Fire Safety · NBC 2016 (SP 7:2016) Volume 1

6.1 Determination of Appropriate Glass Thickness

6.1.1 General

This Section gives provisions to determine the minimum glass thickness to be used to resist the ultimate limit state design wind pressures. However, the location of the glass within the building require additional considerations, such as safety with respect to human which may impose either a minimum glass thickness above the basic calculation of this part or a provision for a specific glass type or both.

In addition to the provisions herein, the design requirements such as wind loads determined in accordance with good practice $[6-8(7)]$ and the serviceability deflection requirement limit given in this Section shall have to be complied.

The provisions under 6 are applicable provided the following parameters are satisfied:

a) Ultimate limit state wind pressure shall not be greater than 10 kPa.

b) For laminated glass, the two sheets are of equal thickness and the interlayer material is either polyvinyl butyral or an equivalent type of interlayer with a modulus of elasticity of about 24 MPa and a Poisson's ratio of 0.50 at 20°C.

c) Design flexural tensile strength of glass depends upon the design strength obtained after applying a factor of safety of 2.5. The

minimum design strength of normal glass for thickness up to 6 mm is 16.7 N/mm $^{2}$ and for thickness above 6 mm is 15.2 N/mm $^{2}$ .

6.1.2 Design Considerations

The following design considerations shall be considered in determination of appropriate thickness of glass:

a) Maximum area of glass panel is restricted to $15\mathrm{m}^2$

b) Maximum span of window is restricted to $4\mathrm{m}$ .

c) Aspect ratio of the glass panel should be greater than 1.5. If it is less than 1.5, next higher available thickness should be selected.

d) Factor of safety used is 2.5 considering the variability in strength of glass.

e) Applicable to normal, reflective, laminated, tempered and insulating glass.

f) Applicable to rectangular panels properly secured.

g) Design minimum thickness of laminated glass will be the maximum value of thickness in accordance with the Table 5.

h) Any recognized method of analysis may be used for design, in consultation with the manufacturer.

6.1.3 Empirical Relationship

Empirical relation between the wind pressure, area of the glass panel and the required glass thickness can be used:

P _ {\mathrm{net}} A = 2 0 0 T ^ {\mathrm{k}} (\text {for} T \leq 6 \mathrm{mm})

6.1.4 Determination of Design Wind Pressure

Net design wind pressure $(P_{\mathrm{net}})$ is an important parameter governing the thickness of glass to be used in the window panels. It depends on factors as given below:

a) Location of the building (wind zone);

b) Construction patterns around buildings (terrain category);

c) Topography of site;

d) Building plan and height, etc.

Net design wind pressure $(P_{\mathrm{net}})$ , may be defined using

the following equation:

6.1.5 Aspect Ratio ( $AR\{max\}$ )

The design of the thickness using empirical relation in accordance with 6.1.3 shall be valid up to a limiting aspect ratio $AR_{\mathrm{max}}$ . The value of $AR_{\mathrm{max}}$ for different thickness (T) of glass is given in Table 16.

6.1.6 Seismic Design

6.1.6.1 Seismic load (EQ)

The design for seismic forces shall be performed in steps to establish upper and lower bound force and movement response parameters. In addition, the response of the structure sensitive to certain parameters such as the damping and the stiffness of the support points may be evaluated.

The principal design criteria for the seismic design are,

a) Structure will remain elastic during the design seismic event.

b) ‘Hangers’ will stiffen the cantilever ‘tree’ structure.

c) ‘Hangers’ will not go slack.

6.1.6.2 Non-structural elements

Depending on response sensitivity, non-structural elements can be classified as deformation sensitive, acceleration sensitive, or both deformation and acceleration sensitive. Table 17 classifies non-structural elements according to their response sensitivity

Table 17Response Sensitivity of Architectural Component (Clause 6.1.6.2)

Sl No.	Component	Sensitivity
Sl No.	Component	Acceleration Sensitive (3)	Deformation Sensitive (4)
(1)	(2)	Acceleration Sensitive (3)	Deformation Sensitive (4)
i)	Exterior skin:
	a) Adhered veneer	S	P
	b) Anchored veneer	S	P
	c) Glass blocks	S	P
	d) Prefabricated panel	S	P
	e) Glazing system	S	P
ii)	Partitions:
	a) Heavy	S	P
	b) Light	S	P
iii)	Interior veneers:
	a) Stone, including marble	S	P
	b) Ceramic tile	S	P
iv)	Parapets and appendages	P	—
v)	Canopies and marquees	P	—
vi)	Stairs	P	S
NOTES
1 P = Primary response.
2 S = Secondary response.

6.1.6.3 Design seismic force

6.1.7 Imposed Loads

The uniform distributed load and point load is to be considered based on application and is to be selected in accordance with good practice [6-8(9)]. Appropriate uniform distributed load (UDL) and concentrated load are selected in accordance to good practice [6-8(9)] based on nature of building (for example, residential, institutional, industrial building, etc) and nature of activity under each building type.

6.1.8 Load Contribution

6.1.8.1 Wind load

The wind load is the effect of wind pressure which is dependent on the location, building height, topography and ground roughness factor. The wind speed is taken from good practice [6-8(7)] for the geographic location.

6.1.8.2 Dead load

In case of inclined sloped glazing, the dead weight of the glazing should be considered. In case of component of sloped glazing, the following corresponding component of the total glazing may be used:

a) Point load shall be applied as a uniformly distributed load over a circular area of $0.01 \, m^{2}$ .

b) For a glazed panel supported on all edges, the point loading shall be applied at the centre.

c) For free glazing edges, the point load shall be applied adjacent to the centre of the free edge.

d) Ultimate limit state design wind pressure shall not be greater than 1.2 kPa. For greater design wind pressures, the glass shall be separately designed to withstand wind loading in accordance with 6.1.4.

6.1.9 Reference Chart Relating Wind Load, Maximum Allowable Area for a Thickness of Glass with respect to Terrain Category

Table 19 to Table 27 provides relation between design wind pressure and maximum allowable area for a thickness of glass with respect to specific terrain category. User may select the type of glass depending on the support conditions.

Specialist literature may be consulted for use of nonlinear analysis and the like for laminated glass.

The deflection at the centre of glass pane can be calculated using the formula in accordance to Annex C.

Typical model calculation to calculate thickness and determine wind load and deflection at the centre of the glazing is given at Annex D.

6.2.1 Basic installation requirements and materials used for glass are given hereunder.

NOTES

1 The provisions under this item do not include the use of other methods or systems for glazing, provided the alternate method or system can be demonstrated to satisfy the requirements for correctly supporting the glass within the frame, or glazing system. 2 Patent and other proprietary systems are not described/ covered here.

