Regarding ECF Safety Specification For Metal Tube Mods

[rolygate]

All I have seen is a self entitled noob trying throw his new found power around in a niave and self deluded feeling that you are the only one capable, because i have seen nothing but evidence that you are not in how you have handled this discussion.

Goodbye, and it was a pleasure meeting you. I haven't enjoyed a thread so much in years.

I hope we can agree on something in the future.

[rolygate]

So would a metal tube mod react the same way with vent hole in the bottom as it would with the blowout plug?

In other words, would a vent hole in the bottom create a rocket to the face? And would that rocket easily overcome the resistance of you holding on to the mod?

Small vent holes handle the first-stage outgas but not the very much stronger second-stage outgas (after about 5 seconds). It needs a 16mm or 18mm hole to vent that amount of gas, you are talking about cubic meters of burning hydrogen being generated, if you have two unprotected Li-ion cells going thermal.

With a big hole like that in the bottom, the device goes off like a rocket. There was a famous example of an early model of a popular metal tube mod this happened to, we call it the 'Atlas 5 launcher' - it started a fire in one room, then rocketed into the next room, starting fires everywhere it went. There were some great cartoons of it at the time.

There is absolutely no way you could hold it because the tube becomes red hot and the thrust is the same as a fair-sized firework rocket. Flames shoot out of the bottom end for a foot or more, for twenty or thirty seconds.

We know that whenever an endcap blows off the bottom, the mod is punched into the face with a short, sharp shock. There will be damage from that although it could be minimal. However if the user had the mod angled slightly upward, the carto could go into an eye. You would almost certainly lose your eye then. The force is enough to cut the tongue with a driptip so it is not to be dismissed.

[rolygate]

i seriously hope this is not where all of this is going. is the ECF talking about banning tube mods with stacked cells? or are we talking about reworking the 3.7v mods we all love? some of the "safety designs that were talked about would totally ruin the design (beauty) of some of the most popular mods. im fully aware of the risks involved with a 3.7v tube mod and i happily accept them. are we talking about banning suppliers that continue to offer mechanical tube mods after june?

No, no, no.

Some time in June we will start to point out to buyers that (a) metal tube mods that appear to have a gas-tight seal could be a bad buy as several different models have exploded and caused severe injury to the user's face; and (b) that the mods listed [below] have implemented an agreed set of safety specifications that will almost certainly avoid this problem.

Mod makers and buyers can do what they like. Education and advice.

Take a look at what we did with batteries and you will see what to expect with the metal tube mod guidelines. It's very much the same sort of thing.

[cbrociuos]

wonder if modders start putting in the instructions that this mod is designed and conforms to ECF specs. seems logical right.

then the battery fails, and consumer gets injured. i think that would open the ECF to a lawsuit. it may even let the modder off the hook, beings you guys are the authority on these matters. this is just one worm in this huge can that you may want to consider.

with respect.

[cbrociuos]

No, no, no.

Some time in June we will start to point out to buyers that (a) metal tube mods that appear to have a gas-tight seal could be a bad buy as several different models have exploded and caused severe injury to the user's face; and (b) that the mods listed [below] have implemented an agreed set of safety specifications that will almost certainly avoid this problem.

Mod makers and buyers can do what they like. Education and advice.

Take a look at what we did with batteries and you will see what to expect with the metal tube mod guidelines. It's very much the same sort of thing.

ive seen you post that the only metal tube mods that have ever exploded (to your knowledge) were ones with stacked cells. i hope this will be taken into account when you do your reviews.

i (as they say) have no skin in the game, and i think safety features are important. what im not a fan of is someone or some organization, or government etc. going off half cocked implamenting all kinds of regulations without thinking them out. i also believe this is beyond the scope of one man. this needs to be done by a group. both those that build the mods and people such as yourself.

[tj99959]

Originally Posted by rolygate

Using the chassis as ground in a car is a source of countless electrical faults as any auto electrician will tell you. It's only done for cheapness as it saves 50% of the wiring. I doubt if it's done on a Bentley

As an automotive engineer (with over 40 years of experience) I can assure you that we know which ckts need insulated grounds (or should I say shielding) and which do not. Believe me, from an engineering point of view ground wires for every ckt in a car has little to do with cost, it's all about space and weight.
Depending upon the composition of the metal used in the chassis, it is every bit as good a ground source as a wire. The same is true with the tubing used to make a mod. It is only when a ckt needs to be shielded that individual grounds become necessary. (and it needs to be shielded wire, not just insulated wire)

[markfm]

There may have only been stacked reported so far, but there are some high energy content single cells out nowadays. There are a lot of watt-hours sitting there when one has an issue.

