Malaysia’s Green Building Index Requirement on Solar Reflectance Index For Paving Materials – Part 2

In recent decades, environmental issues have been discussed and debated all over the world. There are many factors that contribute towards these environmental problems. One of it is the buildings, which play a very important role in this issue; not only during construction but also throughout its service life cycle.

In Part 1 of my article, I’ve touched on the Solar Reflectance Index requirement in Malaysia’s context Breen Building Index. In this part of the article, we will go into details of what is SRI? Urban development is a very important activity for economy stimulation. However, the same development process has brought in some other effects to the surrounding. The surface and air temperature in urban area are higher compared to suburban area; and the trend is in upwards due to more suburban areas are being converted into urban areas. This condition is known as heat island effect; and though there are many factors contributing towards this, solar absorption has been identified one of the main cause for this.

The buildings and paved surface are always exposed to the solar energy, and thus absorbing more heat directly from the sun; which eventually released to the surrounding. Due to this increased surrounding temperature, the usage of air conditioning has increased tremendously which obviously leads to many other environmental problems.

What is SRI? It is a composite value calculated base on equations provided in ASTM E1980. The field value is measured using portable emissometer (ASTM C1371), which measures the surface solar reflectance and emittance value.

Solar Reflectance – is a value measured on the solid material which is indicated on a scale of 0 to 1. The value 1 means that all the solar directed to the material surface is reflected back, while the value 0 means none is reflected. Based on literature, light colors tend to have much higher reflectance value compared to dark colors.

Emittance – is measurement of how well the surface let go the absorbed heat, and also reported on a scale of 0 to 1. The value 1 indicates 100% emittance. Most of the concrete products has an emittance value of 0.85 to 0.95.

As mentioned in Part 1 of this article series, the Green Building Index of Malaysia’s requirement on SRI for concrete pavement is at least 29. Under this guideline, the concrete pavement material to be used not only must achieve the minimum SRI, but also to be used for more 50% of the paving area. Only then the project will qualify for the green points under this criterion.

Look out for my follow-up article on this topic, which will discuss more Green Building Index.