Refers to loads that do, or can, change over time, such as people walking around a building (occupancy) or movable objects such as furniture.
Live loads are variable as they depend on usage and capacity. However, design codes can provide equivalent loads for various structures.
Loads prescribed by codes are empirical and conservative based on experience and accepted practice.
IS875 part 2 deals with imposed loads on buildings produced by the intended occupancy or use.