Choosing the Right Biological Safety Cabinet

Panelists from Our February 15th Webinar Outline Some Key Features to Consider When Purchasing a BSC.

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In February 2011, Lab Manager hosted a “Product Showcase” webinar, focused on the different features and uses of biological safety (or biosafety) cabinets (BSCs). The webinar featured a panel of six experts representing the American Biological Safety Association (ABSA) and some of the leading vendors in the field, who provided their perspectives on what users should consider when deciding which BSC is right for their labs and applications. This online event attracted a large international audience, with members from diverse industries, looking for an opportunity to interact with the panelists in real time and get their advice on the key factors they should consider when making their buying decisions. Each panelist gave a brief presentation to outline the features and uses of BSCs and to help the users decide which one is right for them.

Below are answers to attendees’ follow-up questions, provided by the panelists. Webinar participants included:

Q: How do you determine which biosafety cabinet is right for you?

Byers: Laboratory managers should work with their safety professionals to identify the appropriate biosafety cabinet for the proposed work. This process should have been part of the risk assessment and risk management process that reviews the hazards associated with the proposed work and identifies the controls to minimize risk of exposure to biohazards.

Consideration should be given to the primary function of the biosafety cabinet. Was the biosafety cabinet selected for sterility, biosafety or a combination? What is the risk group of the proposed biohazard that will be handled in the biosafety cabinet? Will other laboratory hazards, such as volatile hazardous chemicals or radioactive materials be utilized? These are just some of the questions that should be asked to determine which biosafety cabinet is right for your lab. Refer to Appendix A: Primary Containment for Biohazards, Selection, Installation, and Use of Biological Safety Cabinets in the CDC-NIH Biosafety in Microbiological and Biomedical Laboratories (BMBL), available online at www.cdc. gov/biosafety/publications/bmbl5/.

Garrett: A BSC should first and foremost offer total safety. You should also consider reliability, productivity, energy savings and user comfort. Price is also important, but not as most of us think of it. The upfront cost of a unit may be attractive, but attention must be given to the operating costs of the unit.

Q: What are the most important factors to be considered when buying or upgrading a biosafety cabinet?

Garrett: The most important factors will be different depending on the customer’s conditions—it may be the size or the price of the unit (operating costs are of extreme importance). Factors could also include ergonomics, product/customer support, and materials of construction. Primary considerations should involve safety and preservation of samples. Secondary thoughts should focus on price and cost of the unit. Once narrowed down, focus on ergonomics, usability, customization and options.

Phillips: When replacing a cabinet, improve. Modern Class II BSCs have more stringent design requirements, so you will probably be safer. Look for a cabinet that compensates for the normal filter loading and alarms if the airflows change too much. If you were using external exhaust as in a canopy connected Type A2, B1 or B2, really review your need. External exhaust is expensive and can result in a cabinet that is more complex to operate safely. Look at energy efficiency and the total cost of ownership.

Q: What are some of the things a user needs to look into for routine maintenance and proper use of biosafety cabinets?

Byers: Certification is essential to ensure that the Class II cabinet is performing according to NSF/ANSI Standard #49-2009 and protecting both the worker and the sterility of the work. The certification testing should be conducted by well-qualified professionals when the biosafety cabinet is installed, annually, and whenever the biosafety cabinet is moved.

Phillips: The best resource is “Biosafety in Microbiological and Biomedical Laboratories (BMBL) 5th Edition” by the CDC and NIH. The BSC operating manual will help make you aware of special features on your cabinet. For routine maintenance, the most important thing is to get the Class II BSC field certified at least annually

Christensen: Many users rely on ultra-violet (UV) light to provide disinfection of the cabinet work area. Others may simply close the window of the cabinet, and put the cabinet into standby mode where the motor continues to run at a slower velocity to maintain the cleanliness of the work area. While these may be useful back up methods, the primary method of disinfecting a biosafety cabinet should be through a spray and wipe down of the cabinet interior with an isopropyl alcohol/water mix or another suitable disinfectant. The cabinet’s HEPA filters and air flows should be checked by an experienced independent certifier on a regular basis to ensure the integrity and safety of the cabinet.

Q: Any advice or recommendations for using disinfectants and burners in the biosafety cabinet?

Byers: The disinfectants used must have demonstrated effectiveness against the microorganisms that may be present in the samples manipulated, and must be used according to the directions on the label. Consult your safety professional to ensure that you have selected the appropriate disinfectant for the potential biohazards in your laboratory. Two common choices are 70% ethanol and 1:100 bleach solution. Appendix B: Decontamination and Disinfection, of the 5th Edition of the CDC/NIH BMBL provides excellent background information on this topic and should be consulted.

