Boiler Venting and Barrier Separation

Where can I find the requirements for heating boiler vent installations? 

Wisconsin Administrative Code sections SPS 323.14(3)(e) and 323.14(3)f), and NFPA-54-2002 7.8c apply.

What kind of fire barrier separation is required for a boiler? 

If a boiler is 15 psi AND 10 horsepower, then the requirements in International Building Code (IBC) Table 508.2 apply. Combustion air requirements provided by a mechanical air supply system are defined under the International Fuel Gas (IFG) Code 304.9 through 304.16.

Are combustion air louvers specifically engineered for a certain specified location allowed per SPS 364.0304 (IFGC 304.8)? 

Calculations supporting the engineered louvers shall be submitted to the HVAC plan reviewer for verification that the engineered louvers provide sufficient combustion air for all components requiring combustion air within the defined room dimensions.