Pneumatic safety issues

[Gasbot]

Re: Pneumatic safety issues

Just been looking at the five or six (in service) ally bottles we have here. Test pressure range from 200-212 Bar, with the max service/design pressure of approx 170 Bar - but they vary slightly by manufacturer. If the burst disk is roughly set at 195 Bar, then on the ones I have to hand the margin is pretty slim - although this might be different in other parts of the world. This probably explains why portable extinguishers end up as a PED Cat III as a minimum (via the module H route though I would guess) - which also possibly explains why there haven't yet been any failures in the extinguisher vessel. After all a notified body isn't going to sign off on any old bit of metal.

I still think its a good idea to get home made components pressure tested though. In my own little world it strikes me as common sense - even more so if the pressure boundry isn't being proved by calculation. In my view I don't see any difference between storage bottles and valve bodies, rams, pipework etc - they are all the same.

Again in my own little world, the only reasons that seem to be on offer for not pressure testing home made pneumatic components is we don't want to do it or we can't do it. Is that a valid reason?

There may not have been any failures yet, but who knows what the future will bring?

[maddox10]

Re: Pneumatic safety issues

Just been looking at the five or six (in service) ally bottles we have here. Test pressure range from 200-212 Bar, with the max service/design pressure of approx 170 Bar - but they vary slightly by manufacturer. If the burst disk is roughly set at 195 Bar, then on the ones I have to hand the margin is pretty slim- although this might be different in other parts of the world. This probably explains why portable extinguishers end up as a PED Cat III as a minimum (via the module H route though I would guess) -

Strange, Except the CO2 oldest bottle I have around, all are actualy pressure tested to 300 bar, have a working pressure of 200 bar, and a 195 bar burst disk.
And the one that doesn't have the 300bar TP/200bar WP stamp is an old UK ali 1.1kg bottle I exchanged for one of the steel ones I got during the Dutch series 2. That one is TP 200bar WP 135bar, and had a 135 bar burst disk. Never could get it refilled over here.

which also possibly explains why there haven't yet been any failures in the extinguisher vessel. After all a notified body isn't going to sign off on any old bit of metal.

It's also perfectly possible that the test pressure doesn't even come close to the burst pressure. If the same safetymargins as for hoses are held, a bottle won't burst untill reaching 600 bar +

I still think its a good idea to get home made components pressure tested though. In my own little world it strikes me as common sense - even more so if the pressure boundry isn't being proved by calculation. In my view I don't see any difference between storage bottles and valve bodies, rams, pipework etc - they are all the same.

Let me rephraze myself then.

The thing I agree upon is that storage bottles need to be certified. By the book.

Reasoning behind this. Bottles wil be transported, and not always in the robot. Filled. If something goes wrong during transport, the concequences can be a lot higher than a failing bottle in the arena.

Also, and that is a very valuable point. The only other critical time is during filling.
There was a reason Mentorn had Fireman Pete in his workshop to refill the bottles. Nobody was allowed to enter that. The first Dutch events I took that task upon me.
Maybe food for thought?

Again in my own little world, the only reasons that seem to be on offer for not pressure testing home made pneumatic components is we don't want to do it or we can't do it. Is that a valid reason?

The can't do it is ony for a part correct.
Most of the time it's: we can't afford a test rig and a robot at the same time.
Or we can't afford to pay a firm to do it.
Independents over here did quote prices up to ‚1000 to test a Robots pneumatics. I'm lucky I know people at an independent firm.

The don't want to do is plain stupidity. If anybody working with pneumatics (or any high energy storage) acts like that, we have a potential Darwin Award contender.

There may not have been any failures yet, but who knows what the future will bring?

If you have enough time and changing circumstances, something will go wrong.
I suggest a nice rubber room and soothing music to avoid most of the process called life.

[Gasbot]

Re: Pneumatic safety issues

It's also perfectly possible that the test pressure doesn't even come close to the burst pressure. If the same safetymargins as for hoses are held, a bottle won't burst untill reaching 600 bar +

And its also possible the bottles aren't the same as hoses so could burst at 225.3 Bar. Who knows... After all the construction and diameter of both are rather different.

Let me rephraze myself then.

maddox wrote:
The thing I agree upon is that storage bottles need to be certified. By the book.

I wasn't refering to bottles, I was refering to home made components, thats why I said

home made components

The can't do it is ony for a part correct.
Most of the time it's: we can't afford a test rig and a robot at the same time.
Or we can't afford to pay a firm to do it.
Independents over here did quote prices up to ‚1000 to test a Robots pneumatics. I'm lucky I know people at an independent firm.

