Science Safety 
Dr. Kenneth Roy 
Table of Contents
How many students can I legally have in my STEAM instructional space?
Most educators and school building administrators are unaware of legal safety standards and better professional safety practices related to occupancy load in science or STEM instructional spaces. Science/STEM instructional spaces (e.g., science/STEM laboratories, classrooms, combination labs/classrooms, field sites, etc.) can create a real problem. This article will explore what you need to know in regard to the occupancy loads in science/STEM instructional spaces and the safer number of students allowed based on the square footage in your rooms.
This resource is an attempt to aggregate the necessary information and access to further analyses and implementation, as well as a road map for overcoming potentially ‘unsafe’ or ‘overcrowded’ occupancy sizes in science/STEM instructional spaces in your school(s). Please verify all information with your local and/or state fire marshal office, which has jurisdiction over the schools in your community.
Occupancy Load in School Instructional Spaces
Occupant load, by definition, is the total number of persons that might occupy a building or portion thereof (like a science/STEM lab, maker space, or classroom) at any one time. If too many people occupy a facility, the risk of injury and illness emergency increases dramatically. According to the National Fire Protection Association (NFPA), one means of addressing life safety involves calculating occupant loads in school buildings and their instructional spaces encompassing classrooms and laboratories. (NFPA 101 Life Safety)
Class Size & Calculating Space
Based on current research, a maximum class size of 24 students providing the legal occupancy load standard is met, which approximates 50 sq. ft. net/occupant in a lab and 60 sq. ft. net/occupant in a “C-lab” or combination lecture/laboratory. Local authorities determine the actual occupancy load (e.g., fire marshal) based on factors such as square footage, type of furniture, utilities, chemical hazards, energy sources, sprinkler system, and the number of exits.
Remember these important legal safety standards and better professional safety practices when calculating the square footage required in your science/STEM instructional space for occupancy load levels :
- 20 square feet net per occupant in a classroom* (NFPA 101 Life Safety Code — 2021)
- 50 square feet net per occupant in a traditional science laboratory (NFPA 101 Life Safety Code – 2021)
- 60 square feet net per occupant in a combination lecture/laboratory instructional site (NSTA Position Statement: Liability of Science Educators for Laboratory Safety)
Based on these equations, your laboratory must be a minimum of 1200 square feet net (with the deductions calculated for furniture and fixtures) and a minimum of 1440 square feet for a combination lecture/laboratory instructional site (C-Lab). These are MINIMUM area calculations, and students with additional needs, support workers, and exits will affect the overall calculation. Please use the NFPA occupancy load calculation metrics located here for each room in your science department.
Engineering Controls for Occupancy Load
*Most science classroom instructional spaces do NOT have laboratory facilities, furniture, master control switches, 1:1 air exchange systems, and other science equipment. Classifying a science lab instructional space as a ‘science classroom’ does not change the occupancy load when the room is used for conducting or performing science activities.*
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.” Academic K–12 science/STEM laboratories have occupancy loads. NFPA defines this (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.”
IBC Definition of Occupancy Load
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.
For educational science laboratories, the requirement is 50 square feet net per person or 4.6 square meters net per person minimum (NFPA 101 – 2021 – table 7.3.1.2 – Shops, laboratories, vocational rooms, pg. 101-83). Generally, a science classroom instructional space has an NFPA occupancy load limitation of 20 square feet net per person or 1.0 square meters. Both fire and building legal standards, like occupancy load codes, are designed to establish and maintain safer teaching/learning experiences in science/STEM instructional spaces.
The National Science Education Leadership Association or NSELA challenges science supervisors and curriculum directors to help meet legal aspects for formal academic science/STEM instructional spaces (primarily secondary levels) and appropriate instructional space equipment for science/STEM activities (primarily elementary level).
