Text consolidated by Valsts valodas centrs (State Language Centre) with amending regulations of: 16 June 2020 [shall come into force from 20 June 2020]; 13 May 2021 [shall come into force from 18 May 2021]; 19 October 2021 [shall come into force from 1 November 2021]; 20 September 2022 [shall come into force from 24 September 2022]; 17 January 2023 [shall come into force from 24 January 2023]. If a whole or part of a paragraph has been amended, the date of the amending regulation appears in square brackets at the end of the paragraph. If a whole paragraph or sub-paragraph has been deleted, the date of the deletion appears in square brackets beside the deleted paragraph or sub-paragraph.

Republic of Latvia Cabinet Regulation No. 310 Adopted 16 June 2015

Regulations Regarding the Latvian Building Code LBN 231-15, Heating and Ventilation of Residential and Public Buildings

Issued pursuant to
Section 5, Paragraph one, Clause 3 of the Construction Law

1. The Regulation approves the Latvian Building Code LBN 231-15, Heating and Ventilation of Residential and Public Buildings.

2. The Ministry of Economics shall, in cooperation with the relevant technical committee for standardisation, recommend to the national standardisation body a list of standards that need to be developed, adapted, and applied in connection with this Regulation.

3. The national standardisation body shall publish on its website www.lvs.lv a list of the Latvian national standards to be applied for the purpose of enforcement of the Latvian Building Code LBN 231-15, Heating and Ventilation of Residential and Public Buildings.

4. The building designs which have been developed or submitted for agreement to a building authority in accordance with specific procedures prior to the date of coming into force of this Regulation pursuant to the requirements of the laws and regulations applied in the relevant time period need not be revised in accordance with the Latvian Building Code LBN 231-15, Heating and Ventilation of Residential and Public Buildings.

5. The construction intention documentation which has been agreed upon (accepted) in accordance with the laws and regulations in the field of construction or submitted for agreement to an authority performing the functions of a building authority, until 25 October 2020, need not be revised in accordance with Paragraph 15.¹ and 15.² of the Latvian Building Code LBN 231-15, Heating and Ventilation of Residential and Public Buildings.

[16 June 2020]

6. The construction intention documentation which has been agreed upon (accepted) in accordance with the laws and regulations in the field of construction or submitted for agreement to an authority performing the functions of a building authority, until 1 January 2023, need not be revised in accordance with Paragraph 25.¹ of the Latvian Building Code LBN 231-15, Heating and Ventilation of Residential and Public Buildings.

[16 June 2020]

7. Paragraph 95.¹ of the Latvian Building Code LBN 231-15, Heating and Ventilation of Residential and Public Buildings, shall be applied to construction intentions initiated after 1 June 2021.

[13 May 2021]

8. The wording of this Regulation that was in force until 31 October 2021 shall be applied to the construction intention documentation which has been agreed upon (accepted) in accordance with the laws and regulations in the field of construction or submitted for agreement to an authority performing the functions of a building authority until 31 October 2021. The wording of this Regulation that was in force until 31 October 2021 shall be applied to the building designs for which the construction permits have been issued until 31 October 2021.

[19 October 2021]

Informative Reference to the European Union Directives

[20 September 2022]

The Regulation contains legal norms arising from:

1) Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (recast);

2) Directive (EU) 2018/884 of the European Parliament and of the Council of 30 May 2018 amending Directive 2010/31/EU on the energy performance of buildings and Directive 2012/27/EU on energy efficiency.

Prime Minister Laimdota Straujuma

Minister for Economics Dana Reizniece-Ozola

 

Approved by
Cabinet Regulation No. 310
of 16 June 2015

Latvian Building Code LBN 231-15, Heating and Ventilation of Residential and Public Buildings

1. General Provisions

1. The Building Code prescribes the requirements to be complied with when designing and installing heating, ventilation, and air conditioning systems for residential and public buildings that are to be newly built, renewed, and rebuilt, as well as the requirements for the design and installation of heating, ventilation, and air conditioning systems for rooms of other types of use in residential and public buildings.

2. The following terms are used in the Building Code:

2.1. outdoor air - air in the immediate surroundings outside the building;

2.1.¹ heating system - a combination of such components which are necessary to ensure the indoor air treatment so that the temperature is increased;

2.2. circulation air - air circulating in a room or extract air which is returned to the same room;

2.3. natural ventilation - air movement due to the difference in air density or the effect of wind;

2.4. two-level furnace - a local heating furnace built on two adjacent floors;

2.5. flue - channels created in the masonry (body) of a local heating appliance, designed for the circulation of combustion products;

2.6. chimney - a vertical fire-resistant structure supported on a foundation or foundation beams in which smoke ducts are built to remove such combustion products from the building which are generated in the heating appliance;

2.7. smoke duct - a channel built in a chimney or non-combustible wall (usually with a constant cross-section), designed for the flow of combustion products;

2.8. chimney flue - a section of smoke duct which connects the heating appliance with the chimney;

2.9. air conditioning - an automatically controlled air handling process that maintains the desired air quality in a room or its part regardless of the changes in outdoor air and the intensity of air pollution in the room;

2.10. air quality - air properties (air composition, concentration of dust and bacteria, temperature, relative humidity, speed of movement) that affect human health or sense of comfort;

2.11. infiltration - a building air intake through insufficiently sealed building envelopes;

2.12. exhaust air - air which is being discharged from the building;

2.13. engineering network shaft (duct) - an air space usually separated by vertical building envelopes with a standardised fire resistance limit in which the risers of ventilation air ducts, sewerage and other engineering networks are placed;

2.14. mechanical ventilation - movement of air using a fan;

2.15. extract air - air that is discharged from the room;

2.16. leakage - undesirable air circulation through insufficiently sealed air ducts;

2.17. transferred air - air which flows from one room to another;

2.18. supply air - air which is supplied to the room (outdoor air, recirculation air, transferred air, or infiltration air);

2.19. recirculation air - air which is reintroduced into the group of rooms from which it was discharged;

2.20. transit duct - air duct crossing a room that it does not service;

2.21. fire safety section - a structural installation of minimum dimensions specified in regulations, made of non-combustible material, which separates the internal plane of the smoke duct or heating appliance from the combustible structure of the building;

2.22. fire safety clearance - the minimum distance specified in regulations from the external surface of the heating appliance to the adjacent combustible structure of the building;

2.23. fireproof insulation - non-combustible fire protection material that increases the fire resistance limit of a structure or equipment;

2.24. fire safe valve - a non-combustible device or structure with a rated fire resistance limit which prevents the spread of fire and waste gases through air ducts between fire compartments or rooms separated by a fire-resistant structure;

2.25. ventilation - the movement and exchange of air in rooms to maintain the desired room air quality;

2.26. ventilation chamber - a room in which ventilation equipment is placed which serves two or more fire compartments;

2.27. ventilating duct - a duct which services one fire compartment and is connected to the ventilation riser, ventilation chamber, equipment servicing the room to be ventilated, or directly with outdoor air;

2.28. airing - periodic air exchange in a room which occurs by opening windows, doors, or special apertures, without the ability to precisely control the amount of exchanged air;

2.29. local heating appliance - a furnace built in a room, a kitchen hearth, a bath stove, fireplace where fuel is burned to heat the room, to prepare food, or to heat water.

