IBC Wind Exposure C definition - Florida Building Code
IBC Wind Exposure C definition - Florida Building Code
(OP)
The 2006 ammendments to the Florida Building Code 2004 have recently changed the definition of wind exposure C to match the definition as listed in the IBC code. I have had many interpretations of this definition and have not had one agree with the other. I am hoping to get some feedback from other engineers who have been working with this definition in the IBC.
The definition reads: "Exposure C. Open terrain with scattered obstructions, including ... ... extending more than 1500 feet from the building site in any quadrant."
The definition then goes on to say "This exposure shall also apply to any building located within exposure B type terrain where the building is directly adjacent to open areas of exposure C type terrain in any quadrant for a distance of more than 600 feet." --This is the part that is getting me. -
Does this mean that an exposure C wind design (which is 1500 feet or wider) must be extended 600 feet into an adjacent exposure B design?
or
Does this mean that the open area (C terrain) only needs to be 600 feet wide next to a building in B terrain to design the building as exposure C? - this seems to contradict the first definition of 1500 feet for exposure C
Any incite into the definition would be greatly appreciated.
The definition reads: "Exposure C. Open terrain with scattered obstructions, including ... ... extending more than 1500 feet from the building site in any quadrant."
The definition then goes on to say "This exposure shall also apply to any building located within exposure B type terrain where the building is directly adjacent to open areas of exposure C type terrain in any quadrant for a distance of more than 600 feet." --This is the part that is getting me. -
Does this mean that an exposure C wind design (which is 1500 feet or wider) must be extended 600 feet into an adjacent exposure B design?
or
Does this mean that the open area (C terrain) only needs to be 600 feet wide next to a building in B terrain to design the building as exposure C? - this seems to contradict the first definition of 1500 feet for exposure C
Any incite into the definition would be greatly appreciated.






RE: IBC Wind Exposure C definition - Florida Building Code
RE: IBC Wind Exposure C definition - Florida Building Code
RE: IBC Wind Exposure C definition - Florida Building Code
RE: IBC Wind Exposure C definition - Florida Building Code
so if my second assumption is correct than does that mean a building in an area of C type terrain which is say 1400 feet wide (<1500 feet) would be designed per exposure B and a building located within B type terrain which is adjacent to an area of 1400 feet wide C type terrain should be designed as exposure C?
this does not make sense to me..what am I missing?
RE: IBC Wind Exposure C definition - Florida Building Code
RE: IBC Wind Exposure C definition - Florida Building Code
RE: IBC Wind Exposure C definition - Florida Building Code
RE: IBC Wind Exposure C definition - Florida Building Code
RE: IBC Wind Exposure C definition - Florida Building Code
1. Exposure C is only defined to land or a site as 1500 ft of open terrain in both directions. It then takes 600 (600 x 600 field) ft of obstruction (30 ft or greater) to transition land as B when it is adjacent (any quadrant) to it.
Building within 600 feet of exposure C (1500 x 1500 flat terain) would still clasify you as C. Since developments are never perfectly squared, this add'l definition clarifies how to handle odd shapes.
This is intended to handle exposures to land adjacent to large bodies of water rather than just addressing the Coastal (CCCL) line.
RE: IBC Wind Exposure C definition - Florida Building Code
I also work in Florida and the code change has finally caught up with things. I use my judgement for B and C and if it is really is borderline than I call the Building Offical and they will tell you what exposure you have.
RE: IBC Wind Exposure C definition - Florida Building Code
I believe the "open patches" is more of an opening (600'+ x 600'+) of the 1500'+ exposure C terrain that actually would be directly adjacent to the building (in any quadrant). It could have been worded better reversed that it takes 600' of transition.
If it was interpreted as 600' deep flat field next to a house constitutes a C, then I believe we would have too much work to do...
RE: IBC Wind Exposure C definition - Florida Building Code