Wood Floor Usage Classes 21 to 34 (EN 685, ISO 10874)

Q: What do the numbers 21, 22, 23, 31, 32, 33 and 34 mean?

The tens digit is the setting, where 2 is domestic and 3 is commercial (and 4 is light industrial), and the units digit is the intensity of use from 1 moderate to 4 very heavy. ISO 10874 lists domestic classes 21, 22 and 23 as light, medium and heavy use, and commercial classes 32, 33 and 34 as medium, heavy and intense use.

Q: Is EN 685 still in use?

The ISO 10874 preview lists EN 685 in its bibliography, and the standard's scope there is resilient, textile and laminate floor coverings. The European edition is EN ISO 10874, and its 2020 Amendment 1 is titled as removing class 22+. The French sheet still describes the classes as NF EN 685.

Q: How is a parquet's class worked out?

The French standard XP B 53-669 reads a class from a table that crosses wear-layer thickness with the Brinell hardness class of the species, from A (10 to 20 N/mm²) to D (over 40 N/mm²).

Q: Does a higher class mean a longer life?

ISO 10874 says the classes follow intensity of use and that wear and appearance are also influenced by installation, maintenance, the subfloor, footwear and concentrated traffic. A class is a rating for a type of use, not a guaranteed lifespan.

Q: What is the UPEC classification?

In France the CSTB sets the UPEC classification, which rates wear (U), indentation (P), water (E) and chemicals (C). The FCBA sheet says it is complementary to the EN 685 classes because the criteria are not identical.

Usage classes are two-digit codes that say how heavy a use a floor covering is rated for. The first digit is the setting (2 domestic, 3 commercial, 4 light industrial) and the second is the traffic, from 1 moderate to 4 very heavy³. The scheme comes from EN 685 and the related standard ISO 10874, published in Europe as EN ISO 10874. This guide explains how the scheme works, how France's parquet standard turns a wood floor's construction into a class, and what to ask when a data sheet quotes one.

What is a usage class?

ISO 10874 sets out a classification of resilient, textile and laminate floor coverings. Its scope says the classification is based on practical requirements for areas of use and intensity of use, and is intended to guide manufacturers, specifiers and consumers in choosing a covering for a given area or room¹.

The standard's Table 1 lists the classes¹:

Setting	Class	Intensity of use	Description
Domestic	21	Moderate/light	Areas with low or intermittent use
Domestic	22	General/medium	Areas with medium use
Domestic	22+	General	Areas with medium to heavy use
Domestic	23	Heavy	Areas with heavy use
Commercial	32	General	Areas with medium use
Commercial	33	Heavy	Areas with heavy use
Commercial	34	Very heavy	Areas with intense use
Light industrial	41	Moderate	Mainly sedentary work with occasional light vehicles
Light industrial	42	General	Mainly standing work and/or vehicular traffic
Light industrial	43	Heavy	Other light industrial areas

The table in the preview also lists a commercial "moderate" row for areas with low or intermittent use, which follows the pattern as class 31. Domestic class 22+ appears in the 2009 table, but the Swedish standards listing for the 2020 amendment is titled "Elimination of class 22+"². If a specification quotes 22+, check which edition it relies on.

The standard adds that the specifier should decide whether a higher or lower class than the one recommended will be sufficient, and that wear and appearance are influenced by installation, maintenance, subfloor condition and the type of footwear and concentrated traffic¹. A class helps choose; it does not predict a service life.

Does the scheme apply to wood floors?

ISO 10874 itself covers resilient, textile and laminate coverings, and its listing does not name wood¹. For parquet, however, the French wood-industry sheet explains that the EN 685 classes were adopted for parquets in the French standard XP B 53-669³. It describes EN 685 as identifying usage classes since 1996 from the type of premises and a level of use, with the tens digit giving the setting and the units digit the traffic³.

Our guide to flooring standards notes that class numbers for wood are a claim to be checked. The FCBA sheet shows where one such method comes from.

How does XP B 53-669 work out a parquet's class?

