CPD 3 2020: Designing daylight solutions for commercial buildings

This CPD, sponsored by VELUX Commercial, looks at how lighting affects health and wellbeing for those working in offices, hotels, transport and industrial buildings
DEADLINE TO COMPLETE: 9 June 2020

Introduction

The availability of artificial light over the last two centuries and the re-structuring of our working day have freed us from the constraints of the natural diurnal cycles of light and dark. However, there is now a huge body of research that shows that this divorce from nature comes at a considerable cost to our individual health and well-being, indeed even to society at large. We are fast becoming the indoor generation, people whose experience of daylight and fresh air during the week can often be restricted to the morning commute to work or school, a quick lunch break or a stop at the supermarket on the way home.

The influence that architecture has on our lives cannot be understated, and the need to create healthier, brighter indoor spaces with greater access to daylight and to the outdoors is a pressing one. Roof glazing can contribute to making our work environments lighter and more connected to nature by offering unobstructed views of the sky and bringing daylight into the heart of a building. Modular skylights provide flexible solutions to facilitate greater natural light and better ventilation in our buildings, while at the same time facilitating considerable energy savings.

This CPD will look at how lighting affects the health and wellbeing of those working in offices, hotels, transport and industrial buildings and the key areas for designers to focus on.

Roof glazing can contribute to making our work environments lighter and more connected to nature

The emergence of the indoor generation
The term “indoor generation” refers to a growing number of people who spend most of their time indoors; 90% of their lives, living, working, learning and playing, and often in dark, poorly ventilated and unhealthy buildings.

Many of us do not realise that the lack of light can affect our sleep patterns and increase the risk of serious health problems including diabetes, heart disease and depression. Indeed, only about half of the 16,000 respondents, who were questioned about their perceptions of indoor living as part of the 2018 YouGov survey were aware that daylight has a significant impact on sleep. Sleep loss and circadian rhythm disruption are most obvious in night-shift workers – more than 20% of the population who are of employment age work at least some of the time outside the normal working day. According to Josephine Arendt, an expert at the University of Surrey on the factors affecting sleep quality, shift workers can have symptoms similar to those of jet lag. This is caused by rapidly changing and conflicting light-dark exposure and activity-rest behaviour and living out of phase with local time cues.

Daylighting needs – how our circadian rhythms are impacted by daylight
While we have adapted to living indoors, we are essentially still outdoor animals, and our gene code is designed for us to live in a natural environment. Prior to living inside our daily lives were determined by the availability of daylight hours and the qualities of light that signalled changes in weather and time. Our physiological systems, especially our circadian cycles were in harmony with these diurnal rhythms of daylight, as were our emotional responses to light and darkness.

Light stimulates the brain, affecting energy levels as well as alertness and productivity. A properly functioning circadian cycle also determines patterns of co-ordination, blood pressure and cardiovascular activity. It affects mood and influences social behaviours and cognitive performance. Brain imaging following light exposure shows increased activity in many areas of the brain that are involved in alertness, cognition and memory (thalamus, hippocampus, brainstem) and mood (amydala).

The impact of daylight on occupants in commercial buildings
Research on office buildings has shown that workers highly value access to a window and to varying degrees of daylight. In a 1992 University of Washington study of seven office buildings in the Pacific Northwest more than 83% of the occupants said they “very much” liked daylight and sunlight in their workspace and valued the seasonal changes in daylight. Even in darker locations within a building, the occupants still expressed satisfaction with the daylight level, providing they could look into a daylit space. In the YouGov survey, 39% of respondents said that daylight significantly impacts their mood.

A study of office workers in a Seattle high-rise building compared the merits of natural daylight against electric light on the grounds of psychological comfort, general health, visual health, work performance, jobs requiring fine observation and office aesthetics. Respondents rated daylight better than electric light on grounds of health, comfort and aesthetics, and rated daylight and electric light equally good for visual tasks.

Incorporating daylight into building design to enhance wellbeing and performance
A study from the Technical University of Denmark revealed that the indoor environment can influence work productivity by up to 10%. Many studies show that the performance and productivity of workers in industrial, office and retail environments can be positively enhanced with the quality of light. Companies have recorded an increase in productivity of its staff of around 15% after moving to a new building with better daylight conditions, resulting in considerable financial gains.

