Frequently Asked Questions

1 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. 

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 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 .