Are these tanks legal?

I know the white Clippard ones are illegal, but we are unsure if these ones are. Unfortunately, they are all unmarked. It would help if we could determine what these are, whether or not they are the white Clippard tanks, since we heard not all white plastic tanks were illegal.

I know some people will argue otherwise, but illegal or not, I would not use ANY plastic tanks on my robot. The failure mode is simply too dangerous.

If they are unmarked, you can’t provide a part number and related specifications to show that they are rated to the required pressure, can you?

so I expect they are not legal just because of that.

The RI will not like them. Don’t use it. That’s my advice

Without a brand it’s sketchy imo. Breaking $50 on new black Clippards could save you a lot of headache (or just heads in general).

Please verify the source of the tanks, they look similar to the pneuair tanks that we have been using for 3 years and other teams have been using since 2010. I’ve use dozens of these from pneuair and never had an issue. The only explicity illegal air tanks are the white clipplard brand air tanks. All other tanks that meet all the rules are legal but it is in the team to show documenation proving it.

Where did you get the tanks? They look a lot like the tanks that AndyMark sells which have no markings on them which are legal.

Here is one of the 3 unmarked tanks they sell.

More specifically, the white Clippard tanks with the green lettering. (Do you have black ones? If yes, use those)

A good rule of thumb is, and this is for any COTS item with a not easily recognizable part number, keep a copy of the invoice or receipt from where it was purchased. A data sheet is even better to show the inspector.

Hmm I can’t imagine using anything BUT the plastic tanks, but you have far more experience than I do. What sorts of failures have you seen in them?

The failure mode of plastic tanks is a catastrophic release of high pressure air that quickly accelerates large sharp plastic pieces. These pieces, with the pressure FIRST allows, could shoot more than 100 feet (IE: into the crowd).

I have been close to a plastic (non-first) 1 liter volume that failed at 100 PSI. I can tell you I am lucky to be here (the volume blew out away from me).

The only way I’ll have plastic pneumatic volumes on my teams robots is if it is completely enclosed in a box (to absorb as much of the energy as possible) and even with this setup, I would be reluctant to do so.

If the tank has no markings, then you can’t prove the white tank is NOT the disallowed tank. Thus I would reject is as an RI.

Are there any PSI markings on the tank? If you can’t prove the tank can hold 125 PSI safely, then that is another reason to reject the tank.


We have been using these tanks since they went on sale back in the day. I can’t tell from here the exact volume or port sizes your tanks feature, but searching up am-2477, am-2478, and am-2479 should give you relevant technical specifications that would help guide all but the most skittish RIs at your events. I also recommend getting some masking tape and writing “NOT CLIPPARD TANKS, PLEASE STOP COMING OVER TO OUR PIT AND TRYING TO TAKE OUR TANKS” because in my experience that will save you some stress.

It’s your job as a team to make sure your robot is easy to inspect just as much as it is an RIs job to know what they need to look for when inspecting a robot.

I believe Allen is an LRI at various events. In this thread he’s probably the foremost authority. I think it would be super if everyone else in legality threads could either feign honest understanding or step back instead of fearmonger, but I’m not a cop and can’t tell people what to do.

The tanks in the picture and the disallowed clippard tanks look nothing a like other than their color and that they are air tanks. The team will need to prove their legality but just dissallowing them because they are unmarked is not a rule.

It’s not a rule, but the introduction to the robot manual says the burden of proof is on the team to prove the legality of any part.

That said, if I remember correctly, the illegal Clippard tanks very clearly say “Clippard” on them.

Correct that is what I’m saying.

Coastal Pneumatics seems to have bought out Pneuaire who we used to purchase from but they seem to be the same tanks.

Here is the data sheet on the storage volume chambers we have been using for several years without incident.

I’ve posted this in other threads, I’ve have never been told of any plastic tank failures other than the white Clippard tanks. It’s also my understanding the white Clippard tanks were the first plastic air storage devices that Clippard produced and they made them specifically for FRC. Clippard is an awesome sponsor of our program and they have gotten the design correct with their updated black tanks. Other companies that have been producing white storage volumes for many years have not had the same issues as the original white Clippard tanks.

