Rack arms are mounted to buildings with support brackets. The bracket of choice is generally the omega. However, other options are available when required or desired. The support distance is the maximum distance between two support brackets.
This support distance is determined by the sturdiness of the rack arm, the weight of the louver, and whether it's an interior or an exterior project. The tables below display at what distance a bracket needs to be mounted for the rack arm of the L-system. Probably stating the obvious, the minimum number of brackets required is two