Health and safety in commercial kitchens

New guidance on preventing exposure to carbon monoxide in commercial kitchens has serious implications for facilities managers, says ductwork specialist Francesca Smith

11 February 2016 | By Francesca Smith

The Health and Safety Executive (HSE) has released guidance for premises using appliances such as tandoor ovens, charcoal grills and wood-fired pizza ovens.

By following guidance in Catering Information Sheet No. 26 (CAIS26)*, FMs with solid fuel appliances on their premises can stop workers, customers, and even people in neighbouring properties from being exposed to harmful levels of carbon monoxide. The poisonous gas is released when solid fuel is burned and can quickly build up without proper ventilation. CAIS26 can be summarised as follows.

1. Installation

When obtaining a solid fuel appliance, seek competent advice on all technicalities relating to installation, ventilation, extraction and maintenance, from organisations such as the official body to approve biomass and solid fuel heating appliances HETAS, Catering Equipment Distributors Association, Catering Equipment Suppliers Association, and the Building and Engineering Services Association.

2. Design

Determine what material your flue/extraction system is constructed from. Stainless steel is not corroded by the gases released during solid fuel combustion, however, many kitchen extraction systems are made from galvanised steel, which is liable to corrosion. This could potentially leak carbon monoxide. An extraction system and its components, such as induction fans, should be designed to withstand high temperatures and corrosive flue gases. Also, ensure that there is minimal risk of heat being transferred to any combustible materials close to the flue/ductwork.

3. Ventilation & extraction

Your flue should be located outside the building and must terminate to the outside of the building at a safe atmosphere or discharge point. Seek advice from your local authority's building control department to make sure you comply.

In commercial kitchens with both a natural draught flue and a mechanical extraction system, gases can be drawn back down the flue into the room. In this instance, having an equal supply of make-up air to compensate for combustion and removal of resulting gases is very important.

4. Maintain, test & clean

Extraction systems for commercial solid fuel appliances must be fully examined and tested by an expert at least once every 14 months. Have an appropriate regular cleaning and maintenance programme carried out by professionals to make sure your extraction system continues to function properly. A specialist contractor may be needed to clean the extraction system.

5. Monitoring

Carbon monoxide gas builds up quickly. A functioning audible carbon monoxide alarm complying with BS EN 50291 should be fitted in accordance with the manufacturer's instructions.Evacuate your premises if the alarm goes off. Repeated activation of the alarm indicates a problem, which should be fully investigated before the appliance is put back into use. Battery - rather than mains-operated devices - should be tested regularly. If possible, the appliance/alarm should be interlocked with any fitted mechanical ventilation.

Make sure that the extraction system fan stays switched on until all solid fuel has been extinguished, even if nobody is on the premises, by running it 24 hours a day or by interlocking the extraction fan to the carbon monoxide detector. This will protect people in neighbouring properties from leaks, and the building will be safe to enter for the next shift.

6. Selecting & storing fuel

Only use fuel suitable for your appliance that is recommended by responsible suppliers/manufacturers, unless your extraction system can safely remove the products of combustion from alternative fuels. Burn only the amount of fuel you need to minimise the amount of carbon monoxide produced and to keep your costs down. Store solid fuel in a dry and ventilated area, or in line with the manufacturer/supplier's storage instructions.

7. Training

Make sure that your workers are aware of the risks and control measures required to operate the solid fuel appliance safely, of the signs and symptoms of carbon monoxide exposure - and how to follow the emergency procedures.

8. Cleaning

Cleaning a ventilation system, which can collect flammable grease, can do more damage than good. Cleaning usually has to be done with a caustic chemical. Any residue can significantly speed up the rate of corrosion, and can corrode stainless steel as well as galvanised steel. This can inadvertently worsen a carbon monoxide leak into a building.

The system must be checked for corrosion as part of a rigorous planned safety check. Grease builds up irrespective of the fabrication, which introduces the need for cleaning with a potentially corrosive chemical.

Cleaning must be tackled by a skilled, accredited specialist person whose methodology is exact enough to remove all traces of caustic chemicals. And, though the guidance states that extraction systems must be examined and tested every 14 months - and cleaned regularly - FMs must check for specific stipulations in their building's insurance. Most insurers won't pay out in the event of a fire or a carbon monoxide leak if they can cite non-compliance..  

Francesca Smith is managing director of ductwork specialist Bright Hygiene