DG 1110-3-106
velocities generally not exceeding 40 feet per minute
that necessary to meet day-to-day operational
for an air-conditioned draft-free environment. If the
requirements. It can be determined by analyzing
building is not air-conditioned a higher air velocity
specific instructional programs on a school-by-school
increases summer thermal comfort.
basis. This space will be located in the technical
library, training aids offices, or other area close to
E. Seating Design.
classrooms and instructor preparation areas. Paragraph
2-4c.(2)(m) above contains additional information on
(1) Instructor-Student Visual Contact.
storage areas. The A-V storage space required can be
Arranging seating to facilitate instructor-student visual
determined from the following table:
contact is of primary importance. Students sitting
Storage Volume
directly in front of the instructor participate
Media
(Units per Cubic Foot)
significantly more than students sitting off to one side.
16mm film (400 ft. reels)
9 reels
Seating arrangements should therefore encourage direct
160 strips
Film strip
visual contact between instructor and students. (Figure
45 loops
3-9). In a classroom containing several rows of seating,
35mm slides
535 slides
a speaker's platform is required; in a large conference
143 cassettes
Audio cassettes
room or an auditorium, tiered risers for student
42 reels
7 inch reel audio tape
40 records
seating are required.
Long playing records
64
Overhead project transparencies
34 films
Microfilm 35mm
(2) Seating Comfort.
68 films
Microfilm 16mm
Seating which is too comfortable may discourage
1,785 cards
Microfiche
student participation and alertness. Seating should be
selected which is reasonably comfortable, but not so
relaxing that it encourages inattentiveness.
C. Visual Field.
Although the eye can perceive objects over an
extremely wide visual field (a horizontal arc of
3-4 Design of Audio-Visual Systems
approximately 200 degrees), the major visual field
consists of a cone of 30 degrees - 15 degrees on either
A. Configurations.
U.S. Army Service Schools use A-V equipment in six
side of center. It has been estimated that 70% of all
vision takes place within this field. To occupy the full
general configurations shown in Figure 3-10.
30 degrees visual field, a display must be located at
B. Storage.
distance from the eye equal to twice the width of the
Sufficient space should be programed within the school
display (2W). Effective viewing, then, requires a
minimum viewing distance of 2W. (Figure 3-11). The
to allow for the storage and maintenance of A-V
equipment and materials. This space is, at a minimum,
A
Instructor
B
Zone of Minimum Participation
C
Zone of Average Participation
D
Zone of Maximum Participation
Figure 3-9
Visual Contact/Discussion Participation Relationship
3-8
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