[16 June 2020; 20 September 2022]

3. The standards the list of which has been published by the national standardisation body on the website www.lvs.lv shall be applied in designing heating, ventilation, and air conditioning systems in buildings.

3.¹ When designing heating systems, the capacity of such equipment which produces thermal energy shall be justified, taking into account the thermal energy demand in the building.

[19 October 2021]

2. Heating

2.1. General Requirements

4. Central heating boilers, central heating boiler equipment, heating furnaces, and fireplaces which are fuelled with solid or liquid fuel or gas, as well as other heating appliances shall be designed and constructed in such a way as to prevent the risk of ignition, explosion, or toxic gas leakage as well as other types of risks to human health and life.

4.¹ For heating residential and public buildings, economically justified heating systems with individual heat energy metering and regulation which ensure the use of renewable energy resources shall be used primarily.

[17 January 2023]

5. Central heating systems shall be designed and use boiler equipment the construction and structure of which meet the requirements of the applicable standards.

5.¹ When designing heating systems, the efficiency assessment of the heating system subsystems (heat output, distribution accumulation, generation) shall be taken into account in accordance with the standard LVS EN 15316-1:2021, Energy performance of buildings - Method for calculation of system energy requirements and system efficiencies - Part 1: General and energy performance expression, Module M3-1, M3-4, M3-9, M8-1 and M8-4.

[17 January 2023]

5.² When designing heating systems, heating loads for rooms shall be determined in accordance with the standard LVS EN 12831-1:2020, Energy performance of buildings - Method for calculation of the design heat load - Part 1: Space heating load, Module M3-3.

[17 January 2023]

5.³ Heating system capacities shall ensure indoor temperature during the heating period at least at category II level in accordance with the standard LVS EN 16798-1:2021, Energy performance of buildings - Ventilation for buildings - Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics - Module M1-6.

[17 January 2023]

6. It shall be permitted to install only non-combustible materials and products with appropriate fire resistance, corrosion resistance, and the necessary gas tightness in heating systems and heating appliances.

7. Heating appliances shall be designed and installed so that the surface temperature of any combustible material or structure near the device does not exceed 80 °C.

8. The fire safety of central heating boiler equipment shall meet the requirement laid down in Paragraph 7 of this Building Code if the distance from the outer surface of the boiler equipment to the combustible material or structure is at least 150 mm.

9. Heating appliances shall be designed and installed so that their maintenance and cleaning do not cause difficulties and complications during operation, and also so that they are sufficiently air-tight.

10. To ensure sufficient air supply into a heating appliance and complete combustion of fuel therein, the following equipment may be installed in the respective room:

10.1. a window equipped with self-regulating devices;

10.2. a self-regulating ventilation system;

10.3. direct outdoor air supply to the combustion chamber.

11. Gas heating systems shall be installed in accordance with the construction standard regarding internal gas line systems and gas equipment as well as the applicable standards.

12. Central heating systems, their pipelines and heaters shall be dimensioned and installed in accordance with the applicable standards.

12.¹ In multi-apartment buildings, a water central heating system shall be designed as a two-pipe heating system that is common for the entire building or part of the building. An independent heating system may be designed separately for each apartment (floor). It is recommended to provide for forced circulation in water heating systems.

[19 October 2021]

12.² If the flow and return distribution pipelines of the water central heating system in a multi-apartment building are located in the basement of the building, it is recommended to provide pressure regulators for the heating system risers.

[19 October 2021]

13. Central heating systems shall be designed and constructed in such a way that the user of the room would be able to regulate autonomously the temperature in each heated room.

14. The heating systems of buildings connected to the centralised heating system shall be equipped with automatic heat regulation and metering devices.

15. Heat regulation and metering devices shall be placed in rooms the height of which is at least 1.9 m and the width is at least 0.7 m.

15.¹ Each group of residential rooms and each group of non-residential rooms in multi-apartment residential buildings connected to a centralised heating system shall be equipped with remotely readable individual thermal energy meters or individual heat cost allocators for each heating element if the installation of individual thermal energy meters is not technically feasible or not economically justified.

[16 June 2020]

15.² Newly constructed buildings shall be equipped with self-regulating devices for separate regulation of air temperature in each room or group of rooms if it is technically feasible and economically justified.

[16 June 2020]

16. It shall be permitted to install local heating appliances operating with solid fuel at construction sites if the maximum parameters referred to in Table 1 of Annex 1 to this Building Code as well as the restrictions and requirements laid down in the environmental protection laws and regulations are complied with. If a building with furnace heating is being renovated or rebuilt, it shall be permitted to retain the furnace heating regardless of the number of floors and the total area of the building.

[19 October 2021]

17. The fireboxes of central heating appliances shall not be placed in rooms where people (except for service personnel) or animals are permanently present or in which easily flammable and combustible materials and substances are stored.

18. Furnaces intended to be fired periodically shall be designed and constructed so that, when fired twice a day, they compensate for the heat loss in the rooms. Air temperature fluctuations in rooms that are heated using intermittently fired furnaces shall not exceed ± 3 °C during a 24-hour period.

19. Furnaces and fireplaces that are fired with solid fuel shall be designed and constructed in accordance with the laws and regulations regarding fire safety, the technical specifications of the manufacturer, and the applicable standards.

20. The fire safety of furnaces and fireplaces fired with solid fuel shall meet the requirement laid down in Paragraph 7 of this Building Code if the distance from the outer surface of the furnace or fireplace to the combustible material or structure of the wall or ceiling is at least 500 mm.

21. Floors under furnaces and fireplaces shall be non-combustible or covered with a solid sheet of non-combustible material that is 150 mm larger than the dimensions of the heating appliance in the plan. The non-combustible material coating in front of the firebox doors of a closed-type heating appliance shall be 300 mm larger than the dimensions of the heating appliance in the plan, but in front of the firebox opening of an open-type heating appliance - 500 mm larger. The thickness of the non-combustible material sheet shall be at least 6 mm.

22. Furnaces fired with solid fuel may be equipped with a manual damper in the smoke duct. The thickness of the damper shall be at least 6 mm. In a closed position, the damper shall ensure free flow of at least 20 cm² in the cross-sectional area.

23. Hot water boilers built into furnaces or fireplaces shall not be connected to closed central heating systems, except for industrially manufactured devices which are designed for central heating systems and the conformity of which has been certified in accordance with the procedures laid down in the law On Conformity Assessment.

24. Furnaces and fireplaces shall not be connected to smoke ducts to which gas-fired heating appliances or air central heating systems are connected.

25. The air consumption required for the combustion process in a heating appliance shall not significantly affect the operation of ventilation systems. If a heating appliance consumes large amount of air, its supply shall be designed separately.

25.¹ Non-residential buildings the nominal rated capacity of which for the needs of a heating system (or combined heating and ventilation system) or the nominal rated capacity of which for the needs of an air conditioning system (or combined air conditioning and ventilation system) exceeds 290 kilowatts shall be equipped with a building automation and control system, if technically feasible and economically justified, which provides:

25.¹ 1. the possibility to continuously monitor, record, analyse, and adjust the energy use of the building;

25.¹ 2. the possibility to comparatively assess the energy efficiency of the building, to detect efficiency losses in the engineering systems of the building, and to inform the building manager of the possibilities for improving the energy efficiency of the building;

25.¹ 3. direct connection to the engineering system of the building and the ability to perform its functions independently of the manufacturer of the engineering system components.

