3 The Regulator (NRCS) has published legislation regarding energy efficiency in new buildings (NBR-XA) Here’s what you need to know for your homeSouth Africa’s mounting energy crisis means that we all need to think of innovative ways to save electricity in our homes and of products that can help you reduce our current electricity usage.The application of this new regulation is good news for the environment and will help you save electricity.The National Building Regulation (NBR) has been updated to include Part X which addresses environmental sustainability and Part XA which establishes requirements for energy efficiency in new buildings.The National Standard SANS (building code) is made up of various parts. Parts A to W are deemed to satisfy rules which, if adhered to, will ensure compliance to the National Building Regulations. Each part covers different aspects of the construction and finishing of buildings. These are the minimum standards that ensure the health and occupational safety of the occupants in these buildings.
4 Heat Loss in the home Buildings typically account for 40% of all energy consumed in South Africa and yet their potential to save energy is huge. Thermal insulation must be included in the design of all new buildings. This, in combination with energy saving techniques, makes it possible to save up to 78% of a building’s energy consumption for space heating, cooling and hot water services.
5 40% of SA total energy currently used in buildings ≈ 35% RoofSummer≈ 10% Air gapsPrinciple of insulation≈ 10%≈ 25%WallsGlazingThermal bridgesWinterFloor≈ 10%≈ 10% GroundCorrectly insulating the building envelope in combination with energy saving techniques can control energy losses and reduce energy consumption by up to 78%5
6 There are three ways of complying with the energy regulation. Option 1:Comply with the SANS XA requirementsOtherwise described as “Deemed to Satisfy”Option 2:Rational designThis option requires input of a relevant professionalThermal performance of building needs to be calculatedPerformance should be equal to or better than SANS XAOption 3:Comparison with a compliant theoretical buildingComparison with the design performance of a “notional” buildingNotional building should be designed to “Deemed to Satisfy” standardsThermal performance calculations software used must be approved by Agrément SA
7 Climatic zones – South Africa South Africa has been divided into six climatic zones according to their humidity and temperatureZone Climatic conditionsZone 1 Cold InteriorZone 2 Temperate InteriorZone 3 Hot InteriorZone 4 Temperate CoastalZone 5 Sub-tropical CoastalZone 6 Arid Interior
9 An important consideration when building is to determine the relevant climatic zone. Each of the climatic zones has a different R-value requirement for certain walls and ceilings.Insulation R-value should be indicated on the packaging.All material has an R-value which is the ability of a product to resist the transfer of heat. Thermal insulation provides a high resistance to the flow of heat from the warm surface to the cold surface in your home, helping you maintain a comfortable living environment, keeping your house cool in summer and warm in winter.
10 Requirements to comply with SANS 10400-XA “Deemed to Satisfy” Building envelope requirements (SANS XA)>> Orientation (Guideline)Compact in plan with most glass on the northern siedLiving spaces on northern sideLonger axis of dwelling to be east-westRoof overhang to shield northern windows in midday summer sun>> FloorsIf under floor heating is installed the floor slab must be insulated with insulation with a minimum R-value of 1.00>> Fenestration (Windows/Glass doors/Skylights)Buildings with up to 15% fenestration area per storeyBuildings with fenestration area per storey exceeding 15% shall comply with the requirements for fenestration in SANS 204Air leakage should comply with SANS 613>> External WallsLight weight (Non brick/Non concrete) walls must achieve a minimum R-value:Of 2.2 for climatic zones 1 & 6Of 1.9 for climatic zones 2, 3, 4 & 5Masonry walls (Brick/Concrete) must achieve a minimum R-value of 0.35Double skin brick with no cavity, plastered internally and either plastered externally or finished with face bricksSingle brick/block with a minimum thickness of 140mm plastered internally and externally
11 Hot water supply requirements (SANS 10400-XA) Geysers A minimum of 50% of the annual average heating requirement for hot water must be provided by means other than electric resistance heating (Geyser) or fossil fuelsSee options below but not only limited to these:Solar HeatingHeat pumpsGeothermal HeatRenewable Combustible FuelHeat recovery from alternative systems and processesAll exposed hot water pipes ≤ 80mm diameter must be insulated with a minimum R-value of 1.00
16 SANS 10400 XA – Roof/Ceiling insulation Roof and Ceilingceiling insulation solutionMust achieve the minimum total R-value specified below:Indicates the direction in which your home loses or gains heat through the roof in each climatic zone.Isover Aerolite (Flexible Rolls)
29 5.5.1 What is an R-Value?Insulation materials are rated for their performance in restricting heat transfer. This is expressed as the R-Value, alsoknown as thermal resistance. The R-Value is a guide to its performance as an insulator-the higher the R-Value, the betterthe insulation (i.e., resistance to heat flow) it provides.R-Values are expressed using the metric unit’s m².K/W, where:• m² refers to one metre squared of the material of a specified thickness;• K refers to a one degree temperature difference (Kelvin or Celsius) across the material;• W refers to the amount of heat flow across the material in watts.Use the nominal R-Values as listed by the manufacturer on the packaging of the insulation to determine the performance.Products which have the same R-Value will provide exactly the same insulating effect as each other, provided they arecorrectly installed. The higher the R-Value the more effective the insulation. Products must be installed in accordancewith the manufacturer’s specifications.The information available on the product data sheet and/or