Executive Summary
Providing suitable lighting in the workplace is complex. Lighting levels should enable workers to see comfortably and distinguish colors clearly when performing tasks. Lighting should also promote alertness, maximize energy efficiency, and minimize the impact of artificial light on the environment, especially at night, including on marine life near offshore installations. The lack of light when working during the daytime and when exposed to light at night (LAN) is increasingly being recognized as an important nonpharmacological determinant of health.
The objective of this guidance document is to provide occupational hygienists and health, safety, and environment (HSE) managers in the energy industries with pragmatic advice on how workplace lighting can limit circadian disruption and promote health, safety, and performance.
More Daylight, Less Light at Night
Research has consistently demonstrated that both a strong morning light signal (from daylight) and evening dark signal (after sunset and during darkness hours) are key to maintaining circadian synchrony with the light/dark cycle of the natural environment. In today’s modern world, however, indoor workplaces tend to be relatively dimly lit during the daytime, and then in the evening and at night many people are exposed to artificial light.
To limit the circadian disruption encountered by daytime workers, it is recommended that practitioners improve light exposure at work (for example, by encouraging workers to spend their breaks outside the workplace, and provide comfortable lighting inside) and educate workers on how to create a “light mode” and a “dark mode.” To create an evening dark mode, lights should be dimmed and blue light, such as that emitted from smartphones and computer screens, should be avoided. Blue is the wavelength of light with the most powerful impact on the body clock, and so there are glasses available that help to block this type of light.
Supporting the Health of Shift Workers
Research into the biological effects of light, including the impact of LAN on circadian disruption, is in its infancy, and lighting strategies intended to improve shift worker health could inadvertently do harm. It is not yet possible, therefore, to provide recommendations on workplace lighting for shift workers. Advice is provided on other strategies that practitioners can use to limit the circadian disruption encountered by shift workers, including planning of work schedules and improving darkness levels before and during sleep. Specific advice is given for onshore and offshore shift schedules, because while circadian adaptation to night shifts does not usually occur onshore, it does occur in isolated offshore settings.