Fire Ratings Explained

Tristone UK Limited is committed to ensuring all users of our products are informed on the quality standards that our products adhere to.

We know that being informed on the characteristics and features of a product is pivotal when specifying for projects; domestic and commercial. That is why we make our certification and classifications publically available on our website and on all our platforms.

To give you a clearer picture of the standards of our products, we have created this page to briefly explain the UK and EU standards for Fire Ratings.

Current and New UK Standards

Current British Standards

The building regulations stipulates the rules and the degree of fire resistance of the elements of structure. The British Standard 476 (BS476) dictates the appropriate fire tests for these elements of structure/materials and grades the level of fire resistance. The tests that are relevant to the Solid Surface industry are the BS476 part 6, and BS476 part 7.

• BS 476 part 6: Fire Propagation Test.

• BS 476 part 7: Surface Spread of Flame Test.

  • The test produces a fire rating of Class 1, 2, 3 or 4 depending upon how far a flame travels over a surface.

What is a Class 1 Building Material?

Class 1 is the best rating i.e. the lowest flame spread. This classification is given after BS476 part 7.

What is the Class 0 Fire Rating?

The Class 0 fire rating is actually a classification as outlined in the UK building regulations for fire safety within and around buildings. This classification is outlined in Parts 1 and 2 of the Fire Safety: Approved Document B which is available on the HM Government Portal.

How does a product achieve the Class 0 Fire Rating?

To achieve a Class 0 Fire Rating, products must meet specific British Standards and pass a series of tests designed to test flame spread and propagation.

• The product must first meet the fire propagation requirements as outlined in BS 476-6:1989+A1:2009

• A product must be also be classified as a Class 1 building material for BS 476 - 7:1997

The New Building Regulations - Building (Amendment) Regulations 2018

The updated regulations surrounding fire safety and compliant building materials came into effect following the Grenfell Tower fire. As part of this, the Building Regulations were amended to insert certain paragraphs and points to clarify areas where new regulations had come into place. The key segment identified and outlined below pertains to point (7) which inserts important prerequisites for what is considered a compliant building material for cladding for relevant building over 18m under the Building (Amendment) Regulations 2018.

(7) After regulation 7(1) (as renumbered) insert—

“(2) Subject to paragraph (3), building work shall be carried out so that materials which become part of an external wall, or specified attachment, of a relevant building are of European Classification A2-s1, d0 or A1, classified in accordance with BS EN 13501-1:2007+A1:2009 entitled “Fire classification of construction products and building elements. Classification using test data from reaction to fire tests” (ISBN 978 0 580 59861 6) published by the British Standards Institution on 30th March 2007 and amended in November 2009.

(3) Paragraph (2) does not apply to—

(a)cavity trays when used between two leaves of masonry;

(b)any part of a roof (other than any part of a roof which falls within paragraph (iv) of regulation 2(6)) if that part is connected to an external wall;

(c)door frames and doors;

(d)electrical installations;

(e)insulation and water proofing materials used below ground level;

(f)intumescent and fire stopping materials where the inclusion of the materials is necessary to meet the requirements of Part B of Schedule 1;

(g)membranes;

(h)seals, gaskets, fixings, sealants and backer rods;

(i)thermal break materials where the inclusion of the materials is necessary to meet the thermal bridging requirements of Part L of Schedule 1; or

(j)window frames and glass.

(4) In this regulation—

(a)a “relevant building” means a building with a storey (not including roof-top plant areas or any storey consisting exclusively of plant rooms) at least 18 metres above ground level and which—

(i)contains one or more dwellings;

(ii)contains an institution; or

(iii)contains a room for residential purposes (excluding any room in a hostel, hotel or boarding house); and

(b)“above ground level” in relation to a storey means above ground level when measured from the lowest ground level adjoining the outside of a building to the top of the floor surface of the storey.”

Full Text Here

What this means:

Point 7 outlines the key criteria that must be met for a product to be used as external wall cladding. It specifically mentions that the material that is used as external cladding for relevant buildings above 18m in height must have a European Classification (see below) of A2-S1-d0 or higher. In this context, point (4) subsection “a” outlines the meaning of the phrase ‘relevant buildings’ which states that ‘relevant buildings’ refers to a building more than 18m above ground level which contains a storey which contains (1) one or more dwellings; (2) an institution or (3) a room for residential purposes (with certain exceptions). Institutions in this instance refers to residential areas, schools, care homes, hospitals, sheltered accommodation, student residences and other institutional accommodation buildings.

European Standards

Testing is standardised through the use of EN 13501-1: Fire classification of construction products and building elements. The most widely recognised standards are the German (DIN 4102) and French (NF P 92 503-507 (M1)). The European classifications based on the EN13501-1 standard break down into codes. Products that have been given a fire rating on the European Classification will look like the following: A2, s1,d1. This classification shows the properties of a product based on 3 criteria.

There are 7 reaction to fire classifications levels available:
The reaction to fire classification determins how much (if any) a material contributes to the spread of flame:

• A1, A2 = Non Combustible Materials.

• B, C, D = Ranges from very limited to medium contribution to fire.

• E, F = High contribution to fire.

The ‘s’ part relates to total smoke propagation, during the first ten minutes of exposure.
These determine a ‘smoke’ index:

• S1 = a little or no smoke

• S2 = quite a lot of smoke

• S3 = substantial smoke

The ‘d’ part relates to ‘flaming droplets and particles’ during the first 10 minutes of exposure.
The index is:

• D0 = none

• D1 = some

• D2 = quite a lot

Transposition between UK and EU Standards

On page 119 of Fire Safety Approved Document B, there is an outline table of the European Standard and the equivalent British Standards. Although they are seen as equivalents in the table, it should be noted that the document clearly states that the building materials must have undergone and passed the relevant testing for both standards to be a compliant building material under UK regulations.

As a result, a direct comparison between the UK and EU testing standards may not necessarily be possible.