Chart Conditional Formatting

I would like to be able to set color thresholds on a bar chart (maybe on all charts).

We have a report that lists and charts the number of system installations scheduled, grouped by week (actually by day but it's always the Monday of any given week). 

We can only physically install a certain number of systems in any given week so I would like to be able to be able to have the bars in the chart show, for example:

- Green (<8 installs)

- Orange (8-10 installs)

- Red (>10 installs)