Duty of Care Required for Occupancy Load
We must address the “Duty or Standard of Care” required for each student by science/STEM teachers acting as a reasonable person to make instructional spaces safer. There is acknowledgment of the limitations of insurance in denying coverage for reckless and intentional acts by science/STEM educators. There is also the potential for individual liability for acts outside the course and scope of the employment. In addressing the occupancy safety issues, the items for consideration should include:
- The number of instructional space occupants makes a significant difference in traffic flow, trip/slip-fall hazards, and individual monitoring.
- Increasing the number of laboratory occupants in a science/STEM instructional space increases the likelihood of accidents.
- A higher pupil/teacher ratio over the 24-student maximum professional standard constitutes a threat to science/STEM instructional space safety based on current research.
- Exceeded occupancy loads challenge a teacher to safely handle, transport, and use hazardous instructional space chemicals and equipment, thereby creating an unsafe working environment.
- Occupancy load mismanagement can also increase classroom management issues, which in turn contribute to unsafe conditions.
Research and Potential Liability Regarding Occupancy Load
A 2020 national research study, Safer Engineering, and CTE Instruction: A National STEM Education Imperative, by Drs. Tyler Love and Kenneth Roy (Love and Roy 2022)—revealed serious safety issues related to PK–12 Technology/Engineering and STEM facilities and instructional practices. 57% of study participants indicated their largest class had 25 or more students enrolled. However, only 26% of participants indicated they had a facility large enough (greater than 1,250 square feet) to host 25 or more students.
This mismatch between enrollment and facility net square footage creates a potential legal and safety issue in the event of an emergency. This is extremely concerning, given that results from previous research studies found a significant increase in school lab accidents as square footage dropped below 60 square feet per occupant, and enrollments in lab-based courses increased to 24 students or more per one instructor (Stephenson et al. 2003; West and Kennedy 2014).
Although a facility may have enough square footage to allow for hosting more than 24 students and 1 teacher as occupants, better professional safety practices clearly advise against this. When a single instructor is tasked with supervising more than 24 students involved in science/STEM instructional spaces/maker space activities, there is a significantly greater chance of an accident occurring.
General Rules for Overcrowding & Occupancy Load
Based on the research findings, Love and Roy (2022) strongly recommended that school districts, administrators, district safety officers, school counselors, STEM educators, and CTE (career and technical education) teachers collaborate to closely reexamine their class occupancy load guidelines to ensure no more than 24 students per instructor are enrolled in science/STEM, maker space, or CTE lab-based classes.
How to Address Overcrowding Safety Concerns in Instructional Spaces
According to Dr. Ken Roy and Dr. Tyler Love, the following actions are recommended to assist science/STEM educators who have exceeded occupancy load and/or overcrowded instructional spaces (e.g., laboratories
Consider Stopping Hands-On Instruction
If you have more than 24 students in a science/STEM course and are the only instructor, or if you have more occupants than the net square footage allows (50 square feet per occupant minus any tables, equipment, or other objects that occupy floor space), you need to consider in earnest temporarily stopping any hands-on instructional space activities or demonstrations.
This is critical if you know or suspect after doing a potential safety hazard analysis and resulting health and safety risk assessment that these potentially unsafe activities do not meet legal safety standards and better professional safety practices. You are potentially not only putting yourself and your students at risk, but you also are potentially placing yourself and your administration in legal jeopardy should a safety incident occur.
Contact Appropriate Responsible Parties
Next, contact in writing the appropriate school system supervisor/administrator and/or other individual(s) responsible for safety (e.g., chemical hygiene officer or facilities safety officer, building administrator, curriculum director, school counselor). Explain your concerns about occupancy load and science/STEM instructional spaces relative to safely implementing the required curricular activities. Provide resources about occupancy load (e.g., NSTA Safety Blog post, Occupant Load Factor Table 7.3.1.2 from NFPA 101, NSTA’s Overcrowding in the Instructional Space white paper, the 2016 article by West, and the free 2022 research book by Love and Roy).
