Question

state any six factor on which efficiency of lighting depends​

Answer 1

Explanation:

UTILIZATION FACTOR:

Utilization Factor or Co-efficient of utilization. It may be defined as “the ratio of total lumens received on the working plane to the total lumens emitted by the light source”.i.e.

Utilization factor =Lumens received on the working plane/Lumens emitted by the lamp

FACTOR EFFECTING UTILIZATION FACTOR:

Type of light, light fitting, Colour surface of walls and ceiling, mounting height of lamps, Area to be illuminated

Its value lies between 0.4 and 0.6 for direct fittings it varies from 0.1 to 0.35 for indirect fittings

2) Depreciation or Maintenance factor

It may be defined as “the ratio of illumination under normal working condition to the illumination when everything is clean or new” i.e.

D.F = Illumination under normal working conditions / Illumination when everything is clean.

The maintenance factor is based on how often the lights are cleaned and replaced. It takes into account such factors as decreased efficiency with age, accumulation of dust within the fitting itself and the depreciation of reflectance as walls and ceilings age. For convenience, it is usually given as three options:

Good = 0.70

Medium = 0.65

Poor = 0.55

3) WASTE LIGHT FACTOR:

When a surface is illuminated by a number of lamps, there is certain amount of wastage due to overlapping of light waves. Its value will be between 1.2 to 1.5

4) REFLECTION FACTOR:

It may be defined as “the ratio of luminous flux leaving the surface to the luminous flux incident on it”. It’s value will be always less than 1

5) ABSORPTION FACTOR:

When the atmosphere is full of snow or smoke fumes, it absorbs some light. Hence absorption factor may be defined as “the ratio of net lumens available on the working plane after absorption to the total lumens emitted by the lamp”. It’s value varies from 0.5 to 1

6) LUMINOUS EFFICIENCY OR SPECIFIC OUT PUT

It may be defined as “the ratio of number of lumens emitted to the electric power in take of a source” it’s unit is lumen/watt (lm/W)