1. Economics

Using identical designs helps provide an economy of scale for this custom element.

2. Pattern of Building Usage

Schools are typically not in session during the summer when solar heat gains have the most negative effect on comfort levels. Solar heat gains would typically help in the winter toward reducing heating loads. A second building usage issue is the time of day school is in session. The peak gains in the west orientation occur around 5:00 pm, after the school day has ended. In order to minimize the morning heat gains from the east orientation, the architect provided only 2 window bays. This is the lowest amount for any orientation. The architect also provided trees in front of the east windows that will provide shade and help to minimize summer gains once they mature.

3. Aesthetics

Subjectively, the horizontal shading device is a much cleaner design element than providing large amounts of vertical fins which might clutter the elevation. Repeating the identical design also helps to reflect in elevation the modular nature of the classrooms which is seen in plan.

4. Daylighting.

As indicated in the previous section, vertical fin shading devices on the east and west orientation are not effective unless they shade the daylighting window above the light shelf. This could diminish the quality of daylighting in these classrooms.

When the building moves to a year round school schedule, summer cooling will be a prime consideration. Since the building does not have a conventional air conditioning system, the 1-ton of cooling capacity represented by the addition of the vertical fins could be critical for thermal comfort. The fins could be designed in such a way that they are either demountable, or the top portion made of glass so that it blocks solar gains, and not visible light.