The don't want to do is plain stupidity. If anybody working with pneumatics (or any high energy storage) acts like that, we have a potential Darwin Award contender.

Cant Do - Won't Do - whats the difference? The end result of both is the same.

we can't afford a test rig and a robot at the same time.

Like cars and car insurance?

Independents over here did quote prices up to ‚1000 to test a Robots pneumatics.

1000 euro for an hours work, I should set up a shop where you are

Maddox, let me ask you a question - how do you quantify your pneumatics components? What kind of certification do you give out with the pneumatics you sell? You've been making pneumatics for people for as long as I can remember, pressure testing & certification should be run of the mill by now.

something will go wrong

Glad we agree on something.

I suggest a nice rubber room and soothing music to avoid most of the process called life.

[maddox10]

Re: Pneumatic safety issues

And its also possible the bottles aren't the same as hoses so could burst at 225.3 Bar. Who knows... After all the construction and diameter of both are rather different.

Correct, depends also on type of hose. Don't try liquid CO trough a standard airhose. Most of the time it will fail immediatly at the connections.
But yes, the larger the diameter the thicker the wall etc etc...

I wasn't refering to bottles, I was refering to home made components, thats why I said

home made components

I do understand.

we can't afford a test rig and a robot at the same time.

Like cars and car insurance?

You don't want to see how many uninsured cars there are... but yes.
It doesn't get better because the current rules.
Several people on the forum can assure the stuff is up to snuff. Unfortunatly, with the current rules those roboteers can't be seen as independents.

Independents over here did quote prices up to ‚1000 to test a Robots pneumatics.

1000 euro for an hours work, I should set up a shop where you are

It's obvious that those quotes didn't come from firms who were interested in the extra work.
The cheapest was 15 000bef (‚372) for Project One (back in 2001), and that guy (one man firm specialising in CO2/halon server-room protection) was rather clear. It's good for your own machine, look at it as a kind of sponsoring.

Maddox, let me ask you a question - how do you quantify your pneumatics components? What kind of certification do you give out with the pneumatics you sell? You've been making pneumatics for people for as long as I can remember, pressure testing & certification should be run of the mill by now.

My licence did run from 2000 to 2010 (didn't realise at first my certificate as pressure tester and safety inspector from my then employer covered it), so every prototype setup I made after march 2010 was tested by my aquintance at the steamgenerator building plant.
But before, it was easy enough. Assemble the component , fill it with light oil, raise pressure with hand or electric pump to 1.75 times work pressure and measure the expansion. If the expansion was lower than what the computer with the FIN calculations prognosed, it was good for me. (I have to admit, the FIN tests weren't done by me. Sometimes by other Dutch roboteers tough, not independents.)Full setups were done likewise, but the pressuretest was done at 1.5 times the working pressure.
To setup the PRV's I first did a pretest with oil, and afterwards with nitrogen to set it at 1000psi.

Dissassemble, rince with a degreaser, assemble, call it a day.

I never tested storage bottles myself. And I have only 1 deviation on the bottle setups. The composite divetank. I had those recertified from 4500 psi diving mix to 3000psi , coupled with a CO2 twist valve- neck is M18*1.5. The valve is a reworked tapered neck twist valve.

I even have a story about such tests.
TAN. When it was a wee infant barely capable of recieving a TX/RX command, we tested the whole setup with a bottle filled at 135 bar Nitrogen. The results were impressive.
But I needed a night to clean up the results on the enviroment.
Nothing failed, except the PRV, what got recalibrated afterwards. But at 2/3ths the originaly designed pressure, but a speed way beyond normal hydraulics....
Let us say the poor bolted down 2 steel tube fence needed some straightening and remounting.

something will go wrong

Glad we agree on something.

I suggest a nice rubber room and soothing music to avoid most of the process called life.

It's robot wars, not bumper cars nor a knitting class. We build machines to go head to head, with the intention to immobilise the oppenent. And we don't want to do that by trowing rosepetals.

Every fight I expect to see a bottle shattered, a combination of HDPE armor and LiPo fire, or even worse mishaps and every fight that doesn't happen I feel a relief.

[xtreme]

Re: Pneumatic safety issues

I have kept out of this Pneumatic safety issues thread up until now, first off because it shouldnt really have been started cos its pointless and going nowhere and secondly its just pathetic with all the arguing and twisting peoples words etc.
Im only posting this now because its quite obvious a few comments have been pretty much aimed at me.

