Frequently Asked Questions

Frequently Asked Questions

1 What is CE Marking?

CE Marking indicates that a product conforms to a European technical specification called a harmonised European Norm (hEN) or a European Technical Assessment.  Once it has been demonstrated that the product complies with the requirements of the relevant hEN, then the manufacturer can affix the CE Marking to the product, its packaging or delivery documentation.

2 What are the benefits of CE Marking?

Benefits include:

  • Declared performance from manufacturers is transparent and open to challenge
  • The supply chain can compare products on a like-for-like basis
  • Testing is independently undertaken by accredited third parties
  • A manufacturer's responsibility is clearly defined
  • Higher 'risk' products (e.g. fire resistant) require greater involvement of third parties

3 What can NSG Group do for me to help me meet the requirements?

As a member of Glass for Europe, NSG Group has been involved in producing a series of guides to CE Marking and the new hENs for glass in building.  These are available to download from

We have also set up a dedicated email address for CE Marking-specific enquiries.  It is:


What is a Declaration of Performance?

A Declaration of Performance (DoP) is an important document for a manufacturer as it contains key information about the manufacturer, product and performance.  A manufacturer is required to draw up a DoP when a product is placed on the market in an EU Member State.

It can be made available electronically, for example via a website.  DoPs for Pilkington products can be downloaded by accessing and selecting the appropriate country.

5 What is AVCP?

The system of assessment and verification of constancy of performance (AVCP) dictates the level of involvement of a third party (Notified Body).  There are several systems that can be applicable, dependent upon the product and its intended use.  Three are relevant for glass in building.

System 1 is where Type Testing & FPC (initial inspection & continuous surveillance of factory) is undertaken by the Notified Body and other tasks are the responsibility of the manufacturer.  For System 3, Type Testing is the responsibility of the Notified Body and other tasks are carried out by the manufacturer.  Under System 4, all tasks can be undertaken by the manufacturer.

6 What will happen to CE Marking after the UK leaves the EU?

The situation regarding Brexit is far from certain.  However, the UK Government announced that, in the event of a 'no-deal' Brexit, it will introduce a UK Conformity Assessed (CA) mark and phase out CE Marking over time.

The UK is still expected to be an active participant in CEN through BSI in order to help develop and maintain European Standards.

7 When did CE Marking commence for glass in building?

NSG Group commenced CE Marking of its first groups of product on 1st September 2005.  These included basic soda lime silicate glass, toughened glass, heat strengthened glass and coated glass.  CE Marking subsequently followed for other product groups such as laminated glass, heat soaked toughened glass, insulating glass units and mirrors.

8 Who 'polices' CE Marking?

Market surveillance is the responsibility of each Member State and will vary from country to country.

A manufacturer must have supporting evidence in its Technical File demonstrating the conformity of the product with the relevant hEN.  The Technical File must be made available to market surveillance bodies in the event of a challenge.

9 Why are only certain glass products affected and not all of them?

It depends on the Date of Applicability of each hEN, which is only confirmed when the appropriate reference is cited in the Official Journal of the European Union.  The Date of Applicability is the earliest date at which products can comply with the hEN and, subsequently, be CE Marked.  This is typically followed by a 12-month transition period, at the end of which it becomes mandatory for products to meet the requirements of the hEN.

Products for which there is no hEN or technical specification cannot be CE Marked.  If you are not sure if a particular product is covered by a hEN, please contact us at


What does CE Marking mean for voluntary certification schemes?

Voluntary mark schemes can exist but they must be VOLUNTARY and not form part of a regulatory requirement.  They cannot conflict with CE Marking, but can include additional characteristics not within the scope of CE Marking and raise the AVCP system (e.g. from System 3 to 1).

11 What does NSG Group have to do to meet the requirements of the harmonised European Norms?

Like other manufacturers, NSG Group ensures that its Factory Production Control (FPC) is consistent with the requirements of the hEN and that the Type Testing (ITT) has been completed, to ensure that the product conforms to its declared values and satisfies EU legislative requirements. 

12 Which glass products are subject to CE Marking?

Most glass products for use in building are covered by a hEN.  A list of hENs applicable to glass in building can be found on our website via .


What is NPD and when can it be used?

NPD stands for No Performance Determined.  It can be declared on the DoP against an essential characteristic that is not relevant for the product or applicable for the Member State in which it is used in a building. 

On the DoP, the performance of at least one of the essential characteristics of the product, relevant to the intended use, must be declared.


14 How do you decide which standards apply to products with multiple functions?

The hENs have developed for each glass type, e.g. basic soda lime silicate, coated, toughened, laminated, insulating glass units, etc. Multiple functions are covered by the intended use of the product and its declared values.

The organisation placing the product on the market is required to show, through appropriate reference to the relevant hENs and declaration of essential product characteristics, that the product is suitable for its intended use.

In the case of Pilkington Pyrostop® incorporating a solar control glass where the intended use is fire resistance, the relevant hEN is EN 14449 (laminated glass) and fire resistance and solar performance characteristics are stated in the DoP.

Note. Any product with the intended use of fire, explosion or bullet resistance is subject to AVCP System 1 requirements.


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