Garrett: Open flames are generally not recommended in BSCs, especially Class II units. The heat from the flame can cause turbulence in the laminar down flow, causing cross contamination, while the flame itself can cause physical damage to the cabinet and its filters.

Christensen: The use of Bunsen burners is generally not recommended, as the flame may disrupt the air flow in the work area. If a burner is used inside a cabinet, then a “demand type” burner would be the choice. This is a burner that is activated by a motion sensor or foot switch.

Q: How amenable are these cabinets to customization? Any requirements for more specialized applications and when working with animals inside the cabinet?

Christensen: Every BSC should be configured to meet the specific needs of the laboratory where it is to be used. The number and location of service valves, right or left hand side, use of a cord pass-thru for tubing and power cords, not to mention the appropriate type of cabinet control system are just a few of the basic considerations to keep in mind. If a Class II BSC is to be used for animal research, then an entirely different set of criteria need to be considered. The access opening needs to be set at 12” (30 cm) to facilitate the movement of cages in and out of the work area. The air barrier also needs to be maintained at 105 FPM to ensure Class II type product and personnel protection.

Guerrero: There is a wide variety of customization available with BSCs. However, anything that affects the airflow through the sash opening such as changing the height of the opening can void the NSF listing. Introducing various types of instrumentation is a trend these days for BSCs. The manufacturer should do its own microbiological testing to prove that the modification does not alter the protection classification of the unit. The basic modifications for animal research work are adding a pre-filter in the work area to capture gross hair and dander and preserve the life of the HEPA filter. Larger sash openings to accommodate larger rodent cages are also typical.

Q: Are there any differences that should be considered when a biosafety cabinet is used in a clinical versus a non-clinical setting?

Garrett: Most clinical labs’ BSCs are recommended or required to undergo certification every six months opposed to annual certification in non-clinical labs. Historically, when BSCs are in use, their airflows change with the loading of HEPA filters. In clinical settings, where patient samples are being processed, there is always a risk of human disease contamination, so there was added emphasis on making sure the BSC was always operating safely. Current BSC technology has allowed for precise airflow control that automatically maintains safe working conditions no matter the load condition of the HEPA filters.

Q: What are some of the improvisations that users are demanding and that companies are now working on?

Byers: Ergonomic features (due to the long periods of time BSCs may be used) are frequently requested by users. The ability to house larger pieces of equipment, such as cell sorters, within biosafety cabinets is also increasing in demand. Finally, customization of BSCs for use in high-risk animal research experiments is another increasingly common request among end-users.

Garrett: Laboratories are energy hogs; many new facilities are trying to find ways to lower operational costs. BSCs are becoming more energy efficient and more suitable for modern scientific needs.

Guerrero: Reduced sound levels, reduced vibration for imaging, improvement on operational costs, and improvements that provide increased productivity are some of the types of improvements that users are demanding.

Q: How can users keep up with new safety requirements and regulations for biosafety cabinets?

Byers: Biosafety cabinet certifiers are an excellent resource for updates of ANSI NSF49 certification requirements. More information regarding the NSF/ ANSI Standard #49-2009 may be found at the following website: www.nsf.org/business/biosafety_accreditation/ standards.asp?program=BiosafetyCabCert

Christensen: Users can keep up with new safety requirements and regulations by visiting the CDC and NIH websites, to download a copy of the current BMBL or websites for organizations such as the WHO (World Health Organization), ABSA, and CETA. A recognized biosafety professional is also a good source of information. Useful information is also available on the websites of biosafety cabinet manufacturers.

To read the full Q&A with the presenters, please visit
www.labmanager.com/bsc-panelists

To view the archived webinar, please visit www.labmanager.com/bscshowcase. The website also hosts a number of biosafety cabinet-related articles, application notes and information on upcoming events and webinars.

A List of Useful Links Related to Biosafety Cabinets

  • www.cdc.gov/od/ohs
  • www.absa.org
  • www.absa-canada.org
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Anyone Using a Biosafety Cabinet Should be Trained in at Least the Following:

  • The rationale for why the biosafety cabinet has been selected (sterility, biosafety, or a combination). This would include the risk assessment process that led to its selection for use.
  • Aseptic technique and good microbiological work practices
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Categories: Laboratory Technology

Published In

Laboratory Etiquette Magazine Issue Cover
Laboratory Etiquette

Published: May 9, 2011

Cover Story

Laboratory Etiquette

Many lab managers still remember them from their student days—a handful of hastily stapled printouts sternly titled “Laboratory etiquette—Acceptable standards of conduct.” Those were rules to live by, and the smallest violation landed a budding laboratory scientist in front of the ticked-off chief instructor.