Page 36 - GRIHA Manual Volume III - Introduction to National Rating System
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Building and system design optimization 29
GRIHA-speciic information
Objective
To apply climate-responsive building design measures, including daylighting and efficient
artificial lighting design, in order to reduce demand for conventional energy.
13.1 Commitment
13.1.1 In order to optimize the building design, appropriate climate-responsive design
strategies should be adopted, such as the following.
1. Optimize the orientation of the building; and/or
2. Place the buffer spaces (such as, toilets, corridors, staircases, lifts, service areas, and so
on) along western and eastern façades; and/or
3. Provide maximum openings towards north and south; and/or
4. Shade the building surfaces receiving maximum solar exposure (such as wall, roof,
courtyard) with the use of external shading devices, for example, space frame, jaalis,
pergola, trees, green wall, terrace garden, and so on; and/or
5. Design appropriate shading for all fenestrations getting direct solar radiation by
using sun path analysis or shading norms (prescribed in tables 9 and 10 of Handbook
on Functional Requirements of Buildings [other than Industrial Buildings] or SP41),
and so on.
13.1.2 The window-to-wall ratio (WWR) shall be limited to a maximum of 60% of gross wall area
and the skylight-roof-ratio (SRR) shall be limited to a maximum of 5% of gross roof area
as prescribed in ECBC-2007.
13.1.3 Demonstrate that the effective solar heat gain coefficient (SHGC)* of the fenestration
(accounting for glazing, overhangs, and/or vertical fins) is compliant with the maximum
SHGC requirement prescribed by ECBC-2007. (Refer table 13.1)
Table 13.1 SHGC requirements for vertical fenestration and skylight
Maximum SHGC
Climate WWR < 40% 40% < WWR < 60% 0% < SRR < 2% 2.1% < SRR < 5%
Composite 0.25 0.2 0.4 0.25
Hot-dry 0.25 0.2 0.4 0.25
Warm-humid 0.25 0.2 0.4 0.25
Moderate 0.4 0.3 0.61 0.4
Cold 0.51 0.51 0.61 0.4
Source Table 4.3 and Table 4.6; ECBC-2007
The effective SHGC is calculated by multiplying the SHGC of the unshaded fenestration
product by a multiplication (M) factor. The M-factor for the proposed fenestration is
derived for each window dimension, orientation, and unique shading condition.
* SHGC is the ratio of the solar heat gain entering the space through the fenestration
area to the incident solar radiation, typically ranging from 0.9–0.1, where lower values
GRIHA-speciic information
Objective
To apply climate-responsive building design measures, including daylighting and efficient
artificial lighting design, in order to reduce demand for conventional energy.
13.1 Commitment
13.1.1 In order to optimize the building design, appropriate climate-responsive design
strategies should be adopted, such as the following.
1. Optimize the orientation of the building; and/or
2. Place the buffer spaces (such as, toilets, corridors, staircases, lifts, service areas, and so
on) along western and eastern façades; and/or
3. Provide maximum openings towards north and south; and/or
4. Shade the building surfaces receiving maximum solar exposure (such as wall, roof,
courtyard) with the use of external shading devices, for example, space frame, jaalis,
pergola, trees, green wall, terrace garden, and so on; and/or
5. Design appropriate shading for all fenestrations getting direct solar radiation by
using sun path analysis or shading norms (prescribed in tables 9 and 10 of Handbook
on Functional Requirements of Buildings [other than Industrial Buildings] or SP41),
and so on.
13.1.2 The window-to-wall ratio (WWR) shall be limited to a maximum of 60% of gross wall area
and the skylight-roof-ratio (SRR) shall be limited to a maximum of 5% of gross roof area
as prescribed in ECBC-2007.
13.1.3 Demonstrate that the effective solar heat gain coefficient (SHGC)* of the fenestration
(accounting for glazing, overhangs, and/or vertical fins) is compliant with the maximum
SHGC requirement prescribed by ECBC-2007. (Refer table 13.1)
Table 13.1 SHGC requirements for vertical fenestration and skylight
Maximum SHGC
Climate WWR < 40% 40% < WWR < 60% 0% < SRR < 2% 2.1% < SRR < 5%
Composite 0.25 0.2 0.4 0.25
Hot-dry 0.25 0.2 0.4 0.25
Warm-humid 0.25 0.2 0.4 0.25
Moderate 0.4 0.3 0.61 0.4
Cold 0.51 0.51 0.61 0.4
Source Table 4.3 and Table 4.6; ECBC-2007
The effective SHGC is calculated by multiplying the SHGC of the unshaded fenestration
product by a multiplication (M) factor. The M-factor for the proposed fenestration is
derived for each window dimension, orientation, and unique shading condition.
* SHGC is the ratio of the solar heat gain entering the space through the fenestration
area to the incident solar radiation, typically ranging from 0.9–0.1, where lower values
