1、Designation: E 2461 05Standard Practice forDetermining the Thickness of Glass in Airport TrafficControl Tower Cabs1This standard is issued under the fixed designation E 2461; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the determination of the thicknessof glass installed in airport traffic control towers (ATCT
3、) toresist a specified design loading with a selected probability ofbreakage less than or equal to either 1 lite per 1000 or 4 litesper 1000 at the first occurrence of the design wind loading.1.2 The procedures apply to common outward sloping cabglass designs for which the specified loads do not exc
4、eed 10kPa (210 psf).1.3 The procedures assume control tower cab glass has anaspect ratio no greater than 2.1.4 The procedures assume control tower cab glass has anarea no less than 1.86 square metres (20 square feet).1.5 The procedures apply only to annealed monolithic,annealed laminated, or anneale
5、d insulating glass having arectangular or trapezoidal shape.1.6 The use of the procedures assumes the following:1.6.1 Annealed monolithic and annealed laminated glassinstalled in ATCTs shall have continuous lateral support alongtwo parallel edges, along any three edges, or along all fouredges;1.6.2
6、Insulating glass shall have continuous lateral supportalong all four edges; and1.6.3 Supported glass edges are simply supported and freeto slip in plane.1.7 The procedures do not apply to any form of wired,patterned, etched, sandblasted, or glass types with surfacetreatments that reduce the glass st
7、rength.1.8 The procedures do not apply to any form of heat treatedglass, chemically strengthened glass, or any type of glass withsurface treatments intended to increase the glass strength.1.9 The procedures address the determination of thicknessand construction type to resist a specified design wind
8、 load ata selected probability of breakage. The final glass thicknessand construction determined also depends upon a variety ofother factors (see 5.3).1.10 These procedures do not address blast loading on glass.1.11 The values stated in SI units are to be regarded as thestandard. The values given in
9、 parentheses are for informationonly.1.12 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and to determine theapplicability of regulatory l
10、imitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 1036 Specification for Flat GlassE 631 Terminology of Building ConstructionsE 1300 Practice for Determining Load Resistance of Glassin Buildings2.2 American Society of Civil Engineers Standard:ASCE 7 Minimum Design Loads for Buildi
11、ngs and OtherStructures33. Terminology3.1 Definitions:3.1.1 Refer to Terminology E 631 for additional terms usedin these procedures.3.2 Definitions of Terms Specific to This Standard:3.2.1 annealed (AN) glass, na flat, monolithic, glass liteof uniform thickness; it is formed by a process whereby the
12、magnitudes of the residual stresses are nearly zero.3.2.2 aspect ratio (AR), nthe ratio of the long dimensionto the short dimension for rectangular glass or the ratio of thelong dimension to the short dimension of the rectangle thatcompletely encloses trapezoidal glass. In these procedures, ARis alw
13、ays equal to or greater than 1.0.NOTE 1The rectangle that completely encloses the trapezoid has twosides parallel to the horizontal edges of the trapezoid and the other twosides perpendicular to the horizontal edges of the trapezoid. All dimen-sions shall be measured from edge to edge of glass.1This
14、 practice is under the jurisdiction of ASTM Committee E06 on Perfor-mance of Buildings and is the direct responsibility of Subcommittee E06.51 onPerformance of Windows, Doors, Skylights, and Curtain Walls.Current edition approved Oct. 1, 2005. Published October 2005.2For referenced ASTM standards, v
15、isit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Society of Civil Engineers, 1801 Alexander BellDrive,Reston, Virginia
16、 20191-44001Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 equivalent rectangular area (ERA), nthe product ofthe longest horizontal glass dimension and the length of theedge perpendicular to the horizontal dimension in the plan
17、e ofthe glass. All dimensions shall be measured from edge to edgeof glass.3.2.4 designated thickness for laminated glass (LG), nthedesignated thickness for LG as Table 1 specifies.3.2.5 designated thickness for monolithic glass, nthedesignated or nominal thickness commonly used in specifyinga partic
18、ular glass product, based on the minimum thicknessespresented in Table 2 and Specification C 1036.3.2.6 glass breakage, nthe fracture of any lite or ply inmonolithic, laminated, or insulating glass resulting from stressthat an applied uniform lateral load induces.3.2.7 insulating glass (IG) unit, nc
