When reading my monthly supply of journals, one article has caught my eye with a title: “Indoor environmental criteria for older adults: Ageing means business”. Not feeling so old, yet, but having older relatives, I decided to read it and I was surprised that most of the findings in this article have common sense. This article nicely describes problems which seem to be omitted when designing other buildings then for elderly.
Today in Europe, average life expectancy is over 80, and by 2020 around 25% of the population will be over 65. There is a need to provide a suitable living for this group of people, not only the private homes or care homes, but also the work spaces need to be adjusted to the people over 65 as they will be the main work force.
Current building regulations focus on the age group between 25 to 65 years of age. Therefore there is a need to focus on the effects of biological ageing on the perception of indoor environment, such as the thermal environment, air and odors, light and lighting, and the acoustical environment.
When getting older, the ability to control the body temperature decreases with age and over the age the declining basal metabolism leads to lower body temperatures. Adults prefer higher ambient temperatures and their thermal sensation is about 0.5 scale units lower compared to young people (ASHRAE 7-point scale). Elderly should be protected from temperature changes; otherwise this might lead to increased systolic blood pressure.
The perception of odors declines over the life and may lead to decreased appetite and poor nutrition. And many elderly need glasses due to the significant loss of focusing power in the eye. Also glare and low levels of light pose problem for older population, especially people require more contrast for proper vision and have difficulties to perceive patterns. At the age of 70, many experience that fine details are harder to see, and color and depth perception are affected. High-frequency pitches are the first to become less audiable and speech recognition is lower at high age.
The authors of the article listed some implications for design and practice: „For designers of work places it might be wise to have a second look at the controllability of the indoor environment given the trend that people have to work longer in relation to a postponed retirement.“
„Novel lighting applications are developed by the industry and applied to improve cognition, mood and behaviour, sleep and vision, such as dynamic lighting systems. To date, we do not know if such expensive systems have better outcomes than static lighting systems, and how such systems interact with available daylight. Vision can be improved by raising general illuminance levels and glare control.“
„The supply of fresh air, elimination of bad odours, reduction of background noise and other aspects of the acoustical environment are recognised as being important, but are not as well-studied as light and lighting. The economic benefits of accounting for these parameters are not yet clear.“
„Recent findings in the realm of thermal comfort research suggest that older adults may have a need for slightly higher indoor temperatures. As long as there are many uncertainties, we suggest to allow for a maximum of user control in buildings.“
„Apart from designing indoor environments that meet the needs of older adults, the accessibility of spaces and other human factors approaches should be considered to optimize a building for use by older occupants.“
This article is based on the article published at the REHVA Journal 3/2013 by J. Van Hoof and A. C. Westerlaken.