What's measured
Before any airflow is measured, a thorough examination and test begins with a careful look at the physical system. The visual and structural stage - checking hoods, ductwork, filters and fans for wear, damage and unauthorised changes - is where many of the biggest defects are found.
The short answer
Before any airflow is measured, a thorough examination and test begins with a careful look at the physical system. The visual and structural stage - checking hoods, ductwork, filters and fans for wear, damage and unauthorised changes - is where many of the biggest defects are found, and it sets up everything the measurements then confirm.
The detail
The examiner works through the system's visible parts: hoods for dents, corrosion and damage; ductwork for splits, disconnected sections, crushed flexible hose and dampers or blast gates left in the wrong position; filters for seal integrity and correct fitting; fans and their drives for wear. Each of these can wreck performance without touching the fan's output - a leaking duct joint or a hood knocked out of alignment quietly bleeds away the capture the system needs. Flexible hose is a frequent culprit, crushing behind machinery or splitting at the cuffs where it flexes, and a blast gate closed off for one job and never reopened can starve a whole branch of the system.
This stage also checks that the system still matches the job it is controlling. Processes move, extra hoods get spliced in, machines are relocated and workarounds appear, so an examiner looks for alterations that were never designed or commissioned. A system that has been quietly modified may no longer control the process it now serves, even if every original component still works.
What it means for you
The visual inspection matters because a large share of real-world LEV faults are mechanical and obvious once you look - a filter fitted without its seal, a duct that has parted at a joint, a damper closed by someone chasing quieter airflow. These are found by eye, not by an anemometer, and they are often the defects that most reduce protection.
It is also the stage that guides the rest of the test. What the examiner sees tells them where to measure and what to expect, so the visual and structural checks and the performance readings work together. A thorough examination that skipped straight to airflow numbers would miss exactly the kind of physical fault that airflow numbers are then used to confirm. It is also where an examiner records the wear that has not yet caused a fault but will, so the report can flag it for attention before the next test rather than after a failure.
The service behind the guide
We start every examination with a thorough visual and structural survey of your system, then measure to confirm what we find, with a clear report and remedial actions.
Questions
No. It begins with a visual and structural inspection of hoods, ductwork, filters and fans, looking for wear, damage, corrosion, blockages and alterations. The measurements come after and confirm what the inspection finds.
Dented or corroded hoods, split or disconnected ducts, crushed flexible hose, dampers left in the wrong position, missing filter seals and worn fans - anything physical that can undermine capture.
Because a system modified after commissioning may no longer control the process it now serves. Spliced-in hoods, relocated machines and undesigned changes can quietly defeat the original design.
Yes, and the reverse is true too. A visible fault like a parted duct joint or an unsealed filter can wreck performance while the fan still runs, which is why the eye comes before the instrument.
What the examiner sees tells them where to measure and what readings to expect, so the inspection and the performance measurements work together rather than in isolation.
Phoenix Duct Clean · by the numbers
We start every examination with a full visual and structural survey of your system, then measure to confirm what we find, with a clear report and remedial actions.