ASTM E2461-12(2017)

Standard Practice for Determining the Thickness of Glass in Airport Traffic Control Tower Cabs

SIGNIFICANCE AND USE
5.1 This standard procedure facilitates determination of the thickness of a glass construction required to resist a specified design load with a selected probability of breakage.  
5.2 This standard procedure addresses the following glass constructions: annealed monolithic, annealed laminated, and insulating glass fabricated with annealed monolithic or annealed laminated glass, or both.  
5.3 Use of these procedures assume:  
5.3.1 The glass is free of edge damage and is properly glazed,  
5.3.2 The glass has not been subjected to abuse,  
5.3.3 The surface condition of the glass is typical of glass that has been in service for several years, and is significantly weaker than freshly manufactured glass due to minor abrasions on exposed surfaces,  
5.3.4 The glass edge support system is sufficiently stiff to limit the lateral deflections of the supported glass edges to less than 1/175 of their lengths. The specified design load shall be used for this calculation, and  
5.3.5 The center of glass deflection shall not result in loss of edge support. Typically maintaining center of glass deflection at or below the magnitude of three times the nominal glass thickness assures that no loss of edge support will occur.  
5.4 Many other factors affect the selection of glass type and thickness. These factors include but are not limited to: thermal stresses, the effects of windborne debris, excessive deflections, behavior of glass fragments after breakage, seismic effects, heat flow, edge bite, noise abatement, potential post-breakage consequences, and so forth. In addition, considerations set forth in federal, state, and local building codes along with criteria presented in safety glazing standards and site specific concerns may control the ultimate glass type and thickness selection.
SCOPE
1.1 This practice covers the determination of the thickness of glass installed in airport traffic control towers (ATCT) to resist a specified design loading with a selected probability of breakage less than or equal to either 1 lite per 1000 or 4 lites per 1000 at the first occurrence of the design wind loading.  
1.2 The procedures apply to common outward sloping cab glass designs for which the specified loads do not exceed 10 kPa (210 psf).  
1.3 The procedures assume control tower cab glass has an aspect ratio no greater than 2.  
1.4 The procedures assume control tower cab glass has an area no less than 1.86 square metres (20 square feet).  
1.5 The procedures apply only to annealed monolithic, annealed laminated, or annealed insulating glass having a rectangular or trapezoidal shape.  
1.6 The use of the procedures assumes the following:  
1.6.1 Annealed monolithic and annealed laminated glass installed in ATCTs shall have continuous lateral support along two parallel edges, along any three edges, or along all four edges;  
1.6.2 Insulating glass shall have continuous lateral support along all four edges; and  
1.6.3 Supported glass edges are simply supported and free to slip in plane.  
1.7 The procedures do not apply to any form of wired, patterned, etched, sandblasted, or glass types with surface treatments that reduce the glass strength.  
1.8 The procedures do not apply to any form of heat treated glass, chemically strengthened glass, or any type of glass with surface treatments intended to increase the glass strength.  
1.9 The procedures address the determination of thickness and construction type to resist a specified design wind load at a selected probability of breakage. The final glass thickness and construction determined also depends upon a variety of other 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 standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.  
1.12 This standard do...

General Information

• Status: Historical
• Publication Date: 31-Mar-2017
• ICS: 81.040.20 - Glass in building
• Technical Committee: E06 - Performance of Buildings
• Drafting Committee: E06.52 - Glass Use in Buildings

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E2461 − 12 (Reapproved 2017)
Standard Practice for
Determining the Thickness of Glass in Airport Traffic
Control Tower Cabs
This standard is issued under the fixed designation E2461; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope a selected probability of breakage. The final glass thickness
and construction determined also depends upon a variety of
1.1 This practice covers the determination of the thickness
other factors (see 5.3).
of glass installed in airport traffic control towers (ATCT) to
resist a specified design loading with a selected probability of 1.10 These procedures do not address blast loading on glass.
breakage less than or equal to either 1 lite per 1000 or 4 lites
1.11 The values stated in SI units are to be regarded as
per 1000 at the first occurrence of the design wind loading.
standard. The values given in parentheses are mathematical
1.2 The procedures apply to common outward sloping cab conversions to inch-pound units that are provided for informa-
glass designs for which the specified loads do not exceed 10 tion only and are not considered standard.
kPa (210 psf).
