17. 8. 2023

Ventilation of buildings - requirements for ventilation of residential and residence rooms

The basic means for ensuring the quality of the indoor environment is to ensure sufficient ventilation.

Nowadays, with constantly rising energy prices, emphasis is placed on building elements mainly in terms of thermal technical properties with a high requirement for air tightness. Windows and doors, which previously ensured natural ventilation by infiltration through window joints, are now installed in buildings almost airtight using sealing systems of self-adhesive strips. For this reason, natural ventilation by infiltration through window joints and leaks in the perimeter shell cannot be used for permanent ventilation of buildings with new and reconstructed windows.

Picture - sealing system of self-adhesive strips

Non-compliance with mandatory requirements

Unfortunately, in practice we often encounter cases of residential buildings that do not meet the required permanent ventilation. This can result in a higher concentration of pollutants or increased humidity in the indoor environment and the formation of mold.

Mandatory requirements

mandatory requirements for ventilation are defined by Decree No. 268/2009 Coll. Decree on Technical Requirements for Buildings and Regulation No. 10/2016 Coll. hl. of Prague, which establish general requirements for land use and technical requirements for construction in the capital city of Prague.

Decree No. 268/2009 Coll. decree on technical requirements for buildings.

This decree refers directly to the ČSN standard values in § 11 on the requirements for ventilation of residential and residential rooms (ČSN EN 15665/Z1 – Ventilation of buildings – Determination of performance criteria for ventilation systems of residential buildings).

Decree No. 268/2009 Coll.

§ 11

Day and artificial lighting, ventilation and heating

(3) Living rooms must have sufficient ventilation with outside air and heating in accordance with standard values, with the possibility of regulating the internal temperature.

(5) Living rooms must have sufficient natural or forced ventilation and must be sufficiently heated with the possibility of regulation internal temperature. For the ventilation of living rooms, a minimum amount of exchanged outdoor air of 25 m3/h per person, or a minimum ventilation intensity of 0.5 1/h must be ensured during the stay of persons. Carbon dioxide CO2 serves as an indicator of the quality of the indoor environment, the concentration of which in the indoor air must not exceed 1500 ppm.

Prague Building Regulations (PSP) - Regulation No. 10/2016 Coll. hl. City of Prague, which lays down general requirements for land use and technical requirements for construction in the capital city of Prague (Prague building regulations)

PSP describe the requirements for ventilation in § 46 Ventilation and heating.

In this paragraph, the basic requirements for the ventilation of residential and residential rooms are given, with the fact that the minimum values of the dose of outdoor air per person in the room are given in Annex No. 1 to this regulation. These values are based on ČSN EN 15665. These are minimum values.

In the case of residential rooms, the requirement to comply with the maximum CO2 concentration specified in paragraph 2 must also be met.

PSP

Ventilation and heating § 46

(1) Residential and living rooms must have sufficient natural or forced ventilation to meet the values specified in point 4 of Annex No. 1 to this regulation and must be sufficiently heated with the possibility of temperature regulation.

(2) Living rooms, with the exception of rooms in structures for family recreation and accommodation units, must be ventilated so that the value of the maximum permissible concentration of carbon dioxide of 1,500 ppm at residence of persons.

(3) Toilets, personal hygiene areas and cooking areas must be effectively ventilated in accordance with the values specified in item 4 of Annex No. 1 to this regulation and must be heated with the possibility of regulating the heat supply. Pantries and food storage chambers must be effectively ventilated.

appendix No. 1 — specific values 4 / ventilation (to the provisions of Section 46, paragraphs 1 and 3)

Collateral Request

Continuous ventilation (outdoor air flow) per person

Minimum value 15 [m3 /h per person]

Shock ventilation (extract air flow)

Kitchen 100 [m3 /h]

Bathrooms 50 [m3 /h]

WC 25 [m3 /h]

Requirements ČSN EN 15665/Z1 – Ventilation of buildings – Determination of performance criteria for ventilation systems of residential buildings

Air flow requirements

The basic requirement of the ČSN EN 15665/Z1 standard is to ensure a permanent supply of outdoor air with a minimum ventilation intensity of 0.3 h-1 in living spaces (rooms, bedrooms, etc.) and kitchens. For a higher required indoor air quality, in accordance with ČSN EN 15251, a ventilation intensity of 0.5 to 0.7 h-1 is recommended.

In other spaces (hallway, utility room, corridors, etc.) it is necessary to ensure air flow according to the purpose and equipment of the room.

Tab. 1 Requirements for ventilation of residential buildings according to ČSN EN 15665/Z1

CSN requirements for the ventilation concept

The quality of ventilation is decisively influenced by the supply of outside air, which can be solved in the following ways:

- Ventilation slits that are integrated into the fillings of building openings

- Specific inlet openings in the perimeter walls (slits, circular openings)

- Ventilation unit

Air supply through window joints cannot be used with new and reconstructed windows.

Conclusion

The mandatory requirement to ensure permanent ventilation of residential buildings is identical in all documents and is based on ČSN. A minimum value of 15 [m3/h per person] is required. These can be ensured by ventilation slits in the window frames, supply holes in the perimeter walls, or a ventilation unit (with recuperation).

Inlet slits and inlet openings must be completed with the installation of a fan ensuring continuous air flow in the apartment. Most often, a two-speed fan is installed in toilets and bathrooms with an electrical input of less than 30 W (necessary to meet the requirements for eco-design of ventilation units of Commission Regulation (EU) No. 1253/2014 of July 7, 2014).

The requirement for permanent ventilation in new buildings cannot be replaced by air intake through window joints, or occasional window ventilation.