Regarding ECF Safety Specification For Metal Tube Mods

[Doomed!]

If I may. In this thread, http://www.e-cigarette-forum.com/for...ry-2012-a.html ecf has said that there are 8 cases of reported explosions and "perhaps" a total of 15 cases including some that went unreported. My question is: with all of the tube mods out there with the capability of stacked batteries, is a potential for 15 cases of explosions significant enough for this kind of action? That's 15 cases out of how many mods used? 1,000? 10,000? More, maybe? What percentage are we talking about? Yes, a catastrophic failure in a mod that leads to an explosion is a concern. Someone suffering an injury is problematic. But before we start declaring that the sky is falling, shouldn't we find out if this is a problem that requires this kind of solution? You can't protect everyone. Even with the ecf approved safety measures in place, batteries will fail and people will get hurt. Those events will always happen. Is 15 explosions out of ? mods over an untold period of time significant, or is just random events that will occur with or without safety measures?

[Doomed!]

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.

Your logic is flawed here. The hundreds of thousands of lives you save don't matter in a legal case. All that matters is the situation that the plaintiff is bringing to court. In your example of a motorcycle light hurting someone, the judge isn't going to consider how much safer the motorcycle is because of a light. It doesn't matter in the particular case he is hearing. All that matters is a) did the light cause an injury? and b) is the manufacturer, or whoever the plaintiff is suing, responsible for the injury? That's it. It's very cut and dry because in legal proceedings you can't open it up to that much interpretation. The light caused the injury or it didn't and the defendant is responsible or not. It's very nice that you want to be the leaders in this movement to make PVs safe, but if you tell someone that a particular mod is safe because of a safety feature and that feature causes an injury, you may be held liable. I would think long and hard before you start labeling things safe or unsafe. The bottom line is, you just don't really know, do you?

[Rocketman]

I think a more open discussion of potentially unsafe mods would be appropreate in the forum.

We obviously talk brands and model number when it comes to batteries and chargers.
The forum even recommends very specific model numbers of AW cells, and Pila chargers.
Takes a position of safe/unsafe for/against brand names. Is it they aren't afraid of liable action from China?

How about the same openness with mods? Or maybe just the design features? Like a threaded on bottom pipe cap?
Like a mod made with an end mill with no bottom cap? Pipe threads on mods? Give me a break

[markfm]

Looks like another "standard" pv on-charger roman candle: http://www.e-cigarette-forum.com/for....php?p=5478955

The standard proprietary pv may only be popping up with bad things happening while charging so far, but they are also coming up with bigger batteries, so when things go wrong they are more violent than in past times. Combine that with some vendors choosing to go reverse polarity on connectors relative to the great majority for a given connector type, and these kinds of events are also likely to become more common.

[Rocketman]

How many start out with the cheap disposables? The ones with the charging smarts in the e-cig battery and a straight through wired USB adapter that looks like a charger. Then move up to the eGo, or 18650 eGo, and try and use that adapter (nothing but 2 wires inside) on their new model. Guaranteed venting.

[rolygate]

as for the internal sleeve: wouldnt this block the slots on the tube. i would guess this would insulate the heat and the initial out gassing (the users first warning something really bad is about to happen).

You are right. This is why the sleeve is not part of the EMS spec. If fitted, it would need to be perforated to allow some gas to escape. Even the smallest holes would be enough.

I also dont see how using the tube body as a groung is a bad thing. im not trying to stir the pot, im just wanting to understand the logic of some of this. sorry if im coming off as being argumentative.

Intelligent questioning cannot be argumentative and in any case this is an argument thread...

Again, an insulated return is not part of the spec as we don't know enough about this area yet, and it requires some engineering to get right.

It is just a general principle that using a machine casing as the negative return is not the ideal arrangement. However, practicality and cost mean that for almost everything made, it is the normal method used. Just because something is 'normal' does not mean it is right. It isn't till you go to marine engineering until you find that you have to do it right because the consequences are catastrophic if you don't. Maybe also in aeronautical engineering but I have no knowledge of that.