1.12 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.3 The procedures assume control tower cab glass has an
responsibility of the user of this standard to establish appro-
aspect ratio no greater than 2.
priate safety and health practices and to determine the
1.4 The procedures assume control tower cab glass has an
applicability of regulatory limitations prior to use.
area no less than 1.86 square metres (20 square feet).
1.13 This international standard was developed in accor-
1.5 The procedures apply only to annealed monolithic,
dance with internationally recognized principles on standard-
annealed laminated, or annealed insulating glass having a
ization established in the Decision on Principles for the
rectangular or trapezoidal shape.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.6 The use of the procedures assumes the following:
Barriers to Trade (TBT) Committee.
1.6.1 Annealed monolithic and annealed laminated glass
installed in ATCTs shall have continuous lateral support along
2. Referenced Documents
two parallel edges, along any three edges, or along all four
edges; 2.1 ASTM Standards:
1.6.2 Insulating glass shall have continuous lateral support
C162 Terminology of Glass and Glass Products
along all four edges; and C1036 Specification for Flat Glass
1.6.3 Supported glass edges are simply supported and free
E631 Terminology of Building Constructions
to slip in plane. E1300 Practice for Determining Load Resistance of Glass in
Buildings
1.7 The procedures do not apply to any form of wired,
2.2 American Society of Civil Engineers Standard:
patterned, etched, sandblasted, or glass types with surface
ASCE 7 Minimum Design Loads for Buildings and Other
treatments that reduce the glass strength.
Structures
1.8 The procedures do not apply to any form of heat treated
glass, chemically strengthened glass, or any type of glass with
3. Terminology
surface treatments intended to increase the glass strength.
3.1 Definitions:
1.9 The procedures address the determination of thickness
3.1.1 For definitions of general terms related to building
and construction type to resist a specified design wind load at
construction used in this practice refer to Terminology E631,
1 2
This practice is under the jurisdiction of ASTM Committee E06 on Perfor- For referenced ASTM standards, visit the ASTM website, www.astm.org, or
mance of Buildings and is the direct responsibility of Subcommittee E06.52 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Glass Use in Buildings. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2017. Published April 2017. Originally the ASTM website.
approved in 2005. Last previous edition in 2012 as E2461-12. DOI: 10.1520/E2461- Available from American Society of Civil Engineers (ASCE), 1801 Alexander
12R17. Bell Dr., Reston, VA 20191, http://www.asce.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2461 − 12 (2017)
TABLE 2 Thickness Designations, Minimum Glass Thickness,
and for general terms related to glass and glass products, refer
and Unit Self-Weight
to Terminology C162.
Nominal thickness or Minimum thickness, Glass weight
3.2 Definitions of Terms Specific to This Standard:
designation, mm (in.) mm (in.) Pa (psf)
3.2.1 annealed (AN) glass, n—a flat, monolithic, glass lite of
2.7 (lami) 2.59 (0.102) 67.0 (1.40)
uniform thickness; it is formed by a process whereby the 3.0 ( ⁄8) 2.92 (0.115) 74.2 (1.55)
4.0 ( ⁄32) 3.78 (0.149) 99.1 (2.07)
magnitudes of the residual stresses are nearly zero.
5.0 ( ⁄16) 4.57 (0.180) 124 (2.59)
3.2.2 aspect ratio (AR), n—the ratio of the long dimension 6.0 ( ⁄4) 5.56 (0.219) 149 (3.11)
8.0 ( ⁄16) 7.42 (0.292) 199 (4.15)
to the short dimension for rectangular glass or the ratio of the
10.0 ( ⁄8) 9.02 (0.355) 248 (5.18)
long dimension to the short dimension of the rectangle that
12.0 ( ⁄2) 11.91 (0.469) 298 (6.22)
completely encloses trapezoidal glass. In these procedures, AR 16.0 ( ⁄8) 15.09 (0.595) 397 (8.29)
19.0 ( ⁄4) 18.26 (0.719) 472 (9.85)
is always equal to or greater than 1.0.
