If I were inspecting your robot, I'd be inclined to reject the Pneuaire chart you linked.
The
Cv of a valve depends on its internal geometry, measured at a given set of working fluid conditions. Relating the port diameter to
Cv is not even remotely accurate—especially when it isn't clear whether those are actual diameters, or nominal NPT diameters. Also, despite a similar-looking valve being pictured (to the 2009-and-earlier Festo valves), there's no model number or manufacturer specified.
Now, with regard to
Cv and that Festo valve, you can derive it from the flow rating in standard cubic feet per minute (SCFM), which is given on the
specification sheet (as "cfm"). The conversion process is documented
here (for example).
Since FIRST hasn't specified the pressure at which the 0.32
Cv rating applies, you might rightly wonder how to calculate the
Cv properly. Manufacturers often provide
Cv at the maximum operating pressure (usually around 120 lb/in
2, but varying considerably depending on the parts). By contrast, FIRST established this limit based on the flow of the 2010 KOP Festo valve at 60 lb/in
2,* but never specified this in the rules.
My calculations for the 2009 KOP Festo valve (unofficially) yield
Cv = 0.395 at 25°C and 60 lb/in
2, and
Cv = 0.177 at the same temperature and 120 lb/in
2. To be absolutely sure, contact Festo using the phone number listed on the datasheet and get the maximum pressure rating, operating pressure rating and
Cv (and the pressure and temperature at which that
Cv is valid).
Of course, you can also run multiple valves in parallel, and increase the flow of the entire system.
*According to the explanation that was provided to robot inspectors by FIRST staff.