19、onsists of any combi-nation of two glass lites, as defined herein, that enclose a sealedspace filled with air or other gas.3.2.8 laminated glass (LG), na flat-lite of uniform thick-ness that is fabricated by bonding two or more monolithic glasslites or plies of equal thickness, as defined herein, to
20、gether withpolyvinyl butyral (PVB) interlayer(s).3.2.9 lateral, adjperpendicular to the glass surface.3.2.10 load, na uniformly distributed lateral pressure.3.2.10.1 design load, nthe magnitude of the 3-secondduration load used to design glass for ATCT cabs. Equationsused herein for computing magnit
21、udes for design loads adjustglass self weight to a magnitude consistent with a 3-secondduration.3.2.10.2 specified design load, nthe magnitude in kPa(psf), type (for example, wind or self-weight) and duration ofthe load. The wind load has a duration of approximately 3seconds. Glass self-weight (Tabl
22、e 2) has a long duration,typically equal to the in-service life of the window glass lite.Earth facing cab glass is only subjected to wind load and itsself-weight.3.2.10.3 long duration load, nany load lasting approxi-mately 30 days or longer.3.2.10.4 short duration load, nany load lasting approxi-ma
23、tely 3 seconds, such as, wind load.3.2.11 minimum thickness of monolithic glass, nthe mini-mum allowable thickness associated with a nominal or desig-nated glass thickness as given in Table 2 and SpecificationC 1036.3.2.12 probability of breakage (Pb), nthe theoretical frac-tion of glass lites or pl
24、ies that would break at the firstoccurrence of the resistance load, typically expressed in litesper thousand.TABLE 1 Thickness Designations for Laminated GlassLaminated glassdesignation, t,mm (in.)Laminated glass constructionnominal thickness, mm (in.)glass/PVB/glassLaminated glass thicknessdesignat
25、ion for use in theseprocedures mm (in.)6(14)2.7/0.76/2.7 (lami)/0.030/(lami)6(14)3/0.76/3 (18)/0.030/(18)3/1.52/3 (18)/0.060/(18)8(516) 4/0.76/4 (532)/0.030/(532) 8 (516)10 (38) 5/0.76/5 (316)/0.030/(316) 10 (38)11 (716) 5/1.52/5 (316)/0.060/(316)12 (12) 6/0.76/6 (14)/0.030/(14) 12 (12)13 (916) 6/1.
26、52/6 (14)/0.060/(14)16 (58)8/0.76/8 (516)/0.030/(516)16 (58)8/1.52/8 (516)/0.060/(516)8/2.28/8 (516)/0.090/(516)19 (34)10/0.76/10 (38)/0.030/(38)19 (34)10/1.52/10 (38)/0.060/(38)10/2.28/10 (38)/0.090/(38)25 (1)12/1.52/12 (12)/0.060/(12)25 (1)12/2.28/12 (12)/0.090/(12)32 (1-14)16/1.52/16 (58)/0.060/(
27、58)32 (1-14)16/2.28/16 (58)/0.090/(58)38 (1-12)19/1.52/19 (34)/0.060/(34)38 (1-12)19/2.28/19 (34)/0.090/(34)TABLE 2 Thickness Designations, Minimum Glass Thickness,and Unit Self-WeightNominal thickness ordesignation. mm (in.)Minimum thickness, mm(in.)Glass weightPa (psf)2.7 (lami) 2.59 (0.102) 67.0
28、(1.40)3.0 (18) 2.92 (0.115) 74.2 (1.55)4.0 (532) 3.78 (0.149) 99.1 (2.07)5.0 (316) 4.57 (0.180) 124 (2.59)6.0 (14) 5.56 (0.219) 149 (3.11)8.0 (516) 7.42 (0.292) 199 (4.15)10.0 (38) 9.02 (0.355) 248 (5.18)12.0 (12) 11.91 (0.469) 298 (6.22)16.0 (58) 15.09 (0.595) 397 (8.29)19.0 (34) 18.26 (0.719) 472
29、(9.85)22.0 (78) 21.44 (0.844) 546 (11.4)25.0 (1)* 24.4 (0.969) 622 (13.0)32 (1 14)A27.38 (1.22) 795 (16.6)38 (1 12)A31.6 (1.47) 943 (19.7)ANot a glazing industry standard thickness designationE24610524. Summary of Practice4.1 The use of these procedures requires a specified designload that shall con
30、sist of the wind load and the factored lateralcomponent of glass weight. The total design load shall notexceed 10 kPa (210 psf).4.2 The procedures specified herein facilitate determinationof the thickness of an annealed window glass constructionrequired to resist the specified design loading for the
31、 selectedprobability of breakage.4.3 This standard procedure uses methods in PracticeE 1300 to determine the approximate lateral deflection of thegeometric center of the window glass construction. Annex A2provides deflection charts for laminated glass thicknesseslarger than those contained in Practi
32、ce E 1300.5. Significance and Use5.1 This standard procedure facilitates determination of thethickness of a glass construction required to resist a specifieddesign load with a selected probability of breakage.5.2 This standard procedure addresses the following glassconstructions: annealed monolithic
33、, annealed laminated, andinsulating glass fabricated with annealed monolithic or an-nealed laminated glass, or both.5.3 Use of these procedures assume:5.3.1 The glass is free of edge damage and is properlyglazed,5.3.2 The glass has not been subjected to abuse,5.3.3 The surface condition of the glass
34、 is typical of glassthat has been in service for several years, and is significantlyweaker than freshly manufactured glass due to minor abrasionson exposed surfaces,5.3.4 The glass edge support system is sufficiently stiff tolimit the lateral deflections of the supported glass edges to lessthan 1/17
