Requirements for Exhaust Fans
Requirements for the ventilation system, based on safety and efficient operation, so they should not be neglected by apartment owners. Here are some basic rules
- Noise levels for ventilation equipment installed in a dwelling may not exceed 30 dB. Only quiet household devices should be used in the bathroom.
- For maximum duct draft in the duct, the ceiling ventilator must be installed in front of the main door where it takes in fresh air.
- The device must be installed as far away as possible from electric heating mechanisms, because it can withstand exposure to temperatures up to 50 degrees. If it rises to a critical level, the fan fails.
- The capacity, performance and energy consumption of the device depend on the size of the room and the frequency of use.
- The ventilation duct must be clean. Standards for the installation and performance of ventilation systems are listed in SNiP 41-01-2003. This document describes the maximum allowable level of dust in the air duct and the norm of air exchange.
Apartments in apartment buildings have a natural ventilation system. This ventilation system consists of communal ventilation shafts through which used stale air is exhausted. In bathrooms, kitchens, installed special louvers, behind which begins ventilation duct.
Good ventilation allows exhaust air to escape outside the apartment. A pressurized supply air stream displaces stale air, filling the space of the rooms. This is how the natural ventilation system works, unless it is disturbed.
But natural ventilation does not always cope with its functions. The reasons why it does not work or works poorly:
- Clogged ventilation ducts. In old buildings ventilation shafts can be clogged with dust, grease, and debris from years of use. This prevents effective air circulation in the apartment.
- Airtightness of the dwelling. The natural air inflow that used to come in through wooden windows and doors is now severely limited. Double-glazed windows installed in houses, apartments save heat, but do not let in fresh air from the street.
- Overlapping of air ducts. If the neighbors blocked the ventilation ducts, which is prohibited, the ventilation system can be disrupted throughout the house.
Calculation of fan performance for bathroom and toilet
To determine which fan to put on the bathroom and toilet, it is necessary to calculate the necessary air exchange. Calculation. a whole system, but when installing a fan, the main focus is on its characteristics: it provides the required speed of air movement. In order not to get into calculations, its performance is taken by the average norms.
Air exchange rate for different rooms. They are used to calculate the ventilation in the bathroom and toilet
As you can see from the table (it’s from SNIP) for the bathroom per hour must be “pumped” at least 25 m ³ / h, for a toilet or combined toilet speed should be twice as much. 50 m ³ / h. These are minimum values. In reality, through the three (or two) technical rooms. kitchen, toilet, bathroom. should leave as much air as is received through fresh air supply ventilation.
Calculation of air intake is carried out by the volume of all residential premises and usually exceeds it by 1.5-2 times, and to ensure the required air exchange the minimum values given in the table is not enough. For this reason, the performance of fans are taken at least twice as much, and for kitchens even more: so there will be no unpleasant smells in the apartment, as well as dampness and fungi. Therefore, going to get a fan in the bathroom with less than 100 m ³ / h it is better not to take.
How to choose an exhaust fan for your home or apartment
The quality of indoor air in residential buildings depends on many parameters and sources. such as:
- The number of inhabitants (time of occupancy of the room);
- emissions from activities (smoking, humidity, intensive cooking);
- harmful emissions from furniture (formaldehyde), materials used in interior decoration (ammonia), detergents, hobbies, etc.д.
In accordance with the State Standards of Ukraine on ventilation, there are recommendations for the minimum supply and exhaust air for each type of room.
It is also possible to choose the quality of indoor climate conditions:
a) Increased optimum. for people with special needs. such as: the disabled, the sick, young children, the elderly.
b) Optimal. create a feeling of thermal comfort and provide conditions for high levels of performance.
c) Allowable. The level of thermoregulatory effort, which is within the limits of physiological adaptation, but does not cause a worsening of the health condition.
The required amount of air for bedrooms and living rooms must be calculated as a replacement of one volume of air per hour, equal to the volume of the room.
Necessary extraction rates for bath, toilet, kitchen are calculated according to the DBN B.2.5-67:2013 Table X4. Minimum ventilation air flow rate for residential buildings.
