1、Designation: F2248 09 F2248 12Standard Practice forSpecifying an Equivalent 3-Second Duration Design Loadingfor Blast Resistant Glazing Fabricated with LaminatedGlass1This standard is issued under the fixed designation F2248; the number immediately following the designation indicates the year oforig
2、inal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONHistorical records show that fragments from glazing that has fa
3、iled as the result of intentional oraccidental explosions present a serious threat of personal injury. Glazing failure also allows blastpressure to enter the interior of buildings thus resulting in additional threat of personal injury andfacility damage. This standard practice provides a means for d
4、esigners to determine equivalent3-second duration design loadings with which they can size blast resistant glazing comprised oflaminated glass or insulating glass fabricated with laminated glass, or both. Blast resistant glazingsystems of this genre can reduce the number and size of glass fragments
5、in an explosion as well asreducing greatly or eliminating blast pressure that enters buildings when an explosion occurs.1. Scope1.1 This practice sets forth a method to specify an equivalent 3-second design loading suitable to use with Practice E1300 toselect the thickness and type of blast resistan
6、t glazing fabricated with laminated glass to glaze a fenestration. Glass plies used toconstruct laminated glass are recommended to be either annealed or heat strengthened glass.1.2 This practice applies to blast resistant glazing fabricated using laminated glass only, including single laminated glas
7、s andinsulating glass fabricated with laminated glass. As a minimum, insulating glass shall use laminated glass for the inboard (protectedside) lite.1.3 This practice assumes that blast resistant glazing shall be adhered to its supporting frame using structural silicone sealantor adhesive glazing ta
8、pe. The width of the structural silicone sealant bead shall be at least equal to the larger of 10-mm (38-in.)or the thickness designation of the glass to which it adheres but not larger than two times the thickness designation of the glassto which it adheres. The minimum thickness of the structural
9、silicone bead shall be 5-mm (316-in.). The width of glazing tape shallbe at least equal to two times but not more than four times the thickness designation of the glass to which it adheres. The widthof silicone or glazing tape is referred to as bite and is shown and discussed in Guide C1564.1.4 This
10、 practice assumes that the structural silicone bead or glazing tape is applied to both sides of single lite laminated glassbut need only be applied to the inboard side (protected side) of insulating glass.1.5 This practice assumes the framing members shall restrict deflections of edges of blast resi
11、stant glazing they support to L/60under 2.0 the load resistance of the blast resistant glazing for inward loading, where L denotes the length of the supported edge.1.6 This practice assumes the framing system supporting the blast resistant glazing shall attach mechanically to the structuralframing s
12、ystem. The system shall be designed to ensure that the glazing fails prior to the framing system that supports the glazingand its attachment to the structural framing system. The fasteners that attach the framing system that supports the glazing to thestructural framing system shall be designed to r
13、esist a uniform load acting on the blast resistant glazing that has a magnitude ofat least:1.6.1 Two (2.0) times the magnitude of the load resistance of the blast resistant glazing if the maximum air blast pressure isgreater than one half the magnitude of the load resistance of the blast resistant g
14、lazing, or1.6.2 One (1.0) times the magnitude of the load resistance of the blast resistant glazing if the maximum air blast pressure is lessthan one half the magnitude of the load resistance of the blast resistant glazing.1.7 Blast resistant glazing designed using this practice recommends the use o
15、f annealed or heat strengthened glass plies for thelaminated glass. Blast testing has shown that use of fully tempered glass plies, when fractured during a blast event, have poorerpost blast performance than annealled or heat strengthened glass plies. Laminated glass fabricated with fully tempered g
16、lass pliesCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1has a tendency to leave the supporting glazing system frame after fracture whereas laminated glass fabricated with annealed or heatstrengthened glass plies will remain in the f
17、rame and absorb remaining load through tensile membrane behavior. Use of theannealed or heat strengthened glass plies will also reduce the amount of load transferred into the structure.1.8 The equivalent 3-second design load as determined herein shall not apply to the design of monolithic glazing, p
18、lasticglazing, or security film applied to existing glazing configurations in an attempt to achieve blast resistance.1.9 The values stated in SI units are to be regarded as the standard. Values given in parentheses are for information only. Forconversion of quantities in various systems of measureme
19、nts to SI units refer to ANSI IEEE/SI 10.1.10 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
20、limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C1036 Specification for Flat GlassC1048 Specification for Heat-Strengthened and Fully Tempered Flat GlassC1172 Specification for Laminated Architectural Flat GlassC1422 Specification for Chemically Strengthened Flat GlassC1564 Guide
21、 for Use of Silicone Sealants for Protective Glazing SystemsE631 Terminology of Building ConstructionsE1300 Practice for Determining Load Resistance of Glass in BuildingsF1642 Test Method for Glazing and Glazing Systems Subject to Airblast Loadings2.2 ANSI Standard:3IEEE/SI 10 Use of the Internation
22、al System of Units (SI): (The Modernized Metric System)23. Terminology3.1 Definitions:3.1.1 blast resistant glazing, nglazing that provides protection against air blast pressure generated by explosions.3.1.2 design load, nmagnitude in kPa (psf) of 3-second duration uniformly distributed lateral pres
23、sure.3.1.3 equivalent TNT charge mass, nmass of TNT placed on the ground in a hemisphere that represents the design explosivethreat.NOTE 1If a different high explosive material comprises the design threat, tables exist to convert its mass to an equivalent TNT mass. Refer to TestMethod F1642, for exa
24、mple.3.1.4 glass breakage, nthe fracture of any lite or ply in monolithic, laminated, or insulating glass.3.1.5 glass types:3.1.5.1 annealed (AN) glass, na flat, monolithic, glass lite of uniform thickness where the residual surface stresses are nearlyzero as defined in Specification C1036.3.1.5.2 c
25、hemically strengthened glass, nglass that has been strengthened by ion-exchange to produce a compressive stress atthe treated surface as defined in Specification C1422.3.1.5.3 fully tempered (FT) glass, na flat, monolithic, glass plate of uniform thickness made from annealed glass subjectedto a spec
26、ial heat treatment process whereby the residual surface compression is not less than 69 MPa (10 000 psi) or the edgecompression not less than 67 MPa (9700 psi) as defined in Specification C1048.3.1.5.4 heat strengthened (HS) glass, na flat, monolithic, glass lite of uniform thickness that has been s
27、ubjected to a specialprocess where the residual surface compression is not less than 24 MPa (3500 psi) or greater than 52 MPa (7500 psi) as definedin Specification C1048.3.1.5.5 insulating glass (IG), nconsists of any combination of two glass lites that enclose a sealed space filled with air or othe
28、rgas.3.1.5.6 laminated glass, na flat lite of uniform thickness consisting of two monolithic glass plies bonded together with aninterlayer material as defined in Specification C1172.1 This practice is under the jurisdiction of ASTM Committee F12 on Security Systems and Equipment and is the direct re
29、sponsibility of Subcommittee F12.10 on SystemsProducts and Services.Current edition approved Nov. 1, 2009Oct. 1, 2012. Published December 2009November 2012. Originally approved in 2003. Last previous edition approved in 20032009as F2248 03.F2248 09. DOI: 10.1520/F2248-09.10.1520/F2248-12.2 For refer
30、enced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W.