22.0 ( ⁄8) 21.44 (0.844) 546 (11.4)
25.0 (1)* 24.4 (0.969) 622 (13.0)
NOTE 1—The rectangle that completely encloses the trapezoid has two
A
32 (1 – ⁄4) 27.38 (1.22) 795 (16.6)
sides parallel to the horizontal edges of the trapezoid and the other two
A
38 (1 – ⁄2) 31.6 (1.47) 943 (19.7)
sides perpendicular to the horizontal edges of the trapezoid. All dimen-
A
sions shall be measured from edge to edge of glass. Not a glazing industry standard thickness designation.
3.2.3 equivalent rectangular area (ERA), n—the product of
the longest horizontal glass dimension and the length of the
edge perpendicular to the horizontal dimension in the plane of
the glass. All dimensions shall be measured from edge to edge 3.2.9 lateral, adj—perpendicular to the glass surface.
of glass.
3.2.10 load, n—a uniformly distributed lateral pressure.
3.2.4 designated thickness for laminated glass (LG), n—the
3.2.10.1 design load, n—the magnitude of the 3-second
designated thickness for LG as Table 1 specifies.
duration load used to design glass for ATCT cabs. Equations
3.2.5 designated thickness for monolithic glass, n—the des- used herein for computing magnitudes for design loads adjust
ignated or nominal thickness commonly used in specifying a glass self weight to a magnitude consistent with a 3-second
particular glass product, based on the minimum thicknesses duration.
presented in Table 2 and Specification C1036.
3.2.10.2 specified design load, n—the magnitude in kPa
3.2.6 glass breakage, n—the fracture of any lite or ply in (psf), type (for example, wind or self-weight) and duration of
monolithic, laminated, or insulating glass resulting from stress the load. The wind load has a duration of approximately
that an applied uniform lateral load induces. 3 seconds. Glass self-weight (Table 2) has a long duration,
typically equal to the in-service life of the window glass lite.
3.2.7 insulating glass (IG) unit, n—consists of any combi-
Earth facing cab glass is only subjected to wind load and its
nation of two glass lites, as defined herein, that enclose a sealed
self-weight.
space filled with air or other gas.
3.2.10.3 long duration load, n—any load lasting approxi-
3.2.8 laminated glass (LG), n—a flat-lite of uniform thick-
mately 30 days or longer.
ness that is fabricated by bonding two or more monolithic glass
lites or plies of equal thickness, as defined herein, together with 3.2.10.4 short duration load, n—any load lasting approxi-
polyvinyl butyral (PVB) interlayer(s). mately 3 seconds, such as, wind load.
TABLE 1 Thickness Designations for Laminated Glass
Laminated glass Laminated glass construction Laminated glass thickness
designation, t, nominal thickness, mm (in.) designation for use in these
mm (in.) [glass/PVB/glass] procedures mm (in.)
