exploding plastic storage tanks

[cgmv123]

Originally Posted by yash101

So that makes me think, if these tanks can easily become such a hazard, why are they legal? We have our tanks outside, right under our catching mechanism so if something fails, the tanks are in risk of being damaged. However, those are the metal tanks

The tanks themselves are perfectly safe. It's using them properly that's the issue. Putting stress on the tank increases the likelihood of it bursting.

[Daniel_LaFleur]

Originally Posted by cgmv123

The tanks themselves are perfectly safe. It's using them properly that's the issue. Putting stress on the tank increases the likelihood of it bursting.

... and this is the core of my issue with the tanks.

You have students that have very little understanding of the forces and failure modes and 'how to use the tanks properly' in an environment where the public is being exposed to that risk.

All it takes is one serious injury. Safety (for our students, mentors and the general public) needs to be the top priority, always.

If it's possible that through ignorance of safe protocol the tanks can injure the public, then we must look at ways to mitigate that danger, including possibly banning their use.

[Steve W]

We are having an LRI conference call this evening. I will make sure that it is brought up. I know that Al is aware of these threads so he may already be working behind the scenes. I will post back tomorrow.

[Alex Cormier]

Originally Posted by Steve W

We are having an LRI conference call this evening. I will make sure that it is brought up. I know that Al is aware of these threads so he may already be working behind the scenes. I will post back tomorrow.

I hope it's not too drastic. I just placed an order for 6 of those black tanks.

[Steve W]

Originally Posted by Alex Cormier

I hope it's not too drastic. I just placed an order for 6 of those black tanks.

I think black tanks should be OK.

[AllenGregoryIV]

I still think people are grouping the tanks into two categories when in reality there are many more than that. Color is not the only distinguishing factor.

2013 Clippard White Tanks - As far as I know are no longer being sold after the manufacture discovered problems and offered to replace them for free.
Only place I have found a photo is in the 2013 pneumatics manual http://www.usfirst.org/sites/default...sInfo_RevB.pdf Teams have had many issues with these tanks some of which have been posted in this thread.

Pneuaire - http://www.pneuaire.com/reca44cuin.html These have been in use for 3 seasons and as far as I know have not had any problems.

AndyMark- http://www.andymark.com/product-p/am-2479.htm I'm not sure who manfactors these tanks but they look similar to the Pneuaire variety and again I don't know of teams having problems with these tanks.

Clippard 2014 Tank - http://www.andymark.com/product-p/am-2649.htm Uses ress in hose fitting and has had at least one failure but not explosive failure.

It's my understanding that Clippard just started making plastic air tanks for the FRC market in 2013. I never saw them on their website before then. Where Pneuaire has been producing them with a burst pressure rating of 500 psi and an operating rating of 125psi for several years before the FRC community started using them.

This is a safety matter but we need to make sure we are getting the facts right.

[Trent B]

Originally Posted by AllenGregoryIV

Pneuaire - http://www.pneuaire.com/reca44cuin.html These have been in use for 3 seasons and as far as I know have not had any problems.

AndyMark- http://www.andymark.com/product-p/am-2479.htm I'm not sure who manfactors these tanks but they look similar to the Pneuaire variety and again I don't know of teams having problems with these tanks.

This is a safety matter but we need to make sure we are getting the facts right.

While Pneuaire and AndyMark look eerily similar, Pneuaire does not sell a 36 cubic inch tank on their website.

Additionally, somehow the Andymark tank is physically larger (Diameter 2.7" vs ~2.5" and Length 12.1" vs 9.9") than the Pneuaire 44 CI tank, but manages to hold less (36 vs 44 cubic inches). Unfortunately I do not have an Andymark tank to compare physical dimensions, weight, volume etc.

[Jon Stratis]

I agree we need to keep our facts straight. I do wonder though how much of the failures we've seen so far are influenced by usage statistics. For example, which tanks are used the most? Which tanks are used more by knowledgeable, experienced teams versus those used by inexperienced teams? Statistics like that could provide an explanation for why we've seen failures in the white 2013 tanks but not the others:

- The white 2013 tanks have been around longer than the black 2014 tanks
- The white 2013 tanks might be more prevalent in FRC than the Pneuaire tanks, due to their availability on FIRST Choice and AndyMark last year.
- The Pneuaire tanks might be used less by inexperienced teams - 3 years ago it was only a few teams pushing the boundaries that used the plastic tanks, and you would expect those teams to be more knowledgeable and having done more research than the teams that just used what everyone else used.

Obviously, the above statements are made with some big assumptions, and I'm not aware of any collected data to show whether those assumptions are correct or not. But without knowing some of those statistics, I also don't think we can limit our concern only to the white 2013 tanks - if there are orders of magnitude more white 2013 tanks in use than the other options, then our sample size for the others simply might not be big enough.

[Trent B]

I would tend to agree that the Pneuaire tanks were used more extensively by experienced teams which extensively researched alternative lighter options to the conventional metal tanks.

If I had to guess I would say the Clippard tanks were used 5-10x as much if not more. Had I not read threads on the Pneuaire tanks on Chief Delphi when people first started using them I probably wouldn't realize they were a "viable" option.

I would also suspect to market for small tanks such as these is relatively small outside of FRC as compared to large 1L+ metal tanks.

[tim-tim]

Originally Posted by AllenGregoryIV

...

Pneuaire - http://www.pneuaire.com/reca44cuin.html These have been in use for 3 seasons and as far as I know have not had any problems.

...

I believe this is the 4th season of the Pneuaire tanks. Here is a little evidence.

[AllenGregoryIV]

Originally Posted by tim-tim

I believe this is the 4th season of the Pneuaire tanks. Here is a little evidence.

Thanks, I didn't know that.

[jwfoss]

Has anyone used the air tanks from Robart? I stumbled across them when looking for an alternative lightweight air storage solution.

[Tristan Lall]

Originally Posted by jwfoss

Has anyone used the air tanks from Robart? I stumbled across them when looking for an alternative lightweight air storage solution.

They have a rather ugly connector on them—like a bayonet fitting, without the tapered ribs. I wouldn't use them for FRC without substantial testing. They work fine on model aircraft for the landing gear.

[AdamHeard]

Originally Posted by jwfoss

Has anyone used the air tanks from Robart? I stumbled across them when looking for an alternative lightweight air storage solution.

I've used them, that fitting has a very small orifice so I'm curious if that would show up as an issue in FRC.

They are not robust in the FRC sense if exposed to direct impact (very thin walls), but would be completely fine if not capable of being hit.

[Alex Cormier]

Originally Posted by jwfoss

Has anyone used the air tanks from Robart? I stumbled across them when looking for an alternative lightweight air storage solution.

Team 174 has a few on the robot. They seemed to really like them.