[16 June 2020]

25.² [17 January 2023]

25.³ [17 January 2023]

25.⁴ The air temperature in the elevator machine room during the warm season shall not be higher than 40 °C.

[19 October 2021]

2.2. Requirements for Central Heating Boiler Equipment and Heating Equipment Fired with Liquid and Solid Fuel

26. Central heating boiler equipment, also heating (boiler) equipment fired with gas, solid and liquid fuel, shall be designed and installed in such a way that their energy efficiency is not lower than that specified in the applicable standards.

27. Rooms in which local central heating boiler devices fired with solid or liquid fuel or gas are located shall be separated from other rooms with fireproof partition walls the fire resistance limit of which is not below EI-60, fireproof ceilings the fire resistance limit of which is not below R-60, and fireproof doors the fire resistance limit of which is not below EI-30.

28. When installing boiler equipment the burner of which is designed for liquid fuel or gas, the burner shall be adjusted according to the capacity and operating mode of equipment. Flue gas losses in nominal operating mode shall not exceed 1.2 %. The soot factor indicator shall not exceed 2. The carbon monoxide (CO) content in flue gases shall not exceed 0.05 %.

29. The safety of heating equipment fired with liquid fuel shall not be less than that specified in the applicable standards.

30. Rooms containing liquid fuel tanks, if the total capacity of the tanks does not exceed 5 t of fuel, shall be separated from other rooms with fireproof partition walls the fire resistance limit of which is not below EI-60, fireproof ceilings the fire resistance limit of which is not below R-60, and fireproof doors the fire resistance limit of which is not below EI-30. For these rooms, an external window shall be constructed with an area of at least 0.05 m², calculating per cubic metre of the room, but no less than 0.25 m².

31. For heating appliances that are fired with liquid fuel, direct supply of outdoor air to the burner equipment is recommended.

32. Stocks of solid fuel exceeding 1000 kg shall be stored separately from central heating boiler equipment and heating equipment.

33. The fuel tank of liquid fuel heating equipment and devices which is exceeding 490 litres shall be equipped with restrictive structures that contain fuel leakage in case of tank damage. The abovementioned requirement shall not apply to tanks with double walls the construction of which prevents uncontrolled leakage of the substance outside the tank in the event of damage to the inner wall.

2.3. Requirements for Centralised Heating Boiler Houses and Boiler Equipment with a Capacity Exceeding 500 kW

34. Boiler equipment shall be equipped with thermal insulation which ensures that the temperature of the external surfaces of the boiler equipment (except for firebox doors, hatches, and other metal parts) does not exceed 35 °C if the indoor temperature of the boiler house is 20 °C.

35. For boilers fired with gas or liquid fuel, with a nominal capacity exceeding 500 kW, the temperature of the exhaust flue gases in stable operating mode shall not exceed 250 °C.

36. Boiler equipment shall be supplied with thermometers for measuring water temperature and exhaust flue gas temperature, as well as with an appropriate opening for taking samples for exhaust flue gas analysis.

37. In the room where the boiler equipment is located, flammable or explosive manufacturing processes shall not be carried out, as well as fire-hazardous or explosive substances and materials shall not be stored there.

38. Rooms containing boiler equipment shall be separated from other rooms with fireproof partition walls the fire resistance limit of which is not below EI-120, fireproof ceilings the fire resistance limit of which is not below R-120, and fireproof doors the fire resistance limit of which is not below EI-90. Exits from rooms containing boiler equipment shall be constructed directly to the outside or through an air-exchange passage, and they shall not have joint evacuation routes with other rooms.

39. Central heating boilers with an overpressure firebox and capacity exceeding 120 kW may only be placed in rooms that have openings for permanent ventilation.

2.4. Requirements for Flues and Chimneys

40. The cross-section of chimney flues and other flues shall be designed according to the capacity of the heating appliance or boiler equipment. The cross-sectional area of the chimney flue and the flue for gas and liquid fuel fireboxes may not be less than 50 cm², and the diameter - not less than 80 mm. For solid fuel fireboxes, the cross-sectional area of the chimney flue and the flue must not be less than 175 cm², and the diameter - not less than 150 mm.

41. A separate chimney or smoke duct shall be installed for each furnace or hearth. It shall be permitted to connect two heating appliances to one smoke duct if they are located in the same apartment and on the same floor. When connecting two chimneys, it is necessary to construct a 12 cm thick dividing partition at a height of at least one metre, measured from the bottom of the connection.

42. Chimneys and smoke ducts built from solid burnt clay bricks shall be vertical and without steps, with walls of at least 120 mm in thickness. For chimneys and smoke ducts built from heat-resistant concrete, the wall thickness shall be at least than 60 mm, and 250 mm deep plinths with cleaning openings shall be formed at the bottom, covering them with quarter-brick thick masonry or doors.

43. If multiple fireboxes are connected to a single flue or chimney, the cross-sectional area of the flue shall be calculated according to the total output of all heat-generating devices connected to the flue and chimney.

44. The construction and arrangement of flues for gas-fired heating appliances shall be determined according to the law or regulation regarding equipment in which gaseous fuel is being used and the applicable standards.

45. A fireplace shall be connected to a separate smoke duct to which flues of other heating appliances or heat-generating devices may not be connected. The cross-sectional area of the smoke duct of the fireplace shall be at least 300 cm². If the area of the fireplace opening does not exceed 250 cm², the cross-sectional area of the smoke duct may be reduced to 175 cm².

46. Smoke ducts and chimneys shall be designed and installed in such a way as to prevent the risk of ignition, explosion, toxic gas leakage, moisture condensation, or any other type of risk to human health and life.

47. It is prohibited to discharge flue gases into airing openings (ducts).

48. In places where combustible structures of buildings (for example, walls, partitions, ceilings, beams, walls with combustible material finishes) adjoin the smoke ducts of local heating appliances, fire safety sections shall be constructed which increase the thickness of the walls of heating appliances, chimneys, and smoke ducts in accordance with Table 2 of Annex 1 to this Building Code. The requirements laid down in Table 2 of Annex 1 to this Building Code shall not apply to fire safety clearances for smoke ducts and chimneys if the manufacturer has specified otherwise.

[19 October 2021]

49. Fire safety sections shall be required in places where combustible structures of buildings adjoin ventilating ducts if they are installed next to smoke ducts.

50. Smoke ducts and chimneys shall be constructed from non-combustible, heat-resistant, and flue gas corrosion-resistant materials.

51. Smoke ducts and chimneys shall be designed and installed so that the temperature of their external surface does not exceed 80 °C.

52. The cross-section and height of smoke ducts and chimneys shall be designed and installed so as to ensure the necessary draught and discharge of flue gases.