Teams please keep track of your purchases and have data sheets ready for your inspectors.

I do not know Allens background when it comes to Pneumatics, but I do know mine as 7 years as a manufacturing engineer with pneumatic devices.

First off – when someone asks what the failure mode is, explaining it to them is not fearmongering.
Second – When people state that they will not use, or will only use under specific criterion, an object due to safety reasons that is their opinion, justified or not, and again not fearmongering.

I know what the failure mode is. I have seen the failure mode UP CLOSE. When I say I’m lucky to be here, I mean it.

FIRST has chosen to make these legal, that is their choice. My decision to put a box around them is an additional safety feature that I CHOOSE to implement as a safety for the audience and to protect the volumes from “robot-to-robot interaction”.

If you CHOOSE to ignore my advice, that is your choice. I hope that you never see the repercussions of that choice.


Seems sketch and unmarked to the max…
If you don’t know what something is why would you put it on your robot?

To answer OP: you need the proper documentation to prove the parts’ pressure ratings to an inspector. Cut and dried IMO.

I did a hefty amount of research into this a few years ago. There were a few root causes:

-The white Clippard tanks had casting voids near their threaded fitting area, weakening a key structural area
-If the threaded fittings were over-tightened cracks could be initiated in the tank
-If tanks were subjected to rapid or extreme temperature cycles they could become prone to failure (plastic shrinks more per unit temperature than the metal fittings screwed into them, generally speaking) one team had a tank burst when pressurizing a robot
-Overly aggressive mounting solutions (like hose clamps that were tightened too much) put undue stresses in the outside of tanks, increasing the chance of failure

The black Clippard tanks have improved mold design to stop voids, molded-in push-to-connect fittings, and are a more ductile plastic. They are a vast improvement over the white Clippards that were the focus of several (many?) failures. My own un-scientific destructive testing convinced me that the black tanks are considerably more robust than the white tanks.

The penalty of failure with plastic tanks is high because (if they fail) they generally undergo brittle failure, that is to say they make shrapnel. A failure in one plastic tank might cascade to adjacent tanks. Metallic tanks (if they fail) generally undergo ductile failure; there no shrapnel, or very little shrapnel.

What are the risks of any tank failing? The plastic shrapnel is sharp and could hurt someone (wear your safety glasses near any active robot) as it gets flung around 30-100 feet. Perhaps the more traumatizing danger (IMO) is the potential for hearing damage.

Having said that, there have been few, if any, failed tanks outside of the white Clippards. There have been no failed metallic tanks that I know of.

Considering the penalty of failure when using plastic tanks our team chooses not to use them. We recognize that many teams have successfully used tanks in the past. However, having done destructive testing on both plastic and metallic tanks, we have not found the compromise in penalty of failure to be worth the weight savings.

The only argument against metallic tanks that I’ve heard is weight. Only using metallic tanks, we have not had an overweight robot in at least 5 years, all of which used pneumatic systems. Careful selection of metallic tanks can reduce the weight penalty associated with them, and careful pneumatic system design can reduce air usage. IIRC 558 had an aluminum tank (2 years ago?) that was lighter and easier to package than the equivalent in any plastic tank.

The issue with the banned white Clippard tanks was that they had threaded ports on either end and if the brass insert was over tightened, the tank could (and did) fail at the threads. I cant tell by the picture, but if it uses threaded ports, as a RI I would fail it even if it were not Clippard and was demonstrated as rated to 125 psi.

Yes, bring documentation of where and what you purchased.

Really hope we never go to an event where you are an LRI.

If a team has built a robot within explicit and objective parts of the rules (specifically 4.11 and R77 in your case) and you fail them anyway, you’re doing an incalculable disservice to that team, Robot Inspectors, and FIRST. I guess you can try to call it an R9 since that rule in theory is pretty wide open, but its implementation is not to make illegal things that are explicitly legal.

I’m not a robot inspector, judge, referee, etc., but myself and my students can in fact read official FIRST documentation and we would really appreciate it if those with power to decide whether or not we are competing within the bounds of said documentation would also read it.

Of all of the absurdity that fills these digital walls, this kind of attitude stands heads and shoulders above in what not to do.