ASTM_F_2248_-_12.pdf

Designation:F224812Standard 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 oforiginal 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 failed 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 designers 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 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 equiva-lent 3-second design loading suitable to use with PracticeE1300 to select the thickness and type of blast resistant glazingfabricated with laminated glass to glaze a fenestration.Glassplies used to construct laminated glass are recommended to beeither annealed or heat strengthened glass.1.2 This practice applies to blast resistant glazing fabricatedusing laminated glass only,including single laminated glassand insulating glass fabricated with laminated glass.As aminimum,insulating glass shall use laminated glass for theinboard(protected side)lite.1.3 This practice assumes that blast resistant glazing shallbe adhered to its supporting frame using structural siliconesealant or adhesive glazing tape.The width of the structuralsilicone sealant bead shall be at least equal to the larger of10-mm(38-in.)or the thickness designation of the glass towhich it adheres but not larger than two times the thicknessdesignation of the glass to which it adheres.The minimumthickness of the structural silicone bead shall be 5-mm(316-in.).The width of glazing tape shall be at least equal to twotimes but not more than four times the thickness designation ofthe glass to which it adheres.The width of silicone or glazingtape is referred to as bite and is shown and discussed in GuideC1564.1.4 This practice assumes that the structural silicone bead orglazing tape is applied to both sides of single lite laminatedglass but need only be applied to the inboard side(protectedside)of insulating glass.1.5 This practice assumes the framing members shall re-strict deflections of edges of blast resistant glazing they supportto L/60 under 2.0 the load resistance of the blast resistantglazing for inward loading,where L denotes the length of thesupported edge.1.6 This practice assumes the framing system supporting theblast resistant glazing shall attach mechanically to the struc-tural framing system.The system shall be designed to ensurethat the glazing fails prior to the framing system that supportsthe glazing and its attachment to the structural framing system.The fasteners that attach the framing system that supports theglazing to the structural framing system shall be designed toresist a uniform load acting on the blast resistant glazing thathas a magnitude of at least:1.6.1 Two(2.0)times the magnitude of the load resistanceof the blast resistant glazing if the maximum air blast pressureis greater than one half the magnitude of the load resistance ofthe blast resistant glazing,or1.6.2 One(1.0)times the magnitude of the load resistance ofthe blast resistant glazing if the maximum air blast pressure isless than one half the magnitude of the load resistance of theblast resistant glazing.1This practice is under the jurisdiction of ASTM Committee F12 on SecuritySystems and Equipment and is the direct responsibility of Subcommittee F12.10 onSystems Products and Services.Current edition approved Oct.1,2012.Published November 2012.Originallyapproved in 2003.Last previous edition approved in 2009 as F2248 09.DOI:10.1520/F2248-12.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 1.7 Blast resistant glazing designed using this practicerecommends the use of annealed or heat strengthened glassplies for the laminated glass.Blast testing has shown that useof fully tempered glass plies,when fractured during a blastevent,have poorer post blast performance than annealled orheat strengthened glass plies.Laminated glass fabricated withfully tempered glass plies has a tendency to leave the support-ing glazing system frame after fracture whereas laminatedglass fabricat