The sheet gives a table in which a parquet's class depends on the thickness of its wear layer (e) and the hardness class of the wood species³. The hardness classes are conventional ones based on Brinell hardness:

Hardness class	Brinell hardness
A	10 to 20 N/mm²
B	20 to 30 N/mm²
C	30 to 40 N/mm²
D	over 40 N/mm²

The sheet places oak, ash and maple in class C, and jatoba, merbau, ipe and wenge in class D, with spruce in class A³. The usage classes it gives are:

Wear layer (e)	A	B	C	D
2.5 mm ≤ e < 3.2 mm	21	21	23	31
3.2 mm ≤ e < 4.5 mm	21	22	31	33
4.5 mm ≤ e < 7 mm	22	23	33	34
e ≥ 7 mm	22	31	34	41

Two things follow. Thicker wear layers and harder species give higher classes, and the species matters as much as the thickness. A 4 mm oak wear layer (class C) reads as 31, while a 5 mm oak layer reads as 33 and a 7 mm layer as 34³. The thickness here is the wear layer, the solid wood above the base, which is the layer that can be sanded; see sanding and refinishing.

The same sheet notes that the standard was revised in 2012 to bring in a characterisation of the finish, and that the French UPEC classification, set under the CSTB, is complementary because its criteria are not identical, covering wear, indentation, water and chemicals³. Our reading of the 2015 table is not a substitute for the current standard.

Why can a maker's class differ from the table?

A class on a data sheet is the maker's claim, and it may rest on a different edition, a different test, or a measurement of the finished product. The French sheet itself says the UPEC classification was under revision for parquets and that a revision of XP B 53-669 had introduced a characterisation of the finish³. When a data sheet states a class, ask:

Which standard and edition is the class based on?
Does it come from a table, a calculation, or a test of the finished floor?
What wear-layer thickness and species does it assume?
What finish is on the surface?

For a comparison across species, see our explainer on Janka hardness. Janka and Brinell are different tests and the figures are not interchangeable.

How do usage classes compare with other ratings?

Classes 21 to 43 rate intensity of use. They are separate from fire class, slip resistance and moisture suitability, and a floor needs each one checked on its own terms. Our page on fire and slip ratings covers the first two. The construction also matters: engineered wood has a wear layer of defined thickness, while solid wood can be sanded through its full thickness.

What does a class 34 floor look like in practice?

Class 34 is the top commercial class in the table, described as areas with intense use¹. One example of a product whose maker states it: Opus end-grain oak, listed by OscarOno Paris as usage class 34, has an 8 mm oak top layer on 12 mm birch plywood⁴. Oak is class C in the French table, and a wear layer of 7 mm or more reads as 34³, so the stated class is consistent with that table. Check the maker's own test evidence if the class matters for your project.

Frequently asked questions

What do the numbers 21, 22, 23, 31, 32, 33 and 34 mean?

The tens digit is the setting, where 2 is domestic and 3 is commercial (and 4 is light industrial), and the units digit is the intensity of use from 1 moderate to 4 very heavy³. ISO 10874 lists domestic classes 21, 22 and 23 as light, medium and heavy use, and commercial classes 32, 33 and 34 as medium, heavy and intense use¹.

Is EN 685 still in use?

The ISO 10874 preview lists EN 685 in its bibliography¹, and the standard's scope there is resilient, textile and laminate floor coverings. The European edition is EN ISO 10874, and its 2020 Amendment 1 is titled as removing class 22+². The French sheet still describes the classes as NF EN 685³.

How is a parquet's class worked out?

The French standard XP B 53-669 reads a class from a table that crosses wear-layer thickness with the Brinell hardness class of the species, from A (10 to 20 N/mm²) to D (over 40 N/mm²)³.

Does a higher class mean a longer life?

ISO 10874 says the classes follow intensity of use and that wear and appearance are also influenced by installation, maintenance, the subfloor, footwear and concentrated traffic¹. A class is a rating for a type of use, not a guaranteed lifespan.

What is the UPEC classification?

In France the CSTB sets the UPEC classification, which rates wear (U), indentation (P), water (E) and chemicals (C). The FCBA sheet says it is complementary to the EN 685 classes because the criteria are not identical³.