DESIGN CONSIDERATION

exterior is the more subjective, aesthetic concern of conveying an image with the building's appearance. Although entry, lighting, and interior design contribute to the image that a building projects, the exterior form is one of the most important elements. Because the exterior profile of an underground building is certain to be smaller and generally less obtrusive than a comparably-sized above-ground structure, a less visible and less monumental image will be projected. For some functions- auditoriums, libraries, museums, parking garages, and factories- this may be an advantage since a minimal presence on the site is often desirable. Other functions, however, may require visibility to the public or may need to serve as a symbol. Although there are instances where an underground design is simply not an effective means of achieving a highly visible or monumental form, a positive image can still be created in most cases without relying on a large building mass. Partial exposure of the building, berms, and extensive landscaping can be de-signed to create forms on the site that will draw attention because they are attractive and provide a contrast with more conventional buildings.

5.2. Negative Psychological Effects

Underground buildings display a wide spectrum of physical characteristics and functional uses. In addition, the physiological and psychological responses of individuals to the environment can be radically different. The combination of these factors generalizes about underground buildings in relation to psychological effects of limited applicability. It is possible, however, to list criteria and considerations that are potentially applicable to an underground building and to discuss how these factors have been assessed by various investigators of the psychological and physiological responses to artificial environments. One major concern related to underground buildings is sensory deprivation. Individuals are stimulated by, and many bodily functions are affected by, interaction with the surrounding Figure

Design Consideration

environment. In addition to physiological effects psychological problems can arise from the reduction of external stimuli to an individual. This reduction of stimuli would occur most significantly in small, enclosed spaces with little interpersonal contact and no contact with the external environment. It should be noted, however, that a reduction of external stimuli is not always negative; it can provide a more productive work environment and reduce stress in otherwise chaotic surroundings. Pleasure is selfexplanatory. Arousal refers to the presence or absence of stimuli discussed above, and dominance relates to feelings of control or influence over the environment. A lowered arousal level is to be anticipated in enclosed spaces, but the effect on feelings of dominance is not as clear. It has been suggested that, because of the practical and environmental advantages of an underground building, users may feel they are exposed to successful attempts to cope with the demands of the environment. It has been found by others, however, that practical features of a building are not important in evaluating user response to working in the space. Nevertheless, for an individual choosing to build a certain type of underground structure, say an earth sheltered house, for energy conservation and environmental reasons, these criteria are often especially important and would be expected to create positive feelings about the environment. A poor response to the environment of an underground building has been linked to anxiety, tension, depression, and other mental health problems, although other studies have indicated no measurable differences in achievement, health problems, or absenteeism. Only a few studies have directly addressed the case of below-grade spaces for working or living environments, and often conflicting data have been gathered. Assessments of the distinct physical characteristics of an underground space are extremely difficult to separate from other general physical characteristics of the space and the interpersonal environment. In spite of the lack of definitive data, however, the major issues are fairly clear and repeatedly emerge in all studies of underground and windowless spaces. There follows below a list of conditions that are associated with producing negative psychological effects in underground buildings. Most of the information also pertains to windowless buildings or interior zones inside conventional buildings.

5.2.1. Lack of natural light.

The lack of natural light is one of the most often mentioned negative characteristics of underground space. Access to natural light is important to users of a building even if the proportion of daylight to artificial lighting for work tasks is relatively low. The feeling produced by daylight, its variability, and the sense of contact with the outside world are important reasons for its desirability. It has been theorized that horizontal accessibility to daylight provides a closer reference to conventional buildings and is therefore preferable to day lighting from overhead sources. In contrast, however, a research study conducted with groups of students viewing slides of building interiors concluded that

Design Consideration

spaces with skylights overhead were most often selected as the most desirably lit. Another important positive psychological association of natural lighting is that sunlight connotes warmth. Direct sunlight is not always welcomed by building users, however. Sunlight can cause excessively uncomfortable conditions in a warm building interior, as well as personal discomfort to a person who must work in the full sunlight. Excessive brightness, glare, and large brightness-to-darkness ratios in buildings not completely illuminated by sunlight are other problems.

5.2.2. Underground location

The location of a building below grade does not preclude providing the above amenities of natural light and view to the interior of the building. There are, however, psychological barriers to the physical location of a space below grade, even if it has identical physical amenities to an interior space m a conventional building. Some individuals may experience claustrophobia or fears related to safety that result in negative reactions to underground spaces. It is difficult to explain the negative association some people have with the concept of being underground even when interior conditions are identical to those in an aboveground space. In addition to fears related to safety concerns, there may be a generally negative association with death and burial related to underground space. It is generally assumed, however, that these attitudes are more closely related to a fear of structural collapse, fear of being trapped in a fire in a windowless building, or fear of flooding in a fully below-grade space. Fears for personal safety need not be related to the actual risk experienced, but merely to the perceived risk. These negative reactions tend to heighten awareness of and exaggerate objects to other physical characteristics of the space that might go unnoticed in a conventional building. For example, small interior spaces, low ceilings, or entry down a narrow, dark stairway may increase these negative associations with being underground.

5.2.3. Undesirable internal conditions

Users of underground or windowless buildings frequently complain of poor temperature and humidity control, and a lack of ventilation and stuffiness. Generally, none of the problems should be any different for a below-grade or windowless building than they are for a sealed, climate-controlled conventional building. In fact, temperature and humidity should be easier to control than in an aboveground building. Thus, in addition to the actual ventilation air change rate provided, perception of ventilation by occupants is important. If awareness of the superior internal environmental control of an underground building is clearly apparent to the occupants, some offsetting positive attitudes may develop.