Biosafety cabinets (BSCs) play a critical role in protecting laboratory personnel, samples, and the surrounding environment from biological contamination. When a biosafety cabinet is not operating properly, it can compromise research integrity, create safety risks, and lead to costly downtime.

To maintain a safe and productive laboratory, it is important to understand the basics of biosafety cabinet troubleshooting and recognize common warning signs before they become larger problems.

Below are five common biosafety cabinet malfunctions, their potential causes, and steps to troubleshoot them.

My Biosafety Cabinet’s Airflow Alarm Keeps Going Off

 Possible Causes:

• Sash positioned too high
• Obstructed front or rear air grills
• Loaded or clogged HEPA filters
• Fan or blower performance issues

Troubleshooting:

• Check Sash Position: Verify the sash is set at the manufacturer-recommended operating height. Incorrect sash positioning is one of the most common causes of airflow alarms.
• Inspect Air Grills: Ensure front and rear grills are free from equipment, supplies, paper, or other obstructions that could disrupt airflow.
• Review Filter Condition: Check your cabinet’s pressure gauge reading and compare it to the value recorded in the most recent certification report.

A significant increase (typically 50% or more from the original measurement) indicates filter loading that requires airflow verification with a thermal anemometer.

• Contact Your Service Provider: If you’ve verified proper sash position, checked for visible blockages, and the alarm persists, contact a BSC certifier.

The cabinet should be tagged as inoperable until a qualified professional can perform airflow testing with a thermal anemometer and determine whether filter replacement, motor repair, or sensor recalibration is needed.

My Biosafety Cabinet is not Maintaining Sterility 

Possible Causes:

• Improper cleaning procedures
• Contaminated work practices
• Compromised HEPA filters
• Airflow disruptions

Troubleshooting:

• Disinfect the Cabinet Thoroughly: Clean all interior surfaces using disinfectants according to laboratory protocols. Deeper disinfections may require contacting your service provider.
• Review Workflow Practices: Keep materials organized and avoid blocking airflow paths within the cabinet.
• Warm-Up Time: Ensure you’re running the cabinet for at least 5-10 minutes before starting work to allow airflow to stabilize and purge the work zone. Starting work immediately after power-on doesn’t allow proper air exchange to establish sterile conditions.
• Verify Certification Status: Ensure the cabinet’s annual certification is current and that airflow performance remains within specifications.

My Biosafety Cabinet is Making Excessive Noise

Possible Causes:

• Worn blower motor components
• Obstructed airflow pathways
• Loose internal hardware
• Aging fan assemblies

Troubleshooting:

• Inspect for Obstructions: Remove any materials blocking airflow pathways or intake grills.
• Listen for Fan Irregularities: Grinding, rattling, or vibrating may indicate wear to the motor or bearings.
• Check for Loose Components: Internal panels or hardware may loosen over time and create excessive noise.
• Schedule Maintenance: Persistent noise often requires professional inspection and diagnostics to prevent larger mechanical failures. Contact your service provider if sounds continue.

My Biosafety Cabinet Has Poor Airflow

Possible Causes:

• Clogged HEPA filters
• Blocked exhaust or intake openings
• Improper cabinet setup
• Blower or motor malfunction

Troubleshooting:

• Inspect Intake and Exhaust Areas: Ensure surrounding equipment or supplies are not restricting airflow.
• Review Pressure Readings: Significant changes in pressure gauges or airflow indicators may signal filter loading.
• Verify Cabinet Setup: Ensure the cabinet is being operated according to manufacturer specifications.
• Contact Your Service Provider: Airflow testing and balancing may be necessary to restore proper performance. 

Biosafety Cabinet Repair, Certification, and Decontamination Solutions from MarathonLS

Biosafety cabinets are essential to maintaining laboratory safety, sample integrity, and regulatory compliance. When issues arise, immediate biosafety cabinet troubleshooting is critical to minimizing downtime and protecting ongoing research.

MarathonLS provides expert biosafety cabinet repair, decontamination, and certification services. With industry-leading response times and experienced field service engineers, MarathonLS helps labs quickly identify and resolve biosafety cabinet issues before they impact operations.

Whether you need routine maintenance or emergency biosafety cabinet repair, MarathonLS helps keep your laboratory running safely and without interruption.