Designing ventilation systems

Designing ventilation systems is a key element in creating a comfortable and safe space, whether in residential, commercial or industrial buildings. An efficient ventilation system not only ensures the maintenance of an optimal microclimate, but also plays an important role in ensuring the health of the occupants.It is the designer’s job to design a system that will effectively remove contaminated air and allow fresh air in. It helps maintain an optimal humidity balance and prevents condensation and mold growth. Air quality affects productivity and concentration.

Modern systems are able to minimize energy consumption while maintaining high performance. This is achieved by using highly efficient EC (electronically commutated) fan and pump motors with up to 90% efficiency instead of standard induction motors (70-80% efficiency).

Recuperative heat exchangers with up to 85% efficiency are also used, allowing heat energy to be returned back to the ventilation system from the exhaust air.

An automated control system based on CO2, humidity and temperature sensors optimizes ventilation operation by switching fans on and off when necessary. This saves 30-50% energy compared to uncontrolled systems.

Ventilation should be designed to prevent the spread of fire and smoke in the event of a fire.

Basic principles and approaches to design

Why do I need a ventilation design?

Different types of buildings require an individual approach to the design of ventilation systems, taking into account their specific features and functional purpose.

Shopping centers and entertainment complexes

In shopping centers and entertainment complexes, ventilation systems should include high-efficiency filters (at least class H13 according to EN 1822) to clean the air from microorganisms. This helps to block the spread of viral and bacterial infections through ventilation. In addition, it is important to organize air flows in such a way that the air from rooms with large crowds of people (e.g., food courts) does not get into other areas of the complex. And negative pressure should be created in bathrooms to prevent unpleasant odors and germs from escaping.

In the event of a fire, the supply and exhaust ventilation systems must switch to evacuation mode to prevent smoke in the escape routes. This is achieved by creating overpressure in stairwells and elevator shafts by supplying outside air.

Exhaust systems from rooms with fire sources shall be switched to the maximum capacity mode. Backup fans and power supply sources shall be provided to ensure continuous operation of the systems during the estimated evacuation time.

Exhaust ventilation from rooms with possible fire occurrence should have backup fans and emergency power supply to maintain the system operation during the time required for evacuation.

Industrial buildings

In industrial buildings, special attention is paid to the removal of harmful emissions and pollutants that may occur during production. Designing a ventilation system in such facilities requires taking into account the specifics of production processes, as well as ensuring the safety and health of workers. It is also important to ensure effective removal of heat generated during the operation of equipment.

Small business facilities

For small businesses such as offices, stores or small cafes, it is important to create a comfortable environment for visitors and employees. Ventilation systems in such facilities should be adapted to the size of the premises and their functional purpose. This can include both general ventilation systems and local exhaust systems, such as for kitchens in cafes.

Private houses and apartments

In residential buildings, including private houses and apartments, the design of ventilation systems is aimed at creating a healthy living environment. It is important to take into account the individual needs of the occupants as well as the design of the building. Ventilation systems in dwellings should provide sufficient fresh air supply, prevent condensation and mold formation, and be energy efficient.

What modern supply and exhaust ventilation consists of

Modern supply and exhaust ventilation is a complex system that provides not only the supply of fresh air into the room, but also the removal of exhaust air. The main elements of such a system include:

1. Air inlets: These are responsible for supplying fresh air into the room. This can be either natural ventilation through windows and ventilation ducts or mechanical ventilation using fans and ducts.
2. Exhaust units: These are responsible for removing exhaust air from the room. These can be exhaust fans installed in bathrooms, kitchens, and other areas.
3. Filters: Clean the supply air from dust, allergens and other contaminants.
4. Heat exchangers: Heat exchangers: Used in heat recovery systems to improve energy efficiency by storing heat from the exhaust air and using it to heat the supply air.
5. Control and automation systems: Allow the ventilation system to be adjusted to meet current needs, such as changing the intensity of ventilation according to the time of day or the number of people in the room.
6. Ductwork and distribution: Used to transport air around the building and distribute it evenly throughout the rooms.

