In the lumen method, the lumens received is calculated by considering which of the following factors?

Lumen method of light calculation

• In lighting design, the lumen method is a simplified method to calculate the light level in a room.
• The lumen method describes the total number of lumens available in a room divided by the area of the room.
• While calculating the lumens received, the depreciation factor must also be taken into consideration.
• The depreciation factor is defined as the ratio of the illumination when everything is clean to illumination under normal working conditions.
• Sometimes due to the accumulation of dirt, dust, and smoke on the lamps they emit less light as compared to when they are new. Hence, during the design of the source of light for a room, the depreciation factor is an important parameter.

Additional Information 1.) Reflection factor

The ratio of the total amount of light reflected by a surface to the total amount of radiation incident on the surface is known as the reflection factor.

2.) Absorption factor

The ratio of net lumens available on the working plane after absorption to the total lumens emitted by the lamp is known as the absorption factor.

3.) Reduction factor

The reduction factor of a source of light is the ratio of its mean spherical candle power to its mean horizontal candle power.