Fire and slip ratings for wood floors

Fire and slip ratings are two separate checks on a wood floor. In Europe, reaction to fire is a class from Afl to Ffl; most coated wood floors reach Dfl-s1 or Cfl-s1, depending on thickness, density, coating and substrate²¹. Slip resistance is measured with different tests, and the UK Health and Safety Executive (HSE) prefers the pendulum test over the German ramp classes that many flooring makers quote⁴. This guide explains both in plain terms and says what to ask a maker.

What is a reaction-to-fire class?

The EU's classification system has two sub-systems: one for construction products such as wall and ceiling linings, and one for floorings, which carry the suffix fl. Both run from class A to class F, where A1 and A2 are non-combustible¹. A flooring class has a letter and a smoke suffix, for example Cfl-s1.

For floorings the main test is the radiant panel test, EN ISO 9239-1, which gives a critical heat flux, the radiant level at which the flame goes out or the level reached after 30 minutes, whichever is lower. A flooring must also pass the small-flame test EN ISO 11925-2 with flame spread under 150 mm within 20 s for classes B to E¹. The thresholds are:

The smoke suffix is s1 where smoke production is below 750 %·min, and s2 where it is not¹. So Cfl-s1 means a critical heat flux above 4.5 kW/m² and low smoke. It describes how a floor reacts to a small fire starting in the room; it is not a measure of the fire resistance of the structure, which the Swedish report treats as a separate characteristic¹.

Which wood floors are classed without testing?

Testing every product is costly, so the Commission lists generic wood floor constructions whose class is known and stable. Two instruments apply, one for coated floors and one for uncoated floors.

Coated floors (Decision 2006/213/EC). Table 1 of the Decision gives the class for coated wood floors by minimum mean density, minimum overall thickness and end-use condition. Some entries²:

The table's notes give the conditions behind these classes. Testing is on a substrate of at least class D-s2,d0 with a density of at least 400 kg/m³, or with an air gap; the glued entries need a substrate of at least class A2-s1,d0; and the coating types and amounts are acrylic, polyurethane or soap at 50 to 100 g/m² and oil at 20 to 60 g/m²². The table also applies to steps of stairs².

Uncoated floors (Delegated Regulation 1292/2014). Uncoated wood floors under EN 14342 have their own list. Examples are solid wood parquet of oak, maple or ash at 8 mm glued to a substrate of at least D-s2,d0, which is Dfl-s1 at an oak density of at least 720 kg/m³, and solid wood floor and parquet not specified elsewhere at 400 kg/m³ and 6 mm, which is Efl³.

Anything outside these tables has to be tested, or is class Ffl, meaning no performance is determined¹. A fire-retardant lacquer or a different build-up could earn a better class if tested¹.

We read the 2006 text as adopted; check the Official Journal for later amendments before using a figure in a specification.

Does a charred or heavily finished floor change this?

The tables assume stated coatings and thicknesses. A different surface treatment is a different product for classification, which is why a maker's Cfl-s1 should come with a test report or a table entry. Our page on charred wood reviews research on how charring affects fire performance. Wall products use a separate table, covered in wood wall panelling.

How is slip resistance measured?

HSE's technical information sheet describes several tests⁴. Its preferred method is the pendulum coefficient of friction test, where a swinging imitation heel with a standard rubber slider sweeps a set area of floor and gives a pendulum test value (PTV). The test is the subject of BS 7976 (parts 1 to 3, 2002), and HSE says it should be operated by a trained, competent person, with tests in several directions for profiled floors⁴. The sheet cites the 2002 edition of BS 7976, so check which edition and method apply today.

Pendulum results are read with these bands, from the UK Slip Resistance Group⁴:

A slider known as Slider 96 gives enough information for shod pedestrians, and Slider 55 is used for barefoot areas⁴.

HSE also describes a surface microroughness test using the Rz parameter. For water-wet pedestrian areas, Rz below 10 µm means high slip potential, 10 to 20 µm moderate and above 20 µm low⁴. Roughness is a useful guide, but not a replacement for the pendulum; the Zagreb study of oak and beech floors found that roughness should be used as a guide and not as the sole indicator of slip potential⁶.

What are R-values and the DIN ramp classes?

Many European makers state a German ramp-test class. DIN 51130 gives R9 to R13, where R9 is slippery when wet and R13 the least slippery; DIN 51097 gives classes A to C for barefoot wet areas⁴. HSE has reservations about these tests because neither uses contaminants typical of workplaces, and says floors classified R9, and in some instances R10, will be slippery when wet or greasy. R10, for example, covers a very wide range of friction values⁴. Its FAQ adds that if a manufacturer does not claim a floor is slip resistant when wet, it will probably be slippery when wet⁵.

What do studies of wood floors show?

The 2021 Zagreb study tested oak and beech floors finished with oil and with polyurethane, by pendulum in dry, water-wet and oily conditions. It found that slip potential was low in dry conditions for all the finished floors, and that water and oil contamination reduced slip resistance for both species⁶. A finish, a cleaning product or a coat of polish can change results, which is why HSE warns that ex-factory data can change after installation, cleaning, polishing, wear and poor maintenance⁴. See our guides to wood floor finishes and cleaning and maintenance.

What should you ask a maker?

1. Which fire class applies, and is it from a Decision table or a test report? For what thickness, density, coating and substrate?
2. For slip, which test was used (pendulum, ramp or other), in what condition (dry, wet, oily), and on a finished floor or a bare one?
3. Is the data for the floor as installed and maintained, or ex-factory?
4. Is the class valid for stairs or walls, if that is your use?

For how these ratings sit alongside other standards, see flooring standards and our guide to usage classes.

This page compiles published data from the sources listed above. Read our editorial policy. Last updated 10 Nov 2026.