Sustainability FAQ

The principal emissions from the float process are to air and arise as products of the combustion of fuel and as carbon dioxide from the decomposition of the limestone and dolomite used in the process. 

The float process emits approx 0.8 kg CO₂ per kg glass sold from both direct (fossil fuels and carbonate decomposition) emissions and indirect (electricity generation) emissions. Approximately 0.3 kg CO₂are released per kg glass sold during the extraction, processing and transportation of the raw materials to our sites. Therefore, approximately 1.1 kg CO₂ is released in order to manufacture 1.0 kg of non-processed, glass. 

Further energy is required for toughening, laminating and coating. The CO₂ emitted during transportation to the customer varies depending on the distance and mode of transportation.

Since its invention by Pilkington, major environmental improvements have been made in the float glass process. Emissions have been reduced significantly and substantial reductions have been made in energy consumption. Glass production will inevitably remain energy-intensive. 

We therefore work hard to minimize energy input, so that the usage of glass contributes net benefit to sustainable development.

Float glass manufacture is an energy consuming process, but many of our products reduce energy consumption when used in buildings. It is important to consider this overall balance when assessing environmental impact. The manufacture of one square metre of low-e double glazing leads to the emission of 25 kg CO₂. However, the CO₂ saved by replacing one square metre of single glazing with low-e double glazing in a typical European building is 91 kg per year, offsetting the CO₂ emitted during manufacture after only 3.5 months in use.

Energy Conservation in Buildings

Energy issues are key to the building glass industry, as glass products can make an important contribution to combating climate change. In our largest market, Europe, research suggests that glass can help to attain the ambitious goal set by the European Union heads of state and government to reduce CO₂ emissions by at least 20 percent by 2020. Different types of glass we have developed over the years, especially low-emissivity double glazing and solar control glazing, can significantly reduce the need for heating and cooling in buildings, thereby reducing energy consumption and associated CO₂ emissions.

CO₂ emissions and solar control glazing

In regions where the ambient temperature is often uncomfortably hot, the increasing tendency, as people aspire to a better lifestyle or have more disposable income, is to install air conditioning and that of course brings with it an energy and carbon burden. In that case, the primary objective is to keep heat out. Residential and non-residential buildings that use more energy than necessary to stay cool are a major source of unnecessary CO₂ emissions.


The potential for solar control glass to cut CO₂ emissions from buildings has been analysed by the Dutch scientific institute TNO in a study undertaken for Glass for Europe. Solar control glass allows sunlight to pass through glazing while radiating and reflecting away a large degree of the sun’s heat. The indoor space stays bright and much cooler than would be the case if normal glass were used. The TNO study concluded that between 15 and 80 million tonnes of CO₂ emissions annually — roughly between 5 percent and 25 percent of the European Union target — could be avoided by the year 2020 by optimal use of solar control glass alone.

In Europe, our glass for building products is manufactured in the UK, Germany, Italy, Sweden and Poland. This distribution minimises transportation distances. We source raw materials locally where suppliers can meet demanding quality and procurement requirements.

It is often difficult to calculate the proportion of this energy generated from renewable resources. Renewable electricity is acquired in a number of ways. Some electrical power is directly generated on site from waste gases, using co-generation installations. 

Electricity supplied directly from wind or solar remains quite low. More is supplied via the existing grid supply system under so called ‘green supply’ contracts. In a number of jurisdictions, electricity suppliers have a legal obligation to generate a proportion of electricity from such sources. 

In 2007 the Group received 8.7 GWh from renewables and waste heat directly, plus a further 38 GWh from combined heat and power. The diversity of generation of grid supplies is taken into account when calculating carbon dioxide emissions resulting from the generation of electricity by taking this into account when using published carbon factors.

Information on the environmental performance of all sites is collected using our Airsweb multilingual global database. The data collected shows that 8% of the total energy used in glass manufacturing came from electricity in 2007 and 2008.   During that period, 92% of total energy used in glass-making sites came from the direct burning of fossil fuels.

For both environmental and financial reasons and wherever practicable, the NSG Group uses natural gas as the fuel of choice for glass melting. The second most utilized fuel is heavy fuel oil. Diesel oil and liquid petroleum gas as fuels are used as back-up fuels in case of the failure of the preferred fuel. Diesel oil is also widely used to power small engines and boilers.

