Section 27-643
§ 27-643 Scope. The provisions of sections 27-644 through 27-648 of
this article shall apply to the use of glass in the exterior wall of a
building and shall be limited to exterior application wherein the glass
would not be subjected to any loads normal to the face of glass other
than those due to wind. For applications involving human impact, the
provisions of section 27-651 of this article shall apply. For other
cases, the strength and mode of installation of glass shall conform to
accepted industry standards.
Section 27-644
§ 27-644 Support for glass panels. Glass shall be firmly held in
place. The supports shall be of adequate strength to resist the
applicable design wind loads as prescribed in subchapter nine of this
chapter.
Section 27-645
§ 27-645 Glass requirements. Glass shall meet the requirements of
reference standard RS 10-68 for the applicable type, size, thickness and
quality.
Section 27-646
§ 27-646 Thickness of glass. Thicknesses of glass panels shall be
chosen either on the basis of statistical probability of breakage (
subdivision (a) of this section) or on the basis of table 10-7, at the
designer's option.
(a) Statistical probability. Thickness of glass panels shall be chosen
so that the statistical probability of breakage when the glass is
initially subjected to the design wind load specified in table RS 9-5-1
does not exceed the values indicated in table 10-6. Probability or load
factors used for design shall be derived by test. The sufficiency and
validity of such test data shall be subject to approval by the
commissioner.
(b) Alternate requirements. Alternative to the requirements of
paragraph (a) above, the thickness of glass panels may be chosen from
table 10-7. For glass with assured minimum thickness greater than
required by reference standard RS 10-68, the maximum areas in table 10-7
may be increased in proportion to the assured minimum thickness.
TABLE 10-6 Probability of Breakage for Glass Panels
(Based on Coefficient of Variation of 25%)
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Elevation Above Grade
of Mid-Point of Glass Area of Panel--Sq. Ft.
------------------------------------------------------------------------
-Ft...................... 0-60 60-80 80-100 100-120 120+
0-50..................... 1.0% 1.0% 1.0% 1.0% 1.0%
50 or more............... 1.0% 0.8% 0.6% 0.4% 0.2%
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TABLE 10-7 Maximum Area of Glass--Sq. Ft.
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Elevation Above Grade of Mid-
Point of Glass--Ft.
Nominal Thickness
of Glass--Inches 0-50 50-300 300-600 600+
------------------------------------------------------------------------
Sheet Glass
Single strength............. 9 9 8 7
Double strength............. 13 13 11 10
3/16"...................... 25 25 21 19
7/32"...................... 32 32 27 24
Plate and Float Glass
13/64"..................... 25 25 21 19
1/4"....................... 37 37 32 28
5/16"...................... 54 54 46 40
3/8"....................... 78 74 63 58
1/2"....................... 114 100 86 75
5/8"....................... 152 120 103 90
3/4"....................... 210 137 118 103
7/8"....................... 241 158 135 118
1"......................... 312 204 175 153
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Section 27-647
§ 27-647 Special glasses. For types of glass other than single
annealed sheet and plate glass, allowable maximum areas may be
determined by multiplying values in table 10-7 by the appropriate
multiplying factor listed in table 10-8.
TABLE 10-8 Multiplying Factors for Various Types of Glass
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Glass Type Multiplying Factor
------------------------------------------------------------------------
Full tempered ....................................... 4.0
Heat strengthened ................................... 2.0
Factory-fabricated double glazing ................... 1.5*
Laminated ........................................... 0.6
Wired ............................................... 0.5
Sandblasted or etched ............................... 0.4
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* For asymmetrical units base strength on thinner lite.
Section 27-648
§ 27-648 Installation of glass panels. Glass panels shall be handled
and installed so that their strength is not impaired by chipping or
scratching, shall be fully and firmly bedded in their supports, and
shall be mounted in a manner that will accommodate differential
movements due to thermal and loading conditions.
Section 27-649
§ 27-649 Protection of glass panels. Glass panels installed in areas
where they will be subject to unusual conditions of construction damage,
such as spatter from welds or locations near materials hoists, shall be
protected by a hardboard covering or its equivalent during the period
that such work is in progress.
Section 27-650
§ 27-650 Deflection of support. The deflection of members supporting
glass panels under the design wind load (measured perpendicular to the
plane of the panel) shall not exceed L/175, where L is the span of the
supporting member. In no case shall such deflection exceed
three-quarters of an inch.
Section 27-651
§ 27-651 Panels subject to human impact loads. Glass in prime and
storm doors, interior doors, fixed glass panels that may be mistaken for
means of egress or ingress, shower doors and tub enclosures, or in
similar installations wherein one or more of the following criteria
apply, shall meet the requirements set forth in table 10-9, or by
comparative tests shall be proven to produce equivalent performance:
(a) openings are located in regularly occupied spaces.
(b) lowest point of panel is less than eighteen inches above finished
floor.
(c) minimum dimension of panel is larger than eighteen inches.
(For Table 10-9 see chapter 839 of the laws of 1986)
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