Ledaire systems help meet ventilation guidelines

Ledaire comments on HSE guidelines for air ventilation in kitchens and food preparation areas.

Without adequate ventilation, caterers run alarming risks to staff safety, food quality and customer satisfaction.

Staff stressed by excessive heat under-perform, food tastes are corrupted and safety precautions risk going down the pan.

There is enough choice out there for customers to be more selective about where they spend their money.

Ventilation is quite simple; air has to be removed, and replaced - constantly.

Enough air has to be removed to take away deadly combustion fumes and corrupting cooking odours, as close to the source as possible.

The HSE especially recommends the trusty hood for coping with the bulk of extraction above gas-fired appliances, and any others for that matter capable of generating heat, water vapour, fumes and odours.

HSE recommendations for canopy overhangs - island canopies between 250mm and 300mm and wall mounted canopies 250mm front and 150mm at ends.

When installing new equipment, it is worth making sure that each appliance's required air extraction rates can be obtained.

Then by adding up the air velocity requirements for each appliance, a total air movement requirement can be calculated for the hood.

The HSE guidelines however, provide some air flow rate estimations for different work capacities.

Recommended air flow rates: light cooking use 0.25l/s; medium cooking use 0.4l/s; heavy duty cooking 0.5l/s.

To be effective, Steve Leonard from Ledaire stresses that a ventilation system must allow for extracted air to be replaced.

The HSE estimates that around 85 per cent of the total air needed tends to be supplied by mechanical ventilation, with the rest coming from adjoining areas.

This keeps the kitchen under negative pressure, which helps to prevent the escape of cooking odours.

Not wanting to scare smaller businesses into wiping out their profits with unnecessary ventilation fitting installations, the HSE points out that they can naturally ventilate for replacement air through wall grilles, doors and windows.

Any air fed into the kitchen should be fed from clean areas where pest entry can be controlled and tobacco smoke is absent.

An air velocity of more than 0.25l/s passing through a serving hatch would probably be considered as too draughty by customers.

This rate may be tolerated or even welcomed in hot areas such as serving counters.

Ledaire systems feed cool air through insulated hood sections, from dampened grilles with individually adjustable supply nozzles for concentrating on hot-spots.

Considerations when installing new equipment, workload levels: cleaning requirements; combustion air requirements; grease removal requirements; building limitations; suitable sources of non-mechanically fed air renewal; elimination of pest entry and grease accumulations; energy efficiency; opportunities to interlock ventilation supply with gas supply for max efficiency.

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