uPVC Cladding Fire Rating vs Composite Cladding

When installing exterior cladding in a residential or commercial property, it is crucial to find out the combustibility of the panels given that they will be affixed to the external walls of the building. Discover how uPVC Cladding compares to Composite Cladding.

It is important to consider the combustibility and fire ratings of your cladding, especially if you are installing them onto external walls of a residential or commercial building. uPVC and Composite Cladding as two of the most common options, so we have compared the two to help you pick the perfect product for your project.

Fire Ratings Explained

A fire-resistance rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test.
As a minimum, most external wall cladding would possess a classification of ‘surface spread of flame’ which helps to suppress the spread of fire, however only fire rated cladding can offer the higher classifications of limited combustibility or non-combustibility.
In the UK and throughout Europe, the fire rating classification for cladding materials comes from the European Reaction to Fire classification system (Euroclass), which assesses the qualities of building materials in case of a fire.
The fire rating classification for cladding material ranges from A1 to F (from lowest flammability to highest) in accordance with the European standard EN 13501-1. The system compares ignitability, flame spread, heat release, smoke production and potential to emit flaming droplets and/or particles.
The letter (e.g B) refers to the classification based on combustibility and contribution to fire. A1 and A2 are defined as non-combustible and are therefore the most fire-resistant materials. B has limited combustibility and is similar to the old class O system which is now defunct. The letter 's' in the Euroclass fire rating refers to the emission of smoke during the first 10 minutes of exposure. Whilst the letter 'd' relates to ‘flaming droplets and particles’ released.
Fire Rating 'S'
The emission of smoke during the first 10 mintues of expsure
Fire RatingExplanation
S1little or no smoke
S2quite a lot of smoke
S3substantial smoke
Fire Rating 'D'
Flaming droplets and particles released
Fire RatingExplanation
D2Quite a lot

uPVC Cladding

uPVC is made from chlorine and ethylene from natural gas or petroleum. These raw materials are made into synthetic polymers, a type of plastic. The plastic content of the cladding will cause the product to warp and melt when it comes into contact with fire. Although the spread of flames may be limited with uPVC panels, they will tend to char and fall away when exposed to fire.Polymers also release toxic dioxins when they burn, chemical compounds which are extremely hazardous to the environment and humans alike.
uPVC and PVC cladding normally has a fire rating of Euroclass C or D, meaning this type of cladding is combustible. C denotes a limited contribution to fire and D a medium contribution to fire. By means of comparison, untreated wood cladding has a fire rating of class D.

Hyperion Sentinel Composite Cladding

EnviroBuild’s Hyperion Sentinel composite cladding is made from recycled wood and High-Density Polyethylene. All cladding has been tested following the strict Euroclass standards and using the EN 13823 and EN ISO 11925-2 fire resistance tests.
Our Sentinel range of composite cladding has been specially treated with fire-retardant additives which gives it a Euroclass rating of B s2-d0.
Sentinel composite cladding would have a very limited contribution to fire and no flashover (the near-simultaneous ignition of most of the directly exposed combustible material in an enclosed area).
Hyperion Sentinel cladding would therefore also release quite a lot of smoke during the first 10 minutes of exposure but no flaming droplets and particles.

uPVC Cladding vs Composite Cladding: Which is More Fireproof?

EnviroBuild’s Sentinel composite cladding is less combustible and flammable than uPVC cladding because it carries a lower Euroclass fire rating of B versus C/D, making it the safer choice. Whereas uPVC cladding would ignite most of the directly exposed combustible material in an enclosed area in around 10 minutes or even less, Sentinel cladding benefits from no flashover.
Last year, the UK set out new regulations which stated that exterior cladding panels on residential buildings, schools, care homes and hospitals over 18 metres must have a fire rating of Euroclass A. However, for office blocks and hotels which are exempt and obviously any building under 18 metres, Sentinel cladding remains to be entirely suitable.
For more detailed information about the legislative changes and new building regulations in the United Kingdom relating to cladding as of December 2018, see
Please note: With regards to load bearing for fire resistance (BS 476-21), it is not possible to separate or independently test external wall cladding from the fire rating of the wall it is affixed to; in all cases please refer to the fire rating of the wall itself as EnviroBuild Sentinel cladding does not affect this.
DISCLAIMER: It is the customer’s responsibility to determine the suitability of Hyperion Cladding for their particular private or commercial installation. It is solely the customer’s responsibility to consult with their local building control to determine fire classification project requirements.