2.7/0.76/2.7 {(lami)/0.030/(lami)}
1 1 1 1
6 ( ⁄4) 3/0.76/3 {( ⁄8)/0.030/( ⁄8)} 6 ( ⁄4)
1 1
3/1.52/3 {( ⁄8 )/0.060/( ⁄8)}
5 5 5 5
8 ( ⁄16) 4/0.76/4 {( ⁄32 )/0.030/( ⁄32)} 8 ( ⁄16)
3 3 3 3
10 ( ⁄8) 5/0.76/5 {( ⁄16)/0.030/( ⁄16)} 10 ( ⁄8 )
7 3 3
11 ( ⁄16) 5/1.52/5 {( ⁄16 )/0.060/( ⁄16)}
1 1 1 1
12 ( ⁄2) 6/0.76/6 {( ⁄4)/0.030/( ⁄4)} 12 ( ⁄2 )
9 1 1
13 ( ⁄16) 6/1.52/6 {( ⁄4 )/0.060/( ⁄4)}
5 5
8/0.76/8 {( ⁄16)/0.030/( ⁄16)}
5 5 5 5
16 ( ⁄8) 8/1.52/8 {( ⁄16)/0.060/( ⁄16)} 16 ( ⁄8)
5 5
8/2.28/8 {( ⁄16 )/0.090/( ⁄16)}
3 3
10/0.76/10 {( ⁄8)/0.030/( ⁄8)}
3 3 3 3
19 ( ⁄4) 10/1.52/10 {( ⁄8)/0.060/( ⁄8)} 19 ( ⁄4)
3 3
10/2.28/10 {( ⁄8 )/0.090/( ⁄8)}
1 1
12/1.52/12 {( ⁄2)/0.060/( ⁄2)}
25 (1) 25 (1)
1 1
12/2.28/12 {( ⁄2 )/0.090/( ⁄2)}
5 5
16/1.52/16 {( ⁄8)/0.060/( ⁄8)}
1 1
32 (1 ⁄4) 32 (1 ⁄4)
5 5
16/2.28/16 {( ⁄8 )/0.090/( ⁄8)}
3 3
19/1.52/19 {( ⁄4)/0.060/( ⁄4)}
1 1
38 (1 ⁄2 ) 38 (1 ⁄2 )
3 3
19/2.28/19 {( ⁄4)/0.090/( ⁄4)}
E2461 − 12 (2017)
3.2.11 minimum thickness of monolithic glass, n—the mini- criteria presented in safety glazing standards and site specific
mum allowable thickness associated with a nominal or desig- concerns may control the ultimate glass type and thickness
nated glass thickness as given in Table 2 and Specification selection.
C1036.
6. Procedure
3.2.12 probability of breakage (P ), n—the theoretical frac-
b
6.1 Select a probability of breakage, glass type or
tion of glass lites or plies that would break at the first
construction, and glass thickness(es).
occurrence of the resistance load, typically expressed in lites
per thousand. 6.2 Compute the design load for monolithic or single
laminated glass according to:
4. Summary of Practice
L 5 L 12L cosθ (1)
D W G
4.1 The use of these procedures requires a specified design
where:
load that shall consist of the wind load and the factored lateral
L = denotes the design load,
D
component of glass weight. The total design load shall not
L = denotes the wind load,
W
exceed 10 kPa (210 psf).
L = denotes the weight of the glass, and
G
θ = denotes the acute angle the glass makes with the
4.2 The procedures specified herein facilitate determination
horizontal. For monolithic or single laminated glazing,
of the thickness of an annealed window glass construction
the user shall obtain L from Table 2 for the nominal
required to resist the specified design loading for the selected G
glass thickness. For insulating glass, L shall consist of
probability of breakage.
G
the weights of both glass lites as determined from
4.3 This standard procedure uses methods in Practice E1300
Table 2.
to determine the approximate lateral deflection of the geomet-
6.3 Monolithic Single Glazing Continuously Supported
ric center of the window glass construction. Annex A2 pro-
Along all Four Edges:
vides deflection charts for laminated glass thicknesses larger
6.3.1 Determine the ERA.
than those contained in Practice E1300.
6.3.2 Determine the AR.
6.3.3 Determine the required glass thickness from Fig. A1.1
5. Significance and Use
(P = 0.001) or Fig. A1.2 P = 0.004) for the design load, ERA,
B B
5.1 This standard procedure facilitates determination of the
and AR.
thickness of a glass construction required to resist a specified
6.3.4 Determine the approximate maximum center of glass
design load with a selected probability of breakage.
deflection using procedures from Practice E1300.
5.2 This standard procedure addresses the following glass
6.4 Single Laminated Glazing Continuously Supported
constructions: annealed monolithic, annealed laminated, and
Along all Four Edges:
insulating glass fabricated with annealed monolithic or an-
6.4.1 Determine the ERA.
nealed laminated glass, or both.
