GENERAL DESIGN CONSIDERATIONS
DG 1110-3-112 May 1979
3-4 BUILDING DESIGN (cont'd)
of human performance show that when temperature and humidity become high, working efficiency
decreases, errors increase, and under extreme conditions health is adversely affected. In areas such
as shops, in which students are working with equipment and machinery, temperature and humidity
control may be required for safety purposes. Likewise, ventilation or exhaust systems may be required
for health. All provisions must be consistent with applicable Occupational Safety and Health Act
(OSHA) standards.
(a) Temperature Control. Whenever the daytime outside temperature is above 55 degrees F., heat
gains will usually outweigh losses. Therefore, the fundamental problem in controlling the thermal
environment in an ACES Center is cooling, rather than heating the facility. The desirable temperature
for a building depends on the activity of its occupants. Acceptable temperature limits vary from 60-70
degrees for vigorous activity to 68-78 degrees for sedentary activity. In an ACES Center, where
learning activities range from sedentary to vigorous, separate temperature zoning should be provided.
For example, shop areas should be zoned for lower temperature than classrooms or staff areas.
(b) Humidity Control. Relative humidity has little influence on comfort, provided that it is in the
intermediate range (30% to 70%). Humidity levels above 70% can impair human performance and
levels below 30% can cause respiratory discomfort and create undesirable levels of static electricity in
activity spaces.
(c) Ventilation. In a closed, occupied space, the amount of oxygen in the air decreases and the
amount of carbon dioxide increases. Normally, ventilation of 6-10 air changes per hour is sufficient for
maintaining the proper balance between oxygen and carbon dioxide. Dust, pollen, and bacteria should
be eliminated by air filtration. Ventilation criteria for individual spaces are summarized in Chapter 4,
Table 4-1. Air distribution systems should provide uniform air velocities generally not exceeding 40
feet per minute for an air-conditioned draft-free environment.
(4) Mechanical Design. Heating, air conditioning and mechanical ventilation shall conform to the
applicable portions of DOD 4270. 1-M and TM 5-810-1. Heating and air conditioning load calculations
shall comply with the procedures of the latest ASHRAE Handbook of Fundamentals. The "U" values
for exterior walls, ceilings, and floors shall be in accordance with DOD 4270.1-M. Design temper-
atures shall be 68F. for heating; 78F. for cooling. Various systems should be considered to
accommodate the environmental requirements of the different types of spaces in the ACES Center.
Selection will be based on performance, least energy use and cost of operation and maintenance.
Energy recovery systems should be investigated and incorporated into the design if economical.
Reasons for selection and rejection of systems must be included in project design analyses.
(5) Lighting. An appropriate visual environment with adequate lighting is essential for effective
learning. A well lighted classroom enhances auditory as well as visual perception.
(a) Illumination Levels. Research has established that a lighting level between 20 and 50
foot-candles is adequate for the comfortable and efficient completion of most tasks. However, it is
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