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Local exhaust ventilation systems are installed to capture contaminants at the source before workers breathe them in. Fume hoods, extraction arms, downdraft tables, spray booth ventilation. They all serve the same purpose. But installation alone does not guarantee they work effectively.
Over time, filters clog, ducts accumulate buildup, fan belts slip and ductwork connections loosen. Even a system that worked perfectly on day one can lose significant capture efficiency within months if it is not monitored and maintained.
Our LEV assessments measure face velocity, duct transport velocity, capture efficiency and static pressure across key points in the system. We compare results against the design specifications and relevant Australian standards to determine whether the system meets performance requirements.
We also assess the positioning and design of capture hoods and enclosures. A ventilation system with adequate airflow but poorly designed hoods will not protect workers effectively.
Australian WHS regulations require that engineering controls, including LEV systems, are maintained in good working condition. The best way to demonstrate compliance is through regular testing with documented results.
We recommend LEV testing at least annually, and more frequently for critical systems or those operating in high dust or fume environments. Testing should also be conducted after any modifications to the system, ductwork changes or when air monitoring results suggest controls are not adequate.
Our report provides clear pass or fail results for each measurement point along with recommendations for any system improvements needed. This might include filter replacement, fan adjustment, ductwork modifications or repositioning of capture hoods.
LEV assessment results feed directly into your workplace exposure management. If air quality monitoring or welding fume assessments show elevated exposures, LEV testing helps determine whether ventilation is the weak link in your control strategy.
For a complete picture of your workplace hygiene controls, consider our hazardous chemical management audit which assesses ventilation alongside other control measures.
We also provide input during the design and commissioning of new LEV systems. A system that is designed and commissioned correctly from the start will perform better and require less corrective maintenance over its lifetime. Getting independent advice during design can identify problems before installation that would be expensive to fix afterwards.
Common design issues we identify include inadequate duct velocities that allow particulate to settle and block ducts, insufficient fan capacity for the number and size of capture points, poor hood placement that does not capture contaminants at the source, and missing balancing dampers that make it impossible to distribute airflow correctly.
For businesses that want to demonstrate to clients or regulators that their LEV systems are maintaining worker health effectively, regular documented testing creates a performance history. This is particularly valuable in industries where LEV system compliance is subject to regulatory scrutiny, like laboratory environments, pharmaceutical manufacturing and facilities handling toxic or carcinogenic substances.
We maintain detailed records of all testing we conduct. If you need historical performance data for a system we have tested previously, we can provide it. Many clients use their LEV testing history as evidence of ongoing due diligence in regulatory communications and client audits.
Local exhaust ventilation (LEV) is a system that captures airborne contaminants at or near their point of generation before they can reach the worker's breathing zone. It consists of a capture hood or enclosure, ductwork, a fan or blower and a filtration or separation system to remove the contaminant from the extracted air before discharge. Unlike general dilution ventilation, LEV removes the contaminant rather than diluting it throughout the workplace.
Australian WHS regulations require that engineering controls, including LEV systems, are maintained in effective working order. Industry guidance typically recommends annual testing for most systems. Regulatory guidance for specific hazards like carcinogens may require more frequent testing. We recommend testing after any modification to the system and after incidents that might have affected performance.
Face velocity is the air velocity measured at the opening of a capture hood. It determines whether the hood generates enough inward airflow to capture contaminants generated in front of it. Insufficient face velocity allows contaminants to escape into the general workspace. The required face velocity depends on the toxicity of the contaminant, the rate of generation and the distance between the source and the hood opening.
Yes. Excessively high face velocities can disturb work, create turbulence that actually draws contaminants away from the capture zone, and waste energy. Excessive duct velocities cause abrasion wear and noise. A well designed system operates at the minimum airflow needed to achieve reliable capture. Our assessments identify systems that are over-performing as well as those that are under-performing.
First, identify and address any immediate causes like clogged filters, damaged ductwork or fan belt issues. These simple fixes often restore performance quickly. If the system still fails after maintenance, more significant modifications may be needed. Implement interim controls like increased ventilation or respiratory protection while repairs are completed. We provide clear repair specifications and can re-test after repairs to confirm the system now meets requirements.