A basic safety specification for mods

[rolygate]

This post contains an outline spec for the basic safety features that ECF believes all mods (e-cigarettes with generic, larger than standard batteries) need to have.

Please note that it is the buyer's responsibility to ensure the manufacturer has included these safety features since ECF cannot determine this. Even if we tried to stop the advertising of unsafe mods on ECF, and stopped some mods being advertised or displayed or mentioned, we could in no way guarantee that all mods seen on ECF are safe. In addition, even if we determined that a given model has the required basic safety features, that does not guarantee that the product you receive will comply.

Please note that a mod with these features is not 'safe' - it is safer than one without them. ECF does not state or imply that a mod with all these features is absolutely safe.

ECF CANNOT and WILL NOT approve or disapprove of any mod. It is the buyer's responsibility to ensure compliance.

IT IS UP TO THE BUYER TO ENSURE THAT THE SUPPLIER WARRANTS THE MOD PURCHASED TO HAVE THESE BASIC SAFETY FEATURES


EMSS
update 2012-01-21
update 2011-11-27
The ECF Mod Safety Specification. After more than a year's satisfactory use, these features have proven valid in actual usage, and many manufacturers have included them.

This comprises a minimum specification and does not address switch ratings (as they are almost impossible to verify), defined battery make and model (as this is a user-purchased consumable), or charger make and model (as this is a consumer purchase decision).

The specification may be updated to reflect new information or practice.

__________________________________________________ ____

A mod should have these safety features to be considered merchantable, in the opinion of ECF:

Protected rechargeable batteries, if supplied
Li-ion rechargeable batteries must have dual protection: both overcharge and short-circuit protection. These are called various names by vendors, such as 'Protected Battery' or 'Battery With PCB'.

Alternatively, a safer technology battery can be used, such as Li-Mn or LiFePO4, which do not need protection.

We advise that the best choice is the largest AW IMR Li-Mn rechargeable that will fit.

We advise that, when choosing a mod, the one that takes the largest AW Li-Mn battery or batteries is chosen.
This is because it has now been shown that mods with smaller batteries are not safer - and especially those fitted with small Li-ion batteries - since smaller batteries tend to fail more often due to the excessive load that running an atomizer causes for these small cells. Initially it was thought that there would be more risk with larger batteries due to the increased power / gas vent capacity / etc - but the opposite has proven true in practice. Larger batteries are safer as they can take the load. It is now known that one of the main causes of failure is the excessive load - about 1.5 to 2.5 amps, on a cell that may have a maximum advised discharge rate of 0.5 amp.

We have had many reports of failures with Li-ion batteries, and one report of failure with Li-FePO4 (probably caused by incorrect charging in a 3.7 volt standard Li-ion charger).

AW-made Li-Mn's have no reports of explosive failures. Note that Li-Mn or Li-FePo4 cells in a mod locked in an 'on' state, jammed in a pocket or case with the switch pressed on, may fail by meltdown. This is even more likely if the battery casing itself has been damaged and is shorted out. MODS NEED A MASTER ON/OFF SWITCH - and this certainly applies to those using an Li-Mn or Li-FePo4 cell (or cells) due to the very high current generated in a short-circuit (dead short). Up to 70 amps can pass during a dead short, with some of these cells.

Mods should be sold with full instructions for use: the type of batteries to buy or not to buy, and the charger to use (this would be especially important with a mod that could have Li-FePo4 cells fitted as these need a different charger).


Gas vent holes
Holes must be drilled to vent gas that might result from heavy charging or discharge or a short-circuit. A minimum of two holes are required, each of which must be of 2mm diameter or larger.


A kill switch
A mod ideally needs a second switch that disconnects the batteries totally during transport and storage, or if a short-circuit occurs, or if overheating occurs while in use. This switch is called a kill switch or master switch.

These are much easier to fit to boxmods than tube mods. It is generally recognized that the practice of part-unscrewing the atomizer for transport in pocket or purse is not a satisfactory solution, some form of safety interlock is required.


A sealed switch
The on/off switch should be sealed, or some other method used, to stop e-liquid running into the back of the switch and shorting it out. If this happens while in a pocket or purse, a meltdown or fire can result (and is why a master switch is needed).


Metal tube mods - bottom-end blowout plug
The most serious mod explosion yet has just occurred at 2012-01-21. A metal tube mod exploded in the face of the user, causing serious facial damage, with the result that the victim was in intensive care, and on breathing support for a time.

It appears from the damage caused that there were no vent holes, and that the top end blew off first, into the user's face. You may be aware that we have warned about this possibility for a long time.

Metal tube mods that can use two stacked batteries need vent holes and a bottom blowout plug (or very large vent slots perhaps).

DO NOT IGNORE ECF WARNINGS -WE KNOW WHAT WE ARE TALKING ABOUT

You are especially cautioned not to listen to mod makers who tell you to ignore our warnings.

__________________________________________________ ____

Risk factors

The risk increases:

• The fewer safety features a mod has.
• With small Li-ion batteries - as they are over-stressed running an atomizer, it draws more current than a small Li-ion such as an RCR123 can deliver while maintaining an adequate safety margin.
• If batteries are stacked in series, as this introduces additional risk elements such as the possibility that a battery can be overdriven by another or take the other out with it if it fails; it increases the voltage and therefore the capacity to destroy circuit components such as switches and atomizers; it increases the power drawn by an atomizer and therefore the power within the circuit.
• If cheap batteries are used, as they are less likely to be double-protected (against overcharge and against high-current discharge) or have thermal and burst protection.
• If standard batteries (ie non-rechargeables) are used, because it is possible that a mistake will be made and the batteries mixed up and charged, resulting in a system overload and failure (and this has happened).
• If the cheapest battery charger option is chosen, since it may not have an overcharge protection facility built in. A charger should be specified that itself has safety features.

YOU ARE STRONGLY CAUTIONED NOT TO BUY
A PRODUCT THAT DOES NOT COMPLY WITH EMSS

EMSS does not make a mod safe - it makes it safer. User error still needs to be guarded against, for example: using standard batteries, charging them by mistake, and putting them in a mod - this is likely to cause serious battery failure; or using Tenergy Li-FePo4 batteries, when we have warned against using these for a long time.


.