3 Installation technique for frameless glazing system is not covered here.

Table 19Maximum Areas for Annealed Glass Fixed on All Four Sides, m² (Clause 6.1.9)

Design Wind Pressure $N/m^2$	Nominal Thickness of Annealed Glass, Tmm
Design Wind Pressure $N/m^2$	3(2)	4(3)	5(4)	6(5)	8(6)	10(7)	12(8)	15(9)	19(10)
500	2.13	3.86	6.03	8.63	13.06	15.00	15.00	15.00	15.00
550	1.93	3.51	5.48	7.85	11.88	15.00	15.00	15.00	15.00
600	1.77	3.21	5.02	7.19	10.89	14.61	15.00	15.00	15.00
650	1.64	2.97	4.64	6.64	10.05	13.48	15.00	15.00	15.00
700	1.52	2.75	4.31	6.17	9.33	12.52	15.00	15.00	15.00
750	1.42	2.57	4.02	5.76	8.71	11.69	14.75	15.00	15.00
800	1.33	2.41	3.77	5.40	8.16	10.96	13.83	15.00	15.00
850	1.25	2.27	3.55	5.08	7.68	10.31	13.01	15.00	15.00
900	1.18	2.14	3.35	4.80	7.26	9.74	12.29	15.00	15.00
950	1.12	2.03	3.17	4.54	6.88	9.23	11.64	15.00	15.00
1 000	1.06	1.93	3.01	4.32	6.53	8.76	11.06	15.00	15.00
1 050	1.01	1.84	2.87	4.11	6.22	8.35	10.53	14.38	15.00
1 100	0.97	1.75	2.74	3.92	5.94	7.97	10.06	13.73	15.00
1 150	0.93	1.68	2.62	3.75	5.68	7.62	9.62	13.13	15.00
1 200	0.89	1.61	2.51	3.60	5.44	7.30	9.22	12.58	15.00
1 250	0.85	1.54	2.41	3.45	5.23	7.01	8.85	12.08	15.00
1 300	0.82	1.48	2.32	3.32	5.02	6.74	8.51	11.61	15.00
1 350	0.79	1.43	2.23	3.20	4.84	6.49	8.19	11.18	14.98
1 400	0.76	1.38	2.15	3.08	4.67	6.26	7.90	10.78	14.44
1 450	0.73	1.33	2.08	2.98	4.50	6.04	7.63	10.41	13.95
1 500	0.71	1.29	2.01	2.88	4.35	5.84	7.37	10.07	13.48
1 550	0.69	1.24	1.94	2.78	4.21	5.65	7.14	9.74	13.05
1 600	0.67	1.21	1.88	2.70	4.08	5.48	6.91	9.44	12.64
1 650	0.64	1.17	1.83	2.62	3.96	5.31	6.70	9.15	12.25
1 700	0.63	1.13	1.77	2.54	3.84	5.16	6.51	8.88	11.89
1 750	0.61	1.10	1.72	2.47	3.73	5.01	6.32	8.63	11.55
1 800	0.59	1.07	1.67	2.40	3.63	4.87	6.14	8.39	11.23
1 850	0.58	1.04	1.63	2.33	3.53	4.74	5.98	8.16	10.93
1 900	0.56	1.01	1.59	2.27	3.44	4.61	5.82	7.95	10.64
1 950	0.55	0.99	1.55	2.21	3.35	4.49	5.67	7.74	10.37
2 000	0.53	0.96	1.51	2.16	3.27	4.38	5.53	7.55	10.11
2 050	0.52	0.94	1.47	2.11	3.19	4.28	5.40	7.36	9.86
2 100	0.51	0.92	1.44	2.06	3.11	4.17	5.27	7.19	9.63
2 150	0.49	0.90	1.40	2.01	3.04	4.08	5.14	7.02	9.40
2 200	0.48	0.88	1.37	1.96	2.97	3.98	5.03	6.86	9.19
2 250	0.47	0.86	1.34	1.92	2.90	3.90	4.92	6.71	8.99
2 300	0.46	0.84	1.31	1.88	2.84	3.81	4.81	6.56	8.79
2 350	0.45	0.82	1.28	1.84	2.78	3.73	4.71	6.42	8.60
2 400	0.44	0.80	1.26	1.80	2.72	3.65	4.61	6.29	8.43
2 450	0.43	0.79	1.23	1.76	2.67	3.58	4.51	6.16	8.25
2 500	0.43	0.77	1.21	1.73	2.61	3.51	4.42	6.04	8.09
2 550	0.42	0.76	1.18	1.69	2.56	3.44	4.34	5.92	7.93
2 600	0.41	0.74	1.16	1.66	2.51	3.37	4.25	5.81	7.78
2 650	0.40	0.73	1.14	1.63	2.46	3.31	4.17	5.70	7.63
2 700	0.39	0.71	1.12	1.60	2.42	3.25	4.10	5.59	7.49
2 750	0.39	0.70	1.10	1.57	2.38	3.19	4.02	5.49	7.35
2 800	0.38	0.69	1.08	1.54	2.33	3.13	3.95	5.39	7.22
2 850	0.37	0.68	1.06	1.51	2.29	3.08	3.88	5.30	7.09
2 900	0.37	0.66	1.04	1.49	2.25	3.02	3.81	5.21	6.97
2 950	0.36	0.65	1.02	1.46	2.21	2.97	3.75	5.12	6.85
3 000	0.35	0.64	1.00	1.44	2.18	2.92	3.69	5.03	6.74
3 050	0.35	0.63	0.99	1.42	2.14	2.87	3.63	4.95	6.63
3 100	0.34	0.62	0.97	1.39	2.11	2.83	3.57	4.87	6.52
3 150	0.34	0.61	0.96	1.37	2.07	2.78	3.51	4.79	6.42
3 200	0.33	0.60	0.94	1.35	2.04	2.74	3.46	4.72	6.32
3 250	0.33	0.59	0.93	1.33	2.01	2.70	3.40	4.65	6.22
3 300	0.32	0.58	0.91	1.31	1.98	2.66	3.35	4.58	6.13
3 350	0.32	0.58	0.90	1.29	1.95	2.62	3.30	4.51	6.04
3 400	0.31	0.57	0.89	1.27	1.92	2.58	3.25	4.44	5.95
3 450	0.31	0.56	0.87	1.25	1.89	2.54	3.21	4.38	5.86

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

Table 19(Concluded)

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
3 500	0.30	0.55	0.86	1.23	1.87	2.50	3.16	4.31	5.78
3 550	0.30	0.54	0.85	1.22	1.84	2.47	3.12	4.25	5.70
3 600	0.30	0.54	0.84	1.20	1.81	2.43	3.07	4.19	5.62
3 650	0.29	0.53	0.83	1.18	1.79	2.40	3.03	4.14	5.54
3 700	0.29	0.52	0.81	1.17	1.77	2.37	2.99	4.08	5.47
3 750	0.28	0.51	0.80	1.15	1.74	2.34	2.95	4.03	5.39
3 800	0.28	0.51	0.79	1.14	1.72	2.31	2.91	3.97	5.32
3 850	0.28	0.50	0.78	1.12	1.70	2.28	2.87	3.92	5.25
3 900	0.27	0.49	0.77	1.11	1.67	2.25	2.84	3.87	5.18
3 950	0.27	0.49	0.76	1.09	1.65	2.22	2.80	3.82	5.12
4 000	0.27	0.48	0.75	1.08	1.63	2.19	2.77	3.77	5.06
4 050	0.26	0.48	0.74	1.07	1.61	2.16	2.73	3.73	4.99
4 100	0.26	0.47	0.74	1.05	1.59	2.14	2.70	3.68	4.93
4 150	0.26

Table 20Maximum Areas for Laminated Glass Fixed on All Four Sides, \mathrm{m}^2 (Clause 6.1.9)

