Lighting requirements and site selection

Requirements of lighting in a building

1. Adequate illumination: Enough light for the task (e.g. 100 to 150 lux for living rooms, 300 lux for classrooms and offices, 500 lux for drawing rooms), as per NBC.
2. Uniform distribution: No dark corners or sharp contrast between bright and dark areas.
3. Freedom from glare: Direct or reflected glare from the sun or lamps must be avoided by shades, louvres and diffusers.
4. Proper direction: Light should come from a direction that avoids shadows on the working plane.
5. Colour rendering: Natural-looking colours, with light of a suitable colour temperature.
6. Daylight use: Windows with an area of not less than about 10 % of the floor area (daylight factor 2 to 5 %), well placed (north light is steady), to save energy.
7. Artificial lighting: General, task and emergency lighting for night; efficient lamps (LED).
8. Control: Switches, dimmers and shading devices; easily maintained fittings.
9. Economy and safety: Low energy use, little heat and no fire hazard.

Principles of site selection and planning

1. Purpose and nearness to services such as roads, water, electricity, schools and markets.
2. Soil: firm and level, with good bearing capacity and a low water table; avoid black cotton soil, marsh and filled ground.
3. Natural drainage and flood-free land; away from landslides, river banks and faults.
4. Good environment: Clean air, sun and wind, away from noise, smoke and odour.
5. Orientation and shape: A regular plot, with the long axis east-west and open to the south and the wind.
6. Legal: Ownership, land use zone, setback and ground coverage as per bye-laws.
7. Planning: Placing the building to give light, ventilation, privacy, room for future expansion and a landscaped open space.
8. Economy: Cost of land and development.