Ventilation expert: Restaurants often do not reopen after a fire

The kitchen is the heart of the restaurant, where the chef combines unique flavors in dishes, giving the place its own special atmosphere. At the same time, the kitchen can also pose the greatest risk for business. In most cases, the restaurant is no longer open after a fire accident. Lauris Kruza, member of the board of the European Ventilation Hygiene Association ( EVHA ) and VEGA 1 Serviss project manager, lists the most common reasons why fires occur in the kitchen, and shares useful tips on how to reduce the risks.

Fire statistics from Australia, Great Britain and the United States show that most restaurant fires occur in kitchens. Half of all commercial kitchen fires start during the cooking process, and almost all of them (90%) end up in kitchen exhaust ventilation systems, through which the fire spreads further throughout the building. One of the main fire risks in the catering business is dirty kitchen exhaust ventilation.

The place of origin of a fire is usually a stove, a deep fryer or an overheated wok- a fire requires all three prerequisites: oxygen, heat and "fuel" or grease. If grease deposits have accumulated in the extract system, they, in combination with oxygen and high heat, result in a fire disaster. Fires in ventilation systems can be very intense and reach temperatures of up to 1000°C within minutes. It is hot enough to melt various metals and ignite the surrounding finishing materials.

"Since oxygen and heat cannot be eliminated from the daily life of the kitchen, one thing that everyone can control to reduce the risk of fire is to clean the ventilation ducts of grease deposits. Grease accumulated in ventilation air ducts serves as a strong catalyst for fire, therefore dirty or unclean ventilation systems are a real threat to a fire accident," Mr.Kruza says. "Based on the recommendations of the London Fire Service for restaurant owners, clean air ducts are important as the first condition for a safe kitchen."

Fire safety of ventilation systems is not only the responsibility of designers and installers of ventilation systems. The actions of building owners, managers, as well as users of the premises are also very important to ensure safety in the building. The regulations of the Latvian Cabinet of Ministers provide a series of conditions for the designer and builder to prevent the spread of fire in buildings and provide a description of preventive actions to keep the building safe for use. They clearly state that any mechanical ventilation system must be inspected and cleaned at least once every five years, while ventilation systems extracting flammable gases, vapors or dust must be inspected and cleaned at least once a year.

How to reduce fire risks in the kitchen?

Kitchen exhaust ventilation systems must be equipped with protective devices that prevent foreign bodies from entering the system - appropriate grease filters. Grease particles can be divided into three categories: grease gas particles ranging from 0.03 to 0.5 microns, grease vapor particles (a combination of grease and water particles) ranging from 0.5 to 6.0 microns, and grease spatter or larger visible particles, ranging from 6.0 to 150 microns. Different filters are designed for different particle size ranges, and not all devices can effectively capture all particle sizes. Elevated temperatures during the cooking process turn some of the fat into a gaseous phase that cannot be captured by the filters, and which eventually condenses and accumulates on the walls of the ventilation ducts. Grease filters cannot prevent grease from entering kitchen exhaust systems, but they can reduce and extend the time between system cleaning intervals.

"Very often, after fire damage, restaurants never reopen. If the restaurant continues to work after the disaster, it is often the case that the flow of people has decreased, as guests prefer other places. Undeniably, the risk increases exponentially for kitchens located on the premises of large structures, i.e. high-rise buildings, hospitals, hotels, airports and shopping malls," says Mr.Kruza. The potential for massive damage is proportional to the size of the building.

Insurance policies may not cover damages if ventilation systems are found not to have been regularly cleaned. Anyone working in the hospitality industry should note that ventilation maintenance and cleaning should be entrusted to professionals who perform it according to the LVS EN15780 standard.