This standard specifies a method for approximately determining the capacity of typical loads carried on the bed of a dump truck. Its capacity is determined from the internal dimensions of the loading platform and the volume of the pile loaded on top. This method is. This is for comparing loading platform capacity, and does not specify the actual loading capacity at the actual site.
JIS A 8422-4:1998 history
1998JIS A 8422-4:1998 Earth-moving machinery -- Dumpers -- Part 4: Body volumetric rating