So just because a ram passes gas it shouldn't be tested - that is quite frankly idiotic.

and

The don't want to do is plain stupidity. If anybody working with pneumatics (or any high energy storage) acts like that, we have a potential Darwin Award contender.

Its quite clear its aimed at me beacuse I was the one that said I thought it was pointless pressure testing the ram, I said id get the full system tested but i just thought the ram was pointless as it isnt been tested in the way its going to be used.
As the EO's have said and Kane has said these machines are being used in an arena made to contain anything that might go wrong with the robots. CO2 bottles should be checked/tested/certified because they are being used outside the arena. And also like has been said before, the way your carrying on about it each individual component would have to be retested every fight.
Plus we went to thorite to get some fittings, if you tell the guy what there being used for he will tell you that they are not designed to be used in the way we are wanting to use them, and if they fail while being used in the way we are using them they or the brand are not responsible for any damage or injury. So as soon as you put them in your robot and in the arena any test certification that off the shelf parts have is invalid. Also with off the shelf rams and valves, mainly low pressure stuff if you tell them your using CO2 they say you cant. There designed to run compressed air.
So really even your off the shelf parts arnt covered.
No matter how much you argue about it you cant get round the fact that we are pretty much using these systems in a way that they shouldnt be used so even though in an ideal situation we would all have tested and certified systems the fact is as soon as your robots in the arena and that door is closed all that certification and the paper work means nothing.
I will have my system tested for my own piece of mind, basically so I know im not going to show up to an event turn the gas on and it leak.
Also James mentioned in an earlier post about pressure switches to show if the gas is on. I have a pressure switch for flow anyway, We had been playing around with the idea just as a cool feature.


Mario I dont want to get into a big argument, Your rams are proven to work and stand up to the pressures and punishment, You build good rams and thats why people use them, I expected people who havent built pneumatic robots or people that dont own a pneumatic robot to complain about this stuff, It happens all the time when sombody doesnt have what sombody else does. Both this subject and the lipo subject are quite similar in a way, They are been pushed and brought to more peoples attention by people that dont run pneumatics or lipos and people that personally dont feel confident with pneumatics or lipos, and once the subject grabs a few peoples attention more people jump on it, Its not just this community/forum it happens in almost any hobby/competition/sport. but even with them complaining I wouldnt have expected it from you because your doing exactly what im doing pretty much, If anything we should have been siding together but you was the first one to start quoting rules in the previous thread, but its ok making it sound like all of your rams and custom components are fully tested, but truth is there not really are they, Do all of your rams and other custom pneumatic components individually independently get tested and certified and released with certification papers to everyone that buys one of your rams? No. So when it comes to the person with one of your rams going through tech check and I say show me the paperwork that goes with that ram to prove its been tested and passed to be used at whatever pressure they are running. What happens then?
(I'd obviously never do that, but if people keep pushing thats whats going to have to happen)

We need to help the hobby/sport progress, These are things that could potentially hold us all back.

Hey cant we all just get along

[xtreme]

Re: Pneumatic safety issues

I have kept out of this Pneumatic safety issues thread up until now, first off because it shouldnt really have been started cos its pointless and going nowhere and secondly its just pathetic with all the arguing and twisting peoples words etc.
Im only posting this now because its quite obvious a few comments have been pretty much aimed at me.

So just because a ram passes gas it shouldn't be tested - that is quite frankly idiotic.

and

The don't want to do is plain stupidity. If anybody working with pneumatics (or any high energy storage) acts like that, we have a potential Darwin Award contender.

Its quite clear its aimed at me beacuse I was the one that said I thought it was pointless pressure testing the ram, I said id get the full system tested but i just thought the ram was pointless as it isnt been tested in the way its going to be used.
As the EO's have said and Kane has said these machines are being used in an arena made to contain anything that might go wrong with the robots. CO2 bottles should be checked/tested/certified because they are being used outside the arena. And also like has been said before, the way your carrying on about it each individual component would have to be retested every fight.
Plus we went to thorite to get some fittings, if you tell the guy what there being used for he will tell you that they are not designed to be used in the way we are wanting to use them, and if they fail while being used in the way we are using them they or the brand are not responsible for any damage or injury. So as soon as you put them in your robot and in the arena any test certification that off the shelf parts have is invalid. Also with off the shelf rams and valves, mainly low pressure stuff if you tell them your using CO2 they say you cant. There designed to run compressed air.
So really even your off the shelf parts arnt covered.
No matter how much you argue about it you cant get round the fact that we are pretty much using these systems in a way that they shouldnt be used so even though in an ideal situation we would all have tested and certified systems the fact is as soon as your robots in the arena and that door is closed all that certification and the paper work means nothing.
I will have my system tested for my own piece of mind, basically so I know im not going to show up to an event turn the gas on and it leak.
Also James mentioned in an earlier post about pressure switches to show if the gas is on. I have a pressure switch for flow anyway, We had been playing around with the idea just as a cool feature.


