What a thorough examination and test really involves

Three parts: a thorough visual and structural examination of the whole system's condition; measurement of its actual performance (airflow, capture velocities, pressures); and assessment of that performance against how it should perform to control the exposure - concluding with a judgement on whether it's adequately controlling the exposure, recorded in a report. A thorough examination and test of LEV involves a structured, three-part process, concluding with a judgement and a report. First, a thorough visual and structural examination: the tester examines the whole system - hoods or capture points, ducting, fan, filter or air cleaner, discharge - for its condition and any faults (damage, wear, corrosion, blockages, leaks, disconnected or modified parts, worn fan, clogged filter) that would degrade the performance. Second, measurement of the performance: the tester takes readings to establish how the system is actually performing in numbers - airflow velocities at the hoods or capture points, capture or face velocities, static pressures in the ducts, and checks on the fan, air cleaning and discharge - the objective evidence of what the system is doing. Third, assessment against a benchmark: the tester compares the measured performance against how the system should perform to control the exposure (the commissioning data, the design intent, or recognised benchmark values), to judge whether it's still adequate. The process concludes with a professional judgement on whether the LEV is providing adequate control, and a report recording the examination, measurements, assessment, faults and actions needed. So it's examination, measurement and assessment, concluding in a judgement and report. So a structured examine-measure-assess process, recorded in a report. This is general information. This is general information.

No - a visual examination is only one of three parts; a proper thorough examination and test also measures the system's actual performance (airflow, capture, pressures) and assesses that against how it should perform, because a system can look fine while performing poorly, so measurement and assessment are essential, not just a look. No - a thorough examination and test is not just a visual check, and treating it as one misses most of what it's for. A visual (and structural) examination is one of the three parts - the tester does inspect the whole system's condition for faults. But on its own, a visual check can't establish whether the system is controlling the exposure, because a system can look perfectly fine while performing poorly (a clogged filter, a worn fan, or a drop in airflow isn't visible from the outside), or look worn while still working adequately. So a proper thorough examination and test also includes measurement - taking readings of the system's actual performance (airflow velocities, capture or face velocities, static pressures) - and assessment - comparing those measurements against how the system should perform to control the exposure. The measurement and assessment are what establish whether the system is genuinely doing its job, which the visual check alone can't. This is why a 'certificate' from someone just glancing at the extraction and signing isn't a proper thorough examination and test: without the measurement and assessment, it doesn't establish the performance. So the visual examination is necessary but not sufficient - the measurement and assessment are what make it a real test. So no - it's examination plus measurement plus assessment, not just a look. So no; measurement and assessment are essential parts. This is general information. This is general information.

Depending on the system: airflow velocities at the hoods or capture points, capture or face velocities, static pressures in the ducts, and checks on the fan, the air cleaning and the discharge - the objective, quantified evidence of how the system is actually performing, which is then assessed against a benchmark. What gets measured during LEV testing depends on the system, but the measurements are the quantified evidence of how the extraction is actually performing. Common measurements include: airflow velocities at the hoods or capture points - to establish whether the system is pulling enough air to capture the contaminant where it's released; capture velocity or face velocity at the hoods - the speed of air at the point of capture, which determines whether the contaminant is drawn in; airflow and static pressures in the ducts - which reveal how air is moving through the system and can indicate blockages or leaks; and checks on the fan (is it performing as it should?), the air cleaning or filtration, and the discharge. These measurements turn 'it seems to be working' into objective numbers about what the system is actually doing - the airflow it's moving, the capture it's achieving. They're the 'test' part of the thorough examination and test, and they're essential because performance can't be judged by eye or by the sound of the fan. The measurements are then assessed against a benchmark (the commissioning data, design intent or recognised values) to judge whether the performance is adequate to control the exposure. So the measurements are airflows, capture velocities, pressures and system checks. So airflow, capture velocity and pressures - the real performance in numbers. This is general information. This is general information.

Against a benchmark of how the system should perform to control the exposure - which can be the commissioning data (its performance when new and known to work), the original design intent, or recognised benchmark values for the system and process; the comparison is what turns the measurements into a judgement of adequate or not. The measured performance is compared against a benchmark of how the system should perform to control the exposure - because measurements alone don't tell you whether the system is adequate until you know what it should be achieving. The benchmark can come from a few sources. Ideally, the commissioning data: the performance the system achieved when it was new, commissioned and known to be controlling the exposure - this is the best benchmark, because it's the system's own proven baseline (which is why commissioning data matters, covered in the commissioning-versus-thorough-examination page). Failing that, the original design intent: what the system was designed to achieve. Or recognised benchmark values: established figures for the type of system and process (for example, typical capture or face velocities for a given kind of hood and contaminant). By comparing the measurements against whichever benchmark applies, the tester judges whether the system is still performing adequately or has degraded below what's needed. This comparison is what makes the measurements meaningful - a raw airflow figure means little until it's set against what it should be. So the performance is assessed against a benchmark, turning numbers into a judgement. So against commissioning data, design intent, or recognised benchmark values. This is general information. This is general information.

A professional judgement on whether the LEV is adequately controlling the exposure, and a report recording the examination, the measurements, the assessment against the benchmark, any faults found, and what needs doing - so you have a documented picture of the system's state and the actions needed, not just a certificate. At the end of a proper thorough examination and test, you get two things: a professional judgement and a report. The judgement is the conclusion of the whole process - an informed professional view, based on the examination, the measurements and the assessment against the benchmark, on whether the LEV is providing adequate control of the exposure. It's not a bare pass/fail, but a reasoned conclusion on whether the system is doing its job. The report then documents it all: the examination (what was inspected and its condition), the measurements (the actual performance readings), the assessment against the benchmark, any faults found, and what needs doing to put them right. So you come away with a documented picture of the system's state, its measured performance, and any action needed - not just a certificate saying 'passed'. This report is valuable in two ways: it tells you what to fix to keep the system working, and it's one of the key documents an HSE inspector asks for (the evidence the LEV is a proven, assessed control). A report that's just a pass slip, with no measurements or detail, isn't the substantive record a proper examination produces. So you get a judgement on the control and a detailed, actionable report. So a judgement and a documented report of performance, faults and actions. This is general information. This is general information.

Because it combines two things: the thorough examination (the systematic inspection of the system's condition) and the test (the measurement of its performance), with an assessment against a benchmark judging it all - both parts are needed, so the name describes the process of examining thoroughly and testing the performance. It's called a thorough examination and test because the process genuinely combines those two distinct activities - a thorough examination and a test - and both are needed to establish whether the system controls the exposure. The thorough examination is the systematic inspection of the system's condition: the tester examines the whole system (hoods, ducting, fan, filter, discharge) for faults that degrade performance - damage, wear, blockages, leaks, worn or modified parts. The test is the measurement of the system's actual performance: the readings (airflow velocities, capture velocities, pressures) that quantify what the system is doing. Both are needed because each catches what the other might miss: the examination finds physical condition faults (a split duct, a clogged filter) that explain or predict a performance problem, while the measurements quantify the performance itself, which the examination alone couldn't establish. An assessment against a benchmark then judges the measured performance against how the system should perform. So the name isn't just a formal label - it describes the process: examine the system thoroughly for its condition, test (measure) its performance, and assess that against the benchmark. Understanding the name helps understand why a mere look-over isn't a proper thorough examination and test - it's missing the 'test' (the measurement). So it's called that because it combines a thorough examination with a performance test. So because it's both a condition examination and a performance test. This is general information. This is general information.