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LEV testing - smart monitoring
One of the hardest things about LEV is that it fails invisibly - the airflow drops and nobody knows. Smart monitoring changes that, with sensors and alarms that warn you the moment performance falls. It is a genuine advance in catching faults early. But it is worth being clear about what self-monitoring does and does not do: it flags faults, it does not replace the statutory test.
The short answer
Smart LEV monitoring uses sensors - typically watching airflow or the pressure across a filter - to detect when performance drops and alert someone in real time, often with a simple indicator or alarm at the workstation. Its great value is catching the invisible decline that is LEV's core weakness: the moment airflow falls below a set point, the system flags it, rather than the drop going unnoticed until the next test. But self-monitoring supplements the thorough examination and test; it does not replace it. The statutory examination by a competent person assesses the whole system against what the process needs - something a fixed sensor watching one parameter cannot fully do.
Solving LEV's core weakness
The central problem with LEV is that it fails without showing it. Airflow drops as a filter loads or a fan declines, and because the system keeps running and looking normal, the loss of capture goes unnoticed - potentially for months, until the next thorough examination measures it. This gap between a fault occurring and it being detected is where exposure quietly happens. Anything that closes that gap - that flags a drop in performance when it happens rather than at the next scheduled test - addresses LEV's core weakness directly.
That is exactly what smart monitoring sets out to do. By continuously watching the system's performance and alerting when it falls, it turns an invisible decline into a visible, immediate signal. Instead of relying on someone noticing weaker pull at the hood, or waiting for the periodic test, the system tells you the moment something is wrong. For a control whose great danger is silent failure, real-time self-monitoring is a genuinely valuable advance - it means a fault is caught early, when exposure has only just begun, rather than after it has been running unnoticed. The appeal is obvious and real.
How it works
Smart LEV monitoring works by fitting sensors that watch a parameter tied to the system's performance - most commonly the airflow in a duct, or the pressure drop across a filter, both of which reflect whether the extraction is doing its job. The sensor feeds a simple logic: if the monitored value stays in the good range, all is well; if it falls below a set point - airflow too low, or filter pressure too high - the system raises an alarm. That alarm is often a straightforward indicator at the workstation, a light or a signal that anyone can see, telling the operator the extraction is no longer performing as it should.
The strength of this is immediacy and simplicity. The operator does not need to interpret readings or understand the system; they need only respond to a clear signal that something is wrong. A green light means the extraction is working; a change means stop and get it looked at. Tying the alarm to a meaningful parameter - airflow or filter pressure - means it responds to the things that actually degrade performance, flagging a loading filter or a declining fan as they happen. So the technology gives a continuous, understandable read on whether the system is performing, and a prompt to act the moment it is not. As a way of catching faults early, it works well.
What it does not do
For all its value, smart monitoring does not replace the statutory thorough examination and test - and it is important to be clear about why. A monitoring system typically watches one or a few parameters at fixed points - the airflow in a duct, say. That tells you whether that parameter has moved, which is genuinely useful, but it is not the same as a competent person assessing the whole system against what the process needs: measuring the capture velocity at each hood, checking the condition of the whole system, and judging whether it is adequately controlling exposure. The sensor watches a number; the examiner assesses control.
There are things a fixed sensor cannot capture. It may not detect a hood that is poorly positioned or a source that has moved out of the capture zone, if the duct airflow it watches is unchanged. It does not inspect the physical condition of the system, spot a developing leak, or exercise the judgement that interprets whether the system as a whole is controlling the hazard. And the thorough examination is a legal requirement in its own right - self-monitoring, however good, does not discharge that duty. So the honest position is that smart monitoring is a powerful supplement: it catches decline early between tests, but the statutory examination is still required and still does things the sensors cannot.
Using them together
The right way to see smart monitoring is as a complement to the thorough examination, not a competitor to it. The two do different jobs and are strongest together. The statutory examination gives a periodic, whole-system assessment by a competent person - the deep, judgement-based check that the system is genuinely controlling exposure. The smart monitoring gives continuous, real-time watchfulness between those examinations - the early warning that catches a fault the moment it develops, rather than letting it run until the next test. One is periodic and thorough; the other is constant and immediate.
Used together, they cover LEV's weakness from both sides. The monitoring closes the gap between tests, flagging decline as it happens so it can be fixed early. The examination provides the rigorous, comprehensive check that confirms the whole system is doing its job and satisfies the legal duty. A business with smart monitoring still needs its thorough examinations; a business with only periodic tests benefits from adding real-time monitoring to catch what happens in between. Neither makes the other redundant. The value of self-monitoring is real - but it is the value of an early-warning supplement, working alongside the statutory test, not the value of a replacement for it.
The takeaway
Smart LEV monitoring uses sensors watching airflow or filter pressure to flag when performance drops, often through a simple alarm at the workstation. It directly addresses LEV's core weakness - the invisible decline that otherwise goes unnoticed until the next test - by turning a silent fault into an immediate, visible signal. As a way of catching faults early, when exposure has only just begun, it is a genuine and valuable advance.
But it flags faults; it does not replace the statutory thorough examination and test. A fixed sensor watching one parameter is not the same as a competent person assessing the whole system against what the process needs - measuring capture velocity at each hood, inspecting the system's condition, and judging whether it controls the hazard - and the examination is a legal duty in its own right. So the two work best together: continuous monitoring for early warning between tests, and the periodic examination for the rigorous, whole-system check. A powerful supplement, not a substitute.
Questions
Sensors fitted to watch a parameter tied to performance - typically airflow in a duct or the pressure drop across a filter - that raise an alarm when the value falls below a set point. The alarm is often a simple indicator at the workstation, telling the operator the extraction is no longer performing as it should.
LEV's core weakness: invisible decline. Airflow drops as a filter loads or a fan declines, and the loss of capture normally goes unnoticed until the next test. Monitoring flags the drop the moment it happens, catching a fault early when exposure has only just begun rather than after months unnoticed.
No. It supplements it. A fixed sensor watching one parameter is not the same as a competent person assessing the whole system against what the process needs - measuring capture velocity at each hood, inspecting condition, and judging control. The examination is also a legal duty in its own right.
Things outside the parameter it watches: a hood poorly positioned or a source that has moved out of the capture zone, if the duct airflow is unchanged; the physical condition of the system; a developing leak; and the judgement that interprets whether the whole system is controlling the hazard. It watches a number, not overall control.
Yes - they are strongest together. Monitoring gives continuous early warning between tests, catching decline as it happens. The thorough examination gives the periodic, whole-system assessment by a competent person and satisfies the legal duty. One is constant and immediate, the other periodic and rigorous.
It can be genuinely valuable, especially for a control whose great danger is silent failure - it closes the gap between tests by flagging faults in real time. Just treat it as a powerful supplement that catches decline early, not as a substitute for the statutory examination it works alongside.
Smart monitoring catches decline early between tests - and our thorough examination provides the whole-system assessment by a competent person that the monitoring supplements but cannot replace.
