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First verified BSL-3 autopsy lab in the U.S. Image: McClaren, Wilson & Lawrie Inc.

The San Francisco Office of the Chief Medical Examiner (OCME) is an essential forensic medical complex with autopsy suite and field investigation facilities required to operate after an earthquake event.

There are four levels of biosafety, from BSL-1, which work with well-characterized agents causing disease in healthy humans and rarely a potential hazard to lab personnel and or the environment, to BSL-4, involving work with dangerous and exotic agents which can cause fatal aerosol-transmitted lab infections and diseases. Further classifications are prescribed by the Center for Disease Control (CDC) for each of the four BSLs (ABSL-1 to 4) when dealing with animals.

The OCME facility contains a BSL-3 suite, which is normally suited for clinical, diagnostic, teaching, research or production facilities working with indigenous or exotic agents that may cause serious or potentially lethal diseases as a result of exposure by inhalation.

Medical examiners perform unique and intriguing science. Their labs must perform in a unique manner, protecting both the working staff and the evidence examined in the form of the human body. Adding further complications to the lab designs and performance are the cases which enter the facilities contaminated with BSL-3 pathogens, such as tuberculosis and meningitis. These level-three pathogens are more common and may cause death, but are curable if treated.

Currently, there are no formal written BSL-3 guidelines for designing higher-containment autopsy labs. Challenges posed to medical examiners when performing high-containment cases begin with the sheer size of the decedent to be autopsied. The human body doesn’t fit inside the typical first line of primary containment, the biological safety cabinet (BSC). In human or public health BSL-3 work, the BSC is the primary containment environment with its built-in HEPA filtration with inward directional


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Chilled water and heating hot water produced concurrently using a unique heat pump chiller. Image: Gurdaver Singh, PE, LEED AP, Guttmann & Blaevoet Consulting Engineers

airflow. Other design features that assist the doctors and their staff in conducting BSL-3 work are as follows:

  • Separate biovestibules for decedents and staff with high concentrations of decontamination materials possible within the decedent vestibule and shower out sequence for staff.
  • Ports for introducing decontamination materials into each possible contaminated room.
  • Method for decontamination of all liquids leaving the suite.
  • Method for decontamination of solid materials leaving the suite.
  • Method of passing decontaminated containers from the BSL-3 out for additional testing by others.
  • A BSC within the suite to review small specimens under added ventilation protection.
  • Materials within the suite that can tolerate chemical decontamination and cleaning.
  • Visual observation safely from outside the suite.

Guidelines (BSL-3 Aut) have been prepared for this type of facility, which are expected to be published in the American Society for Microbiology 3rd Edition. The guidelines provide a solid understanding and resolution of the challenges posed to medical examiners when performing high-containment cases and how their labs assist them in their daily search for the truth.

In addition to the complexities and hazardous nature of the facility, the project is being designed to meet one of the most stringent energy codes in the U.S., the California Energy Code 2013. The facility will also be designed to achieve LEED Gold certification.

The chilled water and heating hot water is produced using a heat pump chiller. The office area is served via a variable refrigerant flow (VRF) system, which can exchange heating and cooling energy between spaces before using any compressor energy. The air from the offices is transferred into the lab area for make-up air when needed by the fume hoods. The general exhaust from the lab goes through an energy-recovery device before exiting via the manifolded exhaust system.

Gurdaver Singh brings over 25 years of experience as principal engineer in mechanical and electrical design for building services in healthcare, higher education, defense and civic/public projects. He’s a proponent of sustainable design with a strong track record of delivering high-performance, low- to net-zero-energy buildings. Russell McElroy, AIA, NCARB, has over 20 years of diversified experience as an architect focused on designing labs and medical examiner facilities. He is responsible for leading MWL Architect’s lab design division.