Fibre Reinforced Facade Encyclopedia: Testing and standards
EN 13501-2 is the European standard that classifies the fire resistance of building elements and building services from the results of the EN 1363, EN 1364, EN 1365, EN 1366 and EN 1634 test methods. A classification is written as one or more letters followed by a period in minutes, so REI 60 means an element that maintained loadbearing capacity, integrity and insulation for sixty minutes. It is the European counterpart of the Australian fire resistance level under AS 1530.4 and of the hourly ratings produced by ASTM E119 in the United States. Like both of them, it applies to assemblies and never to a cladding panel.
Read REI 60 as: R for resistance, the element kept carrying its load; E for etancheite, it stayed sealed against flame and hot gas; I for isolation, it kept the unexposed face cool. Sixty minutes for all three. An E 60 door has integrity only, and EI 30 on a non-loadbearing wall has no R because there is nothing to carry.
At a glance
| Property | Typical value | Note |
|---|---|---|
| Standard | EN 13501-2 Fire classification of construction products and building elements, Part 2: classification using data from fire resistance tests | |
| R | Loadbearing capacity (resistance) | Equivalent to structural adequacy in an Australian FRL |
| E | Integrity (etancheite) | No passage of flame or hot gas |
| I | Insulation | Unexposed face temperature rise limited |
| W | Limited radiation | Radiation at 1 m not exceeding 15 kW/m²; an alternative to I |
| M | Mechanical impact resistance | Applied to walls that must survive impact during a fire |
| S | Smoke leakage | Sa and S200 for doors |
| Classification periods | 15, 20, 30, 45, 60, 90, 120, 180, 240 and 360 minutes | Not all periods apply to all elements |
| External wall exposure | i to o, o to i, or i and o | States which side or sides the element was tested from |
| Applies to a cladding panel | No | The wall assembly behind it carries the classification |
What the letters mean
R is loadbearing capacity: the element continued to carry its applied load, judged against deflection and rate of deflection limits during the test. A non-loadbearing element is not tested for R, which is why so many wall classifications begin with E.
E is integrity: no sustained flaming on the unexposed face, no ignition of a cotton pad held against it, and no gap through which the standard gap gauges pass.
I is insulation: the mean temperature rise on the unexposed face is limited to 140 kelvin and any single point to 180 kelvin above the starting temperature. Those are the same numerical limits used in the Australian test, which is one reason an FRL and an REI classification look similar.
W is a lower grade alternative to I, used where a glazed element cannot meet the insulation criterion but the radiant heat it transmits can be limited, typically to 15 kW/m² measured at one metre. M, C and S are supplementary: mechanical impact for walls that must survive debris during a fire, self-closing for doors and shutters, and smoke leakage for doorsets.
How the classification is produced
EN 13501-2 is a classification standard, not a test method. The testing is done under the EN 1363 general requirements, which fix the standard time and temperature curve, the furnace pressure regime and the instrumentation, and then under an element specific method: EN 1364 for non-loadbearing elements including walls, ceilings and curtain walling, EN 1365 for loadbearing elements including walls, floors, columns and beams, EN 1366 for service installations such as dampers, ducts and penetration seals, and EN 1634 for door, shutter and openable window assemblies.
The classification report converts the raw test times into the standard periods by rounding down, and it states the field of direct application: the range of dimensions, loads, orientations and configurations over which the result may be used without further testing. An extended application report under the EN 15254 or EN 15725 series can widen that range, but only within rules written for the element type.
Reading an EN 13501-2 report
- Confirm which test method was used, and that it matches the element as it will be built
- Check the classification line in full; REI 60 and EI 60 are different products of the same test
- For an external wall, check the exposure direction; a wall classified o to i was tested from the outside only
- Check the field of direct application for maximum tested height, width and aspect ratio
- Check every constituent: stud gauge and spacing, board type and thickness, insulation density, fixing centres, joint treatment and any penetrations
- Check whether the specimen was loaded; an unloaded specimen cannot report R
Why cladding has no EN 13501-2 class
A fire resistance test needs a specimen that separates a furnace from a room, built with its joints, fixings and penetrations as they will be in service. A rainscreen panel does not do that job. It sits outside the fire separating line with a ventilated cavity behind it, and the wall behind the cavity is what resists the fire. Testing the panel alone would measure nothing the regulations ask for.
So a glass fibre reinforced concrete panel, a fibre reinforced polymer panel, terracotta and metal sheet all have no EN 13501-2 classification, and a datasheet offering one for a cladding skin has almost always confused it with the EN 13501-1 reaction-to-fire class. The two standards sit next to each other in the same series and answer completely different questions: EN 13501-1 grades how a product burns, from A1 to F; EN 13501-2 grades how long an assembly holds fire back, in minutes.
ShapeShell-RT is classified B-s2,d0 under EN 13501-1 by Intertek Testing Services. That is a reaction-to-fire classification. It is not a fire resistance classification, it is not an REI period, and neither ShapeShell-RT nor ShapeShell-RC carries one. Where a European project needs a fire resisting external wall, the classification belongs to the wall construction behind the rainscreen.
There is one narrow exception. Where a panel system is tested complete with its framing, insulation, backing and joints as a curtain walling or infill element under EN 1364-3 or EN 1364-4, the classification belongs to that tested assembly and applies only to the tested configuration.
Standards and references
- EN 13501-2 Fire classification of construction products and building elements, Part 2: classification using data from fire resistance tests
- EN 1363-1 and EN 1363-2 Fire resistance tests: general requirements and alternative and additional procedures
- EN 1364 series (non-loadbearing elements, including EN 1364-3 and EN 1364-4 for curtain walling)
- EN 1365 series (loadbearing elements); EN 1366 series (service installations); EN 1634 series (doors, shutters and openable windows)
- AS 1530.4 (the Australian fire resistance test) and ASTM E119 or UL 263 (United States), for comparison
- EN 13501-1, the separate reaction-to-fire classification for products
Related terms
Questions specifiers ask
What does REI 60 mean?
Sixty minutes of loadbearing capacity, integrity and insulation in a fire resistance test to the relevant EN method, classified under EN 13501-2. EI 60 is the same period for integrity and insulation on an element that carries no load.
What is the difference between EN 13501-1 and EN 13501-2?
EN 13501-1 classifies reaction to fire, how a product itself burns, from A1 to F with smoke and droplet sub-classes. EN 13501-2 classifies fire resistance, how long a complete element holds a fire back, in minutes. Different tests, different subjects.
Is REI 60 the same as an Australian FRL of 60/60/60?
They express the same three criteria in the same order and use the same insulation limits, but they come from different test standards with different curves, pressure regimes and restraint conditions. The NCC requires AS 1530.4 results, so an REI classification is supporting evidence rather than a substitute.
Does a cladding panel get an EN 13501-2 classification?
No. Fire resistance is a property of a complete element such as a wall, floor or door assembly. A rainscreen panel sits outside the fire separating line and is classified for reaction to fire under EN 13501-1 instead.
What does the W classification mean?
Limited radiation. It is used where a glazed element cannot meet the insulation criterion but limits the radiant heat transmitted, typically to 15 kW/m² measured one metre from the unexposed face.
ShapeShell systems carry reaction-to-fire classifications, not fire resistance classifications, and the published data says so test by test. See ShapeShell fire test data
Reviewed by Richard Halvorsen, General Manager, ShapeShift Technologies. Last updated September 2026.