Contact Union Representative
If this approach is not effective in rectifying the health and safety science/STEM issues, contact your faculty union representative and get them involved. Schedule an additional meeting to discuss your concerns and the criteria for occupancy load described in the aforementioned resources (See Step 2 above).
Request Local Fire Marshal Participation
If the issue is still not addressed and resolved in Step 3, in writing, request that your school system have the local fire marshal come in and re-evaluate the room’s occupancy load and general fire safety regulations for science/STEM instructional spaces. You also might ask for an updated certificate of occupancy from the local fire marshal and/or building inspector.
Trust Your Instincts-Stay Safer
Repeat the previously mentioned steps as occupancy loads, course activities, and facility space change. Above all, if you believe it is unsafe because of the noted safety factors, do not carry out any instructional space hands-on activities. If you believe that someone is harassing you as a result of these inquiries and telling you to carry out these activities as required by the formal curriculum, then consider securing legal counsel and share your concerns. Remember that the science/STEM instructional space teacher is the one who is the safety specialist and has the major legal responsibility under duty or standard of care to make sure the instructional space is safer for teaching and learning activities.
Final Thoughts on STEAM Occupancy Load
There is evidence from recently published research that overcrowding in science/STEM instructional spaces (e.g., laboratories) is correlated with increased accidents and injuries, which is why establishing and adhering to a policy of no more than 24 people in a Science/STEM instructional space (e.g., laboratory) is the safer decision from a legal, evidence-based and liability perspective.
Teacher unions/federations with the OH&S departments in school systems should establish a firm policy surrounding the number of occupants allowed to be in science/STEM instructional spaces at any one time. Base this decision on legal standards from the NFPA and support from NSTA, NSELA, ITEEA, and other recognized professional associations working towards providing hands-on experiences for students in a safer manner within the walls of the science/STEM instructional spaces.
Do not underestimate the impact that using this occupancy load methodology will have on your risk management practices and reduction of safety hazards and resulting risks, thereby reducing shared liability in case of an accident. There is statistical evidence to limit science classes to 24 students or less based on adequate supervision and safety concerns. Staying safer in the science/STEM instructional space is a combined effort and the foundation of future innovation. Make safer choices and limit the number of people in your science/STEM instructional spaces.
References Used
- Love, T. S., and K. R. Roy. 2022. Safer engineering and CTE instruction: A national STEM education imperative. What the research tells us. International Technology and Engineering Educators Association.
- International Code Council (ICC). 2003. Section 15.1.7 and Table 1004.1.2 Occupant Load.
- Building Officials and Code Administrators (BOCA).
- National Fire Protection Association: Life Safety Code:101
- National Science Education Leadership Association Position Paper, NSELA Safety Position Statement Occupancy Loads in School Science/STEM Laboratories
- Duty or Standard of Care, National Science Teachers Association Safety Advisory Board White Paper
- Overcrowding in the Instructional Space, National Science Teachers Association Safety Advisory Board White Paper:
- Stroud, L., Roy, K. R., & Doyle, K. S. (2021). Science Laboratory Safety Manual (4th ed.). National Safety Consultants, LLC
- Science Safety Inc. Safety Resources
- Factors with the Greatest Impact on Safety in Pennsylvania’s T&E Courses: TEEAPJournal-Spring2021-Vol69-No1 (1)542021.pdf
- Stephenson, A. L., S. S. West, J. F. Westerlund, and N. C. Nelson. 2003. An analysis of incident/accident reports from the Texas secondary school science safety survey 2001. School Science and Mathematics 103 (6): 293–303.
- West, S. S. 2016. Overcrowding in K–12 STEM classrooms and labs. Technology and Engineering Teacher 76 (4): 38–39.
- West, S., and L. Kennedy. 2014. Science safety in secondary Texas schools: A longitudinal study. Proceedings of the 2014 Hawaiian International Conference on Education. Honolulu, HI.
EdCircuit Staff