In my experience, calculate applicable loads, and asses support to a recognised standard (usually structural, that does not always offer the desired mechanical properties - though that is something for those involved to manage).

In the example that you provided, assuming the applications are identical, there could be plenty of "causes", including: the section was selected to achieve set out dimensions (carry/return idler separation), that was the only material available at the time, a standard drawing was updated, or one designer was just more conservative than the other.

There are various papers floating around if you are interested, including as a start:

http://www.beltcon.org.za/docs/b1405.pdf

Regards,

Lyle ■

Lyle's link is about as comprehensive as can be.You

Stringer size depends on the load being carried rather than the belt width. Unless the conveyor is very long the savings in selecting a lighter stringer section are quite small and the mathematics is tedious. What is more important to consider is convenience and availability. A 500 belt with inbound iron ore and outbound tailings might impose more load than a 1000 belt carrying coal one way. Do not worry too much over details until the design is almost finalised. ■

AiDiN google is your best friend. That is what we do. ■