Mario I dont want to get into a big argument, Your rams are proven to work and stand up to the pressures and punishment, You build good rams and thats why people use them, I expected people who havent built pneumatic robots or people that dont own a pneumatic robot to complain about this stuff, It happens all the time when sombody doesnt have what sombody else does. Both this subject and the lipo subject are quite similar in a way, They are been pushed and brought to more peoples attention by people that dont run pneumatics or lipos and people that personally dont feel confident with pneumatics or lipos, and once the subject grabs a few peoples attention more people jump on it, Its not just this community/forum it happens in almost any hobby/competition/sport. but even with them complaining I wouldnt have expected it from you because your doing exactly what im doing pretty much, If anything we should have been siding together but you was the first one to start quoting rules in the previous thread, but its ok making it sound like all of your rams and custom components are fully tested, but truth is there not really are they, Do all of your rams and other custom pneumatic components individually independently get tested and certified and released with certification papers to everyone that buys one of your rams? No. So when it comes to the person with one of your rams going through tech check and I say show me the paperwork that goes with that ram to prove its been tested and passed to be used at whatever pressure they are running. What happens then?
(I'd obviously never do that, but if people keep pushing thats whats going to have to happen)

We need to help the hobby/sport progress, These are things that could potentially hold us all back.

Hey cant we all just get along

[xtreme]

Re: Pneumatic safety issues

I have kept out of this Pneumatic safety issues thread up until now, first off because it shouldnt really have been started cos its pointless and going nowhere and secondly its just pathetic with all the arguing and twisting peoples words etc.
Im only posting this now because its quite obvious a few comments have been pretty much aimed at me.

So just because a ram passes gas it shouldn't be tested - that is quite frankly idiotic.

and

The don't want to do is plain stupidity. If anybody working with pneumatics (or any high energy storage) acts like that, we have a potential Darwin Award contender.

Its quite clear its aimed at me beacuse I was the one that said I thought it was pointless pressure testing the ram, I said id get the full system tested but i just thought the ram was pointless as it isnt been tested in the way its going to be used.
As the EO's have said and Kane has said these machines are being used in an arena made to contain anything that might go wrong with the robots. CO2 bottles should be checked/tested/certified because they are being used outside the arena. And also like has been said before, the way your carrying on about it each individual component would have to be retested every fight.
Plus we went to thorite to get some fittings, if you tell the guy what there being used for he will tell you that they are not designed to be used in the way we are wanting to use them, and if they fail while being used in the way we are using them they or the brand are not responsible for any damage or injury. So as soon as you put them in your robot and in the arena any test certification that off the shelf parts have is invalid. Also with off the shelf rams and valves, mainly low pressure stuff if you tell them your using CO2 they say you cant. There designed to run compressed air.
So really even your off the shelf parts arnt covered.
No matter how much you argue about it you cant get round the fact that we are pretty much using these systems in a way that they shouldnt be used so even though in an ideal situation we would all have tested and certified systems the fact is as soon as your robots in the arena and that door is closed all that certification and the paper work means nothing.
I will have my system tested for my own piece of mind, basically so I know im not going to show up to an event turn the gas on and it leak.
Also James mentioned in an earlier post about pressure switches to show if the gas is on. I have a pressure switch for flow anyway, We had been playing around with the idea just as a cool feature.


Mario I dont want to get into a big argument, Your rams are proven to work and stand up to the pressures and punishment, You build good rams and thats why people use them, I expected people who havent built pneumatic robots or people that dont own a pneumatic robot to complain about this stuff, It happens all the time when sombody doesnt have what sombody else does. Both this subject and the lipo subject are quite similar in a way, They are been pushed and brought to more peoples attention by people that dont run pneumatics or lipos and people that personally dont feel confident with pneumatics or lipos, and once the subject grabs a few peoples attention more people jump on it, Its not just this community/forum it happens in almost any hobby/competition/sport. but even with them complaining I wouldnt have expected it from you because your doing exactly what im doing pretty much, If anything we should have been siding together but you was the first one to start quoting rules in the previous thread, but its ok making it sound like all of your rams and custom components are fully tested, but truth is there not really are they, Do all of your rams and other custom pneumatic components individually independently get tested and certified and released with certification papers to everyone that buys one of your rams? No. So when it comes to the person with one of your rams going through tech check and I say show me the paperwork that goes with that ram to prove its been tested and passed to be used at whatever pressure they are running. What happens then?
(I'd obviously never do that, but if people keep pushing thats whats going to have to happen)

We need to help the hobby/sport progress, These are things that could potentially hold us all back.