Elements of Ventilation Systems
Simply put, in the living areas (bedrooms, living rooms) we supply fresh air, and from the bathroom, kitchen, closets and utility rooms we pull polluted air. This way we can organise a complete air exchange throughout the apartment.
Achievement of indoor air quality depends mainly on three factors:
- removal of contamination from rooms with high humidity (bathrooms, kitchens, toilets). Humidity causes the greatest impact on health and the building itself (condensation, mold).
- General ventilation of all rooms in the dwelling;
- General ventilation of all living areas with a fresh air index in the main rooms (bedroom and living room). Work on the CO2 sensor.
There is ventilation in every home. It is built in the form of small ducts inside the walls of the building and its main purpose. ensure air circulation in all rooms. Unfortunately, natural ventilation ducts tend to clog (and, both in high-rise buildings, as well as in private homes), or may be improperly designed from the beginning, which significantly reduces the efficiency of their functioning, and leads to the need to install additional equipment, such as a fan for exhaust. If appears:
- Heavy indoor air;
- Long-term aeration of unpleasant odors;
- Condensation on the walls and furniture;
- fogging of mirrors and window panes.
This indicates a malfunction of the ventilation system. And the right fan is the only way to solve these problems and return a comfortable indoor climate.
It is a special mechanical device that is installed on the air shaft inlet and significantly enhances the natural processes of air exchange of rooms with the street. It is important to know that to buy the exhaust fan is easy, much harder to make the right choice, as follows in our article.
Supply air damper (duct) for natural ventilation in the house
To ensure an influx of fresh air into the room from the street, supply valves (ducts) are installed in the outer wall or window.
The valve in the wall or window must provide:
- The influx of fresh air into the room from the street in the required volume. The maximum capacity of the supply air damper (m3/hour) Depending on the pressure difference at the inlet and outlet of the duct must be specified in the technical documentation.
- The possibility of regulating the capacity of the supply valve.
- Protection from penetration of street noise through the valve into the room. The degree of street noise reduction must be written on the product data sheet.
- Purification of air fed into the room from outdoor dust and pollen of plants.
- Protection against rain, insects through the valve from the street into the room.
- Thermal insulation to protect the walls against freezing and condensation on the parts of the valve.
It is recommended to install the air inlet valve in the room at a height of more than 2 meters. From the floor, at the top of a window or exterior wall. Cold air coming in through the valve from the street at this height has time to heat up before it reaches the person in the room.
Air inlets are also available for installation in the wall below the window above the radiator. The air coming in from the street is heated by the heat from the radiator.
Sill inlet valve can be made by yourself. For this purpose, under the window sill install a plastic or metal stainless steel box with a cross section of about 600×25 mm., which creates a gap for the air passage from the street. The air in the room comes out of the box from the top downwards. From outside the gap is not visible from the street, as it is covered by an apron of drip moulding. On the room side the box is equipped with a damper to regulate the air flow.
Air inlets that are installed in windows, as a rule, less protect the premises from street noise, dust, pollen of plants than inlets in the wall.
Installing an air inlet channel in the wall is usually more expensive than paying extra for a window with an air inlet valve.
The minimum number of air inlets per floor of the house is determined by calculation. For a building with naturally aspirated exhaust ventilation ducts, it is recommended that the supply air capacity be taken for a pressure differential of 10 Pa. In a house with forced exhaust ventilation, the supply valve capacity is taken for a pressure difference of 20 Pa.
Goods for construction and repair
For example, we have a supply air damper with a maximum capacity of 30 m 3 /hour. at a pressure difference of 10 Pa.
Minimum required capacity of the natural ventilation ducts on the floor of the house is 270 m3 /h (see “Adjusting the air inlets to the floor of the house” on page 24). example above). It is clear that it is necessary to provide the same volume of fresh air into the house from the street.
Then, 270m3 /h : 30m3 /h = 9 pcs. air inlets need to be installed on the floor in the rooms of the house, at a minimum.
