In this post, I would like to clarify the meaning of the Euroclass F due to in many situations the interpretation is wrong, mainly from the publication of Delegated Act.
First of all, we must know that the classification F is the lowest Euroclass of the European classification system for evaluating the reaction to fire according to EN 13501-1.
Publication of the Delegated Regulation
On March 15th 2016, the Delegate Regulation 2016/364 on the classification of reaction to fire properties of construction products was published in the Official Journal of the European Union.
This regulation explains that the definition of class of reaction to fire have to delimited by a minimum value and a maximum value of performance. In consequence, the classes defined as «non-determined performance, NPD» do not be included within the reaction to fire class definition and therefore can not belong to the harmonized system of reaction to fire classification.
Before the publication of this regulation, the classes F, FFL, FL and Fca could be obtained without testing a product (not determined performance) or if the product did not meet the criterion for the previous classes of the classification system (E, D, C, B, ..).
However, with the publication of this regulation, the classification criteria for class F, FFL, FL and Fca are replaced and will be classified with this class only the products do not meet the requirements indicated for classes E, EFL, EL and Eca. Below are showed comparative images to clarify this fact:
Consequences of the Delegated Regulation
The immediate consequence of this regulation is that all products covered by the product standards for the CE marking and if it was necessary to meet the performance of the reaction to fire indicated in the Annex ZA or products subject to reaction to fire requirements, they must be tested to achieve at least class F, because it is not possible to classify a product with class F without performing the test.
The test method to obtain to class F is described in EN ISO 11925-2 «Flammability of construction products when subjected to direct flame action. Part 2: Test with a single flame source. (ISO 11925-2: 2010)». This test is commonly known as the small burner test.
In the future, these modifications will be incorporated to the standard EN 13501-1 and EN 13501-6. This work is being developed within the CEN / TC 127 WG 7 «Classification».