[Al Skierkiewicz]

MK,
B. Solenoid valves with a maximum ⅛” NPT port diameter, and a maximum Cv of 0.32 (if non-KOP valves are used, the team will be required to provide part documentation validating that the valves meet these constraints).
Solenoid valves that are rated for a maximum working pressure that is less than 125psi rating mandated above are permitted, however if employed, an additional pressure relief valve must be added to the low pressure side of the main regulator. The additional relief valve must be set to a lower pressure than the maximum pressure rating for the solenoid valve.
C. Additional 0.160” inside diameter pneumatic tubing functionally equivalent to that provided in the KOP, with the pressure rating clearly factory-printed on the exterior of the tubing,

These two rules generally have teams using push in fittings for tubing. Barbed fitting simply can't meet the 125 psi and 250 psi specs.

<R69> Compressed air for the pneumatic system on the ROBOT must be provided by one and only one compressor...
This rule goes into more detail but essentially answers your question.