provided by laminated glass and safety film in a daylight application. Testing was conducted August 26-29, 1996 at WBE''s test range in EImendorf, Texas near San Antonio. WBE utilized a 3 ft x 3 ft shock tube to produce blast loads for a11 tests. This shock tube has the capability to produce peak pressure up to 3S psi with durations up to 40 ms.
The primary test objective was determination of the maximum blast capacity of filmed windows at various hazard levels. A second objective was to demonstrate the reduction in glass fragment hazard produced by applying safety film to annealed glass. Currently, no standard exists in the United States for evaluating damage and hazard levels of window glass subjected to blast loads. For this reason, WBE used a classification method developed in the United Kingdom. The Explosion Effects Branch of the Safety and facilities Establishment, Department of Environment, England currently endorses this hazard assessment technique; however, it is not an adopted standard. Three levels of hazard are identified: Break Safe, Low Hazard, and High Hazard.
ASTM 1'' 1 64Z - 95 "Standard Test Method for Glazing and Glazing Systems Subject to Air blast Loadings" was used as a guideline for preparation of the test procedures. For this test series, 3 ft x 3 ft (nominal size) windows glazed with nominal 1/4 inch thick annealed glass were used. Clear window size was 32.5 inches x 36 inches.
This report is a summary version condensed from the full report issued November 1996. It contains results for tests for plain annealed glass and anchored film. A summary of the test results is shown in Table I. The values in the table represent maximum pressure which can be applied without causing a higher damage level and are based on a limited amount of test data.
For Specific Test Results Visit the Below Sections of the Report:
- Executive Summary
- Blast Hazards
- Damage Level Classification
- Window Size and Framing
- Summary of Results