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Cladding Fire Rating Guide

Ventilated facade cladding systems can improve the thermal performance of the building and provide a wide choice of colours, textures and materials to choose from to achieve the desired aesthetic finish for the exterior construction. The cavity created between the building substrate and the cladding panels allows space for insulation and creates an air flow gap which keeps the building dry and improves the thermal performance.

It’s important to note that current building regulations state that only fire rated cladding is permitted for use on tall buildings over 18 metres in height, designed in conjunction with the positioning of fire cavity barriers, to reduce the spread and speed of flame within the cavity behind the cladding in the event that a fire reaches the exterior of the building.

Whilst most external cladding types carry a minimum classification of ‘surface spread of flame’ designed to slow and control the spread of fire, only FR (fire rated) cladding provides the higher classifications of either limited combustibility or non-combustibility. These cladding panels carry a fire classification result ranging from A1 to D in accordance with European Standards EN-13501-1.

Some cladding products quote an alternative fire classification offered by the BRE (Building Research Establishment) to their BR 135 standard, this form of testing doesn’t offer a grading as above, but tests a cladding system’s fire resistance to a specific time frame. For building regulation purposes any test using this method needs to be supported with a classification report for the proposed specification, confirming that the specification criteria of BR135 has been met.

Please refer to the relevant manufacturer product datasheets on the fire classification of the cladding product you are considering for your specification ie. Laminate, Fibre Cement, Wood Veneer, specialist composite cladding panels or other.

All the major cladding manufacturers carry out the appropriate required fire testing which results in a classification for their product, and will supply this information upon request. We recommend that you check that the cladding product you may be specifying or installing carries the appropriate cladding fire rating, required by building regulations for your type and height of building.

In addition to fire tests carried out for the cladding manufacturers at BRE approved centres such as Exova Warrington, these manufacturers also often apply for a further overall certification approval such as BBA (British Board of Agreement) or CWCT (Centre for windows and cladding technology). If the product is approved by one of these bodies, the cladding fire testing will have been assessed and will be included as part of their certificate and will be noted within the report. Always ask to see a copy of the façade cladding manufacturer’s classification report and Declaration of Performance for confirmation of compliance.

To help you understand the fire classifications, please see the table below which we found helpful in explaining the different fire classifications and what the letters stand for. (Information taken from Peroni S.p.a rev 02/2013):

Classification according to European Standard EN-13501-1

Definition Construction Products
Non-combustible materials A1
A2 – s1 d0
A2 – s2 d0
A2 – s3 d0
A2 – s1 d1
A2 – s2 d1
A2 – s3 d1
A2 – s1 d2
A2 – s2 d2
A2 – s3 d2
Combustible materials: Very limited contribution to fire B – s1 d0
B – s2 d0
B – s3 d0
B – s1 d1
B – s2 d1
B – s3 d1
B – s1 d2
B – s2 d2
B – s3 d2
Combustible materials: Limited contribution to fire C – s1 d0
C – s2 d0
C – s3 d0
C – s1 d1
C – s2 d1
C – s3 d1
C – s1 d2
C – s2 d2
C – s3 d2
Combustible materials: Medium contribution to fire D – s1 d0
D – s2 d0
D – s3 d0
D – s1 d1
D – s2 d1
D – s3 d1
D – s1 d2
D – s2 d2
D – s3 d2
Combustible materials: Highly contribution to fire E E – d2
Combustible materials: Easily flammable F

The European classifications break down into codes, 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

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

Additional Class Level Definition
 Smoke emission during combustion s 1
2
3
A little or no smoke
Quite a lot of smoke
Substantial smoke
Production of flaming droplets/particles during combustion d 0
1
2
None
Some
Quite a lot

British Standards

As a further guide to the British standards (BS) on cladding fire testing, please see below how the older BS classifications compare to the more recent European classifications.

These were based on tests for burning materials and structures governed by BS 476. This breaks down into two parts relevant to cladding:

Part 7 – surface spread of flame, which measures the spread and extent that a flame would travel across the surface of the material and;

Part 6 – fire propagation, which measures the actual contribution made by the component assembly to the growth of the fire.

British Standard Transposition to Euro Class
Non-combustible A1
Limited Combustibility A2–s3,d2 (or better)
Class 0 B-s3,d2 (or better)
Class 1 C-s3,d2 (or better)
Class 3 D-s3,d2 (or better)
Fire rating by product

Fire rating by cladding

EUROPEAN STANDARD EN-13501-1

Product Std FR
Trespa Meteon  D-s2,d0 B-s2,d0*
Trespa Pura NFC B-s2,d0
Trespa TopLab Base D-s2,d0 B-s2,d0*
Trespa TopLab Vertical D-s2,d0 B-s2,d0*
*B-s1,d0 can be achieved if panel thickness is greater than 8mm and used with a metal frame
Product Std
EQUITONE A2-s1,d0
Cedral Weatherboard A2-s1,d0
Cedral Click A2-s1,d0
Product Std FR F1
 Parklex  C-s2,d0  B-s2,d0 B-s1,d0
Product Std FS-Xtra
Rockpanel range B-s2,d0 A2-s1,d0
Rockpanel Natural B-s2,d0
Rockpanel Ply B-s2,d0
Rockpanel Lines B-s2,d0
Aluminium or Steel sub-construction
When fixed with blind rivets and application of premium FS-Xtra boards, in combination with mineral wool insulation, this meets the requirements for A2-s1,d0.   
Product Std FR
VIVIX D-s2,d0 B-s1-d0
Product Std
Solid A2-s1,d0
Patina / Cembonit A2-s1,d0
Cover A2-s1,d0
Transparent A2-s1,d0
Product Std
Max Exterior F Quality B-s2,d0
Product Std FR
Selekta D-s2,d2 B-s3,d0
Siding D-s2,d2 B-s3,d0
Square D-s2,d0 B-s2,d0
Product Std FR
ProdEX C-s2,d0 B-s1,d0
ProdEX IGN B-s2,d0
Product
Steni Colour B-s1,d0
Steni Vision B-s1,d0
Steni Nature B-s1,d0
Product Std FR
Vitrabond PE B-s1,d0 B-s1,d0
Vitrabond A2 A2-s1,d0
Vitrabond G2 A2-s1,d0
Product Std FR
Larson Class E B-s1,d0
Larson A2
(available from Feb 2018)
A2-s1,d0

 

All manufacturer fire ratings listed have been checked against relevant technical documentation and/or certifications supplied by the manufacturer, either sourced directly or via their websites. We advise you re-confirm with a VIVALDA representative at the time of enquiry.