Efficient Use of Energy in Buildings
On the basis of Articles 8.a and 8.c of the Construction Act (Official Gazette of SRS Nos. 34/84 and 29/86 and Official Gazette of RS Nos. 59/96 and 45/99), the Minister of the Environment and Spatial Planning issues
REGULATIONS
on Thermal Protection and
Efficient Use of Energy in Buildings
I. GENERAL PROVISIONS
Article 1
(1) These regulations lay down technical specifications for thermal insulation and efficient use of energy in the heating of buildings designed for human dwelling and work.
(2) These regulations apply to new constructions and to the changes of utilization of individual rooms in existing buildings. They also apply to building reconstruction provided that their implementation is technically feasible and in accordance with cultural heritage conservation criteria.
Article 2
These regulations do not apply to those buildings belonging to the group of industrial facilities (hereinafter: industrial buildings):
which are not heated or air-conditioned to room temperatures exceeding 12oC; or
in which internal heat sources due to technological processes make up, in the course of heating, more than one half of thermal losses; or
to workshops, factory halls and warehouses which, in the heating period, normally remain open for more than one half of the time of operation; or
to greenhouses and similar buildings designed for agricultural and gardening uses, to aeroplane sheds, garages and shelters.
Article 3
Only the products placed on the market in accordance with the construction product regulations may be built in or installed in buildings.
Article 4
The supervision of the implementation of the provisions of these regulations is carried out by competent construction inspectors.
Article 5
The standards referred to in these regulations are kept by and available from the Slovenian national standardisation body.
Article 6
The terms used in these regulations or in standards referred to herein have the following meanings:
- “Thermal energy demand” is the demand for energy to be supplied into the building in order to achieve design internal temperatures.
- “Building total external envelope area”, A (m2), is the area of the building’s external surface through which heat is transmitted to the environment, as defined in SIST EN 832.
- “Useful area”, Au (m2) is the internal groundplan area of heated space according to the design.
- “Building heated volume”, Ve (m3) is the volume of the building surrounded by the building external envelope through which heat passes to the environment.
- “Building net heated volume”, V (m3) is the volume of the building as defined in the SIST ISO 9836 standard section 5.2.5.
- “Shape factor”, f0 = A/Ve (m-1) is the ratio between the total external envelope area and the building heated volume Ve enclosed within the said envelope.
- “Design external temperature” is the external temperature laid down as the design basis for the sizing of the heating system.
- “Design internal temperature” is the room temperature specified in the design.
- “Internal temperature” is the arithmetic average of the air temperature and the mean radiant temperature at room centre (internal dry resultant temperature).
- “External temperature” is the temperature of external air.
- “Transmission heat losses” (kWh) are the heat losses due to the transfer of heat through the building envelope.
- “Ventilation heat losses” (kWh) are the heat losses due to the exchange of air in the rooms with unheated air from the environment.
- “Internal heat gains” (kWh) is the heat entering the heated room or generated in the heated room from sources other than the heating system.
- “Solar gains” (kWh) is the heat entering into the room due to solar irradiation.
- “Sanitary water preparation heat” (kWh) is the heat required for the heating of water for sanitary purposes in the building.
- “Heat zone” is a part of heated space with a particular design temperature, within which the spatial differences in temperature are negligible.
- “Thermal conductivity”, (W/mK) is a material characteristics measured at the material medium operational temperature and humidity.
- “Thermal transmittance”, U (W/m2K) is the total thermal transmittance defining transfer of heat through a building envelope element, taking into account conduction, convection and radiation.
- “Solar irradiation”, j (kW/m2) is solar energy per unit surface in unit time period.
- “Heated space” is a bounded closed space heated to one or several design temperature(s), “unheated space” is a room or a bounded closed space not being a part of heated space and not heated.
- “Thermal bridge” is a point in the building envelope were heat transmission is increased due to differences in construction materials, thickness or geometry.
- “Heating season duration” is the number of all days between the beginning and the end of the heating season.
- “The beginning of the heating season” is defined as the next day following a contiguous period of three days with external air temperatures lower than 12oC at 9 p.m.