35、5 of their lengths. The specified design load shall beused for this calculation, and5.3.5 The center of glass deflection shall not result in loss ofedge support. Typically maintaining center of glass deflectionat or below the magnitude of three times the nominal glassthickness assures that no loss o
36、f edge support will occur.5.4 Many other factors affect the selection of glass type andthickness. These factors include but are not limited to: thermalstresses, the effects of windborne debris, excessive deflections,behavior of glass fragments after breakage, seismic effects,heat flow, edge bite, no
37、ise abatement, potential post-breakageconsequences, and so forth. In addition, considerations setforth in federal, state, and local building codes along withcriteria presented in safety glazing standards and site specificconcerns may control the ultimate glass type and thicknessselection.6. Procedur
38、e6.1 Select a probability of breakage, glass type or construc-tion, and glass thickness(es).6.2 Compute the design load for monolithic or singlelaminated glass according to:LD5 LW1 2LGcosu (1)WhereLD= denotes the design load,LW= denotes the wind load,LG= denotes the weight of the glass, andu = denot
39、es the acute angle the glass makes with thehorizontal. For monolithic or single laminated glaz-ing, the user shall obtain LGfrom Table 2 for thenominal glass thickness. For insulating glass, LGshall consist of the weights of both glass lites asdetermined from Table 2.6.3 Monolithic Single Glazing Co
40、ntinuously SupportedAlong all Four Edges:6.3.1 Determine the ERA.6.3.2 Determine the AR.6.3.3 Determine the required glass thickness from Fig. A1.1(PB= 0.001) or Fig.A1.2 (PB= 0.004) for the design load, ERA,and AR.6.3.4 Determine the approximate maximum center of glassdeflection using procedures fr
41、om Practice E 1300.6.4 Single Laminated Glazing Continuously SupportedAlong all Four Edges:6.4.1 Determine the ERA.6.4.2 Determine the AR.6.4.3 Determine the required glass thickness from Fig. A1.3(PB= 0.001) or Fig.A1.4 (PB= 0.004) for the design load, ERA,and AR.6.4.4 Determine the approximate max
42、imum center of glassdeflection using procedures from Practice E 1300.6.5 Monolithic Single Glazing Simply Supported Continu-ously Along Two Opposite Sides or any Three Sides:6.5.1 Determine the Unsupported Glass Length.6.5.2 Determine the required glass thickness from Fig. A1.5(PB= 0.001) or Fig.A1.
43、6 (PB= 0.004) for the design load, ERA,and AR.6.5.3 Determine the approximate maximum center of glassdeflection using procedures from Practice E 1300.6.6 Single Laminated Glazing Simply Supported Continu-ously Along Two Opposite Sides or any Three Sides:6.6.1 Determine the unsupported glass length.6
44、.6.2 Determine the required glass thickness from Fig. A1.7(PB= 0.001) or Fig.A1.8 (PB= 0.004) for the design load, ERA,and AR.6.6.3 Determine the approximate maximum center of glassdeflection using procedures from Practice E 1300.6.7 Insulating Glass (IG) with Monolithic Glass Lites ofEqual (Symmetr
45、ic) Glass Type and Thickness.6.7.1 Compute the design load for IG as LDIG= 5(LW+2LGcosu)/9 in which all terms are previously defined. Theweigh of the glass, LG, consists of the weight of both glasslites.6.7.2 Determine the ERA.6.7.3 Determine the AR.6.7.4 Determine the required glass thickness for a
46、 single litein the IG unit from Fig. A1.1 (PB= 0.001) or Fig. A1.2 (PB=0.004) for the design load, ERA, and AR6.7.5 Determine the approximate maximum center of glassdeflection as the deflection of one lite in the IG unit under thedesign load 0.9LDIGusing procedures from Practice E 1300.E24610536.8 I
47、nsulating Glass (IG) with Laminated Glass Lites ofEqual (Symmetric) Glass Type and Thickness.6.8.1 Compute the design load for IG as LDIG5 5LW12LGcosu!/9 in which all terms are previously defined. Theweigh of the glass, LG, consists of the weight of both glasslites.6.8.2 Determine the ERA.6.8.3 Dete
48、rmine the AR.6.8.4 Determine the required glass thickness for a single litein the IG unit from Fig. A1.1 (PB= 0.001) or Fig. A1.4 (PB=0.004) for the design load, ERA, and AR.6.9 Determine the approximate maximum center of glassdeflection as the deflection of one lite in the IG unit under thedesign l
49、oad 0.9LDIGusing procedures from Practice E 1300.7. Report7.1 Report the following information:7.1.1 Date of calculation,7.1.2 The probability of breakage, design wind load, draw-ing of the glass shape with dimensions, glass edge supportconditions, longest horizontal dimension of the glass, thelength of the edge perpendicular to the horizontal dimension inthe plane of the glass, aspect ratio, equivalent rectangular area,glass type(s) and thickness(es), weigh