[Rocketman]

Roly,
I've seen youtube videos of unrestrained cells (held only by the charge wires that were intentionally set off. The cell vented, spewed flames, blew the spiral out the positive end. The cell didn't move much. An 18650 cell ends up with about a 17mm hole in it. A single hole in the bottom of a mod would be similar with the exception of the gas path down along the side of the cell, restricting the flow somewhat, then out the vent hole. A blow out plug with too high a relief would be almost as not having one. If the pressure built up, the plug blew, the cell accelerated out the bottom then the reaction could push the mod toward the user. If the blow out plug released at a lower pressure then the reaction would be less.

I think it would be possible to estimate the reaction force caused by a 20mm plug (entire bottom of a mod for 18mm cells), the blow out pressure, the mass of two 18350 cells (for example) and the remaining (reaction) mass of the mod, less the cells (plus any light drag caused by holding the mod).

Vents that are too small, or have a restricted gas flow path (like the inside of a mod) may allow the pressure to ramp up to an unsafe point and then just blow the weak end. Would the user drop/toss or just FREEZE when gas started venting?

I think your idea of small vents not being enough and that a blowout plug alone won't be failsafe is correct but I think a small set of vents, and a large low pressure plug would both give the user a warning and release massive amounts of gas and cell guts without becoming a rocket. Ejecting the cells under a relatively low pressure should greatly reducethe potential for injury.

Remember Robert's Detonator (sorry Robert, but it just won't go away, will it)? Little vents, whole end of mod blew off with a pop. Wasn't in front of his face, but I don't think the mod jetted into the next room.

Making effective vents with enough internal clearance to 'pass gas' but still hold the cells in alignment and away from the case will require a juggling of diameters. Too much clearance and the cell can contact at an angle. Too little clearance and the gas path is resticted.

Maybe we could make a 750 grain 70 cal li-ion gun from a tube mod and a couple of cheap 18350 cells
For an mod that takes 18mm cells, an internal clearance of 1mm (20mm ID) the area past the cell is about the same as a 9mm hole.

[rolygate]

Originally Posted by rolygate
Some mod makers are the cause of the problem.

OK I am still bothered by a representative of ECF making this kind of blanket statement about modders.

Yes. Maybe it could be misinterpreted. It refers to the fact that there are a small number of mod vendors who are selling provably dangerous products. I define this as meaning that they do not protect the end user from either the mistakes that an end user will make, or the faulty components that the mod maker knows will be fitted.

The user is not at fault when a mod blows up. It is entirely the maker's fault and only the maker's fault. If you don't agree then it is pointless us discussing this further.

When you know that a product is dangerous you cannot disclaim liability. In other words if a plaintiff took one of these vendors to court there is a very strong chance they would succeed, because the products are known to be liable to explode. Therefore the maker should have done something about it. It would be extremely difficult for a manufacturer to present a successful defense, because he well knows there is a likelihood the product could explode; and because there are simple steps he could have taken to prevent it. In a nutshell he has no defense.

One of the largest vendors has admitted to me that they worry everyday about this scenario, because they know they are vulnerable. This is why they will make the changes ECF advises. If nothing else it will give them a defense against a charge they did nothing: they implemented the advised changes. And if the safety specs work it's a double gain: no court cases anyway.

There will be a case for damages for a burnt hand sooner or later, but we will appear for the defendant in this case, because there is no way to get out of this situation without some harm, and it's better than a face job. I know of no guaranteed way to completely avoid injury when two batteries go up, and there is no way to stop that happening somewhere to someone.

If you don't want it happening to you then only buy batteries where you know the complete supply chain (there are huge numbers of counterfeit batteries); make sure that the two cells are safer-chemistry or protected; make sure they have enough C rating for the job; and check the voltage every time they come off the charger.

By the way, if you do all that, you are a saint and very unusual on this earth. That's why batteries go up in smoke.

[rolygate]

wonder if modders start putting in the instructions that this mod is designed and conforms to ECF specs. seems logical right.

then the battery fails, and consumer gets injured. i think that would open the ECF to a lawsuit. it may even let the modder off the hook, beings you guys are the authority on these matters. this is just one worm in this huge can that you may want to consider.

You could be right. But, we don't have much choice at this time. So far this year a mod has exploded in someone's face every month, causing injury and rattling the media's cage. With luck it will slow down now.

I think it unlikely an action against us would succeed because we are the main proponents of safety measures, and this is in its early stages just now. Our actions are without fault, and without us, nothing substantial would be done. If someone burns their hand as a result, the alternative, before, would have been a week in the ER, sedated and on a breathing tube for a couple of days.

What would a reasonable person expect in the circumstances? Riding a motorcycle cannot be described as intrinsically safe. It is intrinsically dangerous. If someone introduces safety gear that tries to improve things (like lights), but one in a million get hurt by it (though another thousand are saved), what is the verdict then? The benefit outweighs the cost to one very unlucky individual.