Definition - What does Lumen mean?
A lumen is a unit of luminous flux in the International System of Units. One lumen is equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions. Expressed simply, lumens equal brightness; hence, the more lumens, the brighter the light.
Lumens (quantity of light) per square meter is also known as lux.
Safeopedia explains Lumen
The amount of light needed for a task varies and depends on the type of task being done, type of surfaces, work environment and the current vision of the worker.
The Occupational Safety and Health Administration (OSHA) has recommended that a work space needs to be ergonomically arranged in order to ensure minimal or reduced glare and the elimination of excessive lighting. This recommendation is based on evidence showing that excessive lighting can result in eye strain and headaches. OSHA has also established minimum lighting requirements for a variety of work environments, as per the standard 1926.56.
It is important to adhere to these minimum lighting requirements as poor lighting can cause misjudgment of the position, shape or speed of an object which can lead to accidents and injury. Poor lighting can also affect the quality of work, specifically in situations where precision is required, as well as overall productivity.