Appendix A – Primary Containment for Biohazards

Appendix A:  Primary Containment for Biohazards:  Selection, Installation and Use of Biological Safety Cabinets

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11 Comments

  1. Anonymous's Gravatar Anonymous
    May 13, 2016    

    Please clarify BMBL guidance on thimble connections of BSCs. The exhaust airflow required for thimble vs. free-standing is significantly different, and presents a real economic burden to facilities when we maintain high airflows on nights and weekends. While we admit it is never required, phrases like “proper method of connecting” turn a guidance into a requirement very quickly, with real economic and facilities burden for very little safety benefit. A growing number of facilities have computer controls which allow for night-time offsets, but we cannot achieve that energy-saving “green” standard when required to maintain high airflows for thimble-connected Class II A2 BSCs. Instead of having to seek a waiver for deviation from a “best practice” established by the BMBL, it would be very useful to have a consideration of energy requirements vs. safety needs, and guidance on how to balance those considerations.

  2. Sonia Godoy-Tundidor, PhD's Gravatar Sonia Godoy-Tundidor, PhD
    May 11, 2016    

    * Classification of Class II biosafety cabinets, pages 294 – 297: Could we please change the order as follows:
    1. II/A1
    2. II/A2
    3. II/B1
    4. II/B2
    Also, is it necessary to keep the references to the old nomenclature? I do not think a lot of people talk about “(NCI)-designed Type 212”, “Type B”, and “A/B3” BSCs other than BSC certifiers provided they are still in use.

    * Page 302: “Only horizontal pipette discard trays containing and appropriate chemical disinfectant should be used within the cabinet” – I am not sure this is the safest practice to discard disposable serological pipettes after use, since you would have to remove the disinfectant and reach for the pipettes afterwards to place them inside a biowaste box or sharps container. I have never seen anybody doing that when I was a researcher…

    * Development of Containment Standards, page 307: I think we should stick to the latest version of the NSF 49 Standard and delete the information about old standards if they are not used any longer.

    * Page 309: Please change “accredited field certifiers are used” to “accredited field certifiers be used”.

    * Table 2, Comparison of BSC Characteristics: Please change order of Class II to II/A1, II/A2, II/B1, II/B2. Also, please change “HELP filtered” to “HEPA filtered” under Class III BSCs.

    * Tables 3 (page 312) and 4 (page 313) for BSC tests: Please follow the same order as in Section “Performance Testing BSCs in the Field” (page 309).

  3. Jessica's Gravatar Jessica
    May 3, 2016    

    Requesting information on recommended controls for cryostats and microtomes. It would be very useful to discuss some of the more common laboratory procedures and the recommended controls. Also language encouraging the applicaton of audible alarms on any biosafety cabinets as well as the importance of calibration of externally exhausted Class II BII’s with their internal fans to prevent blowback.

  4. Maren Roush, NSF International's Gravatar Maren Roush, NSF International
    April 21, 2016    

    Recommend updating the first paragraph of current page 308 of the BMBL 5th edition to read:
    “NSF/ANSI Standard 49 – 2014 “Biosafety Cabinetry: Design, Construction, Performance and Field Certification” is the predominant global standard for BSCs and provides the minimum testing requirements for BSCs to be accepted in the United States. NSF/ANSI 49 establishes basic requirements for design, construction and performance of BSCs. Tests detailed in NSF/ANSI 49 ensure the BSC provides personnel, product and environmental protection; reliable operation; durability; cleanability; noise level and illumination control; vibration control; and electrical safety. NSF Certification of BSCs also includes annual audits of manufacturing facilities and requalification testing of models every five years to ensure compliance to the standard and the program policies.”

