Paint Spray Booth LEV Testing at a Scottish Fabrication Facility

​​The Challenge

The fabrication facility uses a walk-in spray booth for its painting operations.

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An effective extraction system is essential during this process because contaminants generated during spray painting need to be captured and removed from the operator's working area.

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The existing spray booth incorporated filtered extraction designed to draw contaminated air away from the working area before exhausting it outside the building.

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A-Mac Environmental was asked to carry out the statutory Thorough Examination and Test of the LEV system and assess its effectiveness as a control measure.

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The Spray Booth Extraction System

The LEV system consisted of a walk-in spray booth with two large filtered extraction sections.

The system incorporated pleated paper filters with additional glass fiber filter material and a belt-driven extraction fan.

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Contaminated air was drawn through the filtered extraction sections before being discharged to the atmosphere above the building.

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The two filter sections each measured approximately 880 mm x 4,000 mm, providing a substantial extraction area across the booth.

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Our LEV Examination

A Thorough Examination and test involve considerably more than simply checking whether an extraction fan is running.

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A-Mac's engineers examined the spray booth LEV system's components and conducted performance testing to determine how effectively it controlled the paint fumes generated by the process.

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The examination included:

• Visual inspection of the spray booth

• Inspection of the extraction ductwork

• Inspection of the filtration system

• Assessment of the discharge arrangement

• Checking the system's monitoring instrumentation

• Airflow and face velocity measurements

• Qualitative smoke testing

• Assessment of contaminant capture

• Assessment of transport through the extraction system

• Review of the overall effectiveness of the LEV system

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Visual Inspection

The spray booth itself was found to be in good condition.

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The extraction ductwork was also in good condition, and the pleated paper filtration system was in satisfactory condition at the time of the test.

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The system discharged externally above the building.

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A manometer was fitted to the system, providing an indication of pressure across the extraction system.

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Measuring the Spray Booth Airflow

Airflow measurements were taken across both of the booth's filtered extraction sections using an anemometer.

Multiple face velocity readings were taken across each filter rather than relying on a single measurement. This provided a better picture of how air was moving across the extraction face.

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Top Filter Section

Average face velocity: 1.15 m/s

Measured airflow: 14,573 m³/hr

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Bottom Filter Section

Average face velocity: 0.84 m/s

Measured airflow: 10,644 m³/hr

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The examination report identified a minimum acceptable face velocity of 0.5 m/s for fume extraction.

The average measured face velocities across both filter sections were therefore above this value during testing.

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​​​​Smoke Testing the Spray Booth

Airflow measurements tell us how much air is moving through an LEV system, but it is also important to understand what happens to contaminants within the actual working area.

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A-Mac therefore conducted qualitative smoke testing in the spray booth.

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Smoke released within the capture area demonstrated good capture by the extraction system.

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Smoke testing through the ductwork also indicated that transport velocities were sufficient to remove the fumes through the system.

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The test confirmed that captured air was transported through the extraction system and discharged externally above the workshop.

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An Important Finding

Although effective capture was observed within the operator's working area, the smoke testing also identified an opportunity to improve the system.

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Some smoke remained at a high level within the booth during the test.

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A smoke clearance time of approximately 6 minutes and 30 seconds was recorded, with some smoke remaining at a high level.

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This is a good example of why an LEV Thorough Examination and Test involves more than simply measuring airflow.

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A system can be operating and achieving suitable airflow measurements while testing still identifies areas where its overall performance could be improved.

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Our Recommendations

Following the examination, A-Mac recommended:

Increasing the supply air to the spray booth and changing the make-up air filter.

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These measures were recommended to improve airflow within the booth and help restore the LEV system to its benchmark condition.

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The Result

The spray booth extraction system was considered an adequate control measure for the paint and fumes produced by the process, provided that the painting operation was carried out inside the booth and the operator worked in the correct position.

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This last point is particularly important.

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Even a correctly functioning extraction system depends on being used properly. Operator position and working practices can significantly affect the effectiveness of contaminant capture.

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The examination therefore provided the business with both evidence of the system's performance and practical recommendations for maintaining and improving control.

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Why Thorough LEV Testing Matters

LEV systems can change over time.

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Filters become loaded, components wear, airflow can alter, and changes to supply or make-up air can affect the performance of an extraction system.

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A system may also appear to be working because the fan is running without necessarily providing effective contaminant control where the operator is actually working.

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A Thorough Examination and test provide a much more detailed assessment of the condition and performance of the LEV system.

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It can identify:

• Whether contaminants are being effectively captured

• Whether sufficient airflow is being achieved

• Problems with filtration or ductwork

• Changes from the system's intended performance

• Maintenance requirements

• Opportunities to improve contaminant control

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How Often Should Spray Booth LEV Be Tested?

LEV equipment used to control exposure to hazardous substances is subject to statutory Thorough Examination and Testing under the Control of Substances Hazardous to Health Regulations 2002 (COSHH).

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For the spray booth examined in this case study, the maximum legal interval specified for Thorough Examination and Testing was 14 months.

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Where wear and tear or operating conditions could cause an LEV system's effectiveness to deteriorate more quickly, examinations may need to be carried out more frequently.

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Regular maintenance and checks between statutory examinations are also important for keeping an extraction system working effectively.

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Paint Spray Booth LEV Testing in Scotland

A-Mac Environmental provides Thorough Examination and Testing of Local Exhaust Ventilation systems throughout Scotland.

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We can assess paint spray booths and other industrial extraction systems to determine how effectively contaminants are being captured and removed from the workplace.

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Our LEV examinations combine visual inspection with performance measurements and qualitative testing to provide a clear picture of how the system is actually performing.

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Where problems or opportunities for improvement are identified, we provide clear recommendations to help businesses maintain effective control.

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If you operate a paint spray booth and need to arrange a Thorough Examination and Test of your extraction system, speak to A-Mac Environmental.  Protecting Scottish workplaces through effective Local Exhaust Ventilation.