- “End of heating season” is defined by means of the time period when, on three contiguous days, the external air temperature at 9 p.m. exceeds 12oC, and following which, in the particular year, there is no period of three contiguous days with temperatures of 12oC or lower. The third day of the last of such series of three days is the end of the heating season.
- “Temperature deficit”, DD (K*day) is the difference of the internal temperature (20oC) of heated space and the average daily external air temperature. In calculating the temperature deficit, only those days with the average external air temperature lower than 12oC are taken into account.
- “Average daily air temperature” is defined according to the equation: Td = (T7 + T14 + 2T21) / 4, where T7, T14 and T21 are time temperatures measured according to the Central European time zone.
- “Total solar radiation transmittance factor”, g, is the portion of the incident solar energy that actually enters the heated space.
- “Percentage of glazing”, (%) is the percentage of glazed surfaces in the area of an individual building envelope element.
- “Air change rate”, n (h-1) is the number of air changes, calculated based on the net heated building volume, V (m3), taking into account the system of internal building dimensions.
- “Waste or exhaust air heat recovery device efficiency”, (%) is the percentage of heat a device recovers from waste or exhaust air and transfers back to the building interior.
- “Design capacity of heating bodies”, (W) is the capacity of heating bodies according to the mechanical installation design.
- “Intermittent heating” is a heating regime or pattern, where, during certain time periods, temperature is allowed to fall below the design temperature.
- “Air-conditioned building” is a building with an installed system to control air temperature, humidity, ventilation and purity.
- “Heating bodies” are bodies supplying heating energy into the heated space.
- “Thermostat valve” is a valve installed on the heating body serving local control of the room temperature.
- “Non-treadable attic” is an attic not intended for dwelling, storage of objects or similar purposes, and is not used, as well as unheated.
II. REQUIREMENTS REGARDING THERMAL PROTECTION
Article 7
(1) The allowable heat demand for the heating of a dwelling building which is heated, in its intended use, to at least 18oC, per unit of useful area, shall not exceed
Q = 45 + 40 ƒ0 (kWh/m2a)
(2) The allowable heat demand for the heating of a non-dwelling building which is heated, in its intended use, to at least 18oC, per unit of gross building heated volume Ve, shall not exceed
Q = 14,4 + 12,8 ƒ0 (kWh/m3a)
(3) The allowable heat demand for the heating of an industrial building which is heated, in its intended use, for more than three months per heating season to an average interior design temperature within the interval of 10 to 18oC, and in periodically heated sports, cultural and educational buildings, which are heated for a total period of three months or more per heating season to a temperature above 15oC, shall not exceed
Q = 28,8 + 25,6 ƒ0 (kWh/m3a).
Article 8
(1) The predicted heat demand for the heating of a building is calculated according to standard SIST EN 832, chapters 5 to 8 (chapter 9 is not applicable). In the calculation, transmission and ventilation thermal losses, internal heat gains and solar radiation are taken into account.
(2) Buildings shall be constructed so as to minimise the effects of thermal bridges on annual heat demand, applying all available technical and technological options. Thermal bridges with linear thermal transmittance i>0,2 W/mK or e>0,1 W/mK (standard SIST EN ISO 14683) shall be avoided by appropriate corrections of design details.
(3) Effects of other thermal bridges shall be taken into account in the calculation in one of the following manners:
taking into account the effects of thermal bridges according to standards SIST EN ISO 13789, SIST EN ISO 14683, SIST EN ISO 10211-1 and SIST EN ISO 10211-2, or
taking into account a thermal transmittance allowance of 0,1 W/m2K over the entire building envelope.
Article 9
(1) Building external envelope area, A (m2), through which heat is transmitted to the environment, is determined according to the provisions of the SIST EN 832 standard for the buildings with a single heating zone which comprises at least all the heated spaces. In determining the area, the SIST EN ISO 13789, Annex B, External dimension measurement system shall be observed.
(2) Building useful area, Au (m2), representing the internal groundplan area of heated spaces according to the design, shall be determined according to the SIST ISO 9836 standard. In the cases of dwelling buildings, the following simplified formula may be applied:
Au = 0,32 Ve
(3) The building net heated volume”, V (m3) is determined according to the provisions of the SIST EN 832 and SIST ISO 9836, section 5.2.5, or applying the following simplified formula:
V = 0,8 Ve.
