This criterion proposes that the acoustical environment be controlled to minimize background noise, echo and reverberation. The level of such acoustical control should vary according to the level of user-focus required within the space, as well as the skill level and severity of the autism of its users. For example, activities of higher focus should be allowed a higher level of acoustical control and be part of low-stimulus zones, described shortly.
Provisions should also be made for different levels of acoustical control, so students can graduate from one level of acoustical control to the next, slowly moving towards a typical environment in order to avoid the “greenhouse effect”.
The philosophy behind this criterion is to define and limit the sensory environment of each activity, organizing a classroom or even an entire building into compartments. Each compartment should include a single and clearly defined function and consequent sensory quality. The separation between these compartments need not be harsh, but can be through furniture arrangement, difference in floor covering, difference in level or even through variances in lighting. The sensory qualities of each space should be used to define its function and separate it from its neighboring compartment. When coupled with this consistency in activity, this will help provide sensory cues as to what is expected of the user in each space, with minimal ambiguity.
A point never to be overlooked when designing environments for children, safety is even more of a concern for children with autism who may have an altered sense of their environment for example using hot water safety fittings and avoiding sharp edges and corners.
This criterion is based on the concept of capitalizing on the affinity of individuals with autism to routine and predictability. Coupled with the criterion of Sensory Zoning, which will be discussed shortly, Spatial Sequencing requires that areas be organized in a logical order, based on the typical scheduled use of such spaces. Spaces should flow as seamlessly as possible from one activity to the next through one-way circulation whenever possible, with minimal disruption and distraction, using Transition Zones which are discussed below.
Working to facilitate both Spatial Sequencing and Sensory Zoning, the presence of transition zones helps the user recalibrate their senses as they move from one level of stimulus to the next. Such zones can take on a variety of forms and may be anything from a distinct node that indicates a shift, to a full sensory room that allows the sensory re-calibration before transitioning from an area of high-stimulus to one of low-stimulus.
The objective of such spaces is to provide respite for the autistic user from the over-stimulation found in their environment. Empirical research has shown the positive effect of such spaces, particularly in learning environments (Mostafa, 2008, 204). Such spaces may include a small partitioned area or crawl space in a quiet section of a room, or throughout a building. These spaces should provide a neutral sensory environment with minimal stimulation that can be customized by the user to provide the necessary sensory input.
This criterion proposes that when designing for autism, spaces should be organized in accordance with their sensory quality, rather than typical functional zoning. This requires grouping spaces according to their allowable stimulus level, into “high-stimulus” and “low-stimulus” with transition zones aiding the shift from one zone to the next.