There is actually no reason to do something 'right' if there will never be any comeback from doing it another way. If, in a specific application, it makes no difference - then fine, it's of no consequence.

The reason I mention it in this context is because metal tube mods appear to have a greater battery failure rate than boxmods, and even with single battery units. Why is that? One difference I can see is that the casing is metal in one and plastic or wood in the other. There is a possibility that batteries are shorting out to the casing. When this happens, a negative return circuit is created that may be detrimental to the battery due to the position on the battery case, causing a meltdown as it has created a new negative path within the battery; and the new circuit also bypasses a fuse arrangement such as a hot spring.

So it just seems logical that:

• Taping up your batteries
• Inserting an insulating sleeve
• Or even using an insulated return (needs a complete redesign as this requires an isolated atty connector)

...could be a good move - until we have more data. Isolated 2-wire circuits are a theoretical 'ideal', not necessarily required in the real world. However, when a battery shorts to ground then it does point out why this theoretical ideal exists - because it is always 'right', whether or not it is practical to employ.

[rolygate]

The pictures of eGo batts I've seen are reported to be a result of the charger failing to cut off. I've been waiting for an in hand tube meltdown to happen, but haven't seen or heard of that. I may not be searching hard enough.

Yes - we don't know of a mid-size model (eGo type) failing in use. They seem to get cooked on a charger, and far more often than any other type.

So, from what I've read here and other places, there haven't been cases of a single battery tube mod going thermal? If that's correct, it's reassuring.

We do not know of any single-batt mod exploding. There have been many events where a single-battery metal tube mod had a battery melt but not explode.

It is reassuring in that it seems to indicate that it needs two cells for an explosion.

It is not reassuring in some ways, because many single-cell metal tube mods can have two cells inserted instead of one large cell. This can occur even when the mod maker advises against it. It means that we also have to include single-cell mods in any discussion because they will have two cells fitted.

[rolygate]

The thing I found odd about all of this was the trading of a face injury to potentially catastrophic hand injury. Somehow that just doesnt make sense to me. Make it safe if you are going to be the UL for ecigs. Perforated tube inside of a solid tube, possibly some high temperature insulation between them, plastic plug in the bottom with a big "dont point this end at your face" and its a done deal. As big as a beer can but what the heck we might just save a lot of hands that seem to be holding the short end of the stick here.

I have already presented a great deal of information in this thread as to why a blowout plug (by itself) is not a solution.

[markfm]

I'm curious to see how much in the way of perforations would be needed in a simple mylar sleeve. It is overall a much weaker material than the metal tube, I half expect even an initial offgas would tend to punch through (unless it knocked a plug off -- I don't see deleting a plastic endcap if someone already uses one, I know the one on my PV will come out reasonably easily; I'm not saying the plug should replace the slots, just that if a PV already has one there would be no reason to purposefully remove such a thing).


Sorry if some of my comments aren't appropriately argumentative

[Rocketman]

four strips of insulation glued into the mod running the internal length of the tube would align the cells, prevent rattle, could eliminate cell contact with the tube (if thickness and diameter were considered) provide a gas path without taking up a lot of cross section like a sleeve and not block the vents.
Tight clearances (like the front end of the 14670 size of the eGo clone) tend to cut cell wrappers. Taking up extra space inside a tube mod reduces the free volume and would accelerate pressure rise.
Too loose and cells get misaligned.

Mylar is strong.
The typical plastic used in 2 liter bottles has a burst strength of 150 psi.
Take one of those eco-friendly filled air bags used for shipping. Stand on it until it pops. That's probably 1 to 2 mils thick. Auto gasket material like the rubberized fiber or cork isn't near as strong but it still will take up valuable air space inside a mod. Pressure ratios will go up as free space is reduced. A millimeter of space (diameter) is a lot compared to no free space.