Near zone

The near zone is a term that is applicable to surface flow models (SFM). This zone is defined by the length from the duct at which the air velocity is too high for comfortable conditions. When dealing with office space design this velocity is typically set at 0.25 m/s [50 FPM]. Other applications, such as refrigeration, would use 0.15 m/s [30 FPM] due to the colder supply air temperatures, which can cause discomfort at lower terminal velocities.