“TECNALIA’s Optics Laboratory: a key ally in the fight against the urban heat island effect”
The Solar Reflectance Index (SRI) is a strategic tool for designing cooler, more efficient cities that are ready for the future
Cities are increasingly facing periods of extreme heat and the urban heat island effect, a phenomenon that causes temperatures to be significantly higher in urban areas than in the surrounding areas. In this context, the choice of materials used for roofs, paving and other surfaces exposed to the sun takes on strategic importance.
TECNALIA’s Optics Laboratory, which has been accredited by ENAC in accordance with the ASTM E 1980-24 standard, is a key partner in supporting public authorities, architectural firms, manufacturers and town planners in combating the urban heat island effect and designing more sustainable urban environments.
Solar Reflectance Index (SRI): a key indicator of the thermal performance of materials
The Solar Reflectance Index (SRI) is an indicator used to assess the thermal performance of materials. Its value combines two key properties: the ability to reflect solar radiation (solar reflectance) and the ability to release absorbed heat (emissivity).
This combination allows the SRI to provide objective information on a surface’s tendency to heat up when exposed to the sun. The higher the SRI value, the lower the temperature the surface will reach and the smaller its contribution to the overheating of the surrounding environment.
As a result, the SRI has become a key reference tool for materials manufacturers, architects, town planners and public authorities who are trying to:
- Reduce the urban heat island effect in cities.
- Improve thermal comfort in urban areas.
- Reduce the energy consumption associated with heating and cooling buildings.
- Comply with environmental certification requirements such as LEED.
- Incorporate sustainability and climate adaptation criteria into their projects.
Who benefits from TECNALIA’s optics laboratory?
TECNALIA’s Optics Laboratory provides technical support to:
- Manufacturers of building materials who want to validate and improve the thermal performance of their products when exposed to solar radiation.
- Architects and urban planners who need to select solutions that reduce the thermal impact on the urban environment.
- Public authorities working on climate adaptation strategies.
- Builders and building managers who need to demonstrate the energy performance of the materials used in their buildings.
What problem does it solve?
The SRI makes it possible to objectively compare the thermal performance of different finishes and materials. This helps to:
- Select solutions that minimise the urban heat island effect.
- Comply with energy efficiency and sustainability requirements.
- Avoid duplicate testing in other countries due to the fact that ENAC is recognised internationally.
- Speed up entry into global markets with accredited reports.
An accredited laboratory serving industry and cities
TECNALIA’s Optics Laboratory is accredited to measure:
- Solar reflectance: the ability of a surface to reflect solar radiation.
- Thermal emissivity: the ability to emit heat
Both measurements calculate the SRI accurately and reliably, ensuring results that are recognised in over 70 countries.
As Sara Zubia, technical manager of the TECNALIA Optics Laboratory“The SRI is a key data tool for assessing how materials help to reduce the urban heat island effect. A high SRI value means cooler surfaces, more energy-efficient buildings and more comfortable cities. TECNALIA provides industry and urban actors with the assurance of accredited tests, which are essential for moving towards more resilient, sustainable environments.”
Helping to create more liveable cities
This accreditation reinforces TECNALIA’s commitment to climate adaptation, energy efficiency and the development of innovative solutions for a healthier built environment. Consequently, the SRI has become a strategic tool for designing cooler, more efficient cities that are ready for the future.