Design Wind Pressure	Nominal Thickness of Laminated Glass, T mm
Design Wind Pressure	N/m2(1)	5.38(2)	6.38(3)	8.38(4)	10.38(5)	12.38(6)
500	4.47	6.28	10.45	14.02	15.00	15.00
550	4.06	5.71	9.50	12.75	15.00	15.00
600	3.72	5.23	8.71	11.69	15.00	15.00
650	3.44	4.83	8.04	10.79	13.93	15.00
700	3.19	4.48	7.46	10.02	12.94	15.00
750	2.98	4.19	6.97	9.35	12.08	15.00
800	2.79	3.92	6.53	8.76	11.32	15.00
850	2.63	3.69	6.15	8.25	10.66	15.00
900	2.48	3.49	5.81	7.79	10.06	14.21
950	2.35	3.30	5.50	7.38	9.53	13.46
1 000	2.23	3.14	5.23	7.01	9.06	12.79
1 050	2.13	2.99	4.98	6.68	8.63	12.18
1 100	2.03	2.85	4.75	6.37	8.23	11.63
1 150	1.94	2.73	4.54	6.10	7.88	11.12
1 200	1.86	2.62	4.35	5.84	7.55	10.66
1 250	1.79	2.51	4.18	5.61	7.25	10.23
1 300	1.72	2.41	4.02	5.39	6.97	9.84
1 350	1.66

Table 20 — (Continued)	Table 20 — (Continued)	Table 20 — (Continued)	Table 20 — (Continued)	Table 20 — (Continued)	Table 20 — (Continued)	Table 20 — (Continued)
(1)	(2)	(3)	(4)	(5)	(6)	(7)
1 550	1.44	2.03	3.37	4.52	5.84	8.25
1 600	1.40	1.96	3.27	4.38	5.66	7.99
1 650	1.35	1.90	3.17	4.25	5.49	7.75
1 700	1.31	1.85	3.07	4.12	5.33	7.52
1 750	1.28	1.79	2.99	4.01	5.18	7.31
1 800	1.24	1.74	2.90	3.90	5.03	7.11
1 850	1.21	1.70	2.82	3.79	4.90	6.91
1 900	1.18	1.65	2.75	3.69	4.77	6.73
1 950	1.15	1.61	2.68	3.60	4.64	6.56
2 000	1.12	1.57	2.61	3.51	4.53	6.40
2 050	1.09	1.53	2.55	3.42	4.42	6.24
2 100	1.06	1.49	2.49	3.34	4.31	6.09
2 150	1.04	1.46	2.43	3.26	4.21	5.95
2 200	1.02	1.43	2.38	3.19	4.12	5.81
2 250	0.99	1.40	2.32	3.12	4.03	5.68
2 300	0.97	1.36	2.27	3.05	3.94	5.56
2 350	0.95	1.34	2.22	2.98	3.85	5.44
2 400	0.93	1.31	2.18

Table 20 — (Concluded)
(1)	(2)	(3)	(4)	(5)	(6)	(7)
4 100	0.55	0.77	1.27	1.71	2.21	3.12
4 150	0.54	0.76	1.26	1.69	2.18	3.08
4 200	0.53	0.75	1.24	1.67	2.16	3.05
4 250	0.53	0.74	1.23	1.65	2.13	3.01
4 300	0.52	0.73	1.22	1.63	2.11	2.97
4 350	0.51	0.72	1.20	1.61	2.08	2.94
4 400	0.51	0.71	1.19	1.59	2.06	2.91
4 450	0.50	0.71	1.17	1.58	2.04	2.87
4 500	0.50	0.70	1.16	1.56	2.01	2.84
4 550	0.49	0.69	1.15	1.54	1.99	2.81
4 600	0.49	0.68	1.14	1.52	1.97	2.78
4 650	0.48	0.68	1.12	1.51	1.95	2.75
4 700	0.48	0.67	1.11	1.49	1.93	2.72
4 750	0.47	0.66	1.10	1.48	1.91	2.69
4 800	0.47	0.65	1.09	1.46	1.89	2.66
4 850	0.46	0.65	1.08	1.45	1.87	2.64
4 900	0.46	0.64	1.07	1.43	1.85	2.61
4 950	0.45	0.63	1.06	1.42	1.83	2.58
5 000	0.45	0.63	1.05	1.40	1.81	2.56

Table 21Maximum Areas for Tempered Glass Fixed on All Four Sides, m^{2} (Clause 6.1.9)

Design Wind Pressure $N/m^2$	Nominal Thickness of Tempered Glass, T mm
Design Wind Pressure $N/m^2$	3(2)	4(3)	5(4)	6(5)	8(6)	10(7)	12(8)	15(9)	19(10)
500	5.32	9.64	15.00	15.00	15.00	15.00	15.00	15.00	15.00
550	4.84	8.76	13.70	15.00	15.00	15.00	15.00	15.00	15.00
600	4.43	8.03	12.56	15.00	15.00	15.00	15.00	15.00	15.00
650	4.09	7.42	11.59	15.00	15.00	15.00	15.00	15.00	15.00
700	3.80	6.89	10.77	15.00	15.00	15.00	15.00	15.00	15.00
750	3.55	6.43	10.05	14.39	15.00	15.00	15.00	15.00	15.00
800	3.33	6.03	9.42	13.49	15.00	15.00	15.00	15.00	15.00
850	3.13	5.67	8.87	12.70	15.00

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

Table 21(Concluded)

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
2 100	1.27	2.30	3.59	5.14	7.78	10.43	13.17	15.00	15.00
2 150	1.24	2.24	3.51	5.02	7.59	10.19	12.86	15.00	15.00
2 200	1.21	2.19	3.43	4.91	7.42	9.96	12.57	15.00	15.00
2 250	1.18	2.14	3.35	4.80	7.26	9.74	12.29	15.00	15.00
2 300	1.16	2.10	3.28	4.69	7.10	9.53	12.02	15.00	15.00
2 350	1.13	2.05	3.21	4.59	6.95	9.32	11.77	15.00	15.00
2 400	1.11	2.01	3.14	4.50	6.80	9.13	11.52	15.00	15.00
2 450	1.09	1.97	3.08	4.40	6.66	8.94	11.29	15.00	15.00
2 500	1.06	1.93	3.01	4.32	6.53	8.76	11.06	15.00	15.00
2 550	1.04	1.89	2.96	4.23	6.40	8.59	10.84	14.80	15.00
2 600	1.02	1.85	2.90	4.15	6.28	8.43	10.64	14.52	15.00
2 650	1.00	1.82	2.84	4.07	6.16	8.27	10.43	14.24	15.00
2 700	0.99	1.79	2.79	4.00	6.05	8.12	10.24	13.98	15.00

Table 22Maximum Areas for Insulating Glass Fixed on All Four Sides, m² (Clause 6.1.9)