Staff are the most valuable resource in most organisations, typically accounting for 90% of business operating costs, so even a 1% increase in productivity can have a major impact on the bottom line and competitiveness of any business. Employers, building owners, developers, investors and designers are learning in response to an increasing body of evidence, that office design affects the health and wellbeing of occupants in many ways and it is prudent business practice to create green, healthy buildings.

Good building design should facilitate our reconnection to the rhythms of nature, and not just be focused on quantifiable parameters such as levels of humidity and temperature. And yet, defining a suitable daylighting scheme for any building can be a challenge as there are many factors to consider.

Building design – how daylighting needs change by building types

Designing for daylight in offices
After our homes, we spend the next largest part of our lives at work, and our workplaces have moved indoors – especially into office environments. An increasing proportion of global GDP is produced in office environments.

Currently, an average of 36% of the European workforce (about 81.4 million people) work in an office environment, rising to 40% in some countries. Office employees spend roughly 30% of their waking hours each year in offices. Creating comfortable and healthy offices has been proven to have a significantly positive effect on workers’ productivity and efficiency, so investing in good office design is sound business sense and is likely to repay the additional investment many times over. Addressing indoor air quality, thermal comfort, acoustics and lighting are key considerations if sick building syndrome is to be avoided. More than 80% of European workers in office-based environments stated that they are exposed to excessively high or low temperatures close to 25% of the time. Good ventilation, including the use of openable rooflights, can increase the comfort and productivity levels of office occupants.

In a recent global survey a third of respondents stated that the design of an office would affect their decision whether to work for a company. The survey also highlighted just how much they valued having natural light in the workplace. In 1997 the Danish Building Research Institute conducted a survey of over 1800 people working in office buildings and asked them questions such as how they valued windows and a view out to nature in the workplace. The ability to see out and “see the weather” were considered top priorities. Having a view allows one to tolerate a lot more discomfort in the internal environment than if you do not have a view. In the 2018 YouGov Study 63% of respondents stated that they think daylight has a significant effect on productivity. Other studies reveal that most people believe daylight is good for their general health, their visual capability and productivity.

Designing for daylight in hotels and conference venues
Modern hotel buildings now comprise quite disparate, multi-functional areas, for which the management of natural and artificial light can be quite a challenge.

The lobby and reception areas, restaurants, spa and wellness zones, corridors and hallways, guest rooms, and meeting spaces as well as service areas and recreation areas all require different levels of lighting, ventilation and thermal comfort. It is critical to be able to adjust lighting levels, to change the colour of a space and its ambience from bright and lively, to warm and inviting right through to calm and relaxing.

Typically, lighting accounts for 15-45% of electricity consumption in small hotels and restaurants. In regions where there are no large heating or cooling costs, it can be the greatest use of electricity in a hotel. Most lighting energy is used in the 24-hour communal areas of a hotel – the corridors and lobby. In a typical 65-room hotel using traditional lighting, this can add up to 1000 kWh per day in corridors and 370 kWh per day in the lobby. Bedrooms come next, using about 350 kWh per day.

In the lobby and reception area it is essential to create a specific atmosphere in order to express the brand image and its uniqueness, while at the same time it is important for the operation of these areas that there is no glare which might impact on computer screens and work stations. In the restaurants and cafe areas the lighting concept must enhance the dining experience. In hallways and corridors daylight can work in combination with artificial lighting to prevent a tunnel effect and make the routes more inviting as well as safe for guests.

However, the biggest single complaint registered by hotel visitors is the lack of sufficient lighting in guestrooms. Such spaces are multi-functional as this is where guests eat, work and relax as well as sleep. Today’s hotel guests are also seeking to be connected to nature and are prepared to pay premium rates for rooms with a view.

Green Solution House Hotel and Conference Centre in Denmark where modular skylights are a central element

Designing for daylight in high-traffic air and rail concourses
High-traffic public spaces, such as airports, are complex sensory visual environments with the result people often experience these as overwhelming, frustrating and tiring.
With increased air travel passengers want terminals to be more interesting places to spend their time prior to departure and they want to be comfortable.

Over recent years airport authorities have responded to these demands and focused on creating terminals that are more welcoming, more relaxed and offering a variety of activities such as children’s play areas. They also recognise that airy retail spaces in departure lounges and entrance halls filled with lots of natural light encourage passengers to spend more time in these spaces, thereby increasing their revenue potential.

