Local Exhaust Ventilation: Performance vs Effectiveness
Your local exhaust ventilation (LEV) system is running, the airflow readings look good, and the latest test results are consistent with previous years. So, can you be confident it's doing its job?
Not necessarily.
For New Zealand businesses using LEV to manage workplace exposure to harmful contaminants, there's an important distinction between how well the equipment is performing and how effectively it's protecting workers. And if you’re confusing the two, you could be leaving your team exposed to harmful contaminants without even realising it.
What Does LEV Performance Testing Tell You?
Local exhaust ventilation systems are designed to capture airborne contaminants like dust, fumes and vapours before they can be inhaled, and like any machine, their performance can decline over time.
Commissioning and verification tests benchmark the system by tracking airflow measurements over time, which is great for revealing deterioration or maintenance issues. However, there's an important limitation to what the results can tel you, because a system can maintain its performance without necessarily preventing exposure to contaminants.
For example, if the extraction hood on a dust extraction system was poorly positioned when it was first installed, airflow readings could remain consistent year after year, even while harmful dust is escaping into the workspace.
Changes to production processes or equipment can also affect how effectively contaminants are captured, without necessarily causing a noticeable change in the system's mechanical performance.
Why LEV Control Effectiveness Matters
Under New Zealand's Health and Safety at Work Act 2015, businesses have a duty to eliminate or minimise risks to worker health and safety, so far as is reasonably practicable. That means it's not enough to simply have engineering controls like LEV in place. You need to be confident they're controlling contaminants effectively.
Sometimes, the clues are obvious, like lingering fumes or dust escaping from an extraction hood. However, not al contaminants are visible, so the absence of warning signs doesn't necessarily mean that your LEV system is providing adequate protection.
How Occupational Hygienists Assess LEV Effectiveness
Local exhaust ventilation testing shouldn't stop at checking airflow readings and equipment performance. Assessing LEV effectiveness requires an occupational hygiene perspective, looking beyond the equipment itself to consider how well it's controlling exposure in the wider workplace.
Unlike an equipment installer or maintenance technician, an occupational hygienist focuses on the risks to workers. At Air Matters, this means identifying the contaminants being generated, observing how the system is positioned and used during normal operations, and assessing whether workers may still be exposed.
Depending on what we find, we may recommend changes to how the system is used, adjustments to extraction equipment or further exposure monitoring to assess contaminant levels against relevant workplace exposure standards.
How Confident Are You in Your LEV Controls?
If your business relies on LEV to protect its staff, you have a responsibility to ensure that the measures you’re taking are doing the job.
At Air Matters, our occupational hygienists provide LEV testing throughout New Zealand to help protect worker health. And because we don’t offer equipment supply, installation or repair, you can be confident that our assessments are completely independent.
Want to know whether your LEV system is an effective control? Get in touch with our team to discuss an appropriate assessment for your workplace.
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