Effective ventilation in a cafe is no less important than the art of cooks and the quickness of waiters. Fresh air, the absence of “kitchen” smells and a comfortable temperature are indispensable attributes of a successful establishment. The creation and implementation of a cafe ventilation project requires serious costs, as well as the work of competent professionals. The task is complicated when the restaurant has a separate smoking room.
Most often, for the sake of economy, restaurants and cafes are located on the first or ground floor of residential or office buildings. Therefore, we will focus on the arrangement of the ventilation of the cafe in a residential building.
Features ventilation cafes and restaurants
The project is created taking into account the requirements SNiP 2.04.05 - 91 and 2.08.02 – 89 and departmental standards for cafe ventilation. According to which it is allowed to attach or integrate into residential buildings a cafe with a work schedule of up to 11 pm and an area of up to 250 square meters. meters, no more than 50 seats.
Features of ventilation in a cafe and restaurant:
- high density of guests, including smokers;
- it is necessary to preserve the integrity of the decoration of the room, as well as its architectural features;
- A variety of equipment is operating in production and utility rooms, including heat and moisture.
The ventilation installation in a cafe located in a residential building should provide a microclimate in the room, operate quietly, without disturbing the residents, without filling their apartments with steam and restaurant smells.
Therefore, the upper ends of the exhaust pipes must be located at the level of the roof of the house!
In special cases, the cafe’s ventilation outlet is 25 meters from the apartment building.
Most often, such a "decoration" of the facade is undesirable. Therefore, the cafe resort to the installation of filters and noise absorbers ventilation. They are effective, but expensive. For ventilation, a cafe located in a residential building should select the quietest units with minimal vibration.
Zoning a restaurant or cafe
The ventilation project of a cafe or restaurant divides its area into several zones with different loads on the system:
- hall for visitors;
- kitchen;
- Bathrooms
- utility rooms.
If the hall of the restaurant or cafe is small, a unified ventilation system is created for the kitchen and dining area.
According to cafe ventilation standards for large establishments, it is necessary to build several systems, each of which serves a separate zone.
For instance:
- In the kitchen, the general supply and exhaust ventilation system of the cafe is supplemented by local extracts installed above the hobs;
- In the guest area, you need not only blowing off the exhaust air, but also supplying fresh air. The volume of supply air should be slightly larger than the volume of the removed. A backwater is created that prevents the penetration of odors from the kitchen. Smoky rooms create a depleted atmosphere that accelerates the removal of tobacco smoke. That is, the hood prevails over the feed;
- In the utility rooms, their own inflow-blowing system is most often organized, separate from the hall. In pantries for storing food stocks, ventilation is combined with air conditioning.
A lot of heat and moisture is released in the premises of the hot workshop, therefore, proper ventilation of this room largely determines the future atmosphere of the establishment.
An important feature: so that the smells from the hot shop do not fall into the dining room, the latter provides a slight air pressure.
It is also necessary to zon the dining room, especially if it is not possible to make a separate room for smokers. For this, fresh air is fed through slotted gratings. You can use both air from the street, and from the air conditioning system.
The air supplied through the slit grate creates an air curtain - a flow directed from top to bottom and preventing air from mixing in areas for smokers and non-smokers.
The air curtain is supplemented with a slight air supply from the side of the non-smoking room.
Ventilation schemes of hot shops
The ventilation system of the kitchen in the cafe provides for the use of localizing units of the inflow-blowing system, where the inflow is slightly weaker than blowing, which eliminates the spread of smells in the guest area.
The most common scheme is mixing, in which an air supply unit is located in one corner of the ceiling, and an exhaust system in the other. Supply air is supplied 5 to 6 degrees colder than indoor air.
A very effective and gaining popularity scheme is by mixing air flows.
And a very effective scheme based on the principle of displacing exhaust air with fresh.
Air supply is provided from the lower part of the room at a speed of up to 0.3 m \ h, the supply air temperature is 2 degrees lower than the room temperature. The exhaust hole is located under the ceiling.
With this scheme, the air flows are not mixed together, which is necessary, for example, for halls for smokers.
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- Scheme of supply and exhaust installations
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- Exhaust air displacement circuit
Hot Shop Ventilation Rules
The problem of the hot shops is the desire of the owner to minimize the area of the kitchen. Thus, there is an excess of heat-generating units per unit area. With standards up to 210 watts, in fact, the thermal stress can be up to 2 kW per 1 sq. meter. In the hot season, kitchen workers fall into inhuman conditions. An increase in air exchange only creates a draft feeling. Therefore, it is recommended to supply 2/3 of the air to the kitchen from the guest room, which will simultaneously provide a discharge. The air is cooled before being fed. For umbrellas located above the hobs, it is advisable to install a separate fan, and for the general kitchen system - another. Since the temperature and humidity in the kitchen room largely depend on the effectiveness of the umbrellas, separate channels lead to them, to which it is advisable not to connect diffusers and bends.