The wellbeing of both passengers and staff has become central to airport design. Views outside the building satisfies the physiological need of the eye to change focus and provides visual comfort. Optimising natural light for illumination can direct the location and shape of holding rooms and circulation spaces.

Factors such as the site and local climate can have huge relevance in the formulation of daylighting concepts at airports and can determine where the addition of artificial lighting may be necessary to provide appropriate levels of illumination, balance brightness and shadow. With security of paramount importance staff need to have optimal visual conditions to do their job properly. The correct level of daylighting is necessary for facial recognition to avoid glare occurring, while still maintaining visual comfort for staff. Glare causes undue visual fatigue and headaches.

As the use of information technology and digital media for flight information and advertising at airports has significantly increased so have the number of challenges to address. Screens must always remain legible and contrast ratios maintained. Daylighting has an impact on the choice of location for display screens, the control of reflections and the choice of materials which can help to reduce glare.

The Society for Light and Lighting (SLL), part of the Chartered Institution of Building Services Engineers (CIBSE), has produced a series of guidelines to help formulate daylighting strategies. SLL: LG15 Lighting Guide 15: Transport building was produced by SLL to assist designers working within transport environments to create effective lighting strategies that are energy efficient and enhance the passenger experience.

Daylighting strategies that increase the amount of natural light and reduce reliance on electric lighting also create a more welcoming environment. The drop in electric lighting dependence lowers electricity usage but also cuts down on the build-up of heat from lamps. Diffuse daylighting can also allow facilities to operate during daylight hours without artificial lighting, leading to greater energy savings.

Diffuse daylighting can allow facilities to operate during daylight hours without artificial lighting

Designing for daylight in industrial and warehouse buildings
For office lighting design the focus is on health, comfort and the productivity of workers. In industrial settings, which are classed as higher-risk, safety is the overriding priority. Poor quality lighting, whether natural or artificial, or a combination of both, can contribute to a higher incidence of accidents, especially in areas where heavy machinery such as forklift trucks are used. Not only are such accidents very serious, resulting in employee injuries or even in fatalities, but the financial consequences for the company are potentially enormous.

Furthermore, in those industrial environments, which are largely illuminated by artificial lighting, and where working periods are becoming longer, too little natural light may have negative effects on employees, reducing their alertness, and contributing to depressive conditions such as seasonal affective disorder (SAD).

While there are guides available to architects which recommend lighting levels for the industrial sector, quite often the provision of the correct illuminance levels is simply a matter of judgement. In loading bays which are classified as hazardous areas, the recommended level is 150 lux. In warehouses or storage areas the recommended level is 100 lux. In engineering environments, such as tool shops or assembly lines, the levels can vary between 300-750 lux.

Yet even despite the emphasis on using natural daylight where feasible, this may not provide sufficient illuminance throughout a working area, or even throughout the working day, depending on the length and quality of daylight hours during the winter.

Ventilation in industrial environments is another a key priority in such buildings, to ensure that there is a flow of fresh air, and to allow pollutants to escape.

Designing for daylight in industrial and warehouse buildings
For office lighting design the focus is on health, comfort and the productivity of workers. In industrial settings, which are classed as higher-risk, safety is the overriding priority. Poor quality lighting, whether natural or artificial, or a combination of both, can contribute to a higher incidence of accidents, especially in areas where heavy machinery such as forklift trucks are used. Not only are such accidents very serious, resulting in employee injuries or even in fatalities, but the financial consequences for the company are potentially enormous.

Furthermore, in those industrial environments, which are largely illuminated by artificial lighting, and where working periods are becoming longer, too little natural light may have negative effects on employees, reducing their alertness, and contributing to depressive conditions such as seasonal affective disorder (SAD).

While there are guides available to architects which recommend lighting levels for the industrial sector, quite often the provision of the correct illuminance levels is simply a matter of judgement. In loading bays which are classified as hazardous areas, the recommended level is 150 lux. In warehouses or storage areas the recommended level is 100 lux. In engineering environments, such as tool shops or assembly lines, the levels can vary between 300-750 lux.

Yet even despite the emphasis on using natural daylight where feasible, this may not provide sufficient illuminance throughout a working area, or even throughout the working day, depending on the length and quality of daylight hours during the winter.

Ventilation in industrial environments is another a key priority in such buildings, to ensure that there is a flow of fresh air, and to allow pollutants to escape.

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