Page 22 - GRIHA Manual Volume III - Introduction to National Rating System
P. 22
Building and system design optimization 15
Use of Tables 9 and 10 of SP41
An external shading device is characterized by the following components.
# P – It denotes the outward projection of the louver system perpendicular to the wall. All other
dimensions are given in terms of P.
# B – It is the angle of inclination of the louver away from the normal to the wall. A value of B=0
signifies a vertical or horizontal louver normal to the wall.
# Spacing – It is the horizontal or vertical distance between the corresponding points of adjacent
vertical or horizontal louvers respectively. For the same value of P, it always increases with the
increase in the angle of inclination of the louver, thereby reducing their number.
Figure 12 P, B, and spacing of a window are shown
Source: NBC-2005
In tables 9 and 10 of SP41 the spacing between individual louvers is given in terms of their outward
projection for various angles of inclination, the net performance remaining unaltered. Here, the
designer has to decide the outward projection of the louvers. The other characteristics can then be
worked out from the values given in the tables.
Note: Refer Annexure 5 for tables 9 and 10 of SP41.
Use of Tables 9 and 10 of SP41
An external shading device is characterized by the following components.
# P – It denotes the outward projection of the louver system perpendicular to the wall. All other
dimensions are given in terms of P.
# B – It is the angle of inclination of the louver away from the normal to the wall. A value of B=0
signifies a vertical or horizontal louver normal to the wall.
# Spacing – It is the horizontal or vertical distance between the corresponding points of adjacent
vertical or horizontal louvers respectively. For the same value of P, it always increases with the
increase in the angle of inclination of the louver, thereby reducing their number.
Figure 12 P, B, and spacing of a window are shown
Source: NBC-2005
In tables 9 and 10 of SP41 the spacing between individual louvers is given in terms of their outward
projection for various angles of inclination, the net performance remaining unaltered. Here, the
designer has to decide the outward projection of the louvers. The other characteristics can then be
worked out from the values given in the tables.
Note: Refer Annexure 5 for tables 9 and 10 of SP41.