53. Smoke ducts and chimneys shall be designed and installed so as to ensure their convenient cleaning, maintenance, and inspection. Cleaning hatches shall be installed in flues with a cross-sectional area of not less than the cross-section of the smoke duct. In short, straight chimneys which do not exceed 7 m in length, cleaning hatches need not be installed.

54. If the chimney is intended to be cleaned from above, convenient and safe access to it from the roof shall be ensured. Combustible materials and structures may not be closer than the following distances to chimneys and smoke ducts (also their cleaning hatches and other elements) intended for the discharge of flue gases from heating appliances with a total capacity not exceeding 120 kW (measured from the outer surface of the chimney, flue, or hatch):

54.1. 100 mm from masonry and metal chimneys;

54.2. 300 mm from flues;

54.3. 200 mm from cleaning hatches and other elements.

55. Metal flues shall be designed and installed in accordance with the applicable standards.

2.5. Fire Safety Requirements

56. In rooms in which people are permanently present, the maximum surface temperature of heating furnaces shall not exceed:

56.1. 90°C - in pre-school education institutions, general education schools, boarding schools, and other schools, kindergartens, medical institutions, health care, social care, and rehabilitation institutions (except for pharmacies);

56.2. 110 °C - not more than 15 % of the total surface area of the furnace;

56.3. 120 °C - not more than 5 % of the total surface area of the furnace;

56.4. 120 °C - in rooms of other buildings.

57. In non-residential rooms in which people are present temporarily (not longer than four hours per day), it shall be permitted to install a heating appliance with a surface temperature exceeding 120°C if the heating appliance is enclosed on all sides with a protective screen made of non-combustible material.

[19 October 2021]

58. It shall be permitted to heat not more than three rooms located on one floor with a single furnace or fireplace.

59. In two-storey buildings, it shall be permitted to install two-level furnaces with separate fireboxes and flues on each floor, but in two-level apartments - with a single firebox on the first floor.

60. In public buildings, local heating appliances shall be positioned so that their fireboxes can be serviced from auxiliary rooms or corridors which have ventilation windows for natural airing of the rooms.

60.¹ If a new residential building or public building is being constructed or an existing one is being rebuilt, then for a building where it is planned to use autonomous heating, the chimney near an adjacent taller building shall be installed at such height that does not negatively impact nearby buildings and the residents living in them. The chimney shall be installed at such height to ensure normal flue gas flow and so that the air pollution created by the heating equipment is not discharged into the windows, doors, and ventilation systems of an adjacent building.

[19 October 2021]

61. The height of the chimney above the roofing shall be determined, taking into account the following conditions:

61.1. if the chimney is located closer than 1.5 m from the roof ridge, it shall be 0.5 m higher than the ridge;

61.2. if the chimney is located 1.5 to 3 m from the roof ridge, it shall not be lower than the ridge;

61.3. if the chimney is located further than 3 m from the roof ridge, its top shall not be lower than the line drawn from the ridge at an angle of 10° to the horizon.

62. The upper end of the chimney shall be installed no less than 0.5 m above the roofing (also for buildings with a flat roof).

63. The total height of the chimney from the ash box grate to the smoke outlet point shall be at least 5 m.

64. For wood-fired furnaces, two tight dampers shall be installed one after another in the flue duct, but for coal- or peat-fired furnaces - one damper which has a 15 mm (in diameter) hole.

65. Caps and other coverings, including deflectors, may be installed on the chimneys of local heating appliances. The installation of caps, coverings, and deflectors shall not interfere with the correct operation of heating equipment and chimney cleaning works.

[19 October 2021]

3. Ventilation and Air Conditioning

3.1. General Safety Requirements

66. In rooms in which the formation of explosive gases, vapours, and air mixtures is possible, measures shall be provided to prevent a potential explosion that could be caused by the operation of ventilation equipment. Ventilation equipment shall be equipped with sound and light signalling.

67. A location, spatial layout, and constructive solution for a building shall be chosen so that it:

67.1. would reduce the impact of outdoor air pollution and ground radon pollution on ventilation systems, rooms, and the building as a whole;

67.2. would protect the rooms from the effects of increased humidity caused by precipitation, capillary, or condensation moisture;

67.3. would minimise the risk of harmful emissions spreading between rooms and between floors.

68. The thermal inertia of the building envelopes and load-bearing structures and the load of ventilation and air conditioning systems shall be mutually optimised to obtain the minimum total consumption of resources for the construction and operation of the building.

69. Room and storey height allowances for the placement of ventilation equipment and air ducts shall be provided at the stage of developing the building intention documentation.

70. In shafts and interspaces where ventilation air ducts are placed, the distance between air ducts and other engineering networks shall be at least 50 mm. Other engineering networks shall not cross air ducts.

71. Appropriate installation openings shall be provided in the building envelopes of the building for the installation and removal of ventilation equipment.

72. When planning the energy balance of a building, the necessary electrical and heat capacities for the operation of ventilation systems shall be provided for.

73. Natural airing shall be provided for rooms, such as opening windows, windows with special ventilated frames, or special openings in external walls. It shall not be recommended to design rooms in which natural airing is not possible.

74. Smoking areas shall be designed to minimise the risk of passive smoking for non-smokers.

3.2. Design of Ventilation Systems

3.2.1. General Safety Requirements

75. Ventilation systems shall be designed and installed so that:

75.1. human health is not endangered when using rooms for their intended purposes;

75.2. air quality conforming to the sanitary hygiene standards and comfort levels conforming to the applicable standards are ensured in the rooms;

75.3. ventilation systems do not promote the spread of fire flames and smoke gases, and also prevent the formation of explosive gas and vapour mixtures.

76. The energy consumption of ventilation systems shall be technically and economically justified, taking into account the costs of energy resources and the environmental damage caused by energy production and consumption.

77. If there are rooms in the building with elevated air pollution emissions, areas where it is not possible to avoid pollution shall be isolated from other rooms. Air pollution shall be limited to minimise the exposure of people to pollution.

78. It shall not be permitted to use general ventilation systems as smoke extraction systems.

79. Smoke extraction systems shall be designed in accordance with the fire safety requirements laid down in the building codes and the applicable standards.

80. The fire resistance limit of air duct and ventilating duct walls in each fire compartment shall be determined, taking into account the type of room use and the fire load (mJ/m²) in the respective compartment.

81. Ventilation air ducts, their channels, engineering network shafts in which ventilation air ducts and other risers are located shall meet the following requirements:

81.1. the fire resistance limit of transit ducts is:

81.1.1. in rooms in which the fire load is up to 600 mJ/m² (inclusive) - not lower than EI-30;

81.1.2. in rooms in which the fire load is higher than 600 mJ/m² - not lower than EI-60;

81.2. for transit ducts which pass through explosive or fire-hazardous rooms as well as for exhaust transit ducts from hearths, cookers, grills which use an open flame, regardless of the fire load, the fire resistance limit is not lower than EI-120.

82. For air ducts which service only one fire compartment, the fire resistance limit shall not be regulated.

83. Air ducts shall be placed in shafts in accordance with Annex 2 to this Building Code.

84. In an engineering network shaft, air ducts may be installed together with flues the fire resistance limit of which is not below EI-120 if their location is not in contradiction with standard LVS EN 1856-1:2019, Chimneys - Requirements for metal chimneys - Part 1: System chimney products, and standard LVS EN 1856-2:2009, Chimneys - Requirements for metal chimneys - Part 2: Metal flue liners and connecting flue pipes.

