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Preventing Overcrowding in K–12 Science Labs

By Kenneth Roy

Posted on 2016-08-23

Of all the safety concerns expressed by science teachers, class size is high on the list. Thus, occupancy loads in science laboratories should be restricted to create and maintain a safer learning environment.

Ever since the 1996 National Science Education Standards were put in place, science teachers have been encouraged or required to do more laboratory activities with their students. If such hazards as gas, electricity, and hazardous chemicals are present in K–12 science instructional spaces, they are classified as laboratories. The class size refers to the number of students in the lab, whereas occupancy load is the total number of individuals occupying the lab, including the teacher, students, and paraprofessionals.

Better professional practices for occupancy loads have been established by the National Science Teachers Association (see Resource). Generally, K–12 science laboratories require 50 square feet of space per occupant. To maintain a safer learning environment and to determine a safe exiting capacity, science laboratories must be analyzed, either by reading the school’s building plans or with help from the local or state fire marshal. Factors such as type of laboratory furniture, utilities, hazardous chemicals, sprinkler systems, and number of exits are considered in determining the occupancy load. This information usually can be found on the originally approved architectural plans for the science laboratory. If the plans are not available, science teachers must work with administrators and the local or state fire marshal to establish the appropriate occupancy load and to correct any code violation resulting from overcrowding.

Final thoughts

Occupancy loads for labs are both legal standards and a better professional practice, not recommended or suggested as some might believe. As licensed professionals, science teachers are held to a higher expectation by the legal system, as far as adhering to safety in the laboratory and classroom. Science teachers need to work with administrators to improve laboratory safety by having the appropriate occupancy load in place. Negligence and liability are legal issues that could arise from a laboratory accident that occurred while exceeding the occupancy load.

Be proactive by bringing your safety concerns to the attention of administrators in writing, and be supportive by working with them to create a safer working environment.

Submit questions regarding safety in K–12 to Ken Roy at,  or leave him a comment below. Follow him on Twitter: @drroysafersci.


NSTA: Overcrowding in the Instructional Space—

NSTA resources and safety issue papers


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