NBN EN 1022:2005

This European Standard specifies test methods and requirements for the determination of the stability of all types of domestic seating for adults.
The European Standard does not apply to adjustable geometry seating where the backrest is at an angle of 10º or less to the horizontal.
Stability can be determined by either the experimental or the calculative method. Both methods are based on the same forces and points of application.
The calculative method does not apply to seating, which have variable geometry and to seating, which visibly flex under the applied loads.
If the result of the calculative method is uncertain or marginal the result shall be checked, if possible, by the experimental method.