[17 January 2023]

85. Depending on the type of room use, the room ventilation systems shall be connected to central (common) ventilation equipment, taking into account the following requirements:

85.1. it shall be permitted to connect supply air ducts for ventilation equipment in explosive and fire-hazardous rooms to common ducts and ventilation equipment if this equipment does not service bedrooms and living rooms in public buildings;

85.2. it shall not be permitted to connect extract air ducts of ventilation equipment for explosive and fire-hazardous rooms to common ducts and ventilation equipment;

85.3. it shall not be permitted to connect incoming and extract air ducts of ventilation equipment for living rooms and bedrooms in public buildings to ventilation equipment if they service rooms with a different type of use;

85.4. it shall be permitted to connect ventilation air ducts for kitchens and sanitary facilities in residential buildings to common ventilation equipment, each in a separate duct.

86. In public buildings, it shall be permitted to connect supply air ducts for rooms intended for educational, work, and public events to common ducts and ventilation equipment; however, it shall not be permitted to connect extract air ducts to ventilation equipment if they service rooms with a different type of use.

87. It shall be permitted to connect supply air ducts for production and storage rooms to common ducts and ventilation equipment; however, it shall not be permitted to connect extract air ducts to common ventilation equipment.

88. It shall be permitted to connect supply air ducts for a car parking space to common ducts and ventilation equipment; however, it shall not be permitted to connect extract air ducts to common ventilation equipment.

89. It shall not be permitted to connect extract air ducts that service rooms in which harmful and toxic substances or gases may be stored, produced, or used in the manufacturing process to common ventilation systems.

3.2.2. Design Input Data

90. The building design shall specify all input data as well as the requirements which the ventilation systems must comply with. Ventilation systems shall be designed in accordance with the standard LVS EN 16798-1:2021, Energy performance of buildings - Ventilation for buildings - Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics - Module M1-6, and LVS EN ISO 7730:2006, Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria, if no special requirements for the operation of the respective building are specified in the design order.

[19 October 2021; 17 January 2023]

90.¹ If rooms have natural lighting, natural airing equipment shall be designed by providing opening window sashes or other devices to ensure one-time air change per hour.

[19 October 2021]

90.² Kitchens, toilets, bathrooms, and shower rooms in residential buildings shall be ventilated through natural exhaust ducts. In public buildings, forced (artificial) ventilation shall be installed in shower rooms, changing rooms, toilets and their anterooms.

[19 October 2021]

90.³ If a flue is intended for the discharge of flue gases from heat generators, it may not be used as a ventilating duct.

[19 October 2021]

90.⁴ In multi-apartment buildings, local exhaust ventilating ducts for one apartment may be combined into a single duct which is connected to the common duct of the entire building at a level that is at least two metres higher than the level of the rooms being serviced.

[19 October 2021]

90.⁵ Ventilating ducts from kitchens, toilets, bathrooms, shower rooms, and pantries shall not be combined with ventilating ducts from garages and rooms in which heat generators are located.

[19 October 2021]

90.⁶ For public rooms, autonomous ventilation and air conditioning systems shall be designed in accordance with the regulations and technological requirements for their intended use. When designing public rooms in a residential building, it shall be recommended to create autonomous heating systems.

[19 October 2021]

90.⁷ If a multi-apartment building has a warm attic, air from the attic shall be discharged through one exhaust shaft, separately for each section of the building. The shaft must be located at least 4.5 metres above the ceiling of the top floor of the building.

[19 October 2021]

90.⁸ If solid fuel is being used, water heaters and small-size heating boilers for apartment heating and hot water preparation may be installed in the kitchen of the apartment or in a separate room which has natural lighting.

[19 October 2021]

91. The following initial data shall be specified in the building design:

91.1. the layout of the rooms of the building and the location of service zones - in the plan and in a sectional view;

91.2. the functions of the rooms, taking into account that they may change during the use of the rooms;

91.3. the requirements for room air quality and the desired air quality parameters in the relevant room (air temperature higher than 28 °C in summer and lower than 18 °C during the heating period shall be permitted after agreement with the owner or user of the rooms);

91.4. the climatic conditions of the construction site in accordance with the construction standard regarding building climatology;

91.5. the expected number of people in the room at different times of the day, activities of people in the room and their clothing;

91.6. the proportion of smokers, if smoking is permitted in the relevant room, or the zones of the room where smoking is permitted;

91.7. the room air pollution sources, their characteristics and the amount of pollution, including pollution from surface finishing materials and furniture;

91.8. the outdoor air pollution indicators;

91.9. the outdoor noise level;

91.10. information on the explosion hazards, fire hazards, and fire load of materials and substances to be used or stored in the rooms;

91.11. the areas of external glazed surfaces and technical data of the glazing;

91.12. the window opening options or description of window construction;

91.13. the planned shading of windows;

91.14. data on external building envelopes and the building physics properties of the construction products used;

91.15. the acoustic properties of rooms and reverberation coefficients;

91.16. the planned measures for starting up, regulating, and operating ventilation and air conditioning systems;

91.17. the planned measures for maintaining rooms and technological equipment in working order.

92. Air quality and desired parameters in the relevant rooms shall be determined in accordance with the standard LVS EN ISO 7730:2006, Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria, if no special requirements for the operation of the respective building are specified in the design order.

93. During periods when people are not present in the room, a decrease in the room air temperature shall be permitted during the heating period, but not lower than 5 °C, ensuring the restoration of the desired air temperature by the time the use of the room is resumed.

94. In summer, the cooling system shall be switched off when it is not necessary for ensuring comfort.

95. If it is necessary to meet special comfort or technological requirements, the building design may specify the permissible limits for air temperature and relative humidity fluctuations in the room.

95.¹ For the air quality of a public building, it shall be ensured that CO₂ concentration indoors does not exceed 1000 ppm.

[13 May 2021]

3.2.3. Ventilation System Capacity

96. The capacity of ventilation systems shall be calculated according to the input data. The capacity of ventilation systems shall be sufficient to ensure fresh air supply, satisfactory comfort, or technological conditions in the service area. The room air pollution sources shall be assessed in accordance with the standard LVS EN ISO 7730:2006, Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria, and the standard LVS EN 16798-1:2021, Energy performance of buildings - Ventilation for buildings - Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics - Module M1-6, if no special requirements are specified for the operation of the respective building in the design order.

[19 October 2021; 17 January 2023]

97. If the only source of room air pollution is people, the absolute minimum fresh air supply shall be 15 m³/h per person.

98. The fresh air supply shall be balanced with the amount of polluted air which is discharged from rooms, taking into account the desired pressure difference between more and less polluted rooms or room zones.

99. The capacity of ventilation systems shall be calculated to achieve sufficient mixing of fresh air with room air. To reduce energy consumption, air recirculation shall be permitted if no harmful substances, bacteria, or distinctly unpleasant odours are released in the room. Recirculation shall be used in rooms of equal significance, in an individual apartment, hotel room, or family house.

