Page 32 - GRIHA Manual Volume III - Introduction to National Rating System
P. 32
Building and system design optimization 25



5. Institutional buildings
6. Hotels
7. Restaurants
8. Commercial buildings, and
9. Residential buildings.


Note: Annexure 6 provides details on NBC 2005 recommended values on illuminance (lux) for certain spaces. For complete list refer NBC
2005, Part 8, Building Services - Section 1, Lighting and ventilation, Table 4.


The illumination levels recommended in NBC 2005 are to be maintained at all times on the task plane.
In spaces where a certain task is to be carried out in the entire space, the recommended illumination
levels should be necessarily maintained on the working plane. In spaces where the precise height and
location of tasks are not known or cannot be easily specified, the recommended illumination levels
should be met on a horizontal plane 850 mm above the floor level.
2. Recommended lighting power density

The purpose of energy-efficient lighting design is to optimize energy consumption and avoid
overdesign of artificial lighting as prescribed in clause 7.3 of ECBC-2007. The prescriptive lighting
requirement limits the installed electric wattage for interior building lighting. For interior lighting
power requirements, the installed lighting power used by luminaries—including lamps, ballasts,
current regulators, and central devices—is first calculated and then compared with the maximum
permissible interior lighting power densities (LPD) specified for various building types. The LPD
calculation is based on the following two methods.


a. Building area method
b. Space function method

Interior lighting includes all permanently installed general and task lighting shown in the plans.
Interior lighting for a building (or separately metered or permitted portion of a building) should not
exceed the LPD limits recommended in table 7.1 and table 7.2 of ECBC-2007.
The building area method is the simplest one to follow. However, if the entire building is not
listed under the building types specified in table 7.1 of ECBC-2007, then space function method
should be used to determine compliance.

Note Refer Annexure 7 for recommended LPD as per ECBC-2007 and refer 7.3 of ECBC User Guide for details of building area method and space
function method.

Artiicial lighting simulation
There are several software tools available for lighting simulation, such as, AGi32, Dialux, IES, lumen
designer, microlux, and so on. These tools help in analysing the proposed lighting design and
creating efficient and effective lighting scheme.
To design efficient lighting scheme in any software, certain methodology needs to be followed,
which is explained in the following flowchart diagram. The process demonstrates design of effective
and energy-efficient artificial lighting to meet GRIHA requirements.
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