1、Designation: E2461 05 (Reapproved 2011)Standard Practice forDetermining the Thickness of Glass in Airport TrafficControl Tower Cabs1This standard is issued under the fixed designation E2461; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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.1. Scope1.1 This practice covers the determination of the thicknessof glass installed in airport traffic contr
3、ol towers (ATCT) 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 l
4、oads do not exceed 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 lamina
5、ted, or annealed 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 f
6、ouredges;1.6.2 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 redu
7、ce the glass strength.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 specif
8、ied design wind 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 asstandard. The valu
9、es given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.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 stand
10、ard to establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C1036 Specification for Flat GlassE631 Terminology of Building ConstructionsE1300 Practice for Determining Load Resistance of
11、Glassin Buildings2.2 American Society of Civil Engineers Standard:3ASCE 7 Minimum Design Loads for Buildings and OtherStructures3. Terminology3.1 Definitions:3.1.1 Refer to Terminology E631 for additional terms usedin these procedures.3.2 Definitions of Terms Specific to This Standard:3.2.1 annealed
12、 (AN) glass, na flat, monolithic, glass liteof uniform thickness; it is formed by a process whereby themagnitudes 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 sh
13、ort dimension of the rectangle thatcompletely encloses trapezoidal glass. In these procedures, ARis always 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 two1This practice is under t
14、he 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, 2011. Published November 2011. Originallyapproved in 2005. Last previous edition in
15、 2005 as E2421 05 (2011). DOI:10.1520/E2461-05R11.2For referenced ASTM standards, visit 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
16、from American Society of Civil Engineers (ASCE), 1801 AlexanderBell Dr., Reston, VA 20191, http:/www.asce.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.sides perpendicular to the horizontal edges of the trapezoid. All dimen-sio
17、ns shall be measured from edge to edge of glass.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 plane ofthe glass. All dimensions shall be measured from edge to edgeof glass.3.2.
18、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 particular glass product, based on the minimum thicknessespresented in Table 2 and S
19、pecification C1036.3.2.6 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, nconsists of any combi-nation of two glass lites, as defined herein, that enclose
20、 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, together withpolyvinyl butyral (PVB) interlayer(s).3.2.9 lateral, adjperpendicula
21、r 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 magnitudes for design loads adjustglass self weight to a magnitude consistent with a
22、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 (Table 2) has a long duration,typically equal to the in-service life of the window g
23、lass 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-mately 3 seconds, such as, wind load.TABLE 1 Thickness Designations for Laminated
24、 GlassLaminated glassdesignation, t,mm (in.)Laminated glass constructionnominal thickness, mm (in.)glass/PVB/glassLaminated glass thicknessdesignation 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.
25、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) 6/1.52/6 (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)1
26、0/1.52/10 (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 (114)16/1.52/16 (58)/0.060/(58)32 (114)16/2.28/16 (58)/0.090/(58)38 (112)19/1.52/19 (34)/0.060/(34)38 (112)19/2.28/19 (34)/0.090/(34)TABLE 2 Thickness Designations, Minimum Glass Thi
27、ckness,and Unit Self-WeightNominal thickness ordesignation. mm (in.)Minimum thickness, mm(in.)Glass weightPa (psf)2.7 (lami) 2.59 (0.102) 67.0 (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 (0.2
28、92) 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 (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 indu
29、stry standard thickness designation.E2461 05 (2011)23.2.11 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 SpecificationC1036.3.2.12 probability of breakage (Pb), nthe theoretical frac-tion of g
30、lass lites or plies that would break at the firstoccurrence of the resistance load, typically expressed in litesper thousand.4. Summary of Practice4.1 The use of these procedures requires a specified designload that shall consist of the wind load and the factored lateralcomponent of glass weight. Th
31、e 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 selectedprobability of breakage.4.3 This standard procedure uses methods i
32、n Practice E1300to determine the approximate lateral deflection of the geomet-ric center of the window glass construction.AnnexA2 providesdeflection charts for laminated glass thicknesses larger thanthose contained in Practice E1300.5. Significance and Use5.1 This standard procedure facilitates dete
33、rmination 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, annealed laminated, andinsulating glass fabricated with annealed monolithic
34、 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 is typical of glassthat has been in service for several years, and is signif
35、icantlyweaker 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 1/175 of their lengths. The specified design load shall beused for this calculati
36、on, 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 of edge support will occur.5.4 Many other factors affect the selection of glas
37、s 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, noise abatement, potential post-breakageconsequences, and so forth. In addition
38、, 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. Procedure6.1 Select a probability of breakage, glass type or construc-tion, and glass
39、 thickness(es).6.2 Compute the design load for monolithic or singlelaminated glass according to:LD5 LW1 2LGcosu (1)where:LD= denotes the design load,LW= denotes the wind load,LG= denotes the weight of the glass, andu = denotes the acute angle the glass makes with thehorizontal. For monolithic or sin
40、gle 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 Continuously SupportedAlong all Four Edges:6.3.1 Determine the ERA.6.3.2 Deter
41、mine 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 from Practice E1300.6.4 Single Laminated Glazing Continuously SupportedAlong a
42、ll 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 maximum center of glassdeflection using procedures from Practice E1300.6.5 Monol
43、ithic 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.A1.6 (PB= 0.004) for the design load, ERA,and AR.6.5.3 Determine the approximate
44、maximum center of glassdeflection using procedures from Practice E1300.6.6 Single Laminated Glazing Simply Supported Continu-ously Along Two Opposite Sides or any Three Sides:6.6.1 Determine the unsupported glass length.6.6.2 Determine the required glass thickness from Fig. A1.7(PB= 0.001) or Fig.A1
45、.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 E1300.6.7 Insulating Glass (IG) with Monolithic Glass Lites ofEqual (Symmetric) Glass Type and Thickness.6.7.1 Compute the design load for IG as LDIG5 5LW12
46、LGcosu!/9 in which all terms are previously defined. Theweigh of the glass, LG, consists of the weight of both glass lites.6.7.2 Determine the ERA.6.7.3 Determine the AR.E2461 05 (2011)36.7.4 Determine the required glass thickness for a single litein the IG unit from Fig. A1.1 (PB= 0.001) or Fig. A1
47、.2 (PB=0.004) for the design load, ERA, and AR.6.7.5 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 E1300.6.8 Insulating Glass (IG) with Laminated Glass Lites ofEqual (Symmetric) Glas
48、s 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 glass lites.6.8.2 Determine the ERA.6.8.3 Determine the AR.6.8.4 Determine the required glass thickness for a single
49、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 load 0.9LDIGusing procedures from Practice E1300.7. 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 ed
