For BOCA, the reduction of Reducible Live Loads is based on influence area rather than tributary area. The code defines influence area as "...four times the tributary area for a column, two times the tributary area for a beam...". It is important to note that for all members regardless of configuration, the program first calculates the tributary area, determines the portion of that area loaded by Reducible Live Load, then multiplies that area by four when calculating the reduction for columns and by two when calculating the reduction for beams. The reduction is limited to 50% for members receiving load from one floor only and is limited to 60% for members receiving load from more than one floor (the reduced load is not less than 40% of the unreduced value). It is important to note that the output lists the reduction factor as a percent by which the load can be reduced. No reduction is permitted for members having an influence area less than 400 square feet.

There is a special provision in the Code (Section 1606.7.2.3) for live loads greater than 100 psf. The program refers to this type of load as a Storage load and, for loads specified as Storage live loads, a reduction of up to 20% is allowed on columns loaded by more than one level. No such reduction is made on beams even if they receive load from more than one level. If the equation involving influence area indicates a lesser reduction, the reduction is limited to the smaller amount. Note that in calculating the influence area, only the area loaded by Storage live load is considered and is derived from the tributary area as explained above. The user must explicitly designate loads as Storage. Any live load designated by the user as Storage will be treated as explained whether the load is greater than 100 psf or not, and any load not specified by the user as Storage will not be treated as Storage even if it exceeds 100 psf.

Roof live loads are reduced per Table 1607.3. However, any value of Roof live load can be input (not necessarily 20 psf) and the program will reduce it with the appropriate factor. For example, if a Roof live load of 30 psf is assigned to a member carrying over 600 square feet of roof area, the load is reduced to 18 psf (30 psf times 0.60). It is assumed that the roof is flat or has a rise less than four inches per foot. The reduction is based on the tributary area loaded by Roof live load.

No reduction is made on loads specified as Unreducible.