Design Wind Pressure	Nominal Thickness of Insulating Glass, T mm
Design Wind Pressure	N/m2(1)	3+3(2)	4+4(3)	5+5(4)	6+6(5)	8+8(6)	10+10(7)
500	3.19	5.78	9.04	12.95	15.00	15.00	15.00
550	2.90	5.26	8.22	11.77	15.00	15.00	15.00
600	2.66	4.82	7.54	10.79	15.00	15.00	15.00
650	2.46	4.45	6.96	9.96	15.00	15.00	15.00
700	2.28	4.13	6.46	9.25	14.00	15.00	15.00
750	2.13	3.86	6.03	8.63	13.06	15.00	15.00
800	2.00	3.62	5.65	8.09	12.25	15.00	15.00
850	1.88	3.40	5.32	7.62	11.53	15.00	15.00
900	1.77	3.21	5.02	7.19	10.89	14.61	15.00
950	1.68	3.04	4.76	6.82	10.31	13.84	15.00
1 000	1.60	2.89	4.52	6.48	9.80	13.15	15.00
1 050	1.52	2.75	4.31	6.17	9.33	12.52	15.00
1 100	1.45	2.63	4.11	5.89	8.91	11.95	15.00
1 150	1.39	2.52	3.93	5.63	8.52	11.43	14.43
1 200	1.33	2.41	3.77	5.40	8.16	10.96	13.83
1 250

Table 22 — (Concluded)
(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
2 750	0.58	1.05	1.64	2.35	3.56	4.78	6.03
2 800	0.57	1.03	1.61	2.31	3.50	4.70	5.93
2 850	0.56	1.01	1.59	2.27	3.44	4.61	5.82
2 900	0.55	1.00	1.56	2.23	3.38	4.53	5.72
2 950	0.54	0.98	1.53	2.19	3.32	4.46	5.62
3 000	0.53	0.96	1.51	2.16	3.27	4.38	5.53
3 050	0.52	0.95	1.48	2.12	3.21	4.31	5.44
3 100	0.51	0.93	1.46	2.09	3.16	4.24	5.35
3 150	0.51	0.92	1.44	2.06	3.11	4.17	5.27
3 200	0.50	0.90	1.41	2.02	3.06	4.11	5.18
3 250	0.49	0.89	1.39	1.99	3.01	4.05	5.11
3 300	0.48	0.88	1.37	1.96	2.97	3.98	5.03
3 350	0.48	0.86	1.35	1.93	2.92	3.92	4.95
3 400	0.47	0.85	1.33	1.90	2.88	3.87	4.88
3 450	0.46	0.84	1.31	1.88	2.84	3.81	4.81
3 500	0.46	0.83	1.29	1.85	2.80	3.76	4.74
3 550	0.45	0.81	1.27	1.82

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

Table 23Maximum Area for Heat Strengthened Glass Fixed on Four Sides, m^{2} (Clause 6.1.9)

Design Wind Pressure $N/m^2$ (1)	Nominal Thickness of Heat Strengthened Glass, Tmm
Design Wind Pressure $N/m^2$ (1)	3(2)	4(3)	5(4)	6(5)	8(6)	10(7)	12(8)	15(9)	19(10)
500	3.41	6.17	9.65	13.81	15.00	15.00	15.00	15.00	15.00
550	3.10	5.61	8.77	12.56	15.00	15.00	15.00	15.00	15.00
600	2.84	5.14	8.04	11.51	15.00	15.00	15.00	15.00	15.00
650	2.62	4.75	7.42	10.63	15.00	15.00	15.00	15.00	15.00
700	2.43	4.41	6.89	9.87	14.93	15.00	15.00	15.00	15.00
750	2.27	4.11	6.43	9.21	13.93	15.00	15.00	15.00	15.00
800	2.13	3.86	6.03	8.63	13.06	15.00	15.00	15.00	15.00
850	2.00	3.63	5.67	8.13	12.29

Table 23(Concluded)

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
3 500	0.49	0.88	1.38	1.97	2.99	4.01	5.06	6.90	9.24
3 550	0.48	0.87	1.36	1.95	2.94	3.95	4.99	6.80	9.11
3 600	0.47	0.86	1.34	1.92	2.90	3.90	4.92	6.71	8.99
3 650	0.47	0.85	1.32	1.89	2.86	3.84	4.85	6.62	8.86
3 700	0.46	0.83	1.30	1.87	2.82	3.79	4.78	6.53	8.74
3 750	0.45	0.82	1.29	1.84	2.79	3.74	4.72	6.44	8.63
3 800	0.45	0.81	1.27	1.82	2.75	3.69	4.66	6.36	8.51
3 850	0.44	0.80	1.25	1.79	2.71	3.64	4.60	6.27	8.40
3 900	0.44	0.79	1.24	1.77	2.68	3.60	4.54	6.19	8.30
3 950	0.43	0.78	1.22	1.75	2.65	3.55	4.48	6.12	8.19
4 000	0.43	0.77	1.21	1.73	2.61	3.51	4.42	6.04	8.09
4 050	0.42	0.76	1.19	1.71	2.58	3.46	4.37	5.96	7.99
4 100	0.42	0.75	1.18	1.68	2.55	3.42	4.32	5.89	7.89
4 150	0.41

Table 24Maximum Span for Annealed Glass Fixed on Two Opposite Sides, m (Clause 6.1.9)

Design Wind Pressure $N/m^2$ (1)	Nominal Thickness of Annealed Glass, Tmm
Design Wind Pressure $N/m^2$ (1)	3(2)	4(3)	5(4)	6(5)	8(6)	10(7)	12(8)	15(9)	19(10)
500	0.53	0.73	0.92	1.12	1.40	1.77	2.11	2.68	3.36
550	0.51	0.69	0.88	1.07	1.33	1.69	2.02	2.56	3.20
600	0.48	0.66	0.84	1.02	1.27	1.62	1.93	2.45	3.07
650	0.46	0.64	0.81	0.98	1.22	1.56	1.85	2.35	2.95
700	0.45	0.61	0.78	0.95	1.18	1.50	1.79	2.26	2.84
750	0.43	0.59	0.75	0.91	1.14	1.45	1.73	2.19	2.74
800	0.42	0.57	0.73	0.88	1.10	1.40	1.67	2.12	2.66
850	0.41	0.56	0.71	0.86	1.07	1.36	1.62	2.06

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

Table 24(Concluded)

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
1 650	0.29	0.40	0.51	0.62	0.77	0.98	1.16	1.48	1.85
1 700	0.29	0.39	0.50	0.61	0.76	0.96	1.15	1.45	1.82
1 750	0.28	0.39	0.49	0.60	0.75	0.95	1.13	1.43	1.80
1 800	0.28	0.38	0.49	0.59	0.74	0.93	1.11	1.41	1.77
1 850	0.28	0.38	0.48	0.58	0.73	0.92	1.10	1.39	1.75
1 900	0.27	0.37	0.47	0.57	0.72	0.91	1.08	1.37	1.72
1 950	0.27	0.37	0.47	0.57	0.71	0.90	1.07	1.36	1.70
2 000	0.27	0.36	0.46	0.56	0.70	0.89	1.06	1.34	1.68
2 050	0.26	0.36	0.46	0.55	0.69	0.88	1.04	1.32	1.66
2 100	0.26	0.35	0.45	0.55	0.68	0.87	1.03	1.31	1.64
2 150	0.26	0.35	0.44	0.54	0.67	0.86	1.02	1.29	1.62
2 200	0.25	0.35	0.44	0.53	0.67	0.85	1.01	1.28	1.60
2 250	0.25	0.34	0.43	0.53	0.66	0.84	1.00	1.26	1.58
2 300	0.25

Table 25Maximum Span for Laminated Glass Fixed on Two Opposite Sides, m (Clause 6.1.9)