6.4.2 Determine the AR.
6.4.3 Determine the required glass thickness from Fig. A1.3
5.3 Use of these procedures assume:
(P = 0.001) or Fig. A1.4 (P = 0.004) for the design load,
B B
5.3.1 The glass is free of edge damage and is properly
ERA, and AR.
glazed,
6.4.4 Determine the approximate maximum center of glass
5.3.2 The glass has not been subjected to abuse,
deflection using procedures from Practice E1300.
5.3.3 The surface condition of the glass is typical of glass
6.5 Monolithic Single Glazing Simply Supported Continu-
that has been in service for several years, and is significantly
ously Along Two Opposite Sides or any Three Sides:
weaker than freshly manufactured glass due to minor abrasions
on exposed surfaces, 6.5.1 Determine the Unsupported Glass Length.
6.5.2 Determine the required glass thickness from Fig. A1.5
5.3.4 The glass edge support system is sufficiently stiff to
(P = 0.001) or Fig. A1.6 (P = 0.004) for the design load,
limit the lateral deflections of the supported glass edges to less
B B
ERA, and AR.
than ⁄175 of their lengths. The specified design load shall be
6.5.3 Determine the approximate maximum center of glass
used for this calculation, and
deflection using procedures from Practice E1300.
5.3.5 The center of glass deflection shall not result in loss of
edge support. Typically maintaining center of glass deflection
6.6 Single Laminated Glazing Simply Supported Continu-
at or below the magnitude of three times the nominal glass
ously Along Two Opposite Sides or any Three Sides:
thickness assures that no loss of edge support will occur.
6.6.1 Determine the unsupported glass length.
6.6.2 Determine the required glass thickness from Fig. A1.7
5.4 Many other factors affect the selection of glass type and
(P = 0.001) or Fig. A1.8 (P = 0.004) for the design load,
B B
thickness. These factors include but are not limited to: thermal
ERA, and AR.
stresses, the effects of windborne debris, excessive deflections,
6.6.3 Determine the approximate maximum center of glass
behavior of glass fragments after breakage, seismic effects,
deflection using procedures from Practice E1300.
heat flow, edge bite, noise abatement, potential post-breakage
consequences, and so forth. In addition, considerations set 6.7 Insulating Glass (IG) with Monolithic Glass Lites of
forth in federal, state, and local building codes along with Equal (Symmetric) Glass Type and Thickness.
E2461 − 12 (2017)
6.7.1 Compute the design load for IG as L 55~L conditions, longest horiz
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2461 − 12 E2461 − 12 (Reapproved 2017)
Standard Practice for
Determining the Thickness of Glass in Airport Traffic
Control Tower Cabs
This standard is issued under the fixed designation E2461; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice covers the determination of the thickness of glass installed in airport traffic control towers (ATCT) to resist
a specified design loading with a selected probability of breakage less than or equal to either 1 lite per 1000 or 4 lites per 1000
at the first occurrence of the design wind loading.
1.2 The procedures apply to common outward sloping cab glass designs for which the specified loads do not exceed 10 kPa (210
psf).
1.3 The procedures assume control tower cab glass has an aspect ratio no greater than 2.
1.4 The procedures assume control tower cab glass has an area no less than 1.86 square metres (20 square feet).
1.5 The procedures apply only to annealed monolithic, annealed laminated, or annealed insulating glass having a rectangular
or trapezoidal shape.
1.6 The use of the procedures assumes the following:
1.6.1 Annealed monolithic and annealed laminated glass installed in ATCTs shall have continuous lateral support along two
parallel edges, along any three edges, or along all four edges;
1.6.2 Insulating glass shall have continuous lateral support along all four edges; and
1.6.3 Supported glass edges are simply supported and free to slip in plane.
1.7 The procedures do not apply to any form of wired, patterned, etched, sandblasted, or glass types with surface treatments that
reduce the glass strength.
1.8 The procedures do not apply to any form of heat treated glass, chemically strengthened glass, or any type of glass with
surface treatments intended to increase the glass strength.