  5. Maren Roush, NSF International's Gravatar Maren Roush, NSF International
    April 21, 2016    

    1) Appendix A, Section I – Introduction, third paragraph, consider changing “Most BSCs use high efficiency particulate air (HEPA) filters…” to “Most BSCs use high efficiency particulate air (HEPA) or ultra-low penetrating air (ULPA) filters…”
    2) Appendix A, Section I – Introduction, sixth paragraph, replace “training” with “trained”. Also recommend revising the last sentence of this paragraph to “This process is referred to as field certification of the cabinet and should be performed at least annually.”
    3) Appendix A, Section III – Biological Safety Cabinets, The Class II BSC – recommend amending the last sentence of the second paragraph to avoid confusion. “Exhaust air from Types B1 and B2 BSCs is also HEPA-filtered for environmental protection, but must be discharged directly to the outdoors via a hard connection because the technology design relies on a remote exhaust fan.”
    4) Appendix A, Section III – Biological Safety Cabinets, The Class II BSC – fifth paragraph (numbered as 1.), recommend updating the units in this section and throughout the document from “lfm” to “ft/min” for consistency with NSF/ANSI Standard 49. Semantics, I know, but it might be helpful for users.
    5) Appendix A, Section III – Biological Safety Cabinets, The Class II BSC – eleventh paragraph (numbered as 2.), and throughout the document. NSF/ANSI 49 has, in recent revisions of the standard, moved away from defining % recirculated air vs. % of air passing through the exhaust filter for biosafety cabinets (with the exception of total exhaust type B2 BSCs, which exhaust 100%) because different engineering designs may result in higher or lower percentages of recirculation and still be equally effective at biocontainment.
    6) Appendix A, Section III – Biological Safety Cabinets, The Class II BSC – sixteenth paragraph (numbered as 3.). Depending on how many BSCs from prior to the 1980s are still being actively used, consider removing the section stating “Should the building exhaust system fail, the cabinet will be pressurized, resulting in a flow of air from the work area back to the laboratory…” NSF/ANSI 49 requires that internal cabinet fans be interlocked to shut off at the same time alarms indicating a 20% loss of exhaust volume are activated. In addition, the standard states that type B cabinets shall not initiate cabinet blower startup until sensors determine appropriate exhaust flow.
    7) Appendix A, Section VII – Certification of BSCs, Development of Containment Standands – second paragraph. Note that what is currently termed a “Type A1” in NSF/ANSI 49 is not the same as what was termed a “Type A1” in past iterations of the standard. Namely, positive pressure plenums are no longer permitted under the standard for any type of BSC, unless they are surrounded by negative pressure plenums.
    8) Appendix A, Section VII – Certification of BSCs, Development of Containment Standards – third paragraph, and throughout. The 2014 version of NSF/ANSI 49 is the current version (current BMBL references the 2007 version).
    9) Appendix A, Section VII – Certification of BSCs, Development of Containment Standards – eighth paragraph, suggest changing “companies qualified” to “field certifiers qualified”, since NSF Accreditation is tied to individuals’ training, experience, and test results and is not granted at the company level. In the next paragraph, recommend changing the first sentence to “It is strongly recommended that, whenever possible, NSF Accredited field certifiers are used to test and certify BSCs…”
    10) Appendix A, Section VII – Certification of BSCs, Development of Containment Standards – last paragraph. Suggest expanding the last sentence of this paragraph to explain how annual certification procedures keep BSCs functioning properly. May want to say “BSCs consistently perform well when proper annual field certification procedures are followed. Cabinet or filter failures occur infrequently. However, because filters used in BSCs are highly effective, they will load over time (typically over the course of many years, depending on the quality of the room air and the type of work being performed inside the BSC. The downward/inward airflow balance will need to be adjusted periodically to return the airflow velocities to the manufacturers’ recommend nominal set points, which were also tested and verified by NSF International as part of the type test / NSF Certification.”
    11) Current page 308 of BMBL 5th edition: NSF’s fax number is incorrect. It should read 734-769-0109. There is also a toll-free number: 1-800-NSF-MARK (1-800-673-6275)
    12) Appendix A, Section VII – Performance Testing BSCs in the Field – A. Recommend changing to “Downflow Velocity Profile Test: This test is performed to measure the velocity of air moving vertically through the cabinet workspace to ensure the overall average is within 5 fpm (0.025 m/s) of the nominal set point and to verify that no individual velocity readings vary more than +/-25% or 16 fpm (0.08 m/s) from the overall average.”
    13) Appendix A, Section VII – Performance Testing BSCs in the Field – B. Recommend changing to “Inflow Velocity Test: This test is performed to measure inward airflow velocity through the work access opening of the BSC. The primary method for determining inflow velocity is through the direct airflow measurement method. This is also the most accurate means of determining inflow velocity. Alternate, secondary methods may be used to calculate the inflow velocity if those methods were reviewed and approved by the test organization during Certification testing of the model BSC to NSF/ANSI 49.”
    14) Appendix A, Section VII – Performance Testing BSCs in the Field – E. Recommend clarifying that the cabinet integrity test is required only for the “old” type of A1 BSCs that allowed positive pressure plenums along the exterior edge of the BSC. NSF/ANSI 49 no longer allows for any type of BSC to have positive pressure plenums unless they are surrounded by negative pressure plenums.
    15) Appendix A, Section VII – Performance Testing BSCs in the Field – F. It is my personal opinion that the electrical tests that used to be part of Annex F of NSF/ANSI 49 were removed from the standard in error when Annex A of the standard was updated to require UL 61010-1 electrical certification for type tests of BSC models. I believe there is benefit to having field certifiers perform some simple electrical safety checks during field certification, for example checking the polarity of the electrical outlets and testing the ground fault circuit interrupter. I am working with the NSF Standard 49 Joint Committee to see if those field tests can be added back into the standard.
    16) Appendix A, Section VII – Performance Testing BSCs in the Field – J. Verification of the UV lamp is not part of NSF/ANSI 49 (clarification).
    17) Appendix A, Section VII – Performance Testing BSCs in the Field. Recommend adding a letter K for Site Installation Tests required by NSF/ANSI 49 for field certification of BSCs. Of particular importance are the verification of sash alarms and exhaust alarms. Note that exhaust alarms for type B BSCs are verified by reducing the exhaust volume by 20%, whereas the exhaust alarms for canopy-connected type A BSCs are verified by reducing the exhaust volume until there is a loss of capture of the visible medium (no percentage volume reduction is specified).

