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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This criteria applies provisions for glazing, framing, connections and supporting structural elements. Various approaches may be used when designing fenestrations for blast-resistance.
Window Design for Blast Hazard Mitigation
With each assumed case, both the size of the weapon and location of the threat are crucially important. Use of the annealed or heat strengthened glass plies will also c the amount of load transferred into the structure. It is the intent of blast mitigation to control the fracture of glazing in such a way that it does not create these hazards. 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 heat strengthened glass plies.
Views Read Edit View history. Link to Active This link will always awtm to the current Active version of the standard. A range of manufacturers produce various lamination products based on desired response and performance characteristics. 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.
The performance of building envelopes and cladding components during an explosive blast 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. Laminated glass fabricated with fully tempered glass plies has a tendency to leave the supporting glazing system frame after fracture whereas laminated glass fabricated with annealed or heat strengthened glass plies will remain in the frame and absorb remaining load through tensile membrane behavior.
Blast mitigation design is a rapidly evolving trend in the building industry. Batten bars may be used to increase the anchorage capacity of the glass itself. 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. 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.
ASTM F 2248
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. Work Item s – proposed revisions of this standard.
Alexandria, VA Design considerations for both new and existing buildings should include adequate setback and standoff distance. Blast pressures also increase linearly with the weapon size and exponentially with the distance from the explosion. Various damage levels should be considered, ranging from minor or non-structural to major, which may include progressive collapse.
Terrorist activity is highly unpredictable and exists from a wide range of sources, leading to the increasing demand for reducing hazards in the event of an explosive blast.
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. 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.
The main keywords to present asm standard are air blast pressure, blast resistant glazing, explosion, insulating glass, and laminated glass. They can be reached ator This email address is being protected from spambots.
It is the responsibility of the astk of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. A combination of these design approaches also may be used to achieve the desired response. 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.
Retrieved from ” https: The standard explain different methods to check the thickness and type of blast resistant glazing fabricated with laminated glass to glaze a fenestration Asrm main keywords to present this standard are air blast pressure, blast resistant glazing, explosion, insulating glass, and laminated glass.
Steel reinforcement or tubing within the window frame can provide added resistance to blast overpressures. A secondary threat to consider is a hand-carried weapon that may potentially be placed directly against the building envelope.
The width of glazing tape shall be at least equal to two times but not more than four times the thickness designation of the glass to which it adheres.
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.
The purpose of blast resistant design is to minimize the hazards caused by a blast as opposed to preventing damages. Technology News Lewis E. Assistant Editor Onjeinika Brooks obrooks same. The standard explain different methods to check the thickness and type of blast resistant glazing fabricated with laminated glass to glaze a fenestration. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
This load is then used for design of the assembly frame, glazing frame bite, connections, and supporting structural elements.
Given project-specific standoff distance and TNT-equivalent size, a 3-second duration equivalent static pressure load can be interpolated. Many of the leading window manufactures also have specific blast-resistant window models that incorporate these technologies in a singular system.