For dedicated, stand-alone science classrooms for elementary (K-5) schools, the recommended minimum is 40 square feet per student; for middle (6-8) and high schools, the recommended minimum for a combined lab/classroom is 60 square feet per student.
Number of students: Research indicates that 24 students is about the maximum number that can safely be supervised in a science lab/classroom. As class size increases beyond 24 students, the “mishap” rate increases dramatically. Thus, for a dedicated elementary science space, the appropriate minimum size is 960 square feet; and for middle and high school combined lab/classrooms, the appropriate minimum size is 1,440 square feet. Space for storage and prep rooms is in addition to these minimums.
Means of egress: All science lab/classrooms should have two means of egress, although some building codes may require only one. One means of egress should be an out-swinging door which leads directly to a fire-rated corridor; the second means of egress should be a second door, located at least one-half the diagonal dimension of the lab/classroom away from the first door, leading either directly outdoors (at ground level) or to a fire-rated corridor leading directly to the outdoors. In some locales, operable windows may legally serve as a second means of egress; practically speaking, a second, remote door provides the safest response to an emergency within the room.
Ventilation: Science facilities require increased ventilation beyond that required for typical classroom space. Unpleasant odors and/or dangerous fumes may result from demonstrations or investigations or from the storage of chemicals and materials or from the presence of live animals. Allowing these odors and fumes to circulate freely within the central ventilation system of a school is unsafe. ANSI and NFPA national standards require that chemical vapors originating from laboratory operations not be recirculated. A separate ventilation system for the science teaching spaces should, therefore, be provided. This system should increase the amount of fresh air introduced to the space above that required for classrooms (a minimum of six air changes per hour should be provided). Spaces in which chemicals are stored should have separate systems venting directly outdoors, away from fresh air intakes. A ventilation grille at the floor line as well as one at or near the ceiling should be provided in such spaces. Fume hoods should not be used for general ventilation as they are not designed for whole room ventilation and consume large amounts of energy.
Safety equipment: School science facilities should be equipped first to prevent and secondly to deal with a variety of potentially harmful incidents. Students should be provided with lab aprons or lab coats as appropriate to the discipline being taught. Safety goggles, not glasses, designed to prevent infiltration of flying objects or liquids completely around the perimeter of the goggles should be provided in a storage case that sanitizes the goggles between uses. Sufficient sinks for handwashing, with hot and cold water and soap dispenser and towels, should be provided to enable an entire class to clean up quickly.