We are designing a public assembly area in a theatre style setting. As long as I can remember, the code has always required that the design live load not be reduced for public assembly areas. We have noticed that the 2012 IBC has now changed the wording about this.

Table 1607.1 Footnote m states “Live load reduction is not permitted unless specific exceptions of Section 1607.10 apply.” And Section 1607.10.2.3 includes this provision: “live load for any member supporting 150 square feet or more is permitted to be reduced.”

Is reducing the 100 psf assembly live load now permissible?

Answer:

Below is the code change that resulted in the changes you have noted in Section 1607 between the 2009 and the 2012 IBC. The code is interpreted to make Footnote m impose all the same restrictions on live load reduction as were imposed by the 2009 IBC. When Footnote m talks about “specific exceptions of Section 1607.10,” it is interpreted to be about the two exceptions under Section 1607.10.1.2 and the one Exception under Item 1 of Section 1607.10.2. Assembly live loads that could not be reduced under the 2009 IBC and prior codes still cannot be reduced under the 2012 IBC.