31、43rd St., 4th Floor, New York, NY 10036.F2248 1223.1.5.7 DiscussionMany different interlayer materials are used in laminated glass. The information in this practice applies only to laminated glassfabricated with polyvinyl butyral (PVB) interlayers.3.1.6 glazing, ntransparent, translucent, or opaque
32、laminated glass used for windows, doors, or other panels.3.1.7 glazing system, nthe assembly comprised of the glazing, its framing system, and anchorage devices.3.1.8 lateral, adjperpendicular to the glass surface.3.1.9 load, na uniformly distributed lateral pressure.3.1.10 load resistance, nthe 3-s
33、econd duration uniform lateral load that a glass construction can sustain associated with aprobability of breakage of 8 L per 1000 as determined from Practice E1300.3.1.11 maximum air blast pressure, nthe peak reflected positive pressure that the blast resistant glazing will experience.3.1.12 probab
34、ility of breakage (Pb) , nthe fraction of glass lites or plies that would break at the first occurrence of a specifieddesign load, typically expressed in lites per 1000.3.1.13 standoff distance, nthe distance from the glazing surface to the centroid of a hemispherical high explosive charge.4. Summar
35、y of Practice4.1 This practice facilitates the determination of a 3-second duration design load associated with a specified weight of ahemispherical TNT charge located at a specified standoff distance from a building fenestration.4.2 The design load shall be used in conjunction with Practice E1300 t
36、o select the thickness(es) and glass type(s) for blastresistant glazing comprised of a single lite of laminated glass or insulating glass fabricated with laminated glass.5. Significance and Use5.1 This practice provides a design load suitable for sizing blast resistant glazing comprised of laminated
37、 glass or insulatingglass fabricated with laminated glass.5.2 Blast resistant glazing comprised of laminated glass or insulating glass fabricated with laminated glass shall be sized to resistthe 3-second duration equivalent design loading from this standard practice using the procedures described in
38、 Practice E1300.5.3 Blast resistant glazing comprised of laminated glass or insulating glass fabricated with laminated glass sized using the3-second design loading determined from this practice will fracture safely in the event of a blast, thus reducing the potential forpersonal injury, structural a
39、nd non-structural building damage, and cleanup costs should an explosion occur.5.4 In the event a blast loading never occurs to blast resistant glazing comprised of laminated glass or insulating glass fabricatedwith laminated glass sized using the 3-second duration loading determined herein, the bla
40、st resistant glazing will have a probabilityof breakage less than or equal to 8 lites per 1000 at the first occurrence of a loading equal to the 3-second duration design loadingdetermined herein.5.5 Blast resistant glazing designed to resist the 3-second equivalent load as determined herein, properl
41、y supported, will performto minimal hazard as defined in Test Method F1642.6. Determination of Equivalent 3-Second Duration Design Loading6.1 The chart in Fig. 1 relates the mass of an equivalent hemispherical TNT charge (sloping lines), its standoff distance froma fenestration (horizontal axes), an
42、d a 3-second duration design load (vertical axes) suitable for selecting the thickness(es) and glasstype(s) of single laminated glass or insulating glass fabricated with laminated glass.6.2 In Fig. 1 project a vertical line from the point along the horizontal axes that represent standoff distance be
43、tween the highexplosive charge and the fenestration to be glazed with blast resistant glazing.6.3 From the intersection of the vertical line with the sloping line representing equivalent TNT mass, project a horizontal line.For equivalent TNT masses not represented by sloping lines, the user shall in
44、terpolate between the lines.6.4 Read the 3-second duration design load from the vertical axes, interpolating as necessary.7. Report7.1 Report the following:7.1.1 Date of calculation,7.1.2 Mass of hemispherical TNT charge size,7.1.3 Standoff distance of charge from fenestration, and7.1.4 Magnitude of
45、 the 3-second duration equivalent design loading.F2248 1238. Precision and Bias8.1 Precision and BiasNo statement is made concerning either the precision or bias of this practice since the result merelystates whether a glazing or glazing system can resist an airblast loading.9. Keywords9.1 air blast
46、 pressure; blast resistant glazing; explosion; insulating glass; laminated glass; specified design loadASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that d
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