Design Wind Pressure $N/m^2$ (1)	Nominal Thickness of Laminated Glass, T mm
Design Wind Pressure $N/m^2$ (1)	5.38(2)	6.38(3)	8.38(4)	10.38(5)	12.38(6)	16.38(7)
500	0.79	0.95	1.25	1.59	1.92	2.50
550	0.75	0.90	1.19	1.51	1.83	2.38
600	0.72	0.87	1.14	1.45	1.76	2.28
650	0.69	0.83	1.10	1.39	1.69	2.19
700	0.67	0.80	1.06	1.34	1.63	2.11
750	0.65	0.77	1.02	1.30	1.57	2.04
800	0.62	0.75	0.99	1.25	1.52	1.98
850	0.61	0.73	0.96	1.22	1.48	1.92
900	0.59	0.71	0.93	1.18	1.43	1.86
950	0.57	0.69	0.91	1.15	1.40	1.81
1 000	0.56	0.67	0.88	1.12	1.36	1.77

Table 25 — (Concluded)
(1)	(2)	(3)	(4)	(5)	(6)	(7)
2 650	0.34	0.41	0.54	0.69	0.84	1.09
2 700	0.34	0.41	0.54	0.68	0.83	1.08
2 750	0.34	0.40	0.53	0.68	0.82	1.07
2 800	0.33	0.40	0.53	0.67	0.81	1.06
2 850	0.33	0.40	0.52	0.66	0.81	1.05
2 900	0.33	0.39	0.52	0.66	0.80	1.04
2 950	0.33	0.39	0.51	0.65	0.79	1.03
3 000	0.32	0.39	0.51	0.65	0.79	1.02
3 050	0.32	0.38	0.51	0.64	0.78	1.01
3 100	0.32	0.38	0.50	0.64	0.77	1.00
3 150	0.31	0.38	0.50	0.63	0.77	1.00
3 200	0.31	0.37	0.49	0.63	0.76	0.99
3 250	0.31	0.37	0.49	0.62	0.75	0.98
3 300	0.31	0.37	0.49	0.62	0.75	0.97
3 350	0.31	0.37	0.48	0.61	0.74	0.97
3 400	0.30	0.36	0.48	0.61	0.74	0.96
3 450	0.30	0.36	0.48	0.60	0.73	0.95
3 500	0.30	0.36	0.47	0.60	0.73	0.94
3 550	0.30	0.36	0.47	0.60	0.72	0.94

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

Table 26Maximum Span for Tempered Glass Fixed on Two Opposite Sides, m (Clause 6.1.9)

Design Wind Pressure $N/m^2$ (1)	Nominal Thickness of Tempered Glass, Tmm
Design Wind Pressure $N/m^2$ (1)	3(2)	4(3)	5(4)	6(5)	8(6)	10(7)	12(8)	15(9)	19(10)
500	0.62	0.86	1.09	1.32	1.52	1.93	2.30	2.92	3.66
550	0.60	0.82	1.04	1.26	1.45	1.84	2.20	2.78	3.49
600	0.57	0.78	0.99	1.20	1.39	1.76	2.10	2.66	3.34
650	0.55	0.75	0.95	1.16	1.33	1.69	2.02	2.56	3.21
700	0.53	0.72	0.92	1.11	1.29	1.63	1.95	2.47	3.09
750	0.51	0.70	0.89	1.08	1.24	1.58	1.88	2.38	2.99
800	0.49	0.68	0.86	1.04	1.20	1.53	1.82	2.31	2.89
850	0.48	0.66	0.83	1.01	1.17	1.48	1.77	2.24

Table 26(Concluded)

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
3 550	0.23	0.32	0.41	0.49	0.57	0.73	0.86	1.10	1.37
3 600	0.23	0.32	0.40	0.49	0.57	0.72	0.86	1.09	1.36
3 650	0.23	0.32	0.40	0.49	0.56	0.72	0.85	1.08	1.35
3 700	0.23	0.31	0.40	0.48	0.56	0.71	0.85	1.07	1.34
3 750	0.23	0.31	0.40	0.48	0.56	0.71	0.84	1.07	1.34
3 800	0.23	0.31	0.39	0.48	0.55	0.70	0.84	1.06	1.33
3 850	0.22	0.31	0.39	0.47	0.55	0.70	0.83	1.05	1.32
3 900	0.22	0.31	0.39	0.47	0.54	0.69	0.82	1.05	1.31
3 950	0.22	0.30	0.39	0.47	0.54	0.69	0.82	1.04	1.30
4 000	0.22	0.30	0.38	0.47	0.54	0.68	0.81	1.03	1.29
4 050	0.22	0.30	0.38	0.46	0.53	0.68	0.81	1.03	1.29
4 100	0.22	0.30	0.38	0.46	0.53	0.67	0.80	1.02	1.28
4 150	0.22	0.30	0.38	0.46	0.53	0.67	0.80	1.01	1.27
4 200	0.22

Table 27Maximum Span for Heat Strengthened Glass Fixed on Two Opposite Sides, m (Clause 6.1.9)

Design Wind Pressure $N/m^2$ (1)	Nominal Thickness of Heat Strengthened Glass, T mm
Design Wind Pressure $N/m^2$ (1)	3(2)	4(3)	5(4)	6(5)	8(6)	10(7)	12(8)	15(9)	19(10)
500	0.50	0.68	0.87	1.05	1.22	1.55	1.84	2.34	2.93
550	0.48	0.65	0.83	1.00	1.16	1.47	1.76	2.23	2.79
600	0.46	0.62	0.79	0.96	1.11	1.41	1.68	2.13	2.67
650	0.44	0.60	0.76	0.92	1.07	1.36	1.62	2.05	2.57
700	0.42	0.58	0.73	0.89	1.03	1.31	1.56	1.97	2.47
750	0.41	0.56	0.71	0.86	0.99	1.26	1.50	1.91	2.39
800	0.39	0.54	0.69	0.83	0.96	1.22	1.46	1.85	2.31
850	0.38	0.52	0.67	0.81	0.93	1.19	1.41

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

Table 27(Concluded)

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
1 800	0.26	0.36	0.46	0.56	0.64	0.81	0.97	1.23	1.54
1 850	0.26	0.36	0.45	0.55	0.63	0.80	0.96	1.21	1.52
1 900	0.26	0.35	0.45	0.54	0.62	0.79	0.94	1.20	1.50
1 950	0.25	0.35	0.44	0.53	0.62	0.78	0.93	1.18	1.48
2 000	0.25	0.34	0.43	0.53	0.61	0.77	0.92	1.17	1.46
2 050	0.25	0.34	0.43	0.52	0.60	0.76	0.91	1.15	1.45
2 100	0.24	0.33	0.42	0.51	0.59	0.75	0.90	1.14	1.43
2 150	0.24	0.33	0.42	0.51	0.59	0.75	0.89	1.13	1.41
2 200	0.24	0.33	0.41	0.50	0.58	0.74	0.88	1.11	1.40
2 250	0.24	0.32	0.41	0.50	0.57	0.73	0.87	1.10	1.38
2 300	0.23	0.32	0.41	0.49	0.57	0.72	0.86	1.09	1.36
2 350	0.23	0.32	0.40	0.49	0.56	0.71	0.85	1.08	1.35
2 400	0.23	0.31	0.40	0.48	0.56	0.71	0.84	1.07	1.34
2 450	0.23

6.2.2 Site Working and Glass Machining Operation

6.2.2.1 Heat-strengthened and toughened glass shall not be cut or worked after heat treatment. All necessary cutting, drilling, notching and edge-working shall be carried out to correct dimensions prior to value addition to the glass, such as toughening/tempering/heat strengthening. The edges and surfaces of all glass types shall not be damaged during fixing.

