human centric lighting

Illuminating human centric lighting

Office staff working under HCL fixtures report better mood, higher energy: study
Monday, August 20, 2018
By José Ramos

It may be hard to believe, but widespread indoor workplace lighting has only been around for a little more than a century. And the massive shift toward working long hours indoors — under common lighting conditions — has had an enormous impact on people’s daily lives.

By some estimates, such as the U.S. Environmental Protection Agency’s (EPA), 90 per cent of people’s lives takes place indoors, with limited exposure to natural light. As a result, the indoor environment has put significant stress on human health and well-being. Yet most efforts to improve people’s increasingly sedentary indoor lives have focused on air quality, ergonomic and physical activity (which, ironically, also happens inside — in gyms and yoga studios), but not on lighting. This is, however, changing and there is now a fast-growing trend toward what is called human centric lighting (HCL).

HCL may seem an overly broad term — after all, the lighting installed within buildings is meant for humans. But it focuses on the idea that humans’ well-being must be one of the goals of lighting systems. And at the heart of this idea of well-being is the fact that the human body follows a circadian or daily rhythm, which is a type of time clock which takes its cues from the day/night cycle. That is, until artificial lighting began to disrupt it significantly, starting with Edison’s lightbulb. The predominance of interior lighting which, unlike the outdoors, does not vary over the course of a day means that conventional lighting is not considering the human body’s need for light that varies in intensity and color.

But how does HCL actually work? It’s a relatively simple concept, and has been made possible by the advent of LEDs and their widespread adoption. In general, traditional lighting is static as it just turns on and off, and maybe it has dimming functionalities. A typical ceiling fixture delivers only one type of light at a fixed intensity and spectra, as in most offices and factory floors.

HCL fixtures, conversely, generate light that varies in intensity and spectra over the course of the day. Spectra refers to the various colours that make up white light. Most people are familiar with “cool” or “warm” lightbulbs or fluorescent tubes. Cool white light tilts more toward the blue spectra while warm white light tilts toward the red. During bright daylight hours, HCL fixtures deliver light with higher amounts of blue spectra but as the evening approaches the fixtures deliver less blue – as with typical natural lighting, when the sky is blue during the day with the lighting “warming” as natural light does in the late afternoon. Spaces with HCL systems also are generally brighter than traditional workplaces since natural sunlight is actually quite bright compared to typical indoor spaces.

A seven-month study by the University of Twente VU in Amsterdam and CBRE Group Inc., using OSRAM products, revealed a 12-per-cent increase in task performance metrics for office workers who worked under HCL, sometimes called circadian lighting. The control study participants worked under conventional lighting. The HCL systems varied light over the course of the day, looking to mimic the natural daily fluctuation in exterior light levels. Participants in the HCL areas also reported feeling in a better mood (76 per cent), more energetic (71 per cent) and healthier (50 per cent).

This is just one example of the many case studies that show HCL yields positive outcomes in a wide range of environments, from private corporations to educational institutions, and even healthcare settings.

While past standards to improve building performance have focused on efficiency, such as LEED, newer approaches have started to aim at occupant well-being. The WELL Building Standard is such an example. As it turns out, the first WELL Certified™ pilot offices in the world were CBRE’s Global Corporate Headquarters in downtown Los Angeles, California. One of the pillars of the standard is lighting that contributes to well-being, based on the established science around circadian cycles. A visitor to the Los Angeles headquarters will immediately notice that the space is bright and airy. And employees report that they greatly enjoy this type of office configuration.

However, this example of a workplace where HCL plays a central role is not some research facility, art museum or educational institution; it’s a profit-driven institution that makes decisions based on financial metrics such as the return on investment. There is a realization and an understanding that HCL has real and tangible benefits to a company’s bottom line. After all, the largest expenditure for a company is usually its labour costs. If a labour force is the largest financial piece of a company’s balance sheet, then it’s only logical to take steps to increase the value and output of this resource. And this applies equally to an office as it does to a factory floor. Even small productivity gains can mean large financial returns when they are associated with a company’s largest business expense.

The trend is clear — human centric lighting is a technology that results in physical well-being for individuals and financial gain for institutions. Those companies that pursue the installation of HCL systems will reap benefits, ranging from increased employee satisfaction and productivity to improved corporate financial performance.

José Ramos is engineering/business innovation manager, OSRAM Innovation, Americas Region.

Pictured: CBRE’s Amsterdam headquarters, where the study of HCL occurred.

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