¼” screws at four jamb corners – screws bending corners screws bending. – tearing in frame wall at connections pushing limits of ASTM F □ Minimal. Mullion/Frame Design – Allowable Stress Design. ▫ Design Load = Equivalent 3 second design load ASTM F ▫ Info Required –. ▫ 1) Level of Protection. 1 Aug ASTM a, F , “Standard practice for specifying an equivalent 3- second duration design loading for blast resistant glazing fabricated.
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New and improved technologies are continuously being researched, developed and tested. UFC DoD Minimum Antiterrorism Standards for Buildings document was most recently updated in Februaryaatm includes blast resistance criteria for windows in both new and existing facilities.
ASTM F 2248
As a minimum, insulating glass shall use laminated glass for the inboard protected side lite. Load transfer from the glass to the window frame and surrounding walls should be taken into account when designing for window anchorage or structural augmentation of the supporting wall. The width of silicone or glazing 22248 is referred to as bite and is shown and discussed in Guide C It is the intent of blast mitigation to control the fracture of glazing in such a way that it does not 248 these hazards.
A stationary vehicle weapon alongside a secured perimeter of a building is the primary threat to be considered in designing for blast resistance. The width of glazing asmt shall be at least equal to two times but not more than four times the thickness designation of the glass to which it adheres. In addition to specific requirements for glass aatm, lamination, deflection limitation, and testing, UFC design criteria is generally based on ASTM T 22248 project-specific standoff distance and TNT-equivalent size, a 3-second duration equivalent static pressure load can be interpolated.
These include particular design of the glass or window frame components; increased anchorage of the window assembly itself; structural augmentation of the surrounding wall structure; or separate shielding systems and mechanisms designed to catch the debris. As a result of increased terrorist activity in the past few decades, there has been growing demand for explosive blast resistance to be incorporated into the design of building structures and envelope components.
When designing for glazing, it is important to note that glass failure is not quantified in terms of whether or not breakage occurs; rather, it is defined by the hazard it creates. Performance conditions established by GSA are categorized by breakage characteristics ranging from 1, which allows no breakage, to 5, where breakage debris travels ft or farther from the window.
This criteria applies provisions for glazing, framing, connections and supporting structural elements. Differing building shapes can either dissipate or accentuate an explosive blast. Blast mitigation technologies were asrm for saving many lives during the September 11 attack on 224 Pentagon. This load is then used for design of the assembly frame, glazing frame bite, connections, and supporting structural elements.
From Wikipedia, the free encyclopedia. It includes standards for dynamic analysis, testing and explosive weights associated with respective standoff distances. Views Read Edit View history. The performance of building envelopes and cladding components during an explosive atsm is more geared towards mitigating the hazards caused by the blast, as it has been found that many of the injuries and fatalities have been a direct result of flying glass and wall debris.
They can be reached ator This email address is being protected from spambots. One of wstm most common technologies currently being used is laminated glass. Immediately following the Oklahoma City bombing of the Alfred P. The standard explain different methods to check the thickness and type of blast resistant glazing fabricated with laminated glass to glaze a fenestration The main keywords to present this standard are air blast pressure, blast resistant glazing, explosion, insulating glass, and laminated glass.
A range of manufacturers produce various lamination products based on desired response and performance characteristics.
Window Design for Blast Hazard Mitigation
The system shall be designed to ensure that the glazing fails prior to the framing system that supports the glazing and its attachment to the structural framing system. Various approaches may be used when designing fenestrations for blast-resistance. Technology News Lewis E. Common testing methods outlined in these standards include shock tube, where impulse pressures are used to simulate an explosive blast, and open arena, where the test specimen is subjected to an actual explosive blast.
Alexandria, VA Prior to this, there were essentially no government-wide blast resistance standards for security for civilian federal facilities. When designing to minimize damages from an explosion, it is important to balance the security concerns with other design constraints, such as efficiency, feasibility and cost.
Link to Active This link xstm always route to the current Active version of the standard. The fasteners that attach the framing system that supports the glazing to the structural framing system shall be designed to resist a uniform load acting on the blast resistant glazing that has a magnitude of at least:.
Conditions vary with respect to the travel distance of the breakage debris. Yet there are obvious limitations in cases of cities and densely populated areas. Use of the annealed or heat strengthened glass plies d also reduce the amount of load transferred into the structure.
As a supplement to the GSA Security Criteria, ISC issued their own security criteria inestablishing additional requirements for glazing protection, standoff distances, vehicular access control, and security of air intake systems. Structural design for blast resistance focuses on minimizing potential for progressive collapse through structural redundancy.
Engineers at the University of Missouri are developing a layer of glass fiber embedded in plastic that provides a reduced overall glass thickness, added strength to resist blasts, and transparency that many of the laminates do not have. ASTM International which was funded inis an international standards developing organization that develops and publishes standards for a wide range of materials, products, systems, and services.
In the first stage of an explosive blast, the shock wave expansion impacts the exterior envelope and structural components, creating an upward force on the floor levels as it passes through the structure.
Consideration for the type of glass with respect to breaking strength and behavior is also important. The fasteners that attach the framing system that supports the glazing to the structural framing system shall be designed to resist a uniform load acting on the blast resistant glazing that has a magnitude of at least: Many of the leading window manufactures also have specific blast-resistant window models that incorporate these technologies in a singular system.
Blast testing has shown that use of fully tempered glass plies, when fractured during a blast event, have poorer post blast performance than annealled or asttm strengthened glass plies. A secondary threat to consider is a hand-carried weapon that may potentially be placed directly 22448 the building envelope.
The standard explain different methods to check the thickness and type of blast resistant glazing fabricated with laminated glass to glaze a fenestration. Batten bars may be used to increase the anchorage capacity of the glass itself. Since then, ISC has taken on a new approach to address the full spectrum of security threats through a series of documents outlining new security levels; baseline security countermeasures and implementation; risk assessment and identification; and performance measurement.
Window Design for Blast Hazard Mitigation Reducing damage caused by explosive blasts has become an emerging area of interest due to several high-profile incidents over the last two decades.