- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 28 Jul 2021
Janka hardness rating scale
The Janka hardness rating scale was named after Gabriel Janka (1864–1932), an Austrian wood researcher. His work was based on similar studies conducted by August Brinell (1849 –1925), a Swedish metallurgical engineer.
Janka and Brinell were interested in the surface hardness of materials. In both instances, the men conducted tests based on the amount of pressure or effort required to press a steel ball into a certain substance to a specific depth.
The Janka hardness test measures the force required to embed an 11.28 millimetres (0.444 in) diameter steel ball halfway into a sample of wood. This measurement is recorded and repeated several times until an average can be calculated. The end result is the Janka hardness rating.
The Janka scale has become an industry standard for comparing wood flooring. The scale is also useful in the construction industry for giving builders a sense of how difficult it will be to work with different types of wood.
 Related articles on Designing Buildings Wiki
Featured articles and news
Recognising past and present role models for the future.
So why not write something?
LETI publishes guidance for energy efficient home retrofits.
Predictions about adequate post-pandemic IAQ in non-domestic buildings.
Government publishes plans to 'build back greener'.
The contentious nature of claims associated with cladding, fire safety and EWS1 forms.
ECA comments on low-carbon heating systems initiative and Heat and Buildings Strategy.
Cinders and other forms of domestic rubbish created filth but also generated great wealth.
CIC 2050 Group requests input to find out priorities for future industry leaders.