Nine air inlets to be installed in five rooms in the house (from the example above). When allocating the volume of each room, we need to ensure that each room has a multiplicity of airflow of 1 1/hr. (one volume per hour). If necessary, decide on installing additional air inlets.
The additional air inflow that will occur as a result of not sealing the outer shell of the house will create some reserve capacity of the air inlets. Adjust the capacity of the air inlets in each room of the house.
Supply air valve performance in the system of natural ventilation of a private home depends on the pressure difference between the air outside and inside the house. Differential pressure, in turn, is determined by temperature differences in the outdoors and indoors, as well as by wind pressure.
The capacity of the air inlet valve is adjusted manually or automatically during operation.
Automatic air inlets allow a comfort level of humidity to be maintained in the room without human intervention, as well as saving heating energy.
Automatic air inlet valves can vary the capacity depending on the following parameters:
- From differential pressure. An increase in the pressure differential between indoors and outdoors causes the air flow rate to decrease, and vice versa. Thanks to this, the air inflow is restricted when the outside temperature drops, as well as in case of a strong wind.
- Depending on the level of relative humidity in the room. At humidity levels below 35%, the amount of air passing through the damper is limited to a minimum. If the humidity is 70% or more the damper blades open fully.
- From outside temperatures. If the outdoor temperature drops, the amount of air passing through the valve decreases.
Where to install an exhaust fan
The appliance is recommended to be placed in places where unpleasant odors, moisture and high temperatures accumulate (kitchens, bathrooms, showers, laundry rooms).
Bathroom exhaust fans are designed to remove odors and moisture. They are usually equipped with humidity sensors, timers, switches and a high degree of protection against water ingress. Their use ensures no condensation on pipes/walls and no fungus.
A kitchen exhaust fan is characterized by:
A kitchen exhaust fan provides rapid removal of air during cooking and temperature regulation. This appliance will prevent exhaust air from spreading to other rooms and places.
Causes of odors from ventilation
The main reason for unpleasant smells from the ventilation system is the draught overturning effect. The physics of the process is as follows: the higher the ambient air temperature and the lower in the room, the worse the natural draught. Under certain conditions, instead of removing air masses, through the vent. The exhaust grille is filled with air from the grille. In other words, if there is not enough draft in the exhaust duct and the air supply in the apartments is not good, the air flow from the kitchen umbrella of your neighbors can enter the rooms upstream in the riser.
Check for “reverse draft” is simple: hold a strip of paper up to the ventilation grille.
Smells coming out of your neighbor’s exhaust ventilator can be the result of no stopping plugs. For an example, consider the ventilation system of one riser of a typical block of flats (series II-18, I 209A and others).) It consists of a common duct and two dispersal ducts. The system works like this: contaminated air from the apartment must rise through the dispersal channel to a height of 2.5-2.7 m (depending on the project), “run into” the plug (on the floor above) and go through a special “window” into the common mine. The problem is that in 90% of cases there are no such plugs! Without plugs, such a system, consisting of a common shaft with two ducts (separated by plugs in dispersed sections) turns into three transit shafts.
How to choose a fan for bathroom and toilet
It seems simple, we decided that we need a fan, we go to the store and buy. But only cats are born quickly. In the store there’s a big surprise of many kinds and models. Where there are dozens or even a couple of hundred of them. And you will hover over the question of which fan to put in the bathroom?
It’s no wonder. Different types, power, models, installation methods, characteristics can hardly be understood in this variety of technical progress in the field of ventilation. Even the salespeople have a hard time understanding if the assortment is huge.
So we made a guide to bathroom fans. To make your task easier and help you quickly buy the right equipment. And first, let’s deal with the general characteristics of fans for the bathroom
Axial, centrifugal what does it mean
This type or type of fan. It tells you about the design of the equipment and its operation.
An axial fan is a bladed impeller in a casing. Spins the impeller of the motor on whose rotor it is mounted. The blades are tilted inward relative to the plane of placement, they well pull the air and move it in a straight line. That’s why this type is called an axial fan. It has a good efficiency, medium noise level, and is most often used for bathroom installations.
