This European Standard specifies a laboratory method of determining the open assembly time in standard climate (20 ±2) °C and (65 ±5) % relative humidity (hereafter climate [20/65]). This European Standard is intended to determine the open assembly time using a defined procedure for obtaining a reliable base for comparison of open assembly time between adhesives under referenced conditions. The method gives a result that cannot be applied to the safe manufacture of timber structures without taking into account the influence of factors such as timber density, moisture content, factory temperature and relative air humidity.