The optimal type of fan for an umbrella is considered a "snail". As a rule, the fan works for two seasons, failing from the fat adhering to it. If the traction worsens, the chefs remove the grease filters, opening free access to dirty air and grease to the fan blades and even more quickly incapacitating it.
When developing a ventilation project in a cafe, especially a kitchen and a sink, you must take into account the norms for laying ventilation ducts:
- place for filter;
- the bias of the channel towards the sink;
- a mechanism for collecting fat;
- drainage for the outflow of degreasing agents from the ventilation ducts of the kitchen.
When installing ventilation in a cafe, it is important to follow the project instructions and mount the channels with the seams up (if rectangular galvanized ducts are used).
If air heated up to +150 degrees or higher will be removed from the kitchen, thermal insulation of pipes is necessary.
Design of ventilation systems in a cafe and restaurant
The basis for the project is the terms of reference drawn up by the customer. It stipulates important parameters and compiles the ventilation of the restaurant:
- number of seats for visitors;
- number of cafe employees;
- heat input data;
- the location of tables and seats for visitors;
- the presence of a hall or area for smokers;
- technical parameters of kitchen and washing equipment.
Unfortunately, all the guides for designing ventilation in restaurants and cafes were created about 30 years ago and are significantly outdated.
We recommend additionally referring to the following sources:
- terms of reference for the project, which will be implemented ventilation cafe;
- technical specifications of the proposed equipment;
- tables of local suction equipment of hot shops.
Since the most difficult months for ventilation are the hot months, the calculations are carried out precisely on the basis of “summer” loads.
Ventilation covers in hot workshops and washing rooms air volume up to 2 meters from the floor, in the dining room - up to 1.5 meters from the floor.
When creating a ventilation project for a cafe or restaurant, attention is also paid to the design of the hall. The location and size of the ducts crossing the guest area are discussed with the designer. Often, designers are asked to reduce the diameter of the air channels. This should never be done. A consensus needs to be found between design standards and room design. In the process of decorating the room, ventilation ducts are decorated, and their exits are covered with lattices of a suitable shape.
Air exchange rate and design temperature
Norms of air exchange rate and temperature in the premises of public catering enterprises:
- Dining room - temperature +18, the minimum flow of air is 30 cubic meters per hour per seat. Each visitor emits 100 kcal of heat per hour, taking into account this indicator, the temperature of the air drawn from the hall is calculated;
- For each employee, ventilation for a restaurant or cafe counts 60 cubic meters of air per hour;
- Hot shop - temperature +5 (estimated), minimum air flow of 100 cubic meters per hour per worker. Or to calculate the total power consumption of the equipment is multiplied by 80 cubic meters per hour. This is an average indicator that you can focus on. Air is drawn through umbrellas with a temperature of +42 degrees. In the upper part of the kitchen, the air temperature is +30 degrees;
- Smoking room - temperature +18, air supply 110 cubic meters per hour.
To save on the operation of ventilation in a cafe and restaurant, you can provide for its adjustment depending on the number of visitors. The recuperator will also help save 50 - 70% of the energy through the use of heat from the removed air. But the recuperator can be used only from the heat of the dining room. Although very hot air comes from the kitchen, it is saturated with bits of fat. It can only be passed through a recuperator after careful and very expensive filtration.
Possible errors in cafe ventilation equipment
- Lower air consumption. If the owner decided to calculate the ventilation of the cafe with his own hands, an underestimation of air flow is possible. This method is used, for example, when it is impossible to install sufficiently powerful equipment. But the right thing is not to underestimate consumption, but to use heat recovery;
- Common kitchen and lounge system. This attempt to save on expensive equipment leads to a mixture of the smells of the guests' perfumes from the hall and fried onions from the kitchen. Thus, the task of the ventilation system in the cafe is not performed;
- The visitor and the employee are one and the same. Equipping the ventilation in the cafe with his own hands, the owner can calculate the average air exchange per person. Errors in calculations will make themselves felt during the cafe;
- Installation of a single duct air conditioner. Another option for trying to solve the problem of ventilation of a cafe with your own hands, without involving a designer. Ducted air conditioning creates powerful air movement from various parts of the hall. That is, air from the smokers area will enter the non-smoking area. And this is one of the most unpleasant factors that frighten visitors to the institution.
To avoid mistakes in arranging ventilation in a cafe, a video will help.