1.9 The procedures address the determination of thickness and construction type to resist a specified design wind load at a
selected probability of breakage. The final glass thickness and construction determined also depends upon a variety of other 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 standard. The values given in parentheses are mathematical conversions
to inch-pound units that are provided for information only and are not considered standard.
1.12 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory
limitations prior to use.
1.13 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This practice is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.52 on Glass Use in
Buildings.
Current edition approved April 1, 2012April 1, 2017. Published May 2012April 2017. Originally approved in 2005. Last previous edition in 20112012 as E2421 – 05
(2011).E2461-12. DOI: 10.1520/E2461-12.10.1520/E2461-12R17.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2461 − 12 (2017)
2. Referenced Documents
2.1 ASTM Standards:
C162 Terminology of Glass and Glass Products
C1036 Specification for Flat Glass
E631 Terminology of Building Constructions
E1300 Practice for Determining Load Resistance of Glass in Buildings
2.2 American Society of Civil Engineers Standard:
ASCE 7 Minimum Design Loads for Buildings and Other Structures
3. Terminology
3.1 Definitions:
3.1.1 For definitions of general terms related to building construction used in this test method practice refer to Terminology
E631, and for general terms related to glass and glass products, refer to Terminology E1300C162.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 annealed (AN) glass, n—a flat, monolithic, glass lite of uniform thickness; it is formed by a process whereby the
magnitudes of the residual stresses are nearly zero.
3.2.2 aspect ratio (AR), n—the ratio of the long dimension to the short dimension for rectangular glass or the ratio of the long
dimension to the short dimension of the rectangle that completely encloses trapezoidal glass. In these procedures, AR is always
equal to or greater than 1.0.
NOTE 1—The rectangle that completely encloses the trapezoid has two sides parallel to the horizontal edges of the trapezoid and the other two sides
perpendicular to the horizontal edges of the trapezoid. All dimensions shall be measured from edge to edge of glass.
3.2.3 equivalent rectangular area (ERA), n—the product of the longest horizontal glass dimension and the length of the edge
perpendicular to the horizontal dimension in the plane of the glass. All dimensions shall be measured from edge to edge of glass.
3.2.4 designated thickness for laminated glass (LG), n—the designated thickness for LG as Table 1 specifies.
3.2.5 designated thickness for monolithic glass, n—the designated or nominal thickness commonly used in specifying a
particular glass product, based on the minimum thicknesses presented in Table 2 and Specification C1036.
3.2.6 glass breakage, n—the fracture of any lite or ply in monolithic, laminated, or insulating glass resulting from stress that
an applied uniform lateral load induces.
3.2.7 insulating glass (IG) unit, n—consists of any combination of two glass lites, as defined herein, that enclose a sealed space
filled with air or other gas.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Available from American Society of Civil Engineers (ASCE), 1801 Alexander Bell Dr., Reston, VA 20191, http://www.asce.org.
TABLE 1 Thickness Designations for Laminated Glass
Laminated glass Laminated glass construction Laminated glass thickness
designation, t, nominal thickness, mm (in.) designation for use in these
mm (in.) [glass/PVB/glass] procedures mm (in.)