To achieve maximum sustainability products  should be reused at the end of their initial usage life and then if this is not practicable the product or the component materials should be reused or recycled. This is known as the reuse recycling hierarchy. Of course things may be more complicated and some products may be retired before they have reached the end of their useful life because they have been superseded by more efficient products. It is necessary to achieve a balance to minimize overall resource usage.

There is no reason in principle why a window or other glass structure could not be reused. However, in many constructions the frame and size of glazing units is bespoke which would limit re-use in this form. Having said that, most window and glazing materials can be re-used in some form and in the UK some companies are actively collecting and recycling windows.

Glass is 100% recyclable. One of the significant sustainability advantages of glass as a material is that, unlike many other materials, it can be recycled indefinitely. The only real constraint in glass-making terms is colour. Whilst it is possible to use clear glass cullet in the production of coloured glass it is not practicable to do the reverse. However, this does not mean that all glass products can be recycled easily. Removal, segregation and transport impacts can affect the viability and environmental impact of recycling. The level of contamination determines if the glass will be used in the float, container, fibreglass or aggregate  industries.

Aluminium and steel components from Pilkington Planar™ systems are also 100% recyclable.

Internal cullet (recycled glass feedstock) accounts for approx 25% of the product.  All edge trimming and any quality failing glass is re-melted. Cullet is also a useful raw material for other parts of the glass industry, particularly the glass container sector. Up to 95% of waste glass from processing (cutting, manufacture of glazing units etc.) is recycled in some way.

Coated glass (low-e, self-cleaning, etc.) can also be recycled through conventional means and is capable of being recycled into the float process where required.

Glass for recycling is a valuable resource. Wherever practicable we recycle any glass off-cuts or cullet within our own glass melting lines. Glass from our downstream operations and from those of our customers represents a potentially useful resource to us. We gain a double benefit from the use of such cullet.

Firstly, the use of cullet to make glass reduces the requirement for raw materials and of course avoids the problem of disposing of what would otherwise be a waste material. Secondly, there is a net energy saving and  consequent reduction in emissions since it takes less energy to melt glass than to melt the equivalent quantity of raw materials.

In 2007, the Group bought in 197,900 tonnes of cullet to supplement cullet from our own internal recycling (approx 4% of glass sold).

Laminated glass contains a sheet of PVB (poly vinyl butyrate).  All off cuts are returned to the supplier for re-incorporation into PVB products.

The major components of glass are sand and sodium carbonate.  Although not readily renewable, they are some of the planet’s most abundant materials.

Zero per cent. Glass is an inert product that will not biodegrade.

Glass is inherently stable and will exceed the lifetime of the building. 

Replacement is normally driven by breakage, building design or window framework failure rather than a failure in the glass itself. Product specific warranties are available upon request.

ISO 9001 Quality Management Systems

All glass manufacturing sites are independently certified to ISO 9001:2000 quality management system. This ensures maximum yields and minimal waste throughout the supply chain.

ISO 14001 Environmental Management Systems

All of the Group's global glass manufacturing sites have an externally verified ISO 14001:2004 environmental management system. This ensures that all local legislation and significant environmental impacts are identified.  Certification demonstrates that employees are trained in the necessary procedures to meet the legislative requirements and continually reduce their impact on the environment.

Copies of the certificates can be found on the NSG Group website 

Health & Safety Management System

The health, safety and wellbeing of all employees, contractors, visitors, neighbours and customers remain at the forefront of our business activity. The Group’s safety policy is based on the premise that all accidents are preventable. The Group has well developed safety education and training programs, and safety statistics are carefully monitored. We measure safety performance using two key performance indicators. The Lost Time Injury Rate (LTIR) records work-related accidents or illnesses preventing individuals involved being able to report for work on the following day or shift. These are expressed as a rate per 200,000 hours (approximately the time worked by 100 people in one year). The LTIR was 0.25 in 2009; an improvement of 14 percent.

Additional information can be found on the NSG Group website 

In most cases, the finished product does not contain hazardous substances. Glass is produced from non toxic, naturally occurring substances (sand, limestone, dolomite etc.) Glass is an inert material. Hazardous substances may be used during the subsequent processing of the glass. These are carefully managed on our sites to ensure no harmful release to the environment and are rendered harmless in the final product. The Group is active in ensuring that its most critical supplies are REACH compliant.