Article 10
(1) Thermal transmittances of particular constructions, as determined according to the standards SIST EN ISO 6946 and SIST EN ISO 10211-1, shall not exceed the values listed in Table 1 of Annex 1, which is a part of these Regulations.
(2) Thermal transmittances listed in Table 1 also apply to those internal building constructions forming envelope towards such spaces in which, under certain external air temperatures, the temperature may fall below 12oC.
(3) Specific transmission heat losses through the building external envelope surface, of a building permanently heated to at least 18oC, HT' (W/m2K), determined according to the formula:
HT' = HT/A,
where HT represents transmission heat losses according to the SIST EN 832 standard, shall be less than:
where:
DD temperature deficit
in the cases of dwelling buildings and other heated buildings with less than 30% glazed window surfaces, or
in the cases of non-dwelling buildings with more than 30% window surfaces.
Article 11
In the case of a simple dwelling building according to the building construction regulations, the are of which does not exceed 50 m2, compliance may be demonstrated by means of ensuring the maximum thermal transmittances of individual building envelope elements do not exceed the values listed in Table 2 in Annex 1, while the calculation of allowable and predicted heat demand according to the SIST EN 832 is not required.
III. REQUIREMENTS REGARDING ENERGY EFFICIENCY
Article 12
(1)In the heated spaces of buildings, exclusively such glazing is allowed the thermal transmittance of which does not exceed Ust = 1,4 W/m2K and the total solar radiation transmittance factor of which is at least 0,55. Any glazing intended as a shading element, shall have a total solar radiation transmittance factor of at least 0,20.
(2)In the cases the glazing with increased noise protection characteristics (for example, Ar/SF6 filling) is installed in order to comply with building noise protection regulations, the thermal transmittance of such glazing shall be less than Ust = 1,8 W/m2K.
(3)Depending on the frame materials, thermal transmittance of windows shall not exceed 1,6 W/m2K in the case of wooden or plastic frame, respectively 1,8 W/m2K in the case of metal or concrete frames. Thermal transmittance of envelope doors shall not exceed 3,5 W/m2K.
(4)Overall thermal transmittance of any part of the building envelope construction containing roller shutter boxes shall be less than 0,6 W/m2K.
(5)The provisions of the above paragraphs of this article also apply to replacement glazing for existing buildings, except in the cases the compliance with these requirements would require replacement of window or door casings.
(6)The provisions of this article do not apply to shop-windows and glass doors.
Article 13
(1)In the buildings mentioned in Article 7 paragraphs one and two herein, the air change rate, calculated on the basis of the building net heated volume, shall be in the range:
0,5 = n = 0,7 h-1
(2)In the cases of buildings in which the air change rate of more than 0,7 h-1 is required according to the building ventilation and air conditioning regulations, heat recovery from waste air shall be provided. The efficiency of waste air heat recovery devices shall comply with the building ventilation and airconditioning regulations.
Article 14
(1)Heating bodies installed in front of glazed surfaces the thermal transmittance of which exceeds 1,5 W/m2K, shall be fitted, on their back – external surfaces, facing the glazing, with thermal insulation of thermal transmittance not exceeding 0,7 W/m2K.
(2)Any heating body supplying a particular room with at least 60% of the design heat, shall be fitted with thermostat valves, provided that the room useful area exceeds 6 m2.
Article 15
(1)In the buildings of no more than four apartments, in which the building orientation, roof pitch and the actual solar irradiation due to the topographic environment allow utilisation of solar energy for the purposes of sanitary water heating, distribution piping connecting the roof and the boiler rooms shall be provided, to connect solar collectors (hereinafter: SSE) with the heat accumulator.
(2)The roofs with appropriate orientation and pitch according to these regulations are those with one or more sections oriented in a direction in the range from Southeast, through South to Southwest, and the roof pitch in the range 20o to 60o.
