In most industrial environments, airborne contaminants are an accepted part of the process. Dust, fumes, and particulates are generated daily, and LEV systems are relied upon to control them at source.
Over time, a proportion of this material can settle within the ductwork. This build-up is where system behaviour begins to change.
At Vent-tech, we often tell our clients that while LEV air duct cleaning is part of routine maintenance, it has a direct impact on whether the system continues to control exposure effectively or not, and therefore needs regular attention.
LEV systems are designed around expected airflow and contaminant behaviour. In practice, increased production demand or process changes can lead to higher contaminant loading within the system.
This build-up is rarely uniform. Horizontal sections, bends, and branch connections tend to collect material first, often before any visible signs appear.
On paper, airflow readings may still look acceptable. However, capture can already be compromised at the hood level. This is often where performance begins to drift without being immediately recognised.
How Does It Affect LEV Performance?
LEV system cleaning is not just about removing debris. It affects how air moves through the system.
As build-up increases, internal resistance changes. Airflow begins to redistribute unevenly, which means some extraction points perform adequately while others do not. This imbalance is not always obvious during day-to-day operation.
Operators usually notice reduced suction at specific points, but by then the issue has often been developing for some time.
Air velocity readings can be useful. However, they do not confirm effective capture at source.
Regulatory Context in Practice
Under COSHH Regulation 9, LEV systems must undergo a Thorough Examination and Test at least every 14 months. This confirms system performance at the time of testing, in line with guidance such as HSG258. What it does not do is guarantee performance between test intervals. Refer to our quick guide here to determine whether your facility requires a TExT certificate.
LEV Test carries a thorough inspection of all key components, including internal ducts, filter cleaning devices, fan belts and alarms. However, certain environments, especially high-traffic areas, may require more frequent testing or regular LEV cleaning to ensure their LEV systems are in optimal condition and performing effectively.
Where Do Issues Commonly Develop?
From site experience, certain areas tend to present problems more frequently.
Long horizontal duct runs with lower velocities often allow material to settle. Changes in direction can disrupt airflow and lead to accumulation. Branch junctions can become unevenly loaded, particularly where airflow is not well balanced.
In some cases, the cause is design-related. In others, it is linked to process changes that were never accounted for. These issues are rarely identified unless specifically investigated.
LEV Cleaning Is Not Sufficient
LEV system cleaning can improve internal conditions, but it does not resolve underlying faults.
If transport velocities are too low, material will continue to settle. If the nature of the contaminant has changed, the system may no longer be suitable for the process.
This approach works in stable environments with consistent processes. It is less reliable in older workshops or facilities where systems have been modified over time.
Repeated cleaning without addressing the cause tends to provide only temporary improvement.
When LEV Air Duct Cleaning Becomes Necessary?
There are usually early indicators, although they are not always obvious at first.
Reduced capture at hoods is one of the more common signs. Dust appearing in areas that were previously controlled can also suggest a decline in performance. In some cases, changes in system noise or vibration are reported.
These changes tend to develop gradually. By the time they are clearly noticeable, internal duct conditions have often already affected how the system behaves.
Potential Challenges with LEV System Cleaning
Many systems are installed without adequate access points for inspection or cleaning. This limits how effectively LEV system cleaning can be carried out, particularly in older installations.
Sections of ductwork may remain untreated simply because they cannot be reached safely. This tends to affect long-term performance more than expected.
Why Is LEV Air Duct Cleaning Important?
In most cases, duct contamination is not the primary cause of failure. It is a contributing factor that gradually shifts performance away from the original design intent.
Where cleaning is combined with proper inspection and airflow assessment, it can help restore balance within the system. Where it is carried out in isolation, the improvement is usually short-lived.
Most LEV issues do not present as sudden failures. They develop gradually, often without immediate visibility, until exposure control is no longer reliable.
Who Can Help with LEV Cleaning?
If you are unsure whether the duct condition is affecting performance, it is usually worth looking beyond airflow readings alone. Internal build-up, access limitations, and changes over time can all influence capture at source.
You can speak to the Vent-Tech team or arrange a site review to understand how your LEV system is actually performing under normal operating conditions. This allows any issues to be identified in context, rather than relying on design assumptions or historical data.