Coated products

Coatings are all based on oxide materials which are naturally occurring and stable. On-line coatings are deposited onto the glass at high temperature to form hard durable coatings on the surface of the glass between 15 and 350 nm in thickness. The coatings are all designed to pass European Standards (EN1096) which tests the coatings durability to high temperatures and humidity, corrosive atmospheres (sulphur dioxide and salt spray) as well as abrasion to ensure the coatings are not damaged or release materials in service. The only exception to this is Pilkington Activ™ self-cleaning glass. In this product the titanium dioxide surface acts as a photo catalyst accelerating the decomposition of organic dirt on its surface. This process is not harmful and accelerates the decomposition of dirt into carbon dioxide and water vapour. The coated surface is not used up or changed as part of this process as it is a catalytic process.

VOCs are not used in the manufacture of flat glass. Although VOCs may be used during the back painting process, there are no VOCs present in the finished product.

Air emissions: Emissions to air arise primarily from the combustion of fuel used to melt the raw materials. The principal materials emitted are oxides of sulphur and nitrogen. Particulates also arise from trace components in the fuel and from glass formation. Furnace emissions also contain dust and traces of chlorides, fluorides and metals arising as impurities in the raw materials.

Water emissions: Float glass production does not present significant water pollution problems. Water is used mainly re-circulated for cleaning and cooling and can easily be reused or treated.

Waste: The glass manufacturing process itself produces very little waste material. All trimmed glass is recycled back into the melting process and waste is limited to maintenance waste, occasional off specification raw material which cannot be usefully blended and packaging waste. If glass is produced which cannot conveniently be re-melted on site it is sent, where practicable, for external recycling.

NSG Group will ensure that activities are regularly monitored to enable us to reduce the effect of the business on the environment as a whole; efficiently utilise natural resources, reduce releases to the environment, encourage the re-use and recycling of materials and live in harmony with local communities. 
Site specific reduction targets are included in the ISO 14001 improvement plans.

We aim to eliminate or minimise the amount of packaging used to deliver products to customers. Specialised floatliner vehicles are used where possible to eliminate the need for packaging. Returnable metal and a small proportion of recyclable wooden stillages are used where this is not possible. Cardboard spacers can be returned to us and reused.

We are working with Glass for Europe to develop a European flat glass life cycle analysis. The Building Research Establishment has a generic rating for double glazed windows incorporating glass in the Green Guide.

The NSG Group is working closely with key raw material suppliers to ensure that materials are responsibly sourced both to protect and enhance the environment and to ensure the safety and wellbeing of supplier employees.

NSG Group Procurement has functional level policies and procedures that follow the NSG Group Code of Conduct but relate more specifically to the operating practices of the Procurement function.   The NSG Group aims to enjoy the highest reputation worldwide for the professional, legal and ethical way in which it conducts its business. The overriding intention of the NSG Group Supplier Code of Conduct  is that our suppliers will carry out their business in a safe, professional, legal and ethical manner and in a way that demonstrates corporate social responsibility. In order to provide materials or services to NSG Group, suppliers are required to comply with this Code of Conduct.

NSG Group Supplier Code of Conduct   

Social behaviour : All suppliers must conform to the relevant International Labour Organisation Labour Standards as a minimum requirement. This means suppliers must strive to apply employment standards which promote the application of human rights. There should be no intentional discrimination for recruitments, promotions, job transfer, dismissal and other employment related activities on the basis of race, colour, creed, nationality, age, gender, sexual orientation, religion, origin, disability, union membership, political affiliation or other status protected by law. Local laws on age discrimination must be observed. Abuse, harassment or intimidation will not be tolerated under any circumstances nor will the act of pressurising or retaliating against the individual who reports such harassment. While these general principles are applicable to all of our suppliers, each specific case should be carefully reviewed with reference to the law in each of the countries in which they operate.

Environmental Behaviour : Our suppliers must recognise the crucial importance of their role in reducing environmental impact. They must play their part in creating a prosperous and sustainable future by continually seeking to achieve best practice in environmental protection.

Timber from European suppliers has been demonstrated to originate from a sustainable source.  NSG Group are now continuing to question all  global suppliers. We have set targets for sustainable sourcing by 2015.