Built for brains: school design annotates human factors.

ARCHITECTURE CREATES SPACES FOR PEOPLE. HUMAN factors in architecture focuses on health and safety, performance, comfort, and aesthetic pleasantness. Since the beginning of the "built environment," the concern for human factors was integral to the design process--whether assessing angles and acoustics in the hillside Greek Theater at Delphi in 350 B.C. and the Roman Colosseum in 70 A.D., or studying the long-distance roofs and facility maintenance in the cathedrals of the Middle Ages.

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Designing schools in the United States requires no less attention to detail. Human factors is integral to the design, construction, and occupancy process. Students, teachers, administrators, and community groups are affected by a variety of human factors in a school building including noise, glare, lighting, mildew, mold, ventilation, temperature, humidity, furniture, fixtures, equipment, security, technology, function, and aesthetics.

Roots and rules

The colony of Massachusetts passed a law in 1647 requiring towns with 50 or more families to establish, operate, and fund elementary schools and those with 100 or more families to establish secondary-level Latin grammar schools. In the one-room schoolhouse, one teacher taught all grades, typically five to 15 students, and worked directly with small groups of one or two students of the same age and learning ability.

The Lancastrian school system developed with urbanization and lasted until about 1840 leaving its lasting influence of large group instruction. The Transitional School (1840-1850) unified separate reading and writing schools and contained classrooms with small rooms for individual recitation. The first graded public school was Boston's Quincy Grammar School built in 1848 with classrooms between 800 to 900 square feet for 55 students. Regimented instruction gradually gave way to new educational processes of discussion, evaluation, investigation, and self-expression. Class sizes were gradually reduced to 40, 35, and then 30 students. This classroom concept is still used today even though educational curricula and delivery has experienced substantial change.

Henry Barnard, commissioner of public schools in Rhode Island, expressed concern for human factors affecting the health and happiness of the child with respect to heating, ventilation, sanitary requirements, age-appropriate facilities, different accommodations for different studies, and aesthetics. In the same way, Planning Secondary School Buildings, published in 1949, identified three human factor characteristics that apply today:

* Human values. A classroom should conform to the highest standards in the recognition of human values: aesthetics, psychology, community and national spirit, comfort and happiness, physically handicapped, pupils' individual and personal rights, conservation of energy, and rooms constructed on the basis of living.

* Function. Classrooms should conform to the most enlightening ideas of the intended use, design, construction and decoration, and equipment and should further the school program with modern techniques, flexibility, adequate instructional material, and by recognition of the social aspect.

* Mechanics. Acoustics, automatic controls, aesthetics, adaptability to group, comfort, flexibility, heating, lighting, safety, sanitation, and ventilation.

Human factors took a new direction as the 1960s ushered in the windowless classroom, carpeting, air-conditioning, closed-circuit television, and dial-access informational retrieval systems. Flexible modular scheduling and interdisciplinary teaching required personalized learning environments in four instructional modes: large group (100-200 students); medium groups or labs (25-35 students); small groups (6-15 students); and independent study in such areas as the main resource center with its dial-access information retrieval system, subject-area resource centers, and student commons.

Air, ideas circulation

Indoor air quality (IAQ) and noise are two major human factors affecting student learning and behavior. From the 1960s to the 1990s, systems became much more sophisticated with the advent of three things: air-conditioning, energy conservation, and indoor air quality.

During the design of the new high school in Red Wing, Minn., in the 1990s, ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) standards were in the process of changing. Engineers at Armstrong, Torseth, Skold & Rydeen Inc. (ATS & R) needed to be innovative in designing an efficient and economical heating, ventilating, and air-conditioning (HVAC) system with improved IAQ. Life-cycle costing, value engineering, and energy conservation studies resulted in considerable cost benefits to the school district:

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* Rebates totaled $203,000 from the local utility company.

* An annual energy savings tallied $120,000.

* Preconditioning outside air during the heating season reduced the original design boiler capacity requirements by 400 Boiler Horse Power and produced a first-cost savings of more than $500,000.

* Eliminating the need to install heating coils in the air-handling units resulted in an additional first-cost avoidance of $100,000.

* The size of chilled and hot water reduced piping for more first-cost savings.

Mechanical equipment was located close to acoustically critical spaces, such as the media center, classrooms, band, choir, orchestra hall, and auditorium. ATS & R engineers worked with a fan manfacturer and the company's acoustical consultant Steve Kvernstoen to achieve the desired NC (noise criteria) levels. The HVAC system uses a mixed-flow fan design, which reduces airside noise by 20 decibels in the first two octave bands compared to conventional centrifugal fans. The mixed-flow fans and the round ductwork allowed the school to eliminate almost all attenuators and achieve desired acoustical goals.

When a building is initially opened, systems operate as designed. As time goes by, systems gradually function less effectively and efficiently. Unfortunately, some school districts assume their systems will function forever. Not Red Wing. In Red Wing's case, older is better. According to the school district, energy costs are only 95 cents per square foot 10 years later (less than schools that are not even equipped with air conditioning). After several years of operation, a new IAQ management plan was adopted to create an environment that is as healthy as possible. HVAC systems maintenance became much more aggressive and frequent.

All air filters in the district were changed from low- to medium-efficiency, or to high-efficiency particulate air (HEPA) filters (none of which use fiberglass) based on equipment capabilities. Pre-filters are used to extend the life of the particulate air (HEPA) filters. The IAQ plan encompasses regulations pertaining to cleaning supplies and air fresheners (not allowed unless supplied by custodial staff) and plants and animals in the classroom (requires permission). In recent years, heating needs for most of the heating season have been met by converting and only using one otherwise unused portable hot water heater without using the boilers.

Systems continue to become more sophisticated. Additional spaces require air-conditioning, energy conservation, IAQ and classroom acoustics. Positive air displacement systems were used for ventilation upgrade projects in existing classrooms in Minnesota's Anoka-Hennepin school district. ATS & R worked with Trox USA to achieve the acoustics standard and increase IAQ and thermal comfort. As indicated in Figure 1, the positive air displacement terminal allows the outside air to be mixed with room air, which is further conditioned if required and directed into the room at floor level and at low velocity. As a replacement to classroom unit ventilators, this system reduces equipment noise levels in the room while meeting IAQ standards and recovering energy. The benefits are threefold: the system is energy efficient and cost effective, provides a high degree of comfort, and is less disruptive to classroom activities.

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As school districts upgrade their HVAC systems with sophisticated energy saving and improved air quality equipment, the staff needs instruction on proper operations and maintenance. Many school staff personnel have not worked with energy management and energy recovery systems. Even after initial training, some staff members eventually ignore proper procedures, which can lead to equipment problems.

Building commissioning is a relatively new concept that is a very important step after the construction of a new building. It is the systematic process of ensuring that a building's complex array of systems is designed, installed, and tested to perform according to the design intent and the building owner's operational needs. ATS & R is also recommending re-commissioning the system on a five-year cycle to make sure the systems are still operating correctly and provide the energy savings as designed.