At para 4.1 of that same ASCE publication, the Live Load and Roof Live Loads are defined thus:
LIVE LOAD: A load produced by the use and occupancy of the building or other strucure that does not include construction or environmental loads, such as wind load, snow load, rain load, earthquake load, flood load, or dead load.
ROOF LIVE LOAD: A load on a roof produced (1) during maintenance by workers, equipment, and materials and (2) during the life of the structure by movable objects, such as planters or other similar small decorative appurtneances that are ot occupancy related.
In the same ASCE publication Table 4-1, titled "Minimum Uniformly Distributed Live Loads, L-sub-0, and Minimum Concentrated Live Loads", sets the minimum live load for ordinary flat, pitched, and curved roofs at 20 lb/sq ft. But when calculating the load combinations defined at para 2.3.2 is this 20 lb/sq ft the "L" for the roof, or is it the "L-sub-r", or is it both?
Would appreciate some clarification if you're able to provide it.