    Many, many thanks for the opportunity to comment.

    Kind regards,
    Maren Roush
    Business Unit Manager, Biosafety Cabinetry
    NSF International

  6. Pat Godwin's Gravatar Pat Godwin
    April 20, 2016    

    The paragraph on UV lamps in BSC’s may need to be revisited. There is conflicting information between the BMBL and other data concerning the use of UV lamps for decontamination. It is also unlikely that lamps need to be checked weekly, particularly with LED’s.

  7. Jessica McCormick-Ell's Gravatar Jessica McCormick-Ell
    April 19, 2016    

    It would be helpful for the BMBL to take a stance on the use of bunsen burners in cabinets. We have had issues with poor tubing, fires, and people wanting to use the small “safer” models. Alternatives to bunsen burners would be great to mention in this section. There is limited data/ regulatory guidance available except from the BSC manufacturer’s and they discourage them. As a biosafety professional, i can list the risks of their use in the cabinet, but i dont have the ability to prohibit them.

  8. Richard W. Gilpin's Gravatar Richard W. Gilpin
    April 11, 2016    

    Figure 12. Diagram incorrect. Tube below liquid in flask A will cause inoperability. Tube should extend below side-arm, but not further. Flask B should have an air stone attached to the bottom of the tube extending into the fluid.
    As Chair of the NSF International task group revising Annex E of the NSF/ANSI Standard 49, I recommend that the BMBL follow descriptions and diagrams of revised Annex E that will be published online by NSF International this year.

  9. Julie Johnson's Gravatar Julie Johnson
    April 8, 2016    

    I second the comment that the risks of working with >1 person in a BSC at a time and best practice recommendations for if/how this may be done safely needs to be addressed in this section.

  10. Peter Coffey's Gravatar Peter Coffey
    April 8, 2016    

    Appendix A: Facility and Engineering Requirements of the BMBL, Section V (BSC Use by the Investigator: Work Practices and Procedures), describes “Operations within a Class ll BSC.” Specifically, it describes on page 322 “one procedure” for connecting aspiration bottles or suction flasks to building vacuum supply. We propose that this section needs to be updated.

    The procedure described, and illustrated in Figure 12, continues to be satisfactory, but many science buildings are currently being built without central vacuum supply – in part, at least, because of the concerns about contamination of building-wide vacuum lines. For such facilities, local vacuum supply at the BSC is needed, and several companies offer devices for point-source aspiration systems containing integrated vacuum supply. Many users and BioSafety Officers (BSOs) interpret the currently described procedure as the only appropriate procedure. Many BSOs, in our experience, are reluctant to adopt modern technology designed specifically to address the need for safe aspiration in a building without central vacuum supply in the absence of a BMBL statement that the objective is to ensure safety, not just replicate traditional practice, and that new technology might accomplish that safety objective in new ways.

    For example, the integrated fluid aspiration system offered by VACUUBRAND combines a small vacuum pump, shatter-proof receiving flask, level sensor, and 0.2 micron hydrophobic filter to contain bio-aerosols. This device addresses aspiration biosafety issues in the following ways:
    1. The oil-free pump is completely lined with chemical resistant fluoropolymers, so it resists vapors from bleach used as a disinfectant.
    2. Service intervals are exceptionally long (15,000 operating hours, or many years in typical intermittent vacuum use applications), minimizing need for access to the system for service. Oil-free operation eliminates oil changes and the need to dispose of contaminated pump oil.
    3. The system includes a non-contact level sensor, to protect against overflow of the receiving flask, obviating the need for a second flask.
    4. The receiving flask is made of borosilicate glass that is bonded to safety material to avoid shattering, providing secondary containment without a reservoir. The glass flask is resistant to bleach, satisfying the need to provide a disinfectant in the receiving flask.
    5. The unit includes a pressure sensor, so that it operates on demand, remaining continuously available for aspiration, but on quiet, energy-conserving stand-by when not in active use.
    6. The system provides protective support for the receiving flask, to avoid tip-over risk.
    7. The unit includes a 0.2 micron hydrophobic biofilter to contain aerosols, protect the pump from contamination, and to act as a secondary protection against overflow.
    8. The BVC can be exhausted to HEPA filters, if necessary, to provide an additional level of protection (beyond the 0.2 micron disk filter) in BSL3/BSL4 applications.
    9. The unit has been independently tested for tolerance to H2O2 vapor decontamination.
    10. The entire unit is isolated from other building vacuum supply, eliminating the risk of transfer of biologicals to other labs via the vacuum lines, and protecting service workers from this path of potential exposure.

    This combination of features relies on modern technology to accomplish the safety objectives described in the current edition of the BMBL. We respectfully suggest that the next edition of the BMBL address the matter of aspiration devices for buildings without central vacuum supply in addition to the traditional focus on protection of the building vacuum system.

  11. Stacey Kraemer's Gravatar Stacey Kraemer
    April 7, 2016    

    I would recommend that consideration be made to include risks of working with >1 person in a BSC at a time and best practice recommendations for if/how this may be done safely.