I was comparing excavators and wheel loaders and got stuck. I do not know the difference between ISO and SAE standards? Why the difference? When ISO 7451 is stated as the bucket capacity for excavators, I am being told that it is the heaped capacity with a 1 to 1, 45% angle of heap. Some people are telling me that the ISO standard is a water line or a struck capacity. Who is correct and why? Wheel loaders is ISO 7546 and is a 1 to 2 or 30% heap. Is every manufacturer using the ISO standard cubic yards or do they account for an extra % heapage? Any knowledge will help me make a better decision.
CAT uses SAE and states their buckets are rated for both struck and heaped capacity, however the performance book only lists the heaped capacity. I SO 7451 is defined as "ISO 7451:2007 specifies a method for estimating the volume of materials which a hoe-type or grab-type bucket of a hydraulic excavator or backhoe loader can normally contain. The volume assessments are based on the internal dimensions of the bucket and on the representative volumes at the top of the bucket. The method employs the technique of dividing the complex shape of the material in the bucket into simple geometric shapes. This method of assessment is intended to provide a conventional means of comparing bucket capacities. It is not intended to be used to define true capacities." Notice it doesn't specify heaped. I am fairly certain it you can have both struck AND heaped in each measurement, and that it should specify. If it doesn't you should assume it's struck. For example right from CAT here are the capacities for a 740 rock truck: Body Capacities Heaped SAE 2:1 30 yd3 / 22.9 m3 Struck 22.8 yd3 / 17.4 m3 Heaped SAE 1:1 36.6 yd3 / 28 m3