This method is for determining the apparent bulk density (ABD)of loosely packed spherical catalyst particles with an averageparticle diameter of 1.6- to 3.2-mm ID. It is also applicable toextruded catalyst particles having the following dimensions: amaximum diameter of 3.2 mm and a maximum average length of 9.5 mmwith a maximum individual length of 16 mm. Apparent bulk density isthe mass per unit volume of the particulate material.