Common LEV Failures and How to Avoid Them

• Make sure the LEV system is designed for the specific task and type of substance you’re working with.
• Regular maintenance is essential – a competent person should check filters, fans and ducting weekly.
• Don’t overload the system by connecting too many tools or machines.
• Never change or move parts of the LEV system without a competent person retesting its performance.
• Check the airflow regularly using tools like anemometers.

LEV systems play an important role in protecting workers from harmful airborne substances. However, these systems can fail to provide adequate protection if they’re not properly selected, installed, used or maintained. Below are some of the most common LEV failures.

If your LEV system isn’t right for the job, it won’t do much to protect you and your team.

Different tasks produce different types of airborne substances – wood dust, welding fumes, paint vapours, chemical sprays – and they all behave differently. That means your LEV setup needs to be built for the specific work environment and tasks.

If the hood is the wrong shape, too far away, or the airflow isn’t strong enough, it won’t catch what it’s supposed to.

To avoid this, a competent person must be appointed to design the system. They should have the necessary training, skills, experience and knowledge to select and configure the right LEV solution for your workplace.

You must also arrange for LEV testing after installation to verify the system matches the process it’s being used for.

Follow the Health and Safety Executive (HSE) guidance on LEV (HSG258) for proper design, use, maintenance and testing of these systems.

Even the best LEV system won’t last long if you don’t take care of it.

Operators should be trained to conduct pre-use checks every time they use the system. They should look for visible dust, listen for unusual noises and check if the airflow feels strong. If something seems off, it must be reported.

In addition to these everyday pre-use checks, your system must also go through more rigorous examinations. Under the Control of Substances Hazardous to Health (COSHH) Regulations 2002, thorough examination and testing of LEV systems is a legal requirement.

LEV systems must be inspected by a competent person at least once every 14 months. However, more frequent inspections may be necessary for systems that are used in demanding conditions. You should determine your inspection schedule with the help of a competent person.

Overloading happens more often than you’d think. You might try connecting too many tools or machines to one LEV system, thinking it will save time or money. But pushing the limits of your LEV will weaken the airflow, meaning it won’t capture harmful substances like it should.

If you notice the system struggling or if the extraction seems weaker than usual, it could be overloaded.

The fix? Don’t connect more than it can handle. If you need more coverage, speak to a competent professional about upgrading or adding another system.

Sometimes the system is fine, but workers don’t use it properly. Maybe someone forgets to switch it on, works too far from the hood or blocks the airflow with equipment. These mistakes are even more likely when people are rushed or haven’t been shown the right way to use it. That’s why training is so important.

Make sure everyone knows when and how to use the LEV. Remind your team where to position their work and why staying close to the hood matters. Put up signs or floor markings if needed.

Also, explain why the LEV is necessary. If your people understand the system is there to protect them, they’re more likely to use it properly.

Even if your LEV works well, it might not be enough on its own. Some tasks produce more dust or fumes than the system can handle. You might notice lingering smells in the air, or people may complain about headaches, sore throats or coughs. That’s a sign the current controls aren’t doing the job.

Therefore, LEV should not be a standalone solution.  It must fit into a wider control strategy that follows the hierarchy of controls:

1. Eliminate the hazardous substance or process if possible.
2. Substitute with a safer alternative.
3. Use engineering controls like LEV to contain the risk.
4. Change how and when the work is done.
5. Use personal protective equipment (PPE) only as a last resort.

For high-risk substances, COSHH requires exposure monitoring to confirm whether controls are working and if risks remain.

You may need a combination of controls to make work safe. Refer to your risk assessment and seek advice from a competent person.

Even making small changes to the system can reduce airflow. You should never modify an LEV system without checking how it affects performance.

Always speak to a competent person before making any changes. If changes are made, make sure you retest the system to confirm it still protects staff. Keep written records of your actions and retest results to prove that the modification work was necessary and effective.

Without enough airflow, LEV systems can’t reliably capture airborne contaminants.. This often goes unnoticed until someone gets ill or smells chemicals in the air. Common causes include blocked filters, failing fans or duct leaks.

You should measure airflow regularly using simple tools like an anemometer. Set up a routine for checking airflow and train someone on your team to spot issues. Fit pressure or airflow gauges if possible, as these make it easier to monitor the system.

LEV systems work by extracting contaminated air from the workspace, but that air needs to be replaced. If there is no source of clean air to flow back in, the system cannot maintain effective airflow. This is known as a lack of make-up air.

Without make-up air, the LEV system may struggle to capture airborne contaminants efficiently. You may also experience backdrafts, pressure imbalances or stagnant air, all of which reduce system performance and can increase exposure risks. This issue is often worse in winter when windows and doors are kept closed to retain heat.

Effective LEV design must account for a reliable source of replacement air. It doesn’t strictly have to be air from outdoors, just unpolluted and sufficient to balance the volume being extracted. If in doubt, consult a ventilation specialist to ensure the system functions as intended.

Maintaining LEV systems requires coordination between multiple teams and duty holders. Without clear communication and agreed responsibilities, essential upkeep tasks can be missed or delayed.

To ensure the system remains safe and compliant, appoint a responsible person to oversee inspection schedules and track remedial actions. This individual should coordinate across departments to confirm that maintenance tasks are carried out on time and in line with HSE requirements.

Proper planning, shared accountability, and prompt communication help ensure LEV issues are identified and resolved without unnecessary delay.

Your staff are usually the first to notice when something’s wrong. If they mention smells, airborne dust or health symptoms, don’t ignore them. These can be early warning signs of LEV failure.

Set up a simple way for staff to report problems. This could be an online form, a shared log or a quick word with a supervisor. Take every report seriously and follow up quickly. A rapid response not only protects staff but also builds trust and encourages people to speak up in future.

Having the right LEV system isn’t enough if no one knows how to manage it. Poor use, missed checks, LEV failures and a lack of understanding can lead to serious health risks. That’s why proper training is key, especially for those responsible for keeping the system running safely and in compliance with health and safety legislation.

We offer an online course for managers, supervisors and anyone in charge of LEV systems. It covers what the law expects, how to prevent LEV failures with preventative actions and what good management looks like. The course is designed to help you stay compliant with legislation and HSE guidance.

Take the course and make sure your LEV system protects your team the way it should.