Final answer:
The minimum openable area to the outdoors required by building codes for ventilation purposes is a specific percentage of the floor area being ventilated; this percentage can vary by location and code, but often it is around 4 percent as seen in commonly used codes like the IRC.
Step-by-step explanation:
The question is related to a building code requirement that dictates the minimum area of openings for natural ventilation in a habitable space. In the context provided where the floor area is 12.0 m² with an uncertainty of 3 percent (rounded to 0.4 m² due to the level of precision given), the minimum openable area to the outdoors should be a specific percent of the total floor area being ventilated. Since building codes can vary based on location and the specific version of the code adopted, the required percentage is not provided here. However, for example, the International Residential Code (IRC) typically requires that the openable area be at least 4 percent of the floor area served. If we apply this percentage to the 12.0 m² floor area, the minimum openable area would need to be 0.48 m² (which is 4 percent of 12 m²). It is important to consult the applicable building codes for the accurate percentage required in any given jurisdiction.