COSHH, law & TExT
A new system gets proven once at commissioning - and that first set of figures is what every later test is measured against.
The short answer
Commissioning and thorough examination are both tests, but they do different jobs at different points in a system's life. Commissioning is the initial prove-it-works stage when an LEV system is installed or significantly modified: it confirms the system meets its design intent and records the baseline performance figures. The thorough examination and test is the recurring check, at least every 14 months, that the system still conforms to those figures and still controls exposure. One establishes the standard; the other verifies you are still meeting it.
The detail
At commissioning, an installer or specialist measures the system's performance - capture and face velocities at each hood, transport velocities in the ducts, fan and filter performance - and confirms it does what it was designed to do. Those figures are then transferred into the user manual and logbook as the benchmarks the system should maintain.
This is the reference point everything later depends on. Without a commissioning record, there is no agreed statement of what good looks like for that specific system, so every future test has to work from assumptions rather than facts. Commissioning also marks the point where responsibility passes to the system owner to keep it within those parameters.
What it means for you
An ongoing thorough examination measures current performance and asks whether it still conforms to the commissioning benchmarks and still controls exposure. When the baseline exists, that is a clean comparison. When it does not - which is common on older or undocumented systems - the examiner can still carry out the TExT, but has to judge performance against design intent or professional expectation and state that in the report. That absence is itself a finding.
The proper fix is not to keep testing around the gap but to establish a baseline - effectively a new commissioning-level assessment - so future examinations have a firm reference. In short: commissioning and the thorough examination are not interchangeable, and a system that was never properly commissioned carries that weakness into every test until it is put right.
The service behind the guide
We carry out the thorough examination and test, and where there is no commissioning data we can help establish the baseline your future tests need - so the comparison is real, not assumed.
Questions
Commissioning is the initial prove-it-works test on a new or modified system that sets the baseline performance figures. The thorough examination and test is the recurring check - at least every 14 months - that the system still conforms to those figures and controls exposure.
No. They are separate. Commissioning establishes the benchmarks; the thorough examination verifies against them over time. A newly commissioned system still enters the 14-month TExT cycle.
It is the agreed statement of what good performance looks like for that specific system. Without it, every thorough examination has to judge performance against assumptions rather than measured facts, which weakens the assessment.
The examiner can still test it but must judge performance against design intent or professional expectation and record that the baseline is missing - itself a finding. The fix is to establish a baseline so future tests have a reference point.
Whenever a system is significantly modified - new hoods, ducting changes, a different fan or process - because the original baseline no longer describes the system. A re-commissioning-level assessment resets the benchmarks.
Phoenix Duct Clean · by the numbers
We can carry out the thorough examination and, where the baseline is missing, help you establish the reference point future tests need. Call or email to talk it through.