Understanding wood hardness and usage classifications – make the right choice for your floor
Knowing a wood’s hardness is crucial when the wood is to be used for flooring purposes. The harder the chosen material, the greater your floor’s resistance to knocks, abrasions and general wear and tear over time.
Two particular measurements are of special importance for wood flooring:
- Monnin hardness
- Brinell hardness
Monnin hardness
Monnin hardness is measured by means of a special test performed on wood with a moisture content of 10 to 12%. The test provides a good measurement of the penetration resistance of the wood’s radial face. It is performed by applying a force of 1960 newtons using a metal cylinder 30 mm in diameter and greater than 20 mm in length.
Using this test, different types of wood can be classified according to hardness.
- Very soft wood: Monnin hardness < 1.5
- Soft wood: Monnin hardness from 1.5 to < 3
- Mid-hard wood: Monnin hardness from 3 to < 6
- Hard wood: Monnin hardness from 6 to < 9
- Very hard wood: Monnin hardness > 9
Woods that are mid-hard and above are preferred for wooden flooring.
Brinell hardness:
Brinell hardness is calculated by measuring the depth of the indentation left by a 23 mm diameter, 1 kg steel ball dropped from a height of 50 cm. The test is used to measure the wood’s hardness and resistance to dents – a form of wear and tear often found with wooden floors. Brinell hardness is expressed in Newtons/mm2. A four-class system is used to represent this measure.
Usage classification:
In addition to a wood’s hardness, its usage classification must also be taken into consideration.
This classification is defined in terms of traffic intensity and activity type. Each class is denoted by a two-digit number.
The number in the tens column indicates the activity type:
1: domestic
2: commercial
3: industrial
The number in the units column indicates the traffic intensity:
1: moderate
2: general
3: heavy
4: very heavy
A system of symbols is sometimes used to represent these classes.
The following table contains both hardness ratings and usage classifications for different wood floor wear layers.
| Wood species | Wear layer thickness (mm) | Usage classificaton | |
Brinell hardness between 10 and 20 N / mm² | Classe A | Aulne épicéa, pin sylvestre, sapin | 2.5 ≤ e < 3.2 | 21 |
| 3.2 ≤ e < 4.5 | 21 | |||
| 4.5 ≤ e < 7 | 22 | |||
| e ≥ 7 | 22 | |||
Brinell hardness between 20 and 30 N / mm² | Classe B | Bouleau, bossé, châtaignier, mélèze, merisier, noyer, pin maritime, sipo, teck | 2.5 ≤ e < 3.2 | 21 |
| 3.2 ≤ e < 4.5 | 22 | |||
| 4.5 ≤ e < 7 | 23 | |||
| e ≥ 7 | 31 | |||
Brinell hardness between 30 and 40 N / mm² | Classe C | Afromosia, angélique, charme, chêne, érable, eucalyptus,frêne, hêtre, Iroko, makoré, moabi, movingui, orme | 2.5 ≤ e < 3.2 | 23 |
| 3.2 ≤ e < 4.5 | 31 | |||
| 4.5 ≤ e < 7 | 33 | |||
| e ≥ 7 | 34 | |||
Dureté Brinell > 40 N/mm² | Classe D | Cabreuva, doussié, ipé, jatoba, merbau, wengé | 2.5 ≤ e < 3.2 | 31 |
| 3.2 ≤ e < 4.5 | 33 | |||
| 4.5 ≤ e < 7 | 34 | |||
| e ≥ 7 | 41 |
