In civil engineering, specified loads are the best estimate of the actual loads a structure is expected to carry. These loads come in many different forms, such as people, equipment, vehicles, wind, rain, snow, earthquakes, the building materials themselves, etc. In general these loads can be divided into two major classes live loads (loads which are not always present in the structure) and dead loads (loads which are permanent and immovable excepting redesign or renovation).

A good example of specified loads would be the following simplified floor to ceiling sandwich load table (based on the National Building Code of Canada standards)

Floor Finish (Terrazzo) per 10mm thickness = 0.24 kN/m^2
Reinforced Concrete per 10mm thickness = 0.24 kN/m^2
Mechanical Services = 0.35 kN/m^2
Electrical Services = 0.10 kN/m^2

Floor Area (110 mm thickness) = 8 m^2

Total Dead Load = (0.24 + 11*0.24 + 0.35 + 0.10)*8 = 26.64 kN

In order to design to these loads, we would need to convert them to design loads by applying safety factors to them.