GLI GLI Quality Tool
GLI Quality Tool — Version 2.0

Building a preventive maintenance checklist for TB biosafety cabinets

A biosafety cabinet is a primary engineering control in many tuberculosis laboratories. It helps protect staff from infectious aerosols and limits contamination of the work area, but only when its airflow, filters, alarms, seals and work practices remain reliable. A cabinet that appears clean and operational may still have a hidden performance fault.

A useful maintenance checklist turns manufacturer instructions and local procedures into repeatable tasks. It should state what must be inspected, who is authorised to perform the work, how often each task is due, which result is acceptable, and what happens when a check fails. This makes maintenance part of the laboratory quality management system rather than an informal service activity.

Australian TB laboratories also need to account for variable facility designs, contracted service providers and state or territory work health and safety requirements. A laboratory in Sydney, Melbourne, Brisbane or a regional centre may have different access to certified technicians, replacement filters and after-hours support. The checklist should therefore be practical for the equipment and resources actually available.

Why preventive maintenance matters

A Class II biological safety cabinet depends on inward airflow, filtered exhaust and a stable air curtain to contain infectious particles. A blocked pre-filter, damaged sash, poor fan performance or disrupted exhaust connection can reduce protection without producing an obvious visual warning. Preventive maintenance identifies deterioration before the cabinet is needed for high-risk work.

TB procedures can generate aerosols during specimen opening, vortexing, aliquoting, inactivation and manipulation of cultures or molecular material. Maintenance failures may expose workers, while poor positioning of equipment or unnecessary movement can disturb airflow and contribute to cross-contamination. The laboratory should use the phase one roadmap to connect biosafety controls with responsibilities, facilities, equipment management and documented procedures.

A checklist also supports compliance and accountability. Australian laboratories commonly work within NATA accreditation arrangements and must demonstrate that critical equipment is controlled, monitored and maintained. Relevant Australian and New Zealand standards, manufacturer directions, institutional biosafety rules and applicable state or territory legislation should be identified during procedure development. The checklist does not replace those requirements; it provides evidence that they are being applied consistently.

Define cabinet-specific controls

Begin by recording the cabinet’s make, model, serial number, class, installation location, certification label and service contact. Include the date commissioned, the date of the last certification, the next due date and any restrictions placed on use. If the cabinet connects to a building exhaust system, record the connection type and the facilities contact responsible for associated ductwork or fan systems.

The checklist should distinguish user checks from qualified technical servicing. Laboratory staff can usually inspect the sash, work zone, grilles, indicator lights, alarms, visible damage and cleanliness. A competent biological safety cabinet technician should perform airflow measurements, HEPA filter integrity testing, electrical safety checks, alarm verification and other certification activities specified by the manufacturer or relevant standard.

Write acceptance criteria in measurable terms wherever possible. “Airflow satisfactory” is weaker than a field for the measured inflow or downflow value, the instrument used, the technician’s identity and the result. Use the manufacturer’s specifications and the laboratory’s approved certification criteria rather than copying generic values from another cabinet model.

Build a routine inspection schedule

Separate the checklist into daily or pre-use, monthly, six-monthly, annual and event-based activities. Before work begins, staff should check that the cabinet is visibly intact, the sash is at the marked operating height, airflow indicators show normal status, front and rear grilles are unobstructed, and the work surface is clean and free from spills. Any unusual noise, vibration, odour or alarm should be reported before the cabinet is used.

A monthly or scheduled user inspection can include the condition of the sash tracks, seals, work tray, drain valves, electrical leads, service penetrations and signage. Check that disinfectants are compatible with the stainless-steel surfaces and that containers, absorbent materials and waste receptacles do not block airflow. UV lamps, where fitted, should never be treated as a substitute for cleaning, disinfection or proper containment; their use also requires attention to exposure hazards and lamp condition.

Annual certification is a minimum planning point for many laboratories, with additional certification after relocation, significant repair, filter replacement, a failed alarm, building work or a prolonged shutdown. A cabinet moved even a short distance may require a full assessment because levelling, room airflow and exhaust connections can change. Add a trigger in the checklist so staff cannot return the cabinet to service after an event without the required evaluation.

Test performance and document results

Performance testing should cover inflow and downflow velocities where applicable, airflow uniformity, HEPA filter integrity, smoke pattern or visualisation of containment, alarm operation, sash position and electrical safety. For an externally exhausted cabinet, assess the exhaust system and interlocks as part of the installation. Testing should be done with calibrated instruments, and the records should include instrument identification and calibration status.

A failed test requires a clear response. The cabinet should be labelled “out of service” or otherwise restricted, the laboratory supervisor and biosafety contact notified, and affected work assessed for exposure or contamination risk. The corrective action record should identify the fault, immediate controls, service provider, repair date, retest result and authorisation to resume work. A vague note such as “technician attended” does not show that the hazard was controlled.

Keep certificates, service reports, filter records, repair invoices and trend data together in the equipment file. Review repeated faults during management review or internal audit. For example, recurring sash alarms may indicate user training problems, while repeated airflow failures may point to room ventilation changes, overloaded filters or inadequate servicing arrangements.

Link maintenance with TB workflow controls

The cabinet checklist should sit alongside procedures for specimen receipt, opening, aliquoting, culture handling, decontamination and waste disposal. It should state which activities must occur inside the cabinet and which steps are prohibited there, such as storing excess supplies or using open flames that can disrupt airflow. Staff should know the cabinet’s purge or start-up time, shutdown procedure and action to take during a power interruption.

Maintenance is closely connected with contamination control in molecular testing. Clean and dirty areas, unidirectional movement, dedicated equipment and appropriate disinfection all reduce the chance that TB DNA or amplified material will compromise results. The GLI resource on cross-contamination guidance can help laboratories integrate cabinet operation with broader workflow controls rather than treating equipment maintenance as a separate topic.

Australian conditions may add practical complications. Summer heat in western Sydney or Perth can affect room ventilation and technician working conditions, while coastal humidity may accelerate corrosion if spills and cleaning residues are neglected. In remote facilities, a replacement filter or specialist technician may take longer to arrive, so the contingency plan should identify alternative certified work areas and escalation contacts. Never extend a service interval silently because a contractor is unavailable; document the risk decision and interim controls.

Put the checklist into daily practice

The checklist should be short enough for routine use but detailed enough to support an audit. Digital forms can create automatic due-date reminders, attach certificates and prevent closure when a critical field is incomplete. Paper forms remain suitable where connectivity is limited, provided they are legible, signed, dated and transferred into a controlled equipment record.

Use the GLI downloadable checklists as a starting point for adapting quality activities to the laboratory’s phase of development. Add cabinet-specific fields rather than adopting a generic form unchanged. The final document should identify the cabinet, task frequency, acceptance criteria, responsible person, result, defect classification, corrective action and review date.

Recommended checklist features include:

A supervisor should review completed records at a defined interval, such as monthly, and verify that overdue actions are escalated. Include the checklist in induction and refresher training, with staff observing the correct start-up, loading, work and shutdown sequence. Contractors should receive site-specific information about TB risks, room access and decontamination requirements before servicing begins.

A well-designed checklist gives the laboratory a defensible record that its biosafety cabinet is fit for purpose at the time it is used. It also helps reveal wider quality issues, from unreliable facilities support to gaps in staff competency or document control.

Adapt the checklist to each cabinet, approve it through the laboratory’s quality system and begin collecting baseline results during the next scheduled inspection. Review the first cycle with the laboratory manager, biosafety officer and technical staff, then place the approved version under document control so maintenance remains consistent as equipment, personnel and service arrangements change.