(3)In the cases where plate SSE’s are installed, these are taken into account in the calculation of the predicted heat demand as solar gains with an equivalent value of 250 kWh per square meter of installed SSE’s per year, yet only up to 8 m2 per dwelling unit, while in the cases of vacuum SSE’s, with an equivalent value of 600 kWh per square meter of installed SSE’s per year, yet only up to 3 m2 per dwelling unit. In this case, SSE’s shall be installed and put in operation prior to the building technical inspection.
IV. OTHER TECHNICAL REQUIREMENTS
Article 16
Buildings shall be designed and constructed so that, during their intended use, water vapour penetrating into the construction structure due to diffusion, can not condense, and that the total amount of water vapour condensed in the construction structure can not cause any structural damage either during diffusion or after it.
Article 17
(1) The assumption that water vapour condensate having penetrated into the construction structure due to diffusion, will not damage the structure, is warranted in the following cases:
after the end of the period of diffusion, the total mass humidity X'uk of the construction structure material in which water has condensed is less than the maximum allowable humidity Xmaks for the material, i.e.:
X'uk = X'r + X'dif = Xmaks
provided that the entire amount of condensed water vapour, qmz, that has condensed in the construction structure during the period of diffusion humidifying, dries up during the period of diffusion drying.
(2) The average calculation mass humidities and the maximum allowable mass humidities for different construction materials are listed in Table 1 of Annex 3 to these regulations. In those construction structure materials not listed in the said table and for which X'dif and Xmaks are not known, water vapour condensation is not allowed.
Article 18
All building construction structures shall be designed and constructed so that water vapour does not condense on their surfaces even under design conditions.
Article 19
(1)In the cases of non-airconditioned buildings and buildings where no major water vapour generation processes take place, the total calculation number of days of diffusion humidifying and the total calculation number of days of diffusion drying both equal to 60. In the cases of such buildings, in calculating the drying of construction structures, the following assumptions apply:
ti = te = 18 ºC
i = e = 65 %,
where:
ti and tetemperature of internal and external air (oC)
i and erelative humidity of internal and external air (%)
(2)In the cases of airconditioned buildings or buildings where major water vapour generation takes place, the drying of construction structures is calculated applying the actual temperatures and relative humidities of internal and external air.
Article 20
(1)In calculating water vapour diffusion through the construction structure during the winter period, 90% external air relative humidity is to be assumed, and the following external air temperatures:
ter = 5 °C, at external air design temperatures down to –12 °C;
ter = -5 °C, at external air design temperatures down to -18 °C;
ter = -10 °C, at external air design temperatures down to -21 °C;
(2)For the purposes of calculation of water vapour diffusion through construction structures, the internal air temperature and relative humidity data shall be taken from the design brief.
Article 21
(1)Water vapour diffusion through construction structures, the amount of condensate and the drying of construction structures shall be calculated according to the SIST … standard [1]
(2)Water vapour diffusion shall be calculated for external construction structures and those construction structures constituting envelope towards unheated spaces, except for floors and walls facing the ground.
Article 22
(1)All windows, doors, fixed glazing and other site-installed construction elements shall be installed so that the air leakage of a space or of a group of spaces measured according to the SIST ISO 9972 standard, at a vacuum of 50 Pa, does not exceed two air changes per hour.
(2)Air leakage through windows and doors shall meet:
at least requirements of class 2 according to SIST EN 12207 in the cases of buildings not higher than two storeys;
at least requirements of class 3 according to SIST EN 12207 in the cases of two-storey to four-storey buildings;
at least requirements of class 4 according to SIST EN 12207 in the cases of all higher buildings.
(3)Only such windows and doors may be installed for which the class according to the SIST EN 12207 standard can be established based on the declaration of classification or by another acceptable method.
Article 23
All glazing surfaces except those facing North or shaded by some natural or artificial obstable, shall be provided with external solar radiation protection shading. External shading elements of any type and solar radiation protection glazing are considered as the external protection against solar radiation. The quality of protection shall be such that the product of the total solar radiation transmittance factor, g, (glazing and the shading element) and the percentage of glazing, fok = Aok/Af, for each façade face satisfies the following formula: