Chlorine Tablets

[Pandabean]

I have just been going through a cupboard with long forgotten camping items and I have come across a pack of LifeSystems chlorine tablets in the plastic case and foil wrapped. The expiry date on these 02 2013 and I was wondering if they would still be useable or if they should be chucked?

If you can't use them, what causes them to expire or become unusable?

 

[TarHeelBrit]

From what I've found expiry dates are put on for two reasons. 1, the government demands it or 2, the supplier puts short dates on to increase sales If it was me I would think as long as the tablets are still sealed and have no been exposed to any extreme of heat, cold, etc they should be okay. After all we're not talking 10 years out of date.

Over here the FDA madnates a 1 year expiry date on all prescription meds regardless of the actual date from the manufracturer. I found an emergency supply of my wifes pills in the BoB which was well past the pharmacy chuck-out date so I called them and told them the date of filling and the name of the medication. The pharmacists reaction was I quote "Aww hell no your're good for another 2 years on those they're just as good as the day I despensed them" unquote. I have in the cupboard OTC sinus meds two years out of date that are as good as the day I bought them.

While I can see the 1 year date might be useful for some medications see here Drug potency past the date it's usually just a marketing ploy to bump up sales.


Interested to find out others views possibily someone with more information could chime in?

 

[Beefy0978]

I'm no chemist but I imagine they would be fine for while yet. I should imagine they have to have a use by date, usually the dates are set at about three years, and this seems to be because that keeps the stock rotating on the shelves. I would guess the usual rules apply. Packaging must be secure, water/air tight and in good condition. Otherwise I'm sure they would suck in moisture and be spoiled.

 

[FoxyