ENERGY EFFICIENCY PERFORMANCE PRINCIPLES THE BUILDING ENVELOPE Components that constitute the building envelope are: 1.Roofs 2.Fenestration 3.Walls 4.Floors A well designed building envelope controls heat gain and loss in the hotter and colder seasons of the year. Maximize cooling air movement Limits exposure to direct sunlight in summer Trap and store heat from the sun in winter Minimise heat loss to the external environment
SECTIONAL ELEVATION OF A ROOM SHOWING EXTENT OF SUN PENETRATION AND HEAT LOSS/GAIN THROUGH THE BUILDING ENVELOPE
BUILDING REGULATIONS SANS 204 AND SANS 10400XA CORE ASPECTS OF THE STANDARDS ARE THE FOLLOWING: Site orientation Building orientation Shading Building design ( external walls, floors, fenestration, shading, roof assemblies and roof lights) Building sealing ( building envelope, air infiltration and leakage and permissible air leakages) Services (lighting and power, hot water services and appliances) Mechanical ventilation and air conditioning Installed equipment.
FLOORS With the exception of zone 5 (climatic zones), buildings with a floor area of less than 500 m 2 with, a concrete slab on ground shall have insulation around the vertical edge of its perimeter which shall: Have an R-value of not less than 1.0 Resist water penetration in order to retain its thermal properties Be continuous from the adjacent finish ground level a) to a depth of not less than 300 mm b) for the full depth of the vertical edge of the concrete slab-on-ground Application criteria Table 1: Perimeter insulation required (mm) Climatic zone123456 Minimum required R-values for perimeter insulation m 2 K/W 1111-1
FLOORS Where an in-slab or in-screed heating system is installed it shall be insulated underneath the slab with insulation having a minimum R-value of not less than 1,0. Application criteria Table 2: installed under floor heating Climatic zone123456 Minimum required R-values for perimeter insulation m 2 K/W 111111
FLOORS With the exception of climatic zone 5, a suspended floor that is part of a buildings envelope shall have insulation that shall retain its thermal properties under moist conditions and be installed: For climatic zones 1 and 2, with partially or completely unenclosed exterior perimeter, and shall achieve a total R-value of 1,5 : For climatic zones 3, 4 and 6, with a partially or completely unenclosed exterior perimeter, shall achieve a total R-value of 1,0. With an in-slab heating system, and shall be insulated around the vertical edge of its perimeter and underneath with insulation having a minimum R- value of not less than 1,0. Table 3: suspended floor that is part of the building envelope Climatic zone123456 Minimum required R-values for perimeter insulation m 2 K/W 1,5 11-1
FLOORS Detail 1: heat loss through un-insulated floor slabs and walls
FLOORS Detail 2: perimeter and under slab insulation
FLOORS Detail 3: perimeter and cavity insulation
FLOORS Detail 4: cavity insulation and under screed insulation
EXTERNAL WALLS Non- masonry walls shall achieve a minimum total R-value of Climatic zones 1 and 6: 2,2 Climatic zones 2, 3, 4 and 5: 1,9 Application criteria Table 4: Light weight external walls surface density less than 180 Kg/m 2 deemed-to-satisfy minimum total R-Values for each climate Climatic zone123456 Minimum required total R-values for light weight walls insulation m 2 K/W 2.21,9 2,2
EXTERNAL WALLS Masonry walls. For walls with a surface density greater than 180 kg/m2, table 5 sets out the minimum CR product requirements and their application: CR product –the time constant property (hours) of a composite element, such as a wall, and being the arithmetical product of the total C-value and the total R-value) The thermal capacity of a material is known as the C-value and it reflects the ability to store heat during the hot period and to radiate the heat during the cool period. This process is also known as thermal lagging, and masonry products such as bricks Application criteria Table 5: DEEMED TO SATISFY Minimum thermal capacity and resistance CR product, in hours, for external walling occupancies CR-Value per Climatic zone 123456 Residential: E1-E3, H1 –H510080 1006090 Office and institutional: A1-A4, C1-C2, B1-B3, G180 100 80 Retail: D1-D4, F1-F3, J1-J380 1208060100 Unclassified: A5, J4NR Note: NR= No requirement
ROOFS AND CEILINGS A roof assembly shall achieve the minimum total R-value specified in table 6 for the direction of heat flow. Table 6 Minimum required R-Value (m 2.K/W) for Roofs Climatic zones123456 Minimum required total R-values for roof solar absorptance of more than 0.55. 184.108.40.206.72.73.5 Dominant direction of heat flow.Up Down & Up UpdownUP
The tool kit is meant to support the decision making process that determines the use of insulation as energy-saving measures in new and existing buildings, with a focus of the three BASF insulation products (Neopor, Elastopor and Elastospray). This tool for determining recommended insulation levels is to be used in conjunction with other energy efficient design principles such as 1.Design for climate 2.Building orientation, main living areas towards the north 3.Insulation of geysers and pipes 4.Positioning of windows to allow cross ventilation and accommodate glass selection. BASF TOOL KIT
DETERMINING REQUIRED INSULATION THICKNESS Roof Construction Align with Climatic zone dial, Choose the climatic zone e.g. 2 Align with the minimum R-Values required from either the regulation or the rational calculations. See the required R- Value Match to the available R-values from Product manufacturer Product thickness mm
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