Main advantages of design

Designing a ventilation system has a number of important advantages:

1. Creating an optimal microclimate: A properly designed ventilation system helps to maintain comfortable air temperature and humidity, which has a positive effect on people’s well-being.
2. Improved air quality: A ventilation system reduces the concentration of carbon dioxide, odors and harmful impurities in the air, helping to maintain health and improve performance.
3. Energy efficiency: Modern ventilation systems with heat recovery can save on heating costs, as the heat from the exhaust air is used to heat the incoming air.
4. Noise reduction: A well-designed ventilation system reduces the penetration of street noise into the room.
5. Flexibility and adaptability: The design allows for a system that is maximally adapted to the specific conditions and needs of the building.

Regulatory and legislative aspects

Normative documents and standards

The design of ventilation systems must strictly comply with regulations and standards that set out the requirements for the safety, efficiency and environmental performance of ventilation systems. The main regulations and standards include:

1. SNiP (Construction Norms and Rules): These documents contain basic requirements for the design, installation and operation of ventilation systems. They define indoor climate parameters, air quality requirements and fire safety measures.
2. GOSTs (State Standards): This category includes standards regulating the quality and safety of equipment for ventilation systems, as well as test and control methods.
3. Technical regulations: These documents establish minimum requirements for the safety and efficiency of ventilation systems, as well as labeling and documentation requirements.
4. Local building codes and regulations: Different regions may have additional requirements for ventilation systems that take into account climatic conditions and local environmental standards.
5. International standards (e.g. ISO, ASHRAE): In the case of facility design for international companies or international projects, global standards may apply, which are often more stringent than national regulations.
6. Environmental standards (e.g. LEED, BREEAM): These focus on creating environmentally friendly and energy efficient buildings. Compliance with these standards increases the green credentials of the facility and its market value.

Stages of ventilation system design

Preparatory stage

• Technical specification (includes: microclimate parameters, system performance, energy efficiency and environmental requirements)
• Feasibility study (selection of equipment, materials and technologies)
• Development of technical proposal
• Project development
• Preliminary design (basic ideas and concepts, preliminary calculations and schemes)
• Technical design (detailed system design, detailed technical calculations)
• Detail design (final drawings and specifications)
• Preparation of documentation for construction and installation (drawings, technical specifications, installation and operating instructions, estimates for construction and installation work)

Final stage

The project undergoes the necessary expertise to verify compliance with all regulatory requirements and standards. After successful completion of the expertise, the project is approved for implementation.

At the last stage preparations are made for the direct construction and installation of the ventilation system, including the purchase of materials and equipment, as well as the selection of contractors.

Design approaches

Standard and individual design approaches

There are two main approaches to designing ventilation systems: standard and customized.

The standard approach involves the use of standard solutions and equipment. It is used in projects of standard buildings, such as typical residential buildings or office centers. The advantages are speed of design, cost reduction and ease of implementation.

Individual approach is needed in cases when standard solutions are not suitable due to special requirements of the object. These may be buildings with unique architecture, specific operational requirements or special environmental conditions. It ensures maximum compliance of all elements of the ventilation system with the requirements and peculiarities of a particular object, but requires more time and resources for development.

Financial aspect

The following formula can be used to predict the cost of developing design documentation for ventilation systems:
C = S x P x K

Where: S – area of premises for which ventilation is designed, m2 P – an enlarged indicator of the cost of design for 1 m2 (for Ukraine can be taken in the region of 25-35 UAH/m2 depending on the complexity of the object) K – correction factor that takes into account additional factors (1.1 – 1.5).

For example, for an administrative building with an area of 5000 m2: S = 5000 m2 P = 30 UAH/m2 K = 1.2

Then the cost of the project will be: S = 5000 x 30 x 1,2 = 180 000 UAH.

In the case of increasing the area of the object the cost of design will also increase proportionally. The coefficient K can be varied taking into account additional requirements.