In recent Solar Reflectance Index (SRI) testing, the results showed that the cool roof coating, Belzona 3111 (flexible membrane), exhibited high solar reflectance properties with an average* SRI of 99.4%. Considering the vicious cycle of increased global temperatures leading to an increased use of air conditioning, which exacerbates the problem further, polymeric technology like this plays a valuable role in mitigating this damaging process.
 
FIGURE 1 | Cool roof coating reduces internal temperature of structures.

What is a Cool Roof? 

A cool roof strongly reflects sunlight and also cools itself by efficiently emitting any heat that has been absorbed. To measure this effect, SRI testing examines a material's solar reflectance and thermal emissivity. The SRI is a value that combines these figures; it is used to indicate how hot a material will likely become when its surface is exposed to solar radiation. The SRI is defined on a scale of 0-100, with standard black being 0 and standard white being 100.
 
The Air Conditioning Global Warming Trap
Materials with lower SRI values are more likely to absorb a high fraction of the incoming solar energy and become hotter in the sun. A fraction of this absorbed energy is conducted into buildings and structures. With increased internal temperatures, this increases the requirement for air conditioning.

Hand-in-hand with this, this process incurs a considerable carbon footprint. According to research from scientists from NREL and Xerox PARC, in 2022, air conditioning was responsible for 3.94% of global greenhouse gas emissions. This is the equivalent of 1,950 million tons of carbon dioxide released annually—and this figure is set to rise.
 
As global temperatures continue to increase, this will inevitably lead to a rise in the use of air conditioning. The research predicts increases of 14% in the hottest climate studied (Chennai, India) and of 41% in the mildest (Milan, Italy) by 2050.
 
Describing the damaging nature of this process, the research describes how: ‘This causes a self-reinforcing pattern that must be addressed through improved cooling, both for the health of humankind and the stabilization of the climate.’
 
‘Improved Cooling’ Offered by Polymeric Cool Roof Coating

Considering the predicted increase in use of air conditioning, cool roof coatings such as Belzona’s new coating, have an important part to play in helping to minimise this expected growth. 

The new cool roof coating is a cold-applied liquid coating specially designed for long-term roof protection. With outstanding waterproofing and weatherproofing properties, this single-component, water-based roof coating will bond strongly to all types of roofing materials, following even complex roof contours. It is certified by the British Board of Agrement and ETA-Danmark (European Technical Assessment). The isocyanate-free system has also been proven to provide excellent protection of roofs for in excess of 25 years.

When the SRI testing was conducted in accordance with ASTM E1980-11, the coating in white achieved an average SRI of 99.4%.

FIGURE 2 | Belzona 3111 (Flexible Membrane) cool roof coating.
 

This high SRI figure reflects how this system is optimized for rejecting solar radiation. This means that when a roof is coated, a significant reduction in internal temperature can be achieved. 

This figure can be used to demonstrate compliance with some building codes if the measured Solar Reflectance and Thermal Emittance figures do not comply on their own.  
 
FIGURE 3 | Application of roof waterproofing membrane.
 

Reduce Costs and Environmental Impact with Polymeric Technology

Commenting on the recent test result, Technical Coordinator, Isaac Atkinson said: “Belzona 3111 (Flexible Membrane) has an important role to play in helping to alleviate the destructive cycle of increased air conditioning usage. By coating roofs with this cool roof system, this will help to reduce internal temperatures, therefore, asset owners can significantly reduce the need to use air conditioning. As a result, this will enable asset owners to not only make significant financial savings, but to also reduce their carbon footprint as well.”

Other Benefits

• Simple application by brush or roller ensures minimum downtime is incurred.  
• Improved occupant comfort by minimising heat gain inside buildings.
• Long-term weatherproofing and waterproofing protection. 
• Reduced health and safety risks thanks to solvent-free system.   

For more information visit www.belzona.com/en/products/3000/3111.aspx. 

*Average figure based on SRI calculated in low, medium and high winds.

All images courtesy of Belzona.