label must include the R-Value and whether it must beinstalled professionally or DIY. Ensure that it suits your particular application. Ask if performance guarantees and/or testcertificates are available.Material R-Values – the thermal resistance values of bulk/mass type insulation are measured on the product aloneaccording to international standards.System R-Values – the thermal resistance value of reflective insulation is calculated based on international standardsand depend on the product being installed as specified in accordance to manufacturer’s specifications. This is known asa system R-Value which incorporates air spaces.Composite R-Values - the thermal resistance values of composite insulation products are measured by testing thecomposite product as a unit according to international standards.Direction of heat flow effectR-Values can differ depending on the direction of heat flow through the product. The difference is generally marginal forbulk insulation but can be pronounced for reflective insulation.• Up R-Values describe resistance to heat flow upwards (sometimes known as 'winter' R-Values).• Down R-Values describe resistance to heat flow downwards (sometimes known as 'summer' R- values).
30 Integrated Resource Plan – September 2009 Table 2 – South African generation capacity assumed for IRP
33 Current installed generation capacity 2010 42 000 MW Forecast required installed generation capacity 2030MWOf the current installed generation capacity still operation in 2030MWGenerating capacity to be installed betweenMWEquivalent to:35 Koeberg type Power Stations Minimal CO2 outputor16 Conventional Coal Power Stations (4500MW)550 MT CO2 output
34 ComplianceThe provisions of the National Building Regulations shall be satisfied by:Adhering to the requirements of all the prescriptive regulations, orComplying with all functional regulations by:Adopting building solutions that comply with the deemed to satisfy requirements of the corresponding part of SANS 10400Reliably demonstrating or predicting with certainty that an adopted building solution has an equivalent or superior performance to a solution that complies with the deemed to satisfy provisions. (Rational design by competent person)
35 Regulatory FrameworkNational Building Regulations and Building Standards Act, 1977 (Act 103 of 1977).NBR`s are issued in terms of the above act and is a compilation of various parts (A to X:–Part A – General Principles and RequirementsPart B – Structural Design:Part X – Environmental SustainabilityPart XA – Energy Usage in BuildingsSANS is a National Standard: (Building code)The Application of the National Building Regulations (also compiled in many parts to correlate to the National Building Regulations)
36 Routes to Compliance to NBR-XA Option 1: Rational designThis alternative requires input of a professional “competent” personThermal performance of building needs to be calculatedPerformance should be equal or better than specified in SANS 10400XAOption 2 – 4 = “Deemed-to-Satisfy”Option 2: Compliance to SANS 10400XA“Recipe” for building elementsRequirements partially aligned with SANS 204Option 3: Compliance to TablesMax Energy Consumption & Max Energy Demand must comply with tables in SANS XAOption 4: Comparison with a compliant theoretical (reference) buildingBuilding design performance – theoretical max energy consumption & demand shall be less than or equal to that of a reference buildingBuilding should be designed to “Deemed to Satisfy” standardsUse of thermal performance calculations software accredited by Agrement SA
37 Roof and CeilingMust achieve the minimum total R-value specified below:◦Indicates the direction in which your home loses or gains heat through the roof in each climatic zone.Hot water supply requirements (SANS XA)>> GeysersA minimum of 50% of the annual average heating requirement for hot water must be provided by means other than electric resistance heating (Geyser) or fossil fuelsSee options below but not only limited to these:Solar HeatingHeat pumpsGeothermal HeatRenewable Combustible FuelHeat recovery from alternative systems and processes>> All exposed hot water pipes ≤ 80mm diameterMust be insulated with a minimum R-value of 1.00
38 Part XA – Energy Usage in New Buildings XA1 - In order to contribute to the reduction of greenhouse gases, buildings and extensions to buildings in respect of which plans and specifications are to be drawn and submitted in terms of the Act, having A1, A2, A3, A4, C1, C2, E1, E2, E3, E4, F1, F2, F3, G1, H1, H2, H3, H4 and H5 occupancies or building classifications in accordance with Regulation A20, excluding garage and storages areas contained within such occupancies, shall be designed and constructed so that they:a) are capable of using energy efficiently while fulfilling user needs in relation to vertical transport, if any, thermal comfort, lighting and hot water; orhave a building envelope and services which facilitate the efficient use of energy appropriate to its function and use, internal environment and geographical location.Equipment and plant required for conducting the business of the occupant shall be excluded from these requirements.XA2 - At least 50 % by volume of the annual average hot water heating requirement shall be provided by means other than electrical resistance heating including but not limited to solar heating, heat pumps, heat recovery from other systems or processes and renewable combustible fuel.XA3 - The requirements of sub-regulation XA1 shall be deemed to be satisfied when such building is designed and constructed in accordance with the following requirements:a) has an orientation of the longest axis, shading, services and building envelope in accordance with SANS XA; orb) is the subject of a rational design by a competent person, which demonstrates that the energy usage of such building is equivalent to or better than that which would have been achieved by compliance with the requirements of SANS XA; orc) has a theoretical energy usage performance determined using certified thermal calculation software, less than or equal to that of a reference building in accordance with SANS XA.
