# Commission Delegated Regulation (EU) 2016/364 of 1 July 2015 on the classification of the reaction to fire performance of construction products pursuant to Regulation (EU) No 305/2011 of the European Parliament and of the Council (Text with EEA relevance), Division 2: For the purposes of Tables 1 to 4 the following definitions apply:

Extent: E+W+S+N.I.

(1) ‘material’ means a single basic substance or uniformly dispersed mixture of substances;
(2) ‘homogeneous product’ means a product consisting of a single material, having uniform density and composition throughout the product;
(3) ‘non-homogeneous product’ means a product that does not satisfy the requirements of a homogeneous product and that is composed of one or more components, substantial and/or non-substantial;
(4) ‘substantial component’ means a material that constitutes a significant part of a non-homogeneous product; a layer with a mass per unit area ≥ 1,0 kg/m2 or a thickness ≥ 1,0 mm is considered to be a substantial component;
(5) ‘non-substantial component’ means a material that does not constitute a significant part of a non-homogeneous product; a layer with a mass per unit area < 1,0 kg/m2 and a thickness < 1,0 mm is considered to be a non-substantial component;
(6) ‘internal non-substantial component’ means a non-substantial component that is covered on both sides by at least one substantial component;
(7) ‘external non-substantial component’ means a non-substantial component that is not covered on one side by a substantial component.
Two or more non-substantial layers that are adjacent to each other, where there are no substantial components in between the layers, shall be considered as one non-substantial component and shall, therefore, be classified in accordance with the criteria for a layer that is a non-substantial component.

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Source: https://www.legislation.gov.uk/eur/2016/364/annex/division/2 (the official version)
Page: https://openlegislation.uk/eu-regulation-2016-364/annex/division-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.