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Biological Safety Cabinets: Open Flames and Flammable Gas Policy

Read UC San Diego's policy prohibiting open flames and flammable gases in biological safety cabinets.

Open flame burners are not allowed in biological safety cabinets (BSC). Prohibition of open flame is intended to prevent fires or explosion within BSCs and prevent workplace injuries and illnesses for all academic appointees, staff, students, and visitors.

BSCs currently plumbed with a gas line will have their gas lines removed or shut off by Facilities Managment (FM). Environment, Health & Safety (EH&S) will coordinate with FM and the lab to facilitate removal or shut off of gas lines. New BSC installations will not be connected to gas lines.

See alternatives to continuous flame devices below.

Alternatives to continuous flame Bunsen burners

Bacti-CineratorImage of Bacti-Cinerator
Uses infrared heat to incinerate organic material deep within the ceramic funnel.

Electric Bunsen BurnersImage of an electric Bunsen burner
Directs radiant heat up in one direction so user can heat items regardless of their shape.

Glass Bead SterilizerImage of Steri 250 Glass Bead Sterilizer
Glass beads in the well are maintained at 250°C for complete destruction of microorganisms and spores in seconds.

FIREBOY (gas cartridge) Safety Bunsen BurnerImage of FIREBOY Safety Bunsen Burner
Safety enhanced laboratory gas burner with "Touch Free" IR‐Sensor and button function.

Important: BSC Open Flame Exception form (PDF) must be submitted and approved for this type of burner.

ARGOS (gas cartridge) StarFire Bunsen BurnerImage of StarFire Bunsen Burner
Stainless steel body and compact size.

Important: BSC Open Flame Exception form (PDF) must be submitted and approved for this type of burner.

Alternatives to disinfecting instruments in a BSC

Choose instruments that do not need to be disinfected in a BSC:

  • Pre-sterilized inoculating loops and needles
  • A glass bead sterilizer
  • Pre-autoclaved forceps, scalpels, etc., in covered autoclavable plastic containers or the special sleeves manufactured for this use
    • Note: These items can be used individually in the BSC, then placed in an autoclavable discard tray located in the BSC for used or contaminated utensils.

Responsibilities of PIs and Facilities Management

Both PIs and Facilities Management personnel are responsible for implementing this policy, as follows:

Principal investigators

  • Do not request that house natural gas be connected and do not use natural gas that is already connected within BSCs.
  • Do not use other flammable gases in biological safety cabinets.

Facilities Management

  • Do not accept new projects and maintenance requests to add house natural gas to biological safety cabinets.
  • Disconnect natural gas lines to BSCs as they are discovered. When applicable, natural gas lines to BSCs will be physically disconnected and capped during laboratory renovation projects.

Questions? Contact the EH&S Research Assistance Program.

Exception request form

Exceptions to this policy must be approved by EH&S, the Campus Fire Marshal, and UCSD's Institutional Biosafety Committee.

To apply for an exception, principal investigators must submit a BSC Open Flame Exception form (PDF).


Primary reference

Appendix A – Primary Containment for Biohazards: Selection, Installation and Use of Biological Safety Cabinets (PDF), CDC (see p. 290)

Cited quotes from agencies and manufacturers supporting the "no open flames" in BSCs policy

National Institutes of Health and the Centers for Disease Control and Prevention (NIH/CDC)
“Open flames are not required in the near microbe-free environment of a biological safety cabinet. On an open bench, flaming the neck of a culture vessel will create an upward air current which prevents microorganisms from falling into the tube or flask. An open flame in a BSC, however, creates turbulence which disrupts the pattern of HEPA-filtered air supplied to the work surface.”
World Health Organization’s Laboratory Biosafety Manual (WHO)
Open flames should be avoided in the near microbe-free environment created inside the BSC. They disrupt the airflow patterns and can be dangerous when volatile, flammable substances are also used. To sterilize bacteriological loops, micro-burners or electric “furnaces” are available and are preferable to open flames.
Public Health Agency of Canada; Canadian Biosafety Handbook, Second Edition
The provision of natural gas to BSC’s is not recommended. Open flames in the BSC create turbulence, disrupt airflow patterns and can damage the HEPA filter. When suitable alternatives (e.g., disposable sterile loops, micro-incinerators) are not possible, touch-plate micro-burners that have a pilot light to provide a flame on demand may be used.
NSF/ANSI Standard 49 – 2009 published by NSF International, Annex G; Section G.3.3.1 (PDF)
Service valves allow inert gases, air, or vacuum lines to be plumbed into the BSC. Although many users connect gas to a service valve in the cabinet, this practice should be avoided because open flames in a Class II BSC disrupts the airflow, and there is the possibility of a buildup of flammable gas in BSC’s that recirculate their air.
The Baker Company (BSC manufacturer)
The Baker Company does not endorse the use of flammable gases within BSC’s under any conditions. There are alternatives to open flames such as small electrical incinerators, use of disposables, and proper aseptic technique.
NuAire (BSC manufacturer)
NuAire doesn’t recommend the use of natural gas within the BSC and assumes no liability for its use. USE AT YOUR OWN RISK. The Bunsen burner flame within the BSC not only contributes to heat build-up; it also disrupts the laminar air stream, which must be maintained for maximum efficiency. If the procedure demands use of a flame, a Bunsen burner with on demand ignition is strongly recommended. Do not use constant flame gas burners. During use, the Bunsen burner should be placed to the rear of the workspace where the resulting air turbulence will have a minimal effect.
Questions? Contact an EH&S Research Assistance Program specialist or contact EH&S Biosafety.
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