Three duct types
A spray booth's extract is both dry ductwork that loads up with overspray and part of a Local Exhaust Ventilation system that the law says must keep working. Cleaning it sits right where those two jobs meet.
The short answer
A spray booth's exhaust wears two hats. It is dry ductwork - a run that loads up with overspray, paint solids and dust and needs clearing like any other - and it is the business end of a Local Exhaust Ventilation, or LEV, system, the engineered extraction that captures hazardous spray at source and that the law requires to keep working. Cleaning the extract is where those two responsibilities overlap, which is why this page bridges duct cleaning and LEV testing.
What LEV is and why it applies
Local Exhaust Ventilation is the engineered system that captures airborne contaminants where they are generated, before anyone breathes them. In a spray booth that means paint mist, solvent fumes and volatile organic compounds drawn off through a hood, along ductwork, through filters and out via a fan and discharge. Under the Control of Substances Hazardous to Health Regulations, employers must control that exposure, and LEV is usually how they do it. The law also requires most LEV systems to undergo a thorough examination and test by a competent person at least every fourteen months - more often for the highest-risk substances.
The whole point of the system is capture velocity: enough airflow at the hood to pull the contaminant in. Anything that reduces that airflow undermines the protection the LEV is there to provide.
Where cleaning meets testing
Overspray does not stop at the filters. Paint solids and dust settle along the extract ductwork, narrowing it and dragging down the airflow the hood depends on. That causes two connected problems. First, capture suffers: a clogged duct means the booth no longer pulls contaminant away as designed, so operators are less protected and the finish quality drops. Second, accumulated combustible residue in the ductwork is a fire and, with fine dry material, an explosion risk - which is why spray-booth ducting has to be kept clear.
Clean ductwork is what lets an LEV system pass its examination. The clean itself is not the statutory LEV test - that is a separate, competent-person examination under COSHH - but a booth whose extract is choked with overspray will struggle to meet its measured performance. Cleaning restores the airflow the test looks for. If you also need the examination itself, our LEV testing covers that side.
Getting the extract right
The practical job is to clear the whole extract - hood, ductwork, filter housings and fan - of overspray and settled dust so the airflow returns to what the system was designed for. That protects the people using the booth, keeps the finish clean, removes a combustible fire load and puts the system in a state where it can pass its thorough examination. Because overspray builds with use, the sensible pattern is to clean on a schedule tied to how much spraying the booth does, and to coordinate it with the fourteen-month examination cycle so the two work together rather than in isolation.
Questions
It is dry ductwork that loads up with overspray, and it is also part of an LEV system that must keep capturing contaminant. Cleaning it sits where those two responsibilities overlap.
Local Exhaust Ventilation - engineered extraction that captures airborne contaminants at source, before they are breathed. In a spray booth it draws paint mist and solvent fumes through a hood, duct, filters and fan.
Overspray settles along the ductwork and narrows it, dropping the airflow the hood needs. Capture suffers, so operators are less protected, and the combustible residue is also a fire risk.
No. The statutory LEV thorough examination and test is a separate, competent-person job required under COSHH at least every 14 months. Cleaning restores the airflow that examination measures.
On a schedule tied to how much spraying the booth does, coordinated with the 14-month examination cycle so cleaning and testing support each other.
Phoenix Duct Clean · by the numbers
Overspray-loaded ductwork loses capture and fails examinations. We clear the extract so airflow returns and the system stands up to its LEV test. Call to book.