6.2.3 Dimensional Requirement

The dimensions for edge clearance, edge cover, front and back clearance, rebate depth is selected in accordance with the requirements in 4.5.2.

6.2.4 Glazing Materials

6.2.4.1 Compatibility of materials

A glazing material shall be used only when compatible with contiguous materials, including the rebate surface finish, setting or location blocks, distance pieces and glass type are available.

6.2.4.2 Application of materials

The application of glazing materials shall be in accordance with relevant/available Indian Standard or manufacturer's recommendations.

6.2.4.3 Life expectancy of materials

A glazing material shall only be used where its life expectancy (durability) has been established. The manufacturers' advice/guarantee should be sought for information regarding life expectancy.

Distance pieces, as shown in Fig. 13, used where required, shall be,

a) of resilient, non-absorbent material;

b) $25\mathrm{mm}$ long and of a height to suit the depth of the rebate and the method of glazing; and

c) spaced opposite each other, approximately 50 mm from each corner at intervals of not more than 300 mm.

The thickness shall be equal to the front and back clearance, to retain the glass firmly in the frame.

1 Distance pieces are required to prevent displacement of glazing compounds or sealant by external loading, such as wind pressure.

2 Extruded rubber material with 55 - 65 shore A hardness is required.

6.2.8 Rebates and Grooves for Installation

Rebates, grooves and beads shall be cleaned and free from grease, moisture and other contaminants. All sealant surfaces shall be primed or sealed in accordance with the recommendations of the manufacturer of the glazing material.

The number and location of setting blocks and location blocks shall be as shown in Fig. 10 to Fig. 12, wherever necessary to maintain the requisite edge clearance. Each block shall support the full thickness of the glass.

6.2.9 Glazing Beads

Where used, glazing beads shall be capable of restraining the glass under all design forces.

Structural silicone shall be installed such that a full adhesive bond to the substrate is achieved. Application of structural silicone may require prior cleaning and or priming of the substrate.

Applied structural silicones shall not be installed adjacent to other materials that may be chemically incompatible with the structural sealant and cause a loss of adhesion or adverse chemical changes within

the structural silicone that could lead to a loss of strength in the structural silicone. For guidance on the installation of structural silicone, reference to available standards/literatures may be made.

FIG. 13 POSITION OF DISTANCE PIECES

6.3.1 Frame Support Condition

6.3.1.1 Maximum area of glass panels subjected to wind loading

The maximum span for a given standard nominal thickness of ordinary annealed, laminated, heat-strengthened and toughened glass for a given panel size shall be determined in accordance with 6.3.2, 6.3.3 and 6.3.4 as applicable for the relevant support conditions. For heat strengthened laminated and toughened laminated glass, maximum allowable span shall be determined in accordance with 6.3.5. For $3\mathrm{mm}$ monolithic annealed glass, the maximum area shall not exceed $0.85\mathrm{m}^2$ .

The minimum thickness of the nominal glass size shall be as per the accepted practice in accordance with Indian Standard specifications.

For laminated glass composites, the combined minimum thickness of the glass sheets may be used excluding the interlayer thickness. Alternatively, reference to specialist literature may be drawn for the same purpose.

6.3.2 Rectangular Glass Supported on All Four Edges

For rectangular glass supported on all four edges, the maximum area for the design wind pressure shall be determined using the corresponding tables provided for each type of glass. Linear interpolation may be used for any value in between those given therein while maintaining the aspect ratio.

6.3.3 Rectangles of Glass Supported on Two Opposite Edges

For rectangles of glass supported on two opposite edges, the maximum glass area for the design wind

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

pressure shall be determined from Tables 22 to 25 for ordinary annealed, laminated, heat-strengthened and toughened glass, respectively.

6.3.4 Rectangles of Glass Supported on Three Edges

For rectangles of glass supported on three edges, the maximum glass area shall be determined as for two-edge support spanning along the unsupported edge. Alternatively, basic engineering principles shall be adopted in determining the glass thickness for all applications where only three edges of the panel are supported.

NOTE — Butt glazing of adjacent panels in the same plane should not be considered as a support.

6.3.5 Heat-Strengthened Laminated and Toughened Laminated Glass

For heat-strengthened laminated and toughened laminated glass, the maximum span for a given standard nominal thickness for a given panel size shall be determined from Tables 23 and 27, and Tables 20 and 25, respectively, with the design wind pressure being divided by the appropriate glass type factor, $P_{\mathrm{f}}$ (see Table 15), as applicable for the relevant support conditions.

6.3.6 Serviceability Checks

6.3.6.1 Glass complying to Tables 19 to 27 are deemed to meet, the serviceability deflection limits specified (in the absence of any other specified values) or the following values may be had for guidance.

6.3.6.2 Maximum allowable deflection of framing members

a) For mullions:

Single height glazing — Span/175 or 19 mm, whichever is less.
Double height glazing — For spans up to 4 110 mm, same as single height glazing; and for spans above 4 110 mm, the same shall be (Span/240) + 6.35 mm.

b) For transoms:

Span/500 or 3 mm, whichever is the least for dead load.
Span/175 or 19 mm, whichever is the least for wind load.

c) Deflection at the centre of the glass:

Monolithic glass — Shortest span/60 or 19 mm, whichever is the least.
Double glazed unit — Shortest span/90 or 19 mm, whichever is the least.

d) Deflection at edge of the glass: Shall be limited to 15 mm.

6.3.6.2.1 Dielectric separation of dissimilar metals

When the framing member for the glazing is aluminium and reinforcement is required to meet the deflection criteria, the reinforcement may be of aluminium or galvanized steel (red oxide coating being not recommended) with an insulating material between them at contact points. It is recommended to choose materials as close to each other in the galvanic series as possible.

6.3.7 Ultimate Stresses

The ultimate stresses for various types of glass are given in Table 28.

Table 28Ultimate Limit State Design Stresses for Glass Subjected to Wind Loading (Clause 6.3.7)

Sl No.	Glass Type	Standard Nominal Thickness ‘T’ mm	Ultimate Limit State Design Stress at Given Location
Sl No.	Glass Type	Standard Nominal Thickness ‘T’ mm	Away from Edge MPa	At Edge MPa
(1)	(2)	(3)	(4)	(5)
i)	Annealed	3	41.00	32.8
		4	38.99	31.19
		5	37.45	29.96
		6	36.2	28.96
		8	34.33	27.46
		10	32.8	26.24
		12	31.57	25.25
		15	30.15	24.12
		19	28.72	22.98
		25	26.96	21.57
ii)	Toughened	4	97.47	77.97
		5	93.61	74.97
		6	90.49	72.39
		8	85.82	68.65
		10	82.01	65.61
		12	78.91	63.13
		15	75.37	60.3
		19	71.81	57.45
		25	67.41	53.93
iii)	Heat strengthened	3	65.6	52.48
		4	62.38	49.9
		5	59.91	47.93
		6	57.91	46.33
		8	54.92	43.94
		10	52.48	41.99
		12	50.51	40.4
iv)	Annealed laminated	5	37.73	30.18
		6	36.43	29.14
		8	34.41

