The aircraft stands are typically illuminated using high brightness luminaires which are mounted on building or poles. Mounting heights of these units should be as great as possible, the minimum not less than 15m (50 ft) for floodlights, and not less than 9m (30ft) for street lighting types. Lower brightness luminaires, such as flourescent, may be mounted as low as 4.5m (15ft), if proper shielding is used.