Hey cant we all just get along

[maddox10]

Re: Pneumatic safety issues

It seems my point is lost somewere.

To clarify.

If the current rules are enforced, we can forget using Pneumatics, except for a happy few.

[craig_colliass]

Re: Pneumatic safety issues

Thanks for all the responses to this subject

The question I would ask now is, what if anything, we need to do to improve the procedure for making, testing and operating of the pneumatic equipment in robots?

Do the current rules make sense?

If not can they be changed to be practical and so enforceable?

Do we need to change filling the procedure of Co2 bottles?

Now we have discussed the potential problems, let's look at solutions.

[widow_twanky]

Re: Pneumatic safety issues

Now we have discussed the potential problems, let's look at solutions.

I think the starting point has to be that we actually have a very good safety record. Maybe we have a 'if it aint broke don't fix it' situation.

OK maybe we look at new rams and check wall thicknesses etc but there's not a lot else I can see which needs to be changed.

The bottle rule is a wierd one in my view. The BS requires cylinders to be retested every ten years (the certification lasts five but the testing interval is ten). It just doesn't seem to follow that we talk about standards and testing requirements and then just make up our own. That said, it's not really an issue as you do have to draw the line somewhere.

Lipos are slightly different as they are to some degree an unknown quantity and we just have to know how to deal with them (and make sure safety equipment such as lipo bags are from a reputable supplier as there are some fakes on ebay which simply don't do the job).

Question to be asked: when was the last accident involving pneumatics? I have seen burkerts misfire with the locking mechs in when armed but no explosions not related to combat etc.

[terry]

Re: Pneumatic safety issues

Craig just wants a ban on the slugs !

[typhoon_driver]

Re: Pneumatic safety issues

Lipos are slightly different as they are to some degree an unknown quantity and we just have to know how to deal with them

Not meaning to sidetrack but this is garbage. Been running lipos in featherweights for years now without incident and anyone that tells me that a heavyweight experiences a more intense environment these days has not attended a featherweight champs in a long time. Those featherweight spinners are far more dangerous to a lipo pack than anything that a heavyweight has these days.

Rant over

[razerdave]

Re: Pneumatic safety issues

Amen Gary

The only honest pneumatic failiure I have ever seen (Personally) is someones (I think Skink's) CO2 bottle being overfilled and when it was sat on the bench, somethign at the top gave out and it spun like a catherine wheel on the table.

I have seen other pneumatic failiures on RW like Spawn again blowing its ram.

[widow_twanky]

Re: Pneumatic safety issues

Lipos are slightly different as they are to some degree an unknown quantity and we just have to know how to deal with them

Not meaning to sidetrack but this is garbage. Been running lipos in featherweights for years now without incident and anyone that tells me that a heavyweight experiences a more intense environment these days has not attended a featherweight champs in a long time. Those featherweight spinners are far more dangerous to a lipo pack than anything that a heavyweight has these days.

Rant over

Eeerm?? OK, not what I was saying and not what i believe it said and nowhere near the point i was making but OK!

[Gasbot]

Re: Pneumatic safety issues

Just out of interest has anyone seen the build rules for Battlebots? Clicky Section seven makes for an interesting read.

I haven't been to battle bots, although we did get our current design pre-approved many years ago (via design drawings, thickness calcs and the like). Their rules are much stricter than the current FRA rules, especially concerning custom components. Not trying to be sarcastic or pick a fight but their rules didn't seem to have limited innovation etc in any way. Granted I think HPA is/was used in preference to CO2 though but the principal is the same.

Anybody with a lathe can make a ram or buffer tank etc, and there lies the problem. I don't really know of any other way of arriving at a suitable wall thickness from a pressure point of view other than by some form of design calculations, be it calculated by software or done by hand - and I am not pointing fingers here.

In terms of enforcement of the rules, thats going to be a tricky one. If calcs & design verification were to be required for custom components then the person reviewing them will need suitable knowledge to make a valid decision - and that could be a rather steep learning curve for somebody. If left as is and checks are not carried out etc, eventually someone will push the boundaries to the absolute limit and something may well go pop, this could happen in the arena or while arming up, or at home. Or it may never happen - and I hope that this is the case.