Pneumatic's Rules confusion

[dlavery]

Originally Posted by Steve W

Dave maybe you can find the answer to this question. I asked on the Q&A if you could use 6ft coiled connector hoses that are off the shelf. Now according to the rules they are connectors and off the shelf. They are not storage devices. Last year for some reason they were disallowed. They are the same diameter as the current hose that we receive in the KOP. The safety issue that we are concerned about is better because coiled hose does not flop around on the robot or swing in open air. When I asked the question all that was answered was check the flowchart. Why does FIRST not give us a yes or no answer. There is nothing worse than building and getting to a regional to find out that something is disallowed.

I can't give you an official ruling on the connector hoses, only FIRST can do that. But I will say that with our team I tend to be very conservative when it comes to determining if something is in compliance with the pneumatics rules or not. In general, if it did not come in the pneumatics kit or it is not explicitly (rather than implicitly) permitted under <R90> or <R91>, then we don't use it. We try to keep ourselves out of trouble by not over-interpreting the definitions.

With that in mind, as I read <R90> and note where it says you can use an unlimited number of "connecting fittings" I put the simplist interpretation on that phrase that I can. A fitting is a simple, monolithic piece used to connect two other parts with dissimilar physical interfaces, such as the bag of brass fittings that come with the kit. A connector hose is not a single fitting, it is an assembly of two (or more) fittings and a hose. So let's then go through the flow chart for each of the individual parts of the assembly. Each of the individual end fittings would safely fall through the flow chart, and would seem to be OK to use. But the hose is another matter. It falls through these logic blocks: it is a pneumatic component; it is not an air cylinder; it is not a purchased fitting, valve or purchased air cylinder; and it is not a piston or valve from last years robot. Therefore, the hose itself would be illegal. Double checking with <R90> and <R91>, we see that "tubing" is not explicitly listed as an "unlimited" item. So, in the case of our team (and as mentioned above, we take a very conservative approach to the pneumatics rules), we would say that the connector hose failed the flow chart test and would not use it.

This is my opinion only, which is being provided at no cost and is therefore worth what you have paid for it. Your mileage and interpretation may vary.

-dave