2.7/0.76/2.7 {(lami)/0.030/(lami)}
1 1 1 1
6 ( ⁄4) 3/0.76/3 {( ⁄8)/0.030/( ⁄8)} 6 ( ⁄4)
1 1
3/1.52/3 {( ⁄8 )/0.060/( ⁄8)}
5 5 5 5
8 ( ⁄16) 4/0.76/4 {( ⁄32 )/0.030/( ⁄32)} 8 ( ⁄16)
3 3 3 3
10 ( ⁄8) 5/0.76/5 {( ⁄16)/0.030/( ⁄16)} 10 ( ⁄8 )
7 3 3
11 ( ⁄16) 5/1.52/5 {( ⁄16 )/0.060/( ⁄16)}
1 1 1 1
12 ( ⁄2) 6/0.76/6 {( ⁄4)/0.030/( ⁄4)} 12 ( ⁄2 )
9 1 1
13 ( ⁄16) 6/1.52/6 {( ⁄4 )/0.060/( ⁄4)}
5 5
8/0.76/8 {( ⁄16)/0.030/( ⁄16)}
5 5 5 5
16 ( ⁄8) 8/1.52/8 {( ⁄16)/0.060/( ⁄16)} 16 ( ⁄8)
5 5
8/2.28/8 {( ⁄16 )/0.090/( ⁄16)}
3 3
10/0.76/10 {( ⁄8)/0.030/( ⁄8)}
3 3 3 3
19 ( ⁄4) 10/1.52/10 {( ⁄8)/0.060/( ⁄8)} 19 ( ⁄4)
3 3
10/2.28/10 {( ⁄8 )/0.090/( ⁄8)}
1 1
12/1.52/12 {( ⁄2)/0.060/( ⁄2)}
25 (1) 25 (1)
1 1
12/2.28/12 {( ⁄2 )/0.090/( ⁄2)}
5 5
16/1.52/16 {( ⁄8)/0.060/( ⁄8)}
1 1
32 (1 ⁄4) 32 (1 ⁄4)
5 5
16/2.28/16 {( ⁄8 )/0.090/( ⁄8)}
3 3
19/1.52/19 {( ⁄4)/0.060/( ⁄4)}
1 1
38 (1 ⁄2 ) 38 (1 ⁄2 )
3 3
19/2.28/19 {( ⁄4)/0.090/( ⁄4)}
E2461 − 12 (2017)
TABLE 2 Thickness Designations, Minimum Glass Thickness,
and Unit Self-Weight
Nominal thickness or Minimum thickness, Glass weight
designation. mm (in.) mm (in.) Pa (psf)
Nominal thickness or Minimum thickness, Glass weight
designation, mm (in.) mm (in.) Pa (psf)
2.7 (lami) 2.59 (0.102) 67.0 (1.40)
3.0 ( ⁄8) 2.92 (0.115) 74.2 (1.55)
4.0 ( ⁄32) 3.78 (0.149) 99.1 (2.07)
5.0 ( ⁄16) 4.57 (0.180) 124 (2.59)
6.0 ( ⁄4) 5.56 (0.219) 149 (3.11)
8.0 ( ⁄16) 7.42 (0.292) 199 (4.15)
10.0 ( ⁄8) 9.02 (0.355) 248 (5.18)
12.0 ( ⁄2) 11.91 (0.469) 298 (6.22)
16.0 ( ⁄8) 15.09 (0.595) 397 (8.29)
19.0 ( ⁄4) 18.26 (0.719) 472 (9.85)
22.0 ( ⁄8) 21.44 (0.844) 546 (11.4)
25.0 (1)* 24.4 (0.969) 622 (13.0)
A
32 (1 – ⁄4) 27.38 (1.22) 795 (16.6)
A
38 (1 – ⁄2) 31.6 (1.47) 943 (19.7)
A
Not a glazing industry standard thickness designation.
3.2.8 laminated glass (LG), n—a flat-lite of uniform thickness that is fabricated by bonding two or more monolithic glass lites
or plies of equal thickness, as defined herein, together with polyvinyl butyral (PVB) interlayer(s).
3.2.9 lateral, adj—perpendicular to the glass surface.
3.2.10 load, n—a uniformly distributed lateral pressure.
3.2.10.1 design load, n—the magnitude of the 3-second duration load used to design glass for ATCT cabs. Equations used herein
for computing magnitudes for design loads adjust glass self weight to a magnitude consistent with a 3-second duration.
3.2.10.2 specified design load, n—the magnitude in kPa (psf), type (for example, wind or self-weight) and duration of the load.
The wind load has a duration of approximately 3 seconds. 3 seconds. Glass self-weight (Table 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 its self-weight.
3.2.10.3 long duration load, n—any load lasting approximately 30 days or longer.
