Phoenix Journal · LEV Testing
Headachy, drowsy staff who perk up on their day off are rarely just tired - they are often the first sign that your kitchen extraction has quietly stopped protecting them.
When extraction stops protecting people
A kitchen that leaves your team headachy, drowsy and reaching for the back door is not a team having an off week - it is often a warning that the extraction has quietly stopped doing its job.
Good extraction is invisible. You only notice it when it goes wrong, and by then the effects have usually crept up on people for weeks. A canopy that once pulled fumes cleanly away starts to let heat, steam and combustion gases hang in the air. The room feels heavier. Chefs sweat more, tire faster and lose concentration on a hot line where concentration keeps fingers away from knives and burns off pans.
The symptoms are easy to dismiss because they mimic ordinary tiredness - headaches by mid-shift, a fuzzy head, nausea, dizziness when you stand up, watering eyes and a scratchy throat. One person feeling rough is a coincidence. A pattern across the same section, easing on days off and returning within an hour of service, is a signal. That pattern is exactly what tends to surface later in sickness records and return-to-work chats, and it is worth taking seriously the first time you see it rather than the fifth.
Under the Workplace (Health, Safety and Welfare) Regulations 1992 you are required to provide effective and suitable ventilation in every enclosed workplace. A kitchen where staff keep feeling unwell is, on the face of it, a room where that duty is not being met - and the fix usually starts with understanding what the air is carrying.
Cooking on gas or solid fuel produces a cocktail of things you do not want people breathing all day. The extraction is there to capture them at source and carry them outside before they reach the people working under the canopy. When it underperforms, several build up together.
The reason these matter together is that they share symptoms. Nobody in the kitchen is going to feel one gas and not another - they simply feel unwell, and the cause hides in plain sight.
The honest answer is that you often cannot, by feel alone - which is the whole problem. Air that is making people ill gives you no reliable warning through your senses. Carbon monoxide has no smell. Heat you notice, but you acclimatise to it and stop registering how bad it has become. So the tell-tales are usually indirect, and they show up in patterns rather than moments.
These are the same threads that, joined up, tend to appear in the way poor extraction shows up in staff health records long before anyone connects them to the fan on the roof. And if the room feels muggy and close even when the extract is clearly running, that is its own diagnostic clue - there is a reason your kitchen stays humid even with extraction, and it usually points at airflow that is not balanced or not moving what it should.
Common root causes behind all of this are dull and fixable - grease-clogged filters and ductwork choking the airflow, fans that have slipped out of specification, dampers stuck part-closed, or an extract that was uprated over the years while the fresh-air supply was never touched. You will not spot most of these from the floor. They need measuring.
Your kitchen canopy is a form of local exhaust ventilation - LEV - and under Regulation 9 of the Control of Substances Hazardous to Health Regulations (COSHH) it must be given a thorough examination and test at least once every 14 months. HSE’s guidance on controlling cooking fumes points to the same interval. This is not box-ticking - it is the mechanism that turns a vague sense that the air is off into hard numbers.
A proper LEV thorough examination and test, carried out to the HSG258 standard by an engineer holding recognised competence such as the BOHS P601 qualification, does three things. It examines the system - canopy, filters, ductwork, fan and controls - for the faults above. It measures actual performance, including capture and containment at the canopy face and airflow through the system, against the design intent. And it gives you a written report with a clear verdict and a list of the actions needed to bring it back into line. You are required to keep that record for at least five years.
Crucially, the test tells you whether the extraction is genuinely protecting people or merely running. A fan can spin at full tilt and still capture almost nothing if the balance is wrong. Where combustion gases are a concern, testing sits alongside good practice like gas interlock systems, which shut off the gas supply if the ventilation is not running - so the burners simply cannot fire into a room with no working extraction. Together they close the gap between “the extractor is on” and “the air is safe”.
If staff have been feeling ill, the sequence is simple - test the system, act on the report, and re-check that the fix worked. Do that and you replace guesswork with evidence, protect the people on your line, and have the records to show you met your duty.
Questions
It can genuinely make people ill. When extraction underperforms, carbon monoxide, nitrogen dioxide, heat and grease vapour build up in the room. Low-level carbon monoxide alone causes headaches, nausea, dizziness and confusion over a shift, and because it is odourless it is easily mistaken for a passing bug. A pattern of symptoms that eases on days off and returns during service is a strong sign the air is the cause.
Under Regulation 9 of the COSHH Regulations, a kitchen extraction canopy is treated as local exhaust ventilation and must have a thorough examination and test at least once every 14 months, with higher-risk setups tested more often. The test should be carried out to the HSG258 standard by a competent engineer, and you must keep the report for a minimum of five years.
Phoenix Duct Clean · by the numbers
Phoenix examines and tests local exhaust ventilation to HSG258 and COSHH - measured, reported and certificated, UK-wide.