Skip to main content

Safety Blog

Science/STEM Laboratory Occupancy Load Level: It Is the Law

By Ken Roy

Posted on 2021-10-01

I. Science/STEM Labs Can Be Unsafe Places

It is a well-known fact and expectation that students need to do science and STEM (science, technology, engineering, and math), not just read about them! The philosophy of hands-on, inquiry, and process-based science/STEM education continues to influence curriculum development and school building/renovation projects. Another factor has been the COVID-19 pandemic and the need for social distancing within the laboratory, with a recommended three- to six-feet distance between occupants per the Centers for Disease Control and Prevention (CDC) and other health- and safety-related sources. 

These factors are challenging science/STEM teachers, science leadership, and school administrators relative to the required laboratory occupancy load factors. Meeting occupancy load standards helps to secure and maintain a safer teaching/learning environment. Unfortunately, the controversial issue of science/STEM lab overcrowding is now both a health and a safety issue, given the biological, chemical, and physical hazards and resulting potential risks. 

Many building and central office administrators don’t seem to have an understanding or awareness of the health and safety issues related to science/STEM laboratories. In fact, in some cases, they are simply unwilling, for one reason or another, to take the appropriate steps to address the issue. Some think occupancy load requirements are only optional or voluntary, when in fact they are legal safety standard requirements (e.g., International Building Code [IBC], etc.) or better professional safety practices (e.g., NSTA, National Science Education Leadership Association [NSELA], etc.). This presents not only the potential for an unsafe instructional space, but also potential legal jeopardy for both the teacher and administration.

II. Accommodating Science/STEM Lab Occupants

NFPA-45 (National Fire Protection Association, Standard on Fire Protection for Laboratories Using Chemicals [NFPA-45 2019]) defines a laboratory as “an enclosed space used for experiments or tests.” The NFPA bases its standard on classification of a building. Educational facilities with science laboratories have an occupancy load classification as follows:

  •     Classrooms—one person per 20 net square feet (sq. ft.) (1.9 net square meters [sq. m.]);
  •     Shops, laboratories, and similar vocational rooms—one person for each 50 net sq. ft. (4.6 net sq. m.).

The Occupational Safety and Health Administration’s (OSHA) Occupational Exposure to Hazardous Chemicals in Laboratories standard (29 CFR 1910.1450), referred to as the Laboratory Standard, covers laboratories where chemical manipulation generally involves small amounts of a limited variety of chemicals. Most, if not all, secondary science laboratories are usually classified under these and/or other appropriate safety standards. Science educators must remember not to confuse the term “science laboratory” with that of a “science classroom.” A science classroom is for lecture/discussion, the talking about science. The laboratory is about doing the science. This is where the safety standards are most applicable.

Academic K–12 science/STEM laboratories have occupancy loads, which are defined by NFPA (NFPA 101 Life Safety Code, National Fire Protection Association 2021) as “The total number of persons that might occupy a building or portion thereof at any one time.” The IBC defines Occupant Load as follows: “The number of persons for which the means of egress of a building or portion thereof is designed.” In most states, these standards are adopted by state legislatures and become law. Additional legal and quasi-professional occupancy standards have been established by state legislatures, state education departments, and professional organizations such as NSTA and NSELA.

III. What Does Class Size Have to Do With Occupancy Load?

To maintain a safe working environment in a science laboratory at the middle or high school level, the science/STEM laboratory must be analyzed on the basis of determining the design load for safer exiting capacity.  

Factors such as type of furniture, utilities, chemicals, sprinkler system, and number of exits are considered in determining the occupancy load level. The bottom line is that the laboratory needs to be as safe a place as possible for students and teachers to work. Should an accident happen, there must be an effective means for all occupants to safely evacuate the laboratory. A laboratory class size higher than the design load does not meet the standard. Therefore, such a situation would be considered a potentially unsafe working environment for students and teachers. Class size is the maximum number of students allowed in the lab site. Occupancy load is the maximum number of occupants (students, teachers, paras, volunteers, etc.) allowed in the lab site. 

For example, a 1,250-sq. ft. net laboratory having a class size of 24 students and one teacher meets the standard if the design load of the laboratory is 50 sq. ft. net/occupant. On the other hand, the same laboratory with 30 occupants would have a greater density, and therefore could prove to be an unsafe working environment.

An employer such as a school board or superintendent can formally request modification of the 50 sq. ft. net/occupant as an occupant load level by proposing alterations in furniture floor plans, adding sprinkler systems, installing an additional exit door to the laboratory, and/or changing other factors. These factors tend to improve the safety level of the laboratory as a work environment. However, the request for modification must be approved by the “authority having jurisdiction”; i.e., town fire marshal, state fire marshal, or state safety officer.  

IV. How Can Teachers Meet the Challenge?

Science/STEM teachers and school leadership must be knowledgeable about legal and professional codes/standards for a safer teaching/learning environment. They also need to help advocate for the enforcement of these critical laboratory standards. The following are recommendations for new science or STEM lab construction or renovations:

1.    Review NFPA and other relevant building codes for educational institutions (science and/or STEM laboratories). Depending on the facilities’ town and state, additional or alternative codes may be applicable and therefore should be researched.

2.    Consult with the local and/or state fire marshal (authorities of local jurisdiction), building inspector, or safety officer for applicable codes/standards;

3.    Be active and involved in writing education specifications for facilities in efforts to meet occupancy load design expectations; and

4.    Help educate administrators, board of education members, architects, and others associated with decision-making power in efforts to better meet or exceed codes/standards for a safer working laboratory environment.

V. Final Words

The legal system does not look favorably on professionally licensed science teachers or school administrators who were aware of an unsafe laboratory working environment: For example, in the case of a lab with an occupancy load that was surpassed, the administration didn’t attempt to effect any change, and there was a safety incident. Recklessness and liability can be very costly for all involved! Safer laboratory teaching/learning activities take knowledge, planning, commitment, and cooperative initiatives with the school’s administration/board of education.

Submit questions regarding safety to Ken Roy at Follow Ken Roy on Twitter: @drroysafersci.

Administration Biology Chemistry General Science Life Science Physical Science Physics Safety STEM Middle School High School

Asset 2