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Controls and PPE

Ventilation and Extraction for Chemical Safety

How Ventilation and LEV Control Chemical Vapours, Mist, and Cellar Gas

Quick answer

Some of the most serious chemical risks in hospitality are the ones you breathe rather than touch: the vapour from a corrosive cleaner used in a small room, the mist thrown up by spraying a sanitiser, the fumes from cleaning a hot canopy, and the carbon dioxide that can collect in a poorly ventilated cellar. Ventilation is the engineering control that deals with all of these, and it sits high in the hierarchy of control because it protects everyone in the area, not just the person doing the job. This article explains how general ventilation and local exhaust ventilation reduce exposure, where each is needed in a hospitality setting, and what COSHH expects of any extraction system you rely on.

  • Ventilation is an engineering control that protects everyone in the area, which is why it sits above PPE.
  • General ventilation dilutes the air; local exhaust ventilation captures the contaminant at source and is needed for significant or frequent hazards.
  • Cleaning hot canopies, spraying chemicals, warewashing, and cellar gas are the main airborne risks in hospitality.

Key takeaways

Ventilation is an engineering control that protects everyone in the area, which is why it sits above PPE.
General ventilation dilutes the air; local exhaust ventilation captures the contaminant at source and is needed for significant or frequent hazards.
Cleaning hot canopies, spraying chemicals, warewashing, and cellar gas are the main airborne risks in hospitality.
Cellar carbon dioxide is heavier than air and can collect low down, making cellar ventilation a life-safety control.
LEV you rely on must be examined and tested by a competent person at regular intervals, with records kept.

General Ventilation Versus Local Exhaust Ventilation

There are two broad ways to control airborne hazards. General ventilation dilutes the air in a space, through open windows, doors, or a building ventilation system, and is enough for low-level, occasional hazards such as the light vapour from a diluted sanitiser used now and then in a well-aired room. Local exhaust ventilation, or LEV, is engineered extraction that captures the contaminant at or near its source before it reaches the people working, and is needed where the hazard is significant or frequent. The canopy over a cooking line and the extraction over a warewasher are forms of LEV. The principle is that capturing a vapour or mist at source is far more effective than letting it disperse into the room and trying to dilute it afterwards, which is why LEV sits above PPE in the hierarchy of control.
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Where Ventilation Matters Most in Hospitality

A few situations drive the need for good ventilation. Cleaning a hot extraction canopy or a combi oven with a corrosive product releases vapour that is far worse in a confined, warm space, so the work should be done with the extraction running and the area ventilated. Spraying sanitisers and disinfectants creates a breathable mist, which is one reason wiping is preferable to spraying into the air. Warewashing and laundry produce steam and chemical mist that local extraction should carry away. Above all, cellars present a specific and dangerous risk: carbon dioxide and mixed cellar gases are heavier than air and can collect in a poorly ventilated cellar, displacing oxygen, which is why cellar ventilation and, where needed, gas detection are essential. Matching the level of ventilation to where the airborne hazard actually arises is the heart of this control.

Cellar Gas and Confined Spaces

Cellars deserve particular attention because the consequences of getting ventilation wrong are severe. Carbon dioxide used for dispensing, and the gas given off by cask beer, can build up in a cellar that is sealed or poorly ventilated, and because it is heavier than air it gathers low down where someone bending to change a keg is breathing. A high concentration can cause unconsciousness quickly, and the danger is that the gas gives little warning. Adequate cellar ventilation is the primary control, supported by carbon dioxide detection with an alarm where the risk warrants it, secure storage of cylinders, and a rule never to enter a cellar where an alarm is sounding or gas is suspected. This is one of the clearest cases in hospitality where ventilation is not a comfort measure but a genuine life-safety control, and it should be reflected as such in the COSHH assessment for the cellar.

Maintaining and Testing Extraction

Ventilation only protects people if it actually works, and COSHH requires engineering controls to be maintained in efficient working order. For local exhaust ventilation that you rely on as a control, the regulations require a thorough examination and test by a competent person at regular intervals, commonly at least every fourteen months for many systems, with the records kept. Beyond the formal test, day-to-day maintenance matters: greasy, blocked canopy filters lose their pull and become a fire risk as well as letting fumes back into the kitchen, so filters need regular cleaning. Cellar ventilation and gas alarms need checking so they are working when relied upon. A canopy that has not been tested or a gas alarm that has never been checked is a control on paper only. Recording the testing and maintenance of your ventilation is part of demonstrating that your COSHH controls are genuinely in place.

What to do next

Run extraction when cleaning hot equipment

Clean canopies and ovens with corrosive products only with the extraction running and the area ventilated, to carry vapour away from staff.

Check cellar ventilation and gas detection

Make sure cellars are properly ventilated and that any carbon dioxide alarm is fitted, working, and checked, given the risk of gas collecting low down.

Schedule LEV testing and filter cleaning

Arrange a thorough examination and test of extraction you rely on at the required interval, and keep canopy filters clean between tests.

Common mistakes to avoid

Mistake
Relying on a canopy that is never tested or cleaned
Instead
Greasy filters and untested extraction stop pulling fumes away and become a fire risk. Clean filters regularly and have LEV thoroughly examined and tested at the required interval.
Mistake
Treating cellar ventilation as optional
Instead
Carbon dioxide collects low in a poorly ventilated cellar and can cause unconsciousness with little warning. Cellar ventilation and, where warranted, gas detection are life-safety controls, not comfort measures.

Frequently asked questions

What is LEV in COSHH?

LEV stands for local exhaust ventilation, an engineered extraction system that captures a vapour, mist, or fume at or near its source before it reaches the people working. Canopies over cooking lines and extraction over warewashers are examples used in hospitality.

How often does LEV need testing?

Local exhaust ventilation that you rely on as a COSHH control must be thoroughly examined and tested by a competent person at regular intervals, which for many systems is at least every fourteen months. The test records should be kept.

Why is cellar ventilation a COSHH issue?

Carbon dioxide and other cellar gases are heavier than air and can collect low in a poorly ventilated cellar, displacing oxygen and causing unconsciousness with little warning. Cellar ventilation, and gas detection where warranted, are essential controls.

Is opening a window enough ventilation?

General ventilation such as open windows can be enough for low-level, occasional hazards. For significant or frequent airborne hazards, such as cleaning hot equipment with corrosive products, you need local exhaust ventilation that captures the contaminant at source.

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