FESTO rates their valves in L/min. They also state that they test at 6 bar inlet, 5 bar outlet (from their website:
https://www.festo.com/cms/en-us_us/4294.htm#id_10037).
Based on this, and the calculation for Cv (e.g.
http://www.swagelok.com/tools/CV_calculator.aspx), I'd calculate a Cv of 0.39 for their CPE10 valves, which are rated at 350 L/min. So, unfortunately, these would be illegal. However, the VUVG valves are rated at 340-380 L/min, so technically, they'd be illegal too, but, by this GDC response (
http://forums.usfirst.org/showthread.php?t=14428), since they came in the KOP, they're legal. Unfortunately, you can't get new VUVG valves in short order, unlike the CPE10 valves, which ship next day...!
I've asked FESTO for official documentation of Cv at 60 psi supply, but haven't heard back yet.
For future reference, does anyone see a flaw in this logic, or have past experience that this level of documentation is insufficient to prove Cv?
(For reference:
http://www.engineeringtoolbox.com/fl...nts-d_277.html)
Cv = q [SG (T + 460)]1/2/ 660 pi (5)
where
q = free gas per hour, standard cubic feet per hour (Cu.ft/h)
SG = specific gravity of flowing gas gas relative to air at 14.7 psia and 60oF
T = flowing air or gas temperature (oF)
pi = inlet gas absolute pressure (psia)