People in the workplace and living spaces such as homes, hospitals, schools, theaters, hotels should have created the right microclimate to protect their health and well-being. This is particularly important in the aspect of occupational psychology and occupational hygiene.
Microclimate in the encyclopaedic sense is a climate characteristic of a small part of the environment. The geographical microclimate may be characterized by geographical area (eg, a basin or a ravine) as well as a man-made creature (car interior, apartment, production hall).
The influence on the microclimate, especially the factors mentioned above, has a great influence on ventilation.
Ventilation is the exchange of indoor air, which involves removing contaminated or hot air and bringing in clean or cool air.
The visible effects of poor ventilation are:
- rear air through the ventilation grille,
- frosted windows,
- condensed water vapor on cool surfaces of walls and objects,
- air intake through exhaust grates in the kitchen or bathroom,
- swelling of wooden furniture and flooring.
Invisible effects of bad ventilation are:
- pain and dizziness, fatigue, mucosal irritations, throat irritation, skin sensitization, allergies,
- penetration of moisture into the walls and gradual destruction of them.
The consequence of poor ventilation and breathing of contaminated air may be asthma or other airway diseases, and even cancers.
Improper ventilation in rooms with gas heating may lead to the release of carbon monoxide. Carbon monoxide poisoning can have very serious health consequences, can be fatal.
The air outside the buildings is less or more polluted, especially in the summer. They are dense in the air foreign substances in the form of dust, fog, smoke, vapor, steam or gas. Therefore, the important task of ventilation is to ensure that a certain amount of air is maintained in the room. This is achieved not only by constant air freshening in the room, but also by inlet air filtration. The filters and dust collectors are used, and cyclones are used to purge extract air.
For the correct selection of the air filter, the required level of clean air in the room or the permissible values of the pollutant emissions at the exhaust.
Taking into account air purification methods, we divide the filters into:
- Mechanical filters (nonwoven) - the dust is separated by mechanical means. The effects of inertia and diffusion of dust particles are used. These particles reach the surface of the fiber and remain there until the corresponding amount of the material accumulates. The retention of individual dust particles occurs through electrostatic forces. The better the non-woven filter and the thicker the sealant, the higher its percentage of retention, but the higher the pressure drop.
- Adsorption filters - primarily activated carbon is used as the filter material. Filter cartridges or plate filter elements made of activated carbon serve to separate organic substances as well as microbial contaminants containing bacteria and viruses. These filters should be replaced when saturation is reached.
- Electrostatic precipitators - a kind of dust collector in which the removal of dust from the gas (process gas, exhaust gases or other exhaust gases, air) takes place by using electrostatic force (Coulomb's law) acting on particles of this dust.
According to the degree of separation (filtration) of pollutants, the filters are divided into:
- Coarse filter (pre-filter) - they have good filtration efficiency only dusts larger than 10 μm. They are used as pre-filters in equipment requiring multi-stage purification.
- Fine filters - used in ventilation and air conditioning of rooms with average requirements, for particulate matter with a particle size greater than 1 μm.
- Very fine filters - are used to separate very fine particles of dust, such as soot from the paint nebula in the paint booths.
- Slurry filters - are used wherever the amount of suspensions and embryos contained in the intake air must be very low. They are mainly used for air sterilization.
The filters used in ventilation, taking into account their construction can be divided into:
- Tape filters - the filter element is a nonwoven tape; A roll with a clean filter tape is attached to the upper part. They are installed in comfortable air conditioning systems to clean the intake air and also as pre-filters in hospital facilities. The width of the tape is between 900 and 2000 m. The velocity of the air flow is between 2.5 and 3 m / s, hence the air flow in the individual filters reaches max. 90 000 m / h.
- Circulatory filters - The filter tape is arranged in a V-shaped housing to increase the filter surface. These filters can be equipped with an automatic cleaning system.
- Chamber filters - are made as wall, ceiling or duct filters; Bag or bag filters, used as suspension filters, are particularly suitable.
Multi-stage air filtration technology:
1. microparticle HEPA filter
2. odor and gaseous filter
3. pre-treatment filter
Pre-filters - are used in ventilation and air-conditioning systems of rooms with average air quality requirements and in rooms with high air purity requirements as pre-filtration filters with higher filtration efficiency.
Fine filters - are used as the last filtration step in ventilation and air conditioning systems of rooms with high air purity requirements and in ventilation systems of rooms with very high air purity requirements against high efficiency filters.
Active carbon is a material commonly used as an absorbent material (in various cleansing techniques).
Active carbon allows you to absorb a variety of substances, mainly organic, in the air, and also neutralize odors.