6.3.8 Insulating Glass Units

6.3.8.1 Determining thickness of structural silicone

The structural bite requirement is directly proportional to the wind load and the dimension of glass. Higher the wind load and larger the dimensions of the glass are, the greater the amount of structural bite required. The controlling variables which affect the structural bite requirement are the maximum short span dimension of glass and the design wind load which the structural glazing system shall be designed to accommodate.

a) Structural bite calculation for wind load and glass dimension

\frac {\text {Minimum}}{\text {structural}} = \frac {\frac {\text {Glass short span dimension} \times}{\text {Wind load} \times 0 . 5}}\frac {\text {Maximum allowable design stress}}{}\}

NOTES

1 Glass' short span dimension (SSD) is the shorter of the two dimensions (in m) of the rectangular glass panel. 2 Wind load is the maximum wind pressure, in Pascal, for a return period of 10 years based on local regulations. 3 The maximum allowable design stress for type of the structural sealant is selected as per manufacturer's recommendations.

b) Determination of thickness of structural silicone — With a sealed IGU, there may be load sharing between the two lites (panes) of glass. If so and both panes are of the same thickness, the lateral load (P) is shared almost equally; thus the secondary seal bite is calculated as one half that of the structural sealant bite, but should meet the minimum requirement. If of unequal thickness, the load shared by each pane will vary, depending on the difference in thicknesses. Further details are to be obtained from the manufacturer.

c) Structural bite calculation for dead load

\begin{array}{c} \text {Minimum} \\ \text {bite (m)} \end{array} = \frac {\text {Weight of glass (kg)}}{\text {Perimeter of the glass (m)} \times \text {Sealant dead load design}} \text {strength (kg / m^{2})}

= \frac {\rho \mathrm{g} T A}{P s}

6.3.9 Safety during installation

Glass and the coating layer (if any) should not be, exposed to/in direct contact, with aggressive materials such as acid, solvent, cement mortar, etc.

The fixing system of the panel should, in no case, cause shear stresses in the panel, and particularly the bonding interface between the glass sheet and the frame, either under the effect of external forces or due to differential expansion of components.

The protection of glass panel by means of a polyethylene sheet is recommended and shall provide ventilation for the glass in order to prevent thermal breakage.

6.3.10 Handling and Transportation

6.3.10.1 Transportation

During the transportation of the flat glass (clear, tinted), coated glass (solar control and mirror), lacquered or

FIG. 14 TYPICAL STRUCTURAL GLAZING DETAIL

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

painted glass the following methods (if other standard packaging specifications are not available) of storage, packing and interleaving shall be followed:

a) Flat glass shall be transported vertically;

b) Glass panes should not come into direct contact with each other by using appropriate interleaving such as powder or foam or paper. The lacquer opacified/ enamel coated/ screen printed glasses shall be separated by paper or foam; and

c) The packing and packing material shall be protected from water and if the glass is wrapped and sealed, the seal should remain closed until the product is used and precautions taken to not damage the packing while handling with a hoisting apparatus.

6.3.10.2 Handling

During the handling of the flat glass (clear, tinted), coated glass (solar control and mirror), lacquered or painted glass, the following guidelines shall be followed:

a) Glass shall be handled with dry, clean gloves, specifically after washing to prevent stain marks on them.

b) Care shall be taken to avoid contact or friction of the coating or the opacified/ enamel/screen printed side with any rough surface or hard objects.

c) A better practice is to handle glass with vacuum cups, and ensure that the vacuum cups and the glass are clean; and

d) It is recommended to keep it clean, if glass sheets are stored again before their processing or installation in the facade.

6.3.11 Storage at Site

To prevent staining, the storage area at site shall be,

a) a dry, well ventilated location at a sufficiently constant temperature;

b) protected from rain and running water;

c) protected from wide changes in temperature or humidity;

d) protected from alkaline material;

e) protected from direct contact of aggressive products such as corrosive vapors, acids, etc; and

f) glass panes are stored vertically on a soft surface such as wooden boards/battens.

6.3.12 Storage after Cutting

6.3.12.1 While stacking of coated glass/ mirror in the unpacked condition, the glass surface shall be facing towards the front (paint/coating backing towards the back).

6.3.12.2 Direct stacking of the mirror/coated glass one above the other should be prevented and suitable interleaving material as mentioned in 6.3.9 should be used between two glass panes.

6.3.12.3 The support material for glass storage should not have affinity towards moisture absorption.

6.4.1 This Section covers the requirement and selection of fire safety glass for buildings. General fire safety provisions for buildings shall be in accordance with Part 4 'Fire and Life Safety' of the Code. It is important for any fire rated glass to provide sufficient amount of human impact safety feature even during fire or in general situations. The level of human impact safety of glass in buildings shall be in accordance with 7. It is necessary that the fire rated system shall withstand the standard time-temperature curve during a fire test and shall give adequate time to the occupants for safe evacuation. This Section does not deal with the safety and security of people or goods in relation to risks of,

a) vandalism, riots, burglary or break in protection;

b) protection from explosion (terrorist attack);

c) natural disasters like earthquakes, cyclone, etc; and

d) plastic glazing, safety and security glazing, etc.

The requirements given here are minimum fire resistance requirements. In circumstances wherein the requirements of other Indian Standards exceed the requirements of this Section, in such cases the higher requirements shall become applicable.

6.4.2 Glass for Fire Resistance

6.4.2.1 Glazing system shall be so constructed, treated, or combined with other materials as to reduce loss of life or property during an event of fire, in comparison with ordinary sheet or flat glass, thereby preventing the passage of flame, hot gases, and smoke.

6.4.2.2 The following are the products in the scope of this Section that may be used for fire resistance in glazing provided they meet the relevant available standards:

a) Wired glass,

b) Annealed fire resistant glass (AFG),

c) Tempered fire resistant glass (TFG),

d) Intumescent laminated fire resistant glass (LFG), and

e) Double glazed fire resistant glass (DFG).

6.4.2.2.1 Wired glass (Not recommended in doors except as vision panel and for window sizes not greater than in Table 29)

It is a type of glass into which a wire mesh is embedded during production. Wired glass has an impact resistance similar to that of annealed glass, but in case of breakage, the mesh retains the pieces of glass. Value addition such as tempering and lamination is not possible using wired glass.

6.4.2.2.2 Annealed fire-resistant glass

A single piece of fire resistant glass (borosilicate glass) that is tested for fire resistance for the required duration. These types of glasses can be used only in areas where human impact safety is not an issue, typically in areas like vision panels of doors, oven doors, etc. This type of glass has lower coefficient of expansion and cannot be tempered.

6.4.2.2.3 Tempered fire-resistant glass

A single piece of specially heat-treated or chemically treated glass that is tested for fire resistance for the required duration and which has a stress pattern such that the piece when fractured reduces to numerous granular fragments, with no large jagged edges. Additionally these glasses should have a impact resistance of highest classification.

6.4.2.2.4 Intumescent laminated fire resistant glass

Two or more pieces of glass held together by an interleaving layer or layers of materials and that as a complete system is tested for fire resistance. Fire side of the glass shall crack and break during the fire or under sufficient impact, but the pieces of glass tend to adhere to the inter-layered material and do not allow the fire to penetrate the last layer of glass.