A centrifugal fan works differently. The air is sucked in by a turbine with blades. Inside the housing, the flow is wound into a spiral and is accelerated by centrifugal force. The flow does not exit in a straight line, but at an angle of 90 degrees in a special device volute. The centrifugal fan is also called a centrifugal fan.
It has a lower capacity than axial, but can produce a flow of varying degrees of pressure. Noise levels are low or medium depending on the direction of the rotor blades. It makes less noise with a front bend and more noise with a back one, but it saves energy.
Overhead or ducted
Ventilation equipment is available for outdoor installation and for indoor. Outdoor type of installation is mounted on the wall or ceiling at the outlet of the ventilation hole in the shaft or in the pipe system. Duct fan is a built-in equipment that is placed inside the ventilation duct (air duct). Ventilation duct systems are made of metal or plastic. For the bathroom, plastic duct systems are often used, such as those by Vents.
Often, the outlet to the ventilation shaft is located in the toilet. For bathroom exhaust put duct with intake grille. A ventilation sleeve is pulled up to a shaft window. Duct fan with an extra grille is installed in the toilet. The hood simultaneously draws air from the entire bathroom and directs it into the ventilation shaft of the house. Outdoor and duct fans can be either axial or centrifugal.
Choosing a bathroom fan by capacity
The power level or fan capacity is one of the main features. In fact it is used to select the right extraction system when paired with the technology (axial/centrifugal). Performance tells how many cubic meters of air the fan pumps in an hour 100, 200, 300.
To choose the right power, you need to calculate the volume of the bathroom and multiply it by 8. An eight is the sanitary requirement for the number of air changes per hour. Simply put, the fan must pump the volume of your eight bathrooms. Then it will be clean, beautiful and no mold.
How to calculate the volume? Very simply, take the length of the room, the width, the height of the ceiling, multiply and you get the desired number. Multiply that by eight and you have the minimum capacity.
Choice of a fan in the bathroom by noise level
Hoods are noisy, of course, but not too noisy. If you want a completely silent take an axial model from the Silent line. They have a motor mount on silent blocks that dampens noise and vibration. Among the quiet ones, you can choose a model with a noise level of even 22 dB.
Centrifugal fans are louder because the turbine pumps the air under pressure. But they make about as much noise as a computer cooler. It doesn’t stop you from watching movies, listening to music or playing games. So too, the fan will just be the background if you’re in the bathroom when it’s on.
What is the best bathroom fan or toilet fan reviews about additional features
Modern technology can do a lot, and fans are available with a variety of additional functions. Their list includes:
- Additional sensors. They measure humidity or react to motion.
- Off timer. On it sets the time delay off, a minimum of 2 minutes maximum 30.
- Light indicator. Lights up while the fan is running.
- Lanyard switch. You can turn the hood on and off when you need it. Like when you take a shower or a bath. That is, when the bathroom light comes on, the fan does not start automatically.
- Automatic blinds. They are used to close the ventilation grille after turning off the duct fan.
- Non-return valve. Its main task is to prevent the penetration of foreign odors from the ventilation shaft.
Feedback from our customers shows that they mostly buy models with humidity sensors and timer switches. A non-return valve that closes the air flow from the duct or duct back to the fan has already become a part of the design. It is very seldom sold separately and is considered an option.
The degree of moisture protection
All bathroom fans have an increased moisture protection rating of 4-5, dust protection can be either zero or 3-4. The equipment certificate will indicate IP X4, 34, 44, 45.
We have got the characteristics, now let’s talk about the range.
Is it necessary to have an extractor fan in the bathroom if there is a window?
In this case the answer is also yes. definitely necessary. The principle of operation of the ventilation system in any room is the exhaust of exhaust air masses and the subsequent influx of fresh air from outside (t.е. from the street).
In case of natural ventilation, the air is drawn in through open windows, doors, through gaps/slots and the air is exhausted through natural draught (ventilation shafts). Therefore, if there is a window in the bathroom, this will not ensure that the exhaust air can be removed to its full extent. Besides, during winter time air and temperature outside won’t allow to open windows very often.