3.2.10.4 short duration load, n—any load lasting approximately 3 seconds, such as, wind load.
3.2.11 minimum thickness of monolithic glass, n—the minimum allowable thickness associated with a nominal or designated
glass thickness as given in Table 2 and Specification C1036.
3.2.12 probability of breakage (P ), n—the theoretical fraction of glass lites or plies that would break at the first occurrence of
b
the resistance load, typically expressed in lites per thousand.
4. Summary of Practice
4.1 The use of these procedures requires a specified design load that shall consist of the wind load and the factored lateral
component of glass weight. The total design load shall not exceed 10 kPa (210 psf).
4.2 The procedures specified herein facilitate determination of the thickness of an annealed window glass construction required
to resist the specified design loading for the selected probability of breakage.
4.3 This standard procedure uses methods in Practice E1300 to determine the approximate lateral deflection of the geometric
center of the window glass construction. Annex A2 provides deflection charts for laminated glass thicknesses larger than those
contained in Practice E1300.
5. Significance and Use
5.1 This standard procedure facilitates determination of the thickness of a glass construction required to resist a specified design
load with a selected probability of breakage.
5.2 This standard procedure addresses the following glass constructions: annealed monolithic, annealed laminated, and
insulating glass fabricated with annealed monolithic or annealed laminated glass, or both.
5.3 Use of these procedures assume:
5.3.1 The glass is free of edge damage and is properly glazed,
5.3.2 The glass has not been subjected to abuse,
5.3.3 The surface condition of the glass is typical of glass that has been in service for several years, and is significantly weaker
than freshly manufactured glass due to minor abrasions on exposed surfaces,
E2461 − 12 (2017)
5.3.4 The glass edge support system is sufficiently stiff to limit the lateral deflections of the supported glass edges to less than
1/175 ⁄175 of their lengths. The specified design load shall be used for this calculation, and
5.3.5 The center of glass deflection shall not result in loss of edge support. Typically maintaining center of glass deflection at
or below the magnitude of three times the nominal glass thickness assures that no loss of edge support will occur.
5.4 Many other factors affect the selection of glass type and thickness. These factors include but are not limited to: thermal
stresses, the effects of windborne debris, excessive deflections, behavior of glass fragments after breakage, seismic effects, heat
flow, edge bite, noise abatement, potential post-breakage consequences, and so forth. In addition, considerations set forth in federal,
state, and local building codes along with criteria presented in safety glazing standards and site specific concerns may control the
ultimate glass type and thickness selection.
6. Procedure
6.1 Select a probability of breakage, glass type or construction, and glass thickness(es).
6.2 Compute the design load for monolithic or single laminated glass according to:
L 5 L 12L cosθ (1)
D W G
where:
L = denotes the design load,
D
L = denotes the wind load,
W
L = denotes the weight of the glass, and
G
θ = denotes the acute angle the glass makes with the horizontal. For monolithic or single laminated glazing, the user shall
obtain L from Table 2 for the nominal glass thickness. For insulating glass, L shall consist of the weights of both glass
G G
lites as determined from Table 2.
6.3 Monolithic Single Glazing Continuously Supported Along 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 (P = 0.001) or Fig. A1.2 P = 0.004) for the design load, ERA,
B B
and AR.
6.3.4 Determine the approximate maximum center of glass deflection using procedures from Practice E1300.
6.4 Single Laminated Glazing Continuously Supported Along 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 (P = 0.001) or Fig. A1.4 (P = 0.004) for the design load, ERA,
B B
and AR.
6.4.4 Determine the approximate maximum center of glass deflection using procedures from Practice E1300.
6.5 Monolithic Single Glazing Simply Supported Continuously 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 (P = 0.001) or Fig. A1.6 (P = 0.004) for the design load, ERA,
B B
and AR.
6.5.3 Determine the approximate maximum center of glass deflection using procedures from Practice E1300.
6.6 Single Laminated Glazing Simply Supported Continuously Along Two Opposite Sides or any Three Sides:
6.6.1 Determine the unsupported glass length.
6.6.2
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