100. To save energy resources, a possibility shall be provided to vary the capacity of the ventilation system depending on room air pollution which may change during the use of the room.

101. Elevator shafts shall be provided with natural ventilation openings that occupy no less than 1 % of the cross-section of the shaft. In elevator machine rooms, natural ventilation directly to the outside shall be provided if no special air quality parameters are specified for the equipment in an elevator machine room.

102. The building design shall indicate (for the information of room owners and users) the conditions under which the designed room air parameters can be maintained, if the room usage characteristics and the amount of harmful pollution mentioned in the input data are preserved.

3.2.4. Selection of Ventilation Systems

103. When selecting ventilation systems, the following shall be taken into account:

103.1. the input data;

103.2. the requirements for air quality in rooms;

103.3. the calculated capacity of ventilation systems;

103.4. the existing energy resources;

103.5. technical rooms and free volumes in the building for system placement.

104. In order to save energy, preference shall be given to natural ventilation systems in rooms, providing for the possibility to regulate the amount of exchanged air according to variable outdoor air parameters.

105. If it is not possible to ensure the air quality requirements in the serviced area with natural ventilation, mechanical ventilation systems shall be designed.

105.¹ If a new educational institution is being built, the construction of a centralised mechanical ventilation system shall be mandatory.

[19 October 2021]

106. For rooms or room zones where natural ventilation is not possible, mechanical ventilation systems shall be provided.

107. Mechanical exhaust ventilation systems shall be used to localise harmful emissions in the room air, creating an appropriate pressure difference between rooms in which the volume of harmful emissions varies. Air must flow from rooms in which the air is cleaner to rooms in which the air is more polluted.

108. The amount of air extracted from rooms by mechanical exhaust ventilation systems shall be compensated with a corresponding amount of supply air that is prepared and delivered to rooms by mechanical supply ventilation systems. The supply air delivery speed shall not exceed the comfort level specified in the applicable standards.

109. It shall be permissible to design mechanical exhaust ventilation without providing for mechanical supply ventilation if the amount of air is not large and the heat release in the room or the heating system can cover the amount of heat required to warm up the infiltrated air and there is no draft or vacuum effect in the rooms. The use of the abovementioned system shall not be permissible if the dust concentration in the outdoor air is greater than the permissible dust concentration in rooms.

3.3. Components of Ventilation Systems

110. Outdoor air intake openings shall be positioned so that as little dust as possible enters the ventilation system and they are not blocked by snow in winter. If there are no other conditions, outdoor air intake openings shall be installed not lower than 2 m above the surface of the ground. Outdoor air intake openings may be installed lower if measures have been taken to prevent dust suction and snow drifts.

111. If the outdoor air intake location is situated in a heavy traffic zone, it shall be recommended to take outdoor air at the roof level of the building, taking into account the roof heating in summer.

112. Outdoor air intake openings shall be distanced from contaminated air exhaust points in both horizontal and vertical planes to prevent discharged air from flowing into the outdoor air intake location, especially if recirculation is not permissible.

113. Air handling units shall be designed in accordance with the standard LVS EN 1886:2008, Ventilation for buildings - Air handling units - Mechanical performance, if no special requirements are specified for the operation of the respective building in the design order.

114. Air handling units shall be placed in designated rooms within the building. It shall be permissible to place air handling units in the serviced rooms if this is provided for in the design order and measures have been taken to prevent the spread of vibration and noise in accordance with the law or regulation regarding the procedures for noise assessment and management.

115. Rooms where air handling units are located shall be separated from other rooms with fireproof partition walls the fire resistance limit of which is not below EI-60, fireproof ceilings the fire resistance limit of which is not below R-60, and fireproof doors the fire resistance limit of which is not below EI-30.

116. Air handling units shall be equipped with heaters of appropriate capacity or other heating appliances for heating air in winter. The reserve of water heater heating surface shall not be recommended to be greater than 10 % to avoid increasing the risk of the heater freezing. If water is used as a heat carrier in the system and the heater has an increased heating surface, the system shall not be operated without a small circuit circulation pump.

117. The air handling unit shall be equipped with an air humidifier if it is otherwise not possible to achieve the necessary air humidity in the room.

118. If the air handling unit is also intended to cool air, an assessment shall be made whether the compression cycle cooling method may be replaced with direct or indirect adiabatic cooling method in order to reduce environmental impact.

119. Energy resource saving measures must not negatively affect room air quality. In order to save energy resources, air handling units shall be equipped with heat and cold recovery devices for exhaust air. The type of recovery device shall be selected, taking into account technical and economic calculations.

120. A fan with the highest efficiency coefficient shall be selected.

121. If the ventilation equipment is installed outside, it shall be thermally insulated to prevent unnecessary heat loss and water vapour condensation.

122. Ventilation equipment shall be fitted with devices (vibration isolators, flexible gaskets, noise suppressors) in accordance with the law or regulation regarding noise assessment and management procedures which dampen vibration and noise and prevent the spread of vibration and noise in rooms or outside the building.

3.4. Air Ducts

123. [17 January 2023]

124. [17 January 2023]

125. The material and thickness of air ducts shall be selected to ensure the necessary fire resistance.

126. The wall thickness of air ducts with rectangular cross-section shall be selected in accordance with Table 1, but for ducts with circular cross-section - in accordance with Table 2.

Table 1

Length of the longest rectangular side S (mm)	Wall thickness (mm)
	for steel ducts	for aluminium ducts
S < 300	0.5	0.7
300 < S < 800	0.7	0.9
S > 800	0.9	1.2

Table 2

Nominal duct diameter (mm)	Wall thickness (mm)
	for steel ducts	for aluminium ducts
d < 320	0.5	0.7
d > 320	0.7	0.8

127. Metal air ducts shall be electrically earthed.

128. Extract air ducts for hearths, cookers, and grills shall be made only of steel, and their wall thickness shall be at least 1.2 mm.

129. [17 January 2023]

130. Fire safe valves shall be designed for air ducts of airing systems which service explosive or fire-hazardous rooms as well as for local extract air ducts intended for explosive mixtures at locations where air ducts cross fireproof barriers of the serviced room which have a standardised fire resistance limit.

131. Fire resistance limit is not standardised for air ducts located in ventilation chambers and outside the building.

132. The fire resistance limit of transit ducts for air overpressure and smoke extraction systems and local exhaust of explosive mixtures shall be at least EI-60, but not less than the fire resistance limit of the fireproof barrier being crossed.

133. If transit ducts pass through walls, partition walls, or intermediate coverings which have a standardised fire resistance limit, the fire resistance limit of transit ducts shall not be lower than EI-60.

134. If transit ducts cross a stairwell, the fire resistance limit of transit ducts shall not be lower than the fire resistance limit of the walls of the stairwell being crossed.

135. In places where air ducts cross fireproof barriers, the openings in walls shall be filled with fireproof sealing materials which have the appropriate fire resistance limit.

136. It shall not be permitted to install gas pipes, pipelines containing flammable substances, electrical installations, and sewer pipelines in air ducts and on their surfaces. The abovementioned engineering networks shall not cross air ducts.

137. Air duct fixings shall have the same fire resistance limit as the air ducts.

138. Ventilation air ducts that service explosive and fire-hazardous rooms as well as local extract air ducts for explosive mixtures shall be earthed.

