Light Health Occupational Safety
Lighting • Colour Design • Safety Guidance Systems

Rüschenschmidt • Reidt
2nd Revised Edition • January 2006
ISBN: 978-3-934966-54-3
116 pages • € 10,90

The quality and volume of light is of decisive importance to the health of the human being. Daylight has a higher quality than artificial light and should, therefore, enjoy preference. 

Over the past decades artificial lighting has gone partly in the wrong direction. The quality of light has been lowered for quantity. In the meantime, a situation has been reached where the development has caught up with those that initiated it. Lighting installations are predominantly assessed according to energy consumption (W/m²), ignoring the needs of the workers who have a right to the type of light that is conducive to health. 

This publication deals more deeply with the interaction between the human being and light and its meaning for occupational safety and the prevention of health hazards at the workplace.

Basically it should be noted that the human being is a daylight creature and is used to luminous intensities of illumination which prevail outside during the day. These are values of around 5 000 lx on a dull winter day and around 100 000 lx on a sunny summer day. 

The luminous intensity values of artificial lighting installations, however, generally range between 100 and 1 000 lx. 

Lighting influences the human being physically, emotionally and mentally. The illuminance values up to now intended for artificial lighting installations are merely based on the visual process. However, even these values are in no way optimum values for the visual process, they merely constitute minimum values that are meant to enable an eight-hour long visual process under a certain visual task. 

Fatigue due to insufficient light occurs to a lesser extent to the eye itself, but to the whole of the organism, so that insufficient or bad lighting cannot be considered as a cause for fatigue or accidents. 

Reference in literature points to the fact that about 30 % of all accidents can directly or indirectly be attributed to poor lighting. It would appear illogical to principally view the influence of lighting on workplace safety differently than the proven effect of light on the work performance and the number of errors reflects. 

Occasional press releases stating that „too little light does not harm the eyes“ are wrong as overall statements. Too little light is only then of no harm to the eye if the eye does not have to perform a particular visual task. 

At most workplaces, however, the situation is that certain visual tasks must be performed over an eight hour shift. 

This trend is even on the increase, due to the fact that heavy physical work is on the decrease and control and supervision tasks are on the increase. The quality of light and lighting will in future become more important for reasons of workplace safety as well as health promotion.

Contents:

1 Light  
● The significance of daylight
● Artificial lighting 
● Illness due to lack of light 
● Mental effects of light 
● Need for light, age and processes not connected to seeing 

2 Seeing
● Influence of light on the visual acuity 
● Seeing at the workplace  
● Colour of light and visual acuity
● Adaptation (light and dark adaptation) 

3 The eye 
● The human eye 
● Individual visual defects 
● Optical illusions 

4 Lighting
● Influence of lighting on the working person 
● Bad lighting causes accidents 
● General remarks on lighting installations 
● Lighting at visual display unit (VDU) workplaces 
● Lighting of workplaces in the open

5 Colours at the workplace
● Lighting and colour go together 
● The basic rules of the theory of colours
● Comparison between additive and subtractive mixture of colours

6 Safety markings

7 Visual safety guidance systems 

8 Terminology of lighting engineering

9 Electrical safety
● Requirements for electrical safety 
● Maintenance of lighting installations 
● Measuring of lighting installations