When your client asks you how he or she should classify the new laboratory space they are designing, how do you answer? Beyond the broad brush of wet chemistry, dry physics and electronics, or biology, is there more criteria available to identify the lab type?

Fortunately, there is. For biology, microbiology, and life science laboratories, the most common reference utilized for operational classification is the publication Biosafety in Microbiological and Biomedical Laboratories1 (BMBL), 5th Edition. The BMBL describes the protocols, physical attributes, and safety measures for laboratories in an increasing order of criticality from Biological Safety Level 1 to Biological Safety Level 4. This classification is short-handed to BSL-1, BSL-2, BSL-3 and BSL-42.

For the laboratory planner or design engineer, the essential elements necessary for achieving safety in the laboratory are additive. That is, a BSL-2 laboratory must have all the criteria of a BSL-2, and so forth. It is also important to remember that as the BSL level increases, so does the cost and complexity. All levels must have common microbiological practices in place, and these administrative or procedural controls are backed up by engineered controls such as access limitations, air filtration, and other facility requirements.
Almost any space that is identified as “lab” can qualify as a BSL-1 lab. There are, in fact, no special requirements for a BSL-1 laboratory, other than good planning and common sense. Doors are required to limited access. A hand sink is required for hand washing. Floors and walls should be cleanable. Laboratory furniture and especially laboratory counter tops should be impervious to water and be able to be decontaminated3.

A BSL-2 laboratory must have all the requirements of a BSL-1 laboratory, plus significant special practices and substantial safety equipment and personal protective equipment. This may include Biological Safety Cabinets (BSC’s), chemical fume hoods, or other forms of primary containment as well as laboratory coats, safety goggles, and gloves. Doors must be self-locking, and an emergency eyewash station must be readily available.

The special systems and engineering and design features required for a BSL-3 laboratory are significantly more complex and sophisticated than for a BSL-2 laboratory. The major difference is that there must be a method of decontaminating all laboratory waste produced in the laboratory. This may be an autoclave, chemical disinfection, or other validated decontamination methodology.

A BLS-4 laboratory is one of the most complex buildings in use for modern research. There are a limited number of BSL-4 facilities in the U.S., most are owned and operated by the U.S. government, and all are highly regulated and controlled. In the movie “Outbreak” starring Dustin Hoffman, there is a depiction of a BSL-4 laboratory with all of the people in the laboratory wearing completely enclosed plastic suits with separate breathing air lines attached.

DBR Engineering Consultants have the technical expertise and experience to help our clients design and build state of the art laboratories. If you have any questions or need any guidance on lab types or systems design approaches, please contact K. Dan Milgrim, Director of Science and Technology at email hidden; JavaScript is required or (469) 992-4071. The DBR Science and Technology Team are ready to assist you with all your laboratory and healthcare needs.


  1. HHS Publication No. (CDC) 21-1112, Revised December, 2009. Published by the U. S. Department of Health and Human Services, Public Health Services, Centers for Disease Control and Prevention, and the National Institutes of Health. 5th Edition.
  2. There is also specific information and requirements for animal research facilities. The designations are similar in that these facilities are classified as ABSL-1, 2, 3, or 4.
  3. Section IV of the BMBL describes in detail the administrative, facility, and special engineering controls necessary to achieve the desired safety level.

by K. Dan Milgrim, PE

With more than 25 years of experience in design and construction management for medical, pharmaceutical, and laboratory environments, Dan Milgrim, PE, Director of Science & Technology, provides clarity and value expertise to advanced science and technology design teams. Dan completed his undergraduate degree in Mechanical Engineering from San Diego State University.