What To Do When Your Laminar Flow Hood Fails a Certification Test

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August 5, 2026

Here’s the good news: a failed certification doesn't always mean replacement. Sometimes fume hood repair is a better option. Laminar flow hoods play a critical role in maintaining clean, particle-controlled environments for laboratories, pharmacies, healthcare facilities, and manufacturing operations. With routine certification you can verify that your lab equipment is meeting performance standards and operating safely. But from time to time, it is possible that your laminar flow hood fails certification. In these instances it's important to understand what the results mean and what next steps are most appropriate.

Why Laminar Flow Hood Certification Matters

Certification is done for many reasons. It helps to verify proper airflow performance and ensure that HEPA filters are operational and working properly. Certification also ensures that air velocity is meeting proper levels and that you are meeting cleanliness standards for your lab equipment. Taken together, these functional markers let you and others know that you prioritize safe operation, compliance with applicable industry standards, and the wellbeing of your lab workers. And that helps to build your lab’s good reputation in your industry. Regular certification also helps to ensure that your laminar flow hood is providing the intended level of contamination control and meeting the promised standards–it’s a good way to know if a unit is defective, or just having issues.

While a failed certification is disheartening, and should be addressed promptly, in many cases the issue can easily be identified and corrected through troubleshooting, maintenance, or fume hood repair. A failed certification likely does not automatically mean that the equipment is beyond repair. Instead, it often points to performance criteria that were not met. These could include:

  • Airflow issues
  • HEPA filter performance
  • Air balance
  • Mechanical components
  • Electrical systems
  • Other operational deficiencies

Common reasons that a laminar flow hood fails certification could be many, but they often rest in a few key areas.

HEPA Filter Damage

Whether from age, physical damage, filter leaks, or improper installation, a malfunctioning HEPA air filter must be addressed immediately. This is one for the professionals–a DIY approach is never recommended. Regular replacement is vital.

Incorrect Airflow Velocity

Proper airflow velocity is central to a fume hood operating properly. Air flow that is too high or too low may indicate root causes such as blower issues, motor wear, fan imbalance and airflow obstruction. If you aren’t performing regular checks on airflow, it will eventually become problematic.

Worn or Failing Blower Motor

Over time, blower components can wear, reducing the hood's ability to maintain proper airflow. This is simply a matter of routine checks and maintenance that every owner of lab equipment must do. If neglected, it could lead to a failed certification test.

Damaged Gaskets or Seals

Compromised gaskets or seals can quickly affect top priorities like air containment, filter performance, and ultimately impact overall system efficiency. If the materials you are testing in your fume hood are especially noxious or potentially harmful, tight seals and air containment are a must.

Electrical or Control Problems

Electrical or control problems can easily lead to crossed wires and malfunctioning lab equipment. For example, you may be dealing with faulty switches, controller malfunctions, sensor failures, or a range of alarm system issues. Whatever the case, these electrical problems mean that you do not have a good grasp on the true state of your lab equipment.

Lack of Routine Maintenance

When you neglect or become too busy to perform daily, weekly, monthly or annual maintenance checks, it shows. Your lab equipment could become bogged down with accumulated dust while trying to work with worn components. If you also have a record of deferred service visits, these can all combine to contribute to certification failures.

What To Do Now

Now that you’re holding a failed certification, you could be wondering about next steps. First of all, if the hood no longer provides proper contamination control, it’s probably best to stop using it until you can resolve the problem. Follow your facility's specific procedures for this situation, which may include removing the unit from service. At the very least, you should avoid using it for critical applications until corrective actions are completed.

Take a close look at the certification report. This will tell you what parts of the unit failed key tests. DigeLab technicians are also happy to share results and interpret them for you. Your report will tell you measured airflow values, filter test results, and should also recommend corrective actions. More often than not, fume hood repair is a viable option as opposed to outright replacement. The better you understand the report, the more you’ll be able to prioritize repairs.

This is also a good time to schedule a professional inspection. A qualified service technician can confidently diagnose the underlying problem during a thorough inspection of all mechanical and electrical systems. They can properly evaluate filter condition, and then offer recommendations for repairs or replacement components. Repairs are often preferred when the matter is something simple, like replacing HEPA filters, adjusting controls, servicing motors, or if some minor mechanical issues are identified. On the other hand, replacement may be recommended if your lab equipment has sustained extensive structural damage. The same is often true if major components have simply reached the end of their useful life, if repair costs are nearly as high as the cost of a new unit, or if the equipment no longer meets operational requirements.

Once repairs have been made, or the unit has been replaced, another round of certification is required. This certification will ensure that airflow, filter integrity, and performance levels are ideal. It is vital to note that it is only after passing certification that the hood should be returned to regular use, especially in critical applications.

How To Prevent Future Certification Failures

On the one hand, you cannot account for every mishap. Sometimes a unit will fail despite your best efforts. However, more often than not, when you implement lab equipment maintenance best practices, you are far less likely to see certification failures.

Here are some top ways to prevent future certification failures:

  • Follow a preventive maintenance schedule
  • Replace worn components promptly
  • Keep the hood clean
  • Train staff on proper use
  • Avoid blocking airflow
  • Schedule routine certification

Regularly scheduled preventive maintenance helps to identify small issues before they become large and begin to negatively impact performance. In between these certifications and inspections, there are some key signs to look for that could indicate that your lab equipment is starting to develop serious issues. These could include:

  • Unusual noises
  • Reduced airflow
  • Warning alarms
  • Difficulty maintaining proper operation
  • Visible damage
  • Increased vibration

Paying attention to these signs and not dismissing clear signals can allow you to take steps to early intervention, which could help to prevent larger, more costly repairs in the long run.

Rely On DigeLab Solutions For Lab Equipment Certification

A failed certification should never be ignored, but it doesn't necessarily mean that your laminar flow hood needs to be replaced. Prompt evaluation, professional repairs, and re-certification can often restore safe, reliable performance while also helping to protect your personnel, products, research and reputation.

But you want to work with an experienced service provider, like the team of expert technicians at DigeLab Solutions. Our professionals can perform key diagnostics, replace HEPA filters, repair mechanical and electrical components, and complete certification testing. We are also happy to help you and your staff maintain compliance with applicable standards. When you need help maintaining your fume hood, biosafety cabinet, and other lab equipment, call on the experts–rely on DigeLab Solutions. We’re here to help, contact us 24/7.