The R-Value refers to the resistance of an element to transferring heat, and is widely used in engineering design and in Australia’s building regulations. However, the R-value of any given material is derived under standard test conditions, when the material is heated to a set temperature and its resistivity measured only when the material reaches a “steady state” in heat flow. These tests may be scientific and logical, but do not take into account critical real-world performance factors, such as the amount of time it takes for the material to absorb the heat and reach a steady state.
When designing buildings, the amount of time the building takes to heat up or cool down can make a real difference to the comfort level of the occupants. Concrete blocks are said to have thermal mass, which is an energy-saving characteristic of dense material that allows blocks to absorb, store and release heat over time. This is why concrete blocks are cool to the touch in the day and warm in the evenings. This is thermal mass at work. According to the Australian Greenhouse Office, appropriate use of thermal mass throughout your home can make a big difference to comfort and heating and cooling bills.
The Mass-enhanced R-Value Calculator for Brick will now offer a new perspective that takes into account the real-world performance and energy-saving benefits of concrete block. The Mass-Enhanced R-Value Calculator is available for both concrete blockwork walls and brick (available from the Think Brick Australia website), and takes into account the different climate zones and different building classes in the Building Code of Australia (BCA). It simplifies compliance with building regulations with a user-friendly interface.
The calculator is available for download as a Microsoft Excel spreadsheet. Please make sure you have Microsoft Excel installed on your computer.
On the Main tab of the spreadsheet you will find fields to input your project information.
Fill in this information and choose from various type of walls including thickness, type of insulation, shading angle, climate zones and building classes as defined by the BCA. You can refer to the explanatory notes and climate map in the second and third tabs of the spreadsheet.
The calculator will then calculate both the R-Value of the wall you are working on, as well as the Mass-Enhanced R-value. It will also show whether it achieves compliance with the 2014 National Construction Code.
You can then click the button “Print Certificate” to be used as documentary evidence of compliance with the BCA.