139. The outlets of air ducts from explosive rooms and local extract air ducts for explosive mixtures shall be protected against the primary and secondary effects of lightning.

140. In explosive rooms, the distance between extract air duct outlets and supply air duct inlets horizontally shall not be less than 10 m, vertically - not less than 6 m.

141. Outlets for smoke extraction to the atmosphere and local exhaust outlets for explosive mixtures shall be located:

141.1. not lower than 2 m above the roof of the building;

141.2. not lower than 1.5 m from the ground surface and not closer than 10 m from the building.

142. Ventilation systems shall be cleaned through hatches in air ducts. The fire resistance of cleaning hatches shall correspond to the fire resistance limit of the air duct.

143. In rooms in which leakage of gases heavier than air and vapours of these gases is possible, 75 % of the required openings in ventilation extract air ducts shall be placed in the lower part of the room and 25 % - in the upper part of the room.

144. In rooms in which hydrogen leakage is possible, the necessary openings in extract air ducts shall be placed not lower than 0.4 m from the horizontal building envelopes of the rooms, for example, ceilings, floor slabs, and combined roofs.

145. In ventilation systems, air ducts with circular, rectangular, or other cross-sections shall be used, and they shall be manufactured in accordance with the standards LVS EN 1505:2021, Ventilation for buildings - Sheet metal air ducts and fittings with rectangular cross-section - Dimensions, LVS EN 1506:2007, Ventilation for buildings - Sheet metal air ducts and fittings with circular cross-section - Dimensions, and LVS EN 12220:2003, Ventilation for buildings - Ductwork - Dimensions of circular flanges for general ventilation, if no special requirements are specified for the operation of the respective building in the design order. The need to use rectangular cross-section air ducts which have a side ratio greater than 2:1 shall be justified with aerodynamic calculation.

[17 January 2023]

146. When designing and installing air duct systems, air duct cleaning shall be intended in accordance with the standard LVS EN 12097:2021, Ventilation for buildings - Ductwork - Requirements for ductwork components to facilitate maintenance of ductwork systems. The contamination in air ducts shall not create explosion hazards, fire hazards, or hygiene-related problems.

[17 January 2023]

147. Air ducts where water vapour condensation is possible and air ducts intended to be washed during operation shall be designed and installed with a slope of 0.005 in the direction of the air flow. Air ducts shall be divided into sections with drainage provided at their ends.

148. Air ducts shall require appropriate thermal insulation:

148.1. to prevent the formation of internal condensate in extract air ducts if they cross unheated rooms or are located outside the building;

148.2. to prevent external condensate from forming on the surface of outdoor air and cooled air ducts where they cross warm and humid rooms;

148.3. to prevent excessive heat losses from the supply air ducts where they cross unheated rooms;

148.4. to prevent cooled air from warming up in the supply air ducts.

149. If mineral wool is used for noise attenuation in certain sections of air ducts, the wool layer covering shall be dense to prevent erosion of the wool layer and contamination from entering the room air.

150. In places where air ducts cross fireproof barriers with a specified fire resistance limit, automatic fire safe valves with an appropriate fire resistance limit shall be installed.

151. Places where transit ducts cross walls, partition walls, or intermediate coverings shall be sealed with non-combustible material, ensuring the necessary fire resistance limit of the structure to be crossed.

152. In vertical and horizontal main collection and distribution air ducts, branches shall be connected in such a way as to prevent smoke leakage from one room to another in case of fire.

153. The building design shall specify the ancillary aid for aerodynamic balancing for the air duct network, locations for air flow measurements, and air duct cleaning hatches in accordance with the standard LVS EN 12097:2021, Ventilation for buildings - Ductwork - Requirements for ductwork components to facilitate maintenance of ductwork systems.

[17 January 2023]

154. Contaminated air discharge points shall be positioned to prevent the impact of contaminated air on external walls, surrounding windows, and ventilation openings for air intake.

155. Air intake grilles and air duct ends outside the building shall be structurally designed to prevent precipitation from entering them and to reduce the effect of wind.

3.5. Air Distributors and Air Exhaust Confusers and Grilles

156. Air distribution systems shall be designed and installed to ensure uniform supply air distribution in the serviced area of the room, without exceeding the permitted air flow velocity and without interfering with the operation of local exhaust systems in accordance with the standard LVS EN ISO 7730:2006, Ergonomics of the thermal environment - Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria, and the standard LVS EN 16798-1:2021, Energy performance of buildings - Ventilation for buildings - Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics - Module M1-6.

[19 October 2021; 17 January 2023]

157. The air flow velocity shall not be regulated within one metre of the air distributor.

158. If air flow distribution is planned in the room, adjustable air distribution diffusers shall be required which can effectively distribute cooled air in summer and warm air in winter.

159. Diffusers, confusers, and ventilation grilles shall be designed and installed to prevent aerodynamic noise in accordance with the law or regulation regarding the procedures for noise assessment and management.

3.6. Fire Safe Valves

160. The purpose of a fire safe valve shall be to prevent or contain the spread of flame and smoke gases from one fire compartment to another fire compartment and from a fire compartment to the common ventilation chamber and through it to other fire compartments and rooms separated by a fire-resistant structure or rooms separated by a fire-resistant structure.

[16 June 2020; 19 October 2021]

161. Fire safe valves shall be constructed so that they do not interfere with the discharge of smoke gases from ventilation systems into the atmosphere.

162. Fire safe valves shall be attached directly to fireproof barriers. The fire resistance limit of the fasteners shall be equal to the fire resistance limit of the fire safe valve.

163. Gaps between the fireproof barrier and the fire safe valve shall be filled with non-combustible sealing materials which have the appropriate fire resistance limit.

164. The fire resistance limit of the fire safe valve shall not be lower than the fire resistance limit of the fireproof barrier crossed by the air ducts or:

164.1. shall not be lower than EI-120 if air ducts cross fireproof barriers the fire resistance limit of which is EI-150 and higher;

164.2. shall not be lower than EI-9, if air ducts cross fireproof barriers the fire resistance limit of which is not higher than EI-120;

164.3. shall not be lower than EI-60 if air ducts cross fireproof barriers the fire resistance limit of which is not higher than EI-90;

164.4. shall not be lower than EI-30 if air ducts cross fireproof barriers the fire resistance limit of which is not higher than EI-60.

165. The electrical supply of ventilation systems for explosive and fire-hazardous rooms as well as local exhaust ventilation systems for explosive mixtures shall meet the following requirements:

165.1. continuous power supply from two independent electrical supply sources;

165.2. sound and light signalling if the respective system begins to operate intermittently, is damaged, or is not functioning;

165.3. a separate electrical circuit of the electrical equipment of the system which is not connected to electrical circuits of other electrical equipment;

165.4. emergency lighting in room ventilation chambers;

165.5. devices for remote activation of the system located outside the explosive and fire-hazardous compartment at evacuation exits.

3.7. Ventilation Chambers

166. Ventilation equipment and other air handling units shall be placed in a ventilation chamber. The ventilation chamber shall be separated from other rooms with fireproof partition walls the fire resistance limit of which is EI-60, fireproof ceilings the fire resistance limit of which is R-60, and fireproof doors the fire resistance limit of which is EI-30.

