Dear Martin, A book,
Guidelines for Laboratory Design: Heatlh, Safety, and Environmental Considerations, 4th Ed., Chapter 1, Section 2, has an explanation of a process to set safe and reasonable occupancy standards that make sense for specific research (or teaching) work done in the laboratories for institutions, corporations, and agencies.. Please read that for some guidance for what will be right for Drexel U. In the Guidelines book (Ch 1.2), there is a table of net area per full-time lab occupant (for higher-ed academic institutions) to guide you in your deliberations.
The research group has 40 members. Are the majority of them undergraduate students who may work a limited number of hours each week? How many of the 40 are truly full-time laboratory workers? How does the PI organize the research activities? How well does the physical facility of 900 nsf safely and efficiently accommodate this work and range of activities? These are a few of the factors you may want to consider in developing your own space standards.
Janet Baum, AIA
Co-author, Guidelines for Laboratory Design, 4th Ed.
Washington University in St. Louis