The lighting in a space changes the mood of a room just as it does the perceived size of a room. Placement and type are important aspects of interior design, and they work in conjunction with color selections, room size, availability of natural light and furniture selection. The elements that come together when the right lighting is achieved transform a room into a seamless combination of functionality and style
LIGHT
Luminance – Refers to reflected or emitted by a surface.
Illuminance – Measure of light falling on a surface per square meter or lux.
ILLUMINANCE
Measure of light falling on a surface per square meter or lux.
It is measured in foot candles or lux (fc/lx)
Understanding lux
One lux is always equal one lumen per square meter.
1lx = 1lumen/m2
1 Kilo lux = 1000lx
A flux of a 1000 lumen in an area of 1 m2 will give 1000 lx but the same flux in an area of 10 m2 will give an illuminance of 100 lx
i.e.
1000 lx/ 1m2 =1000lx
1000 lx/10m2 =100lx
ISSUES OF ROOM LIGHTING
Room lighting affects most of our lives on a daily basis .It influences our mood and sets the trend on the activities we partake in that specific room.
Considerations in room lighting
-Room proportions this is to help in calculation of the lux levels to have in a room.
-Ceiling height
-Reflectance from various surfaces in the room ie from walls and ceilings etc
-Type of work to be done in the room.
-Color of surfaces
-Type of fixture/ pattern output efficiency-light loss due to ageing.
-Allowance for dirt conditions.
LIGHTING CONDITIONS
General lighting
Illumination on task
Combined general lighting and supplement lighting.
GENERAL LIGHTING
Use 30lx for public areas with dark surroundings
Use 75 lx for simple orientation for temporary visits.
Use 150lx for working spaces where visual tasks are occasionally performed
ILLUMINATION ON TASK
Use 300lx for performance of high contrast printed matter typed original handwriting in ink-ordinary inspection, rough bench and machine work rough assembly.
Use 750 lux for reading medium pencil, roughly printed work-difficult inspection and medium assembly
Use 1500 lx for high visual task handwriting in hard pencil difficult inspection, high precision jobs eg chip assembly
ILLUMINATION ADJUSTMENTS
The maximum lighting ratio of 5:1 is recommended when passing from one area to another for adaptation and psychological reasons.
e.g. A corridor next to a room with 750 lx should be at least at 150 lx
STANDARD LUX LEVELS CHART
