What fire rating do I need in 2020?
Fire safety is extremely important in today’s world. Existing and new commercial construction projects have to be exact with their fire ratings.
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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 – The 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) |
BS 476-6:1989+A1:2009. Fire tests on building materials and structures. Method of test for fire propagation for products.
BS 476-7:1997. Fire tests on building materials and structures. Method of test to determine the classification of the surface spread of flame of products.
Fire Safety Approved Document B. Building regulation in England covering fire safety matters within and around buildings.
Ministry of Housing, Communities and Local Government. Final Impact Assessment: Ban on combustible materials in external wall systems.
A fire-resistance rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test. This can be quantified simply as a measure of time, or it may entail a host of other criteria, involving other evidence of functionality or fitness for purpose.