6.4.2.2.5 Double glazed fire resistant glass

Fire resistant glass that is used as a double glazed unit has to be tested as a complete Double Glazed Unit (DGU) or other multiple glazed units as the case may be. Double glazed fire resistant glass can be a combination of intumescent laminated fire rated or tempered fire resistant glass. Fire resistant glass cannot be combined with another glass and used as a DGU unless the combined double glazed or multiple glazed units are also tested. Both the panes of the double glazed unit will need to satisfy the required impact safety as mentioned in 7.

NOTE — It should be noted that use of any fire rated glass has to be installed in a tested system. Fire rated glass alone cannot provide the desired fire resistance since the fire resistance of a partition or a door assembly or any glazed building element is a function of the glass, frames, hardware, gaskets and fixings which forms the glazed system.

6.4.2.3 Testing procedures

Any fire rated glazed building element needs to be tested as per accepted standard [6-8(10)]. The fire rating criteria of any building element shall be in accordance with Part 4 ‘Fire and Life Safety’ of the Code.

Table 29Limiting Size of Wired Glass Panel (Clause 6.4.2.2.1)

Sl No.	Opening Fire Protection Rating	Maximum Area	Maximum Height	Maximum Width
(1)	min(2)	$m^2$ (3)	m(4)	m(5)
i)	60 to 90	0.064 5	0.838	0.254
ii)	45	0.836	1.372	1.372
iii)	20	No limit	No limit	No limit

6.4.2.4 Identification of glass used for fire resistance

a) All glass used for resisting fire shall conform to and preferably certified against available Indian Standards.

b) Since a fire resistant glass is not easily distinguishable from normal types of glass, it is imperative that every fire rated glass panel/unit should preferably have an indelible mark on all the panels/units of fire resistant glass showing the name of the manufacturer and the name of the product.

c) Rating of the glass panel may also be provided, although the rating of glazing system is of primary concern.

The glass used for fire resistance shall be in accordance with the requirements of Part 4 ‘Fire and Life Safety’ of the Code.

6.4.3 Precautions

6.4.3.1 Fire resistant glass alone shall not be enough to protect occupants from fire. Glass is only one component of the complete system.

6.4.3.2 Fire test certificate report conducted for one application shall not be substituted for any other application. For example, a report for a partition shall not be used for a door application although the glass used and the fire ratings are the same. Approval in vertical orientation cannot be considered for acceptance in horizontal or inclined orientation.

6.4.3.3 The maximum glass size as mentioned in the test report should not be exceeded in practice with respect to the bigger linear dimension or area, unless otherwise validated by an assessment report issued by the testing lab. The aspect ratio may be modified provided that none of the linear sides has a dimension greater than that of the largest dimension of originally tested glass.

6.4.3.4 The dimensions of the profile need to be the same as that tested.

6.4.3.5 In case of any change in hardware they should be replaced following the guidelines laid down in the standard against which the test was conducted.

PART 6 STRUCTURAL DESIGN — SECTION 8 GLASS AND GLAZING

6.4.3.6 Factors like edge cover, types of gaskets and type of fixtures also play a very vital role in achieving the fire performance of the building element. These have to be used and installed as per the test report/available standards.

Sl No.(1)	Glass Type(2)	$P_{\mathrm {f}}$ (3)
i)	Normal (Annealed)	1.00
ii)	Laminated	0.80
iii)	Tempered	2.50
iv)	Insulated	1.50
v)	Heat strengthened	1.60
vi)	Wired glass	0.50

Table 16 Thickness and Corresponding $AR_{\text{max}}$ Values(Clause 6.1.5)
T, mm	3	4	5	6	8	10	12	15	19	25
$AR_{\text{max}}$	7.3	6.8	6.5	6.3	5.9	4.9	4.3	3.8	3.3	2.9

Sl No.	Architectural Component or Element	$a_p$ (see Note)	$R_p$
(1)	(2)	(3)	(4)
i)	Interior non-structural walls and partitions:
	a) Plain (unreinforced) masonry walls	1.0	1.5
	b) All other walls and partitions	1.0	2.5
ii)	Cantilever elements (braced to structural frame above its centre of mass):
	a) Parapets	1.0	1.5
	b) Chimneys and stacks	1.0	2.5
	c) Exterior non-structural walls	1.0	2.5
iii)	Exterior non-structural wall elements and connections:
	a) Wall element	1.0	2.5
	b) Body of wall panel connection	1.0	2.5
	c) Fasteners of the connecting system	1.25	1.0
iv)	Veneer:
	a) High deformability elements and attachments	1.0	2.5
	b) Low deformability elements and attachments	1.0	1.5

6.1 Determination of Appropriate Glass Thickness

6.1.1 General

6.1.2 Design Considerations

6.1.3 Empirical Relationship

6.1.4 Determination of Design Wind Pressure

6.1.5 Aspect Ratio ( AR{max}AR\{max\}AR{max} )

6.1.6 Seismic Design

6.1.6.1 Seismic load (EQ)

6.1.6.2 Non-structural elements

6.1.6.3 Design seismic force

6.1.7 Imposed Loads

6.1.8 Load Contribution

6.1.8.1 Wind load

6.1.8.2 Dead load

6.1.9 Reference Chart Relating Wind Load, Maximum Allowable Area for a Thickness of Glass with respect to Terrain Category

6.2.2 Site Working and Glass Machining Operation

6.2.3 Dimensional Requirement

6.2.4 Glazing Materials

6.2.4.1 Compatibility of materials

6.2.4.2 Application of materials

6.2.4.3 Life expectancy of materials

6.2.8 Rebates and Grooves for Installation

6.2.9 Glazing Beads

6.3.1 Frame Support Condition

6.3.1.1 Maximum area of glass panels subjected to wind loading

6.3.2 Rectangular Glass Supported on All Four Edges

6.3.3 Rectangles of Glass Supported on Two Opposite Edges

6.3.4 Rectangles of Glass Supported on Three Edges

6.3.5 Heat-Strengthened Laminated and Toughened Laminated Glass

6.3.6 Serviceability Checks

6.3.6.2.1 Dielectric separation of dissimilar metals

6.3.7 Ultimate Stresses

6.3.8 Insulating Glass Units

6.3.8.1 Determining thickness of structural silicone

a) Structural bite calculation for wind load and glass dimension

c) Structural bite calculation for dead load

6.3.9 Safety during installation

6.3.10 Handling and Transportation

6.3.10.1 Transportation

6.3.10.2 Handling

6.3.11 Storage at Site

6.3.12 Storage after Cutting

6.4.2 Glass for Fire Resistance

6.4.2.2.2 Annealed fire-resistant glass

6.4.2.2.3 Tempered fire-resistant glass

6.4.2.2.4 Intumescent laminated fire resistant glass

6.4.2.2.5 Double glazed fire resistant glass

6.4.2.3 Testing procedures

6.4.2.4 Identification of glass used for fire resistance

6.4.3 Precautions

6.4.3.4 The dimensions of the profile need to be the same as that tested.

6.1.3.1 Glass supported on two opposite sides

6.1.4.1 Laminated/tempered/insulating glass

6.1.6.4 Seismic relative displacement

6.3.8.2 Maximum allowable span for glass and type

6.1.5 Aspect Ratio ( $AR\{max\}$ )