This guidance is primarily aimed at public procurers involved in a range of contracting agreements related to building materials and products. This includes the purchase of building materials for construction works, but may also extend to material extraction, manufacturing, building, retrofit, refurbishment, design, interior fit out, and end-of-life demolition or deconstruction processes. 

Glass is a material inextricably linked with human civilization. It is also the product of an energy intensive industry. About 75% to 85% of the total energy requirements to produce glass occur when the raw materials are heated in a furnace to more than 1500 °C. During this process, large volumes of emissions arise. The container and flat glass industries, which combined account for 80% of total glass production, emit over 60 million tonne of CO2 per year.

The glass industry is part of the energy-intensive industry posing a major challenge to fulfill the CO₂ reduction targets of the Paris Climate Agreement. The segments of the glass industry, e.g., container or flat glass, are quite diverse and attribute to different glass products with different requirements to product quality and various process options.

In Germany, according to the "Kreislaufwirfschaft Bau", 14.6 million tonnes of construction site waste were generated in 2014.  In a position paper, Glass for Europe estimate that float glass accounts for less than 1% of construction site waste.  Even this apparently small amount is not negligible as glass is predestined for closed-loop recycling.  The use of glass cullet not only conserves natural raw material resources, but also reduces the melting energy required, and thus, also the CO₂ emissions.

The increased attention paid to resource efficiency, sustainable use of natural resources and sustainable buildings has raised awareness of the potential of the building sector to contribute to Europe’s goals in these areas.

The Resource Efficiency Roadmap identifies the building sector as one of the sectors that is key to addressing the challenges of energy, climate change and resource efficiency. The Roadmap recognises that increased waste recycling, among other measures, will contribute to a competitive construction sector.

The transition to a carbon neutral EU requires deep energy demand reductions in key sectors of the economy such as buildings and transport, and that the remaining energy consumed is carbon neutral. Such transformations can only be achieved if the conditions are created for all actors and industrial sectors to maximise their multi-faceted contributions to this low-carbon revolution.

Glass is a highly recyclable material, despite which, end-of-life building glass is almost never recycled into new glass products.

In the UK alone, almost 200,000 tonnes of glass is currently sent to landfill each year. In the EU, the proper recycling of all building glass waste could avoid 925,000 tonnes of landfilled waste every year and save around 1.23 million tonnes of primary raw materials annually.

Over the last few decades, glass manufacturers have increased their sustainability through innovation, and they are expected to continue to do so through the rollout of new technologies and processes such as carbon capture. The sector also has a key role to play in boosting sustainability in other sectors, whether through lighter glass packaging or glass fiber used for wind turbine blades.

The Inventory of Carbon and Energy (also know as the ICE database) is an embodied carbon database for building materials which is available for free on this page. It contains data for over 200 materials, broken down into over 30 main material categories. The first version was released in 2005 and it has been updated at periodic intervals. 

The Construction Material Pyramid from CINARK at the Royal Danish Academy makes it possible to compare, for example, CO2 footprints between different categories of materials or between material types within the same category. It also makes it possible to view different kinds of environmental impacts across the different materials. It thus offers a tangible, interactive calculation tool and at the same time opens up a dialogue about more detailed studies of the materials’ position in the pyramid and later their place in the project design.