39 Additional Requirements Competent person (where necessary) – Submit documentationLocal authority as per SANS AOn PlansWhere provided – location, type & capacity of water heating installationsWhere provided – details ofFenestrationInsulation
40 SANS 10400 XA Hot Water Supply – XA2 Regulation: A minimum volume fraction of 50% of the annual average heating requirement for hot water shall be provided by means other than electric resistance heating or fossil fuels including, but not limited to:Solar heatingHeat pumpsGeothermal heatRenewable combustible fuelHeat recovery from alternative systems and processes
41 SANS 10400 XA2 Hot Water Supply – compliance The functional requirements of sub-regulation XA2 shall be satisfied when:The population for which such building is designed is determined in accordance with Regulation A21;The hot water demand is determined in accordance with table 2 and table 5 of SANS :2004;The storage requirement is based on maintenance of a hot water temperature of 60 0C;Solar water heating systems shall comply with SANS 1307, SANS and SANS based on the thermal performance determined in accordance with the requirements of SANS and SANS All exposed hot water service pipes (SANS ) shall be clad with insulation with a minimum R-value in accordance with SANS 184.108.40.206 Thermal insulation, if any, shall be installed in accordance with the manufacturer’s instructions.
42 Internal diameter of pipe 1. Roof/Ceiling systemsSANS XA Geyser systems and Pipe Insulation – XA 2RequirementsAll exposed hot water service pipes shall be clad with insulation with a minimum R-value in accordance with the table below.Internal diameter of pipeMinimum R-value<80mm1.0>80mm1.5Determined with a hot surface temperature of 60 °C and an ambient temperature of 15 °C.
43 SANS 10400 XA – Geyser and Pipe Insulation 1. Roof/Ceiling systemsSANS XA – Geyser and Pipe InsulationSaint-Gobain geyser and pipe insulation solution1 – Isover Geyser Insulation Pack(Flexible blanket & pipes)Geysers use % of a households energySystem including pipes!Reduced heating cyclesNo switching on/offHeat loss savingGeyser blanket 21%Pipe insulation 37%Total savings 58%Savings can vary depending on the length of the pipes insulated and the thermostat setting. Thermostat setting should ideally be 55ºC
44 SANS 204 Energy Efficiency in Buildings Far more comprehensive than the building regulations and SANS – XARequirements significantly more stringentIn the longer terms regulation to be upgraded and trend toward SANS 204It is a voluntary standardBasic minimum for green star rating
45 Thermal conductivity, (K-value) All materials conduct heat, some better than others. Good insulation materials must have a LOW conductivity.Eg. The heat from one side of a wall must travel very slowly towards the other side of the wall.Thermal conductivity is calculated in W/mK (Watts per meter Kelvin degrees), therefore if two products with similar densities are tested at the same temperature and one has a K value of W/mk and the other has a K value of W/mK, the material with the lower K value insulates better.
46 Thermal conductivity, (K-value) The ability of a product to conduct heatSteel is a good conductor of heatWood is a poor conductorCalculated in W/m.K (Watts per meter Kelvin degrees)K values of typical building materialsThe lower the K value the lower the heat flow through the productTypical Building ProductsK value ( W/m.K)Corrugated steel roof sheets1.000Clay roof tiles1.150Gypsum ceiling board0.170Wooden roof truss0.120Polyester ceiling insulation ( 10 kg/m³)0.045Glasswool ceiling insulation ( 12 kg/m³)0.040Glasswool ceiling board ( 50 kg/m³)0.032
47 Thermal resistance, (R-value) The ability of a product to resist the transfer of heatTo calculate the R value you need to know (R value = )The Thermal conductivity (K value) of the productThe product thicknessCalculation of R-Values for typical Roof/Ceiling Construction ProductsTotal R-value of a construction element (Wall or roof) can be obtained by adding the R-values of the different componentsThe higher the R value the better the products thermal resistanceThickness in metersK value
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