167. It shall be permitted to place ventilation equipment on building roofs.

168. In public buildings, it shall be permitted to place ventilation equipment outside ventilation chambers if the ventilation equipment services only one room, except for explosive and fire-hazardous rooms.

169. If ventilation equipment services only one fire compartment and is located in it, the equipment need not be placed in a ventilation chamber, except for explosive rooms.

170. Air supply equipment and air exhaust equipment shall normally be placed in the same ventilation chamber.

171. Air supply fans and air exhaust fans which service explosive and fire-hazardous rooms shall be placed in separate rooms.

172. Explosion-proof protection shall be provided for ventilation equipment, airing, air conditioning, and heating system equipment which service explosive and fire-hazardous rooms as well as for local exhaust equipment for explosive mixtures.

173. The explosion hazard or fire hazard category of a ventilation chamber shall be equated to the explosion hazard or fire hazard of the rooms which the respective chamber services.

174. Equipment of ventilation systems for explosive rooms shall be placed in a separate ventilation chamber. Fans and electrical equipment of these systems shall be explosion-proof.

175. If a ventilation chamber services rooms which have different explosion hazard or fire hazard classifications, the explosion hazard and fire hazard category of the ventilation chamber shall be determined according to the most hazardous category.

176. Pipelines containing highly flammable and combustible substances or gases shall not be placed in ventilation chambers.

3.8. Ventilation System Control

177. Ventilation systems shall be equipped with automatic control, electrical switching, and electric drive equipment.

178. The level of automation shall be determined by technological requirements and economic justification. Automatic control systems of a building shall be designed in accordance with the applicable standards.

179. The automation, electrical switching, and electric drive system shall ensure the fulfilment of the following minimum requirements:

179.1. control of air handling processes, air heating, cooling, humidification, recirculation, heat and cold recovery;

179.2. electric motor protection;

179.3. water heater protection against freezing by monitoring water and air temperature;

179.4. automatic shutdown of ventilation systems, except for ventilation systems that extract smoke or systems that create overpressure in stairwells, elevator shafts, corridors without natural lighting, or small fireproof air-exchange passages, upon receiving a signal from the automatic fire detection and alarm system or the automatic fire extinguishing system about the fire outbreak.

3.9. Installation of Ventilation Systems

180. Ventilation systems shall be installed according to the approved building design and in compliance with the applicable standards.

181. Ventilation and air conditioning systems shall be commissioned and put into service in accordance with the standard LVS EN 12599:2013, Ventilation for buildings - Test procedures and measurement methods, when putting into service ventilation and air conditioning systems, and LVS ISO 10780:2002, Stationary source emissions - Measurement of velocity and volume flowrate of gas streams in ducts.

182. Ventilation systems shall be activated after their inspection and comparison with the building design and after verification of the electrical network parameters.

183. The results of the aerodynamic adjustment of ventilation systems and the hydraulic adjustment of heat and cooling supply systems of air handling units shall be summarised in protocols. Based on the protocols, a system passport shall be drawn up.

184. A protocol regarding the commissioning of the ventilation system shall be drawn up. The following documents shall be appended to the protocol:

184.1. a set of building design drawings and detailed drawings modified under author's supervision;

184.2. passports of the installed equipment and documentation certifying the compliance of the construction products used;

184.3. statements of covered works;

184.4. protocols and passports of the aerodynamic and hydraulic adjustment of the system;

184.5. schemes of automatic regulation and electrical switching systems;

184.6. a description of system operation and the safety instructions;

184.7. a protocol confirming that the personnel has been trained to operate the system.

Minister for Economics Dana Reizniece-Ozola

 

Annex 1
Latvian Building Code LBN 231-15,
Heating and Ventilation of Residential and Public Buildings
(approved by
Cabinet Regulation No. 310
of 16 June 2015)

Maximum Parameters for Buildings in which It is Permitted to Install Local Heating Appliances Using Solid Fuel

Table 1

No.	Type of use of buildings or premises	Number of storeys	Total area (m2)
1.	Residential buildings (does not apply to fireplaces which are used as additional heating appliances)	2	-
2.	Pre-school educational institutions, general education schools, boarding schools and other schools, children's homes, medical, health care, social care, and rehabilitation institutions (except for pharmacies)	1	300
3.	Other public buildings	2	500
4.	Production and storage rooms with low fire load in residential and public buildings	2	1000

Fire safety clearances from smoke ducts and chimneys

Table 2

No.	Periodically operating local heating appliances	Fire safety clearance from the inner surface of the smoke duct (chimney) from structures (mm)
		combustible	fire-resistant
1.	With an operating time of up to three hours	380	250
2.	With an operating time exceeding three hours	510	380

Minister for Economics Dana Reizniece-Ozola

 

Annex 2
Latvian Building Code LBN 231-15,
Heating and Ventilation of Residential and Public Buildings
(approved by
Cabinet Regulation No. 310
of 16 June 2015)

Placement of Air Ducts in Engineering Network Shafts and Insulation of Shaft Walls and Air Ducts which Have Different Fire Resistance

Fig. 1.	Fig. 2.
Designations: 1 - sewer pipe made of non-combustible material; 2 - air duct. Note. The fire resistance of shaft walls is not standardised if air ducts have a standardised fire resistance limit and the places where they cross shaft walls are sealed.	Designations: 1 - sewer pipe made of non-combustible material; 2 - air duct; 3 - shaft wall. Note. The fire resistance of shaft walls is not standardised if air ducts do not have a specified fire resistance limit.

Fig. 3.	Fig. 4.
Designations: 1 - rooms with fire load f > 600 MJ/m2 (EI-60); 2 - rooms with fire load f ≤ 600 MJ/m2 (EI-30); f - fire load in the room serviced by the duct.	Designations: 1 - rooms with fire load f ≤ 600 MJ/m2 (EI-30); 2 - rooms with fire load f > 600 MJ/m2 (EI-60); f - fire load in the room serviced by the duct.

Fig. 5.	Fig. 6.
Designations: 1 - fire-hazardous or explosive room (EI-120); 2 - rooms with fire load f > 600 MJ/m2; 3 - rooms with fire load f ≤ 600 MJ/m2. Note. Insulation of shaft walls and three air ducts that have different fire resistance limits.	Designation. 1 - fire safe valve. Note. Air ducts which have different fire resistance limits, without insulation. Fire safe valves with appropriate fire resistance limits shall be installed at points where shaft walls are crossed.

Fig. 7.	Fig. 8.
Designations: 1 - sewer pipe made of non-combustible material; 2 - pipe made of non-combustible material; 3 - air duct.	Designations: 1 - sewer pipe made of combustible material; 2 - pipe with combustible insulation; 3 - air duct.

Minister for Economics Dana Reizniece-Ozola

 

Annex 3
Latvian Building Code LBN 231-15,
Heating and Ventilation of Residential and Public Buildings
(approved by
Cabinet Regulation No. 310
of 16 June 2015)

Internal Air Temperature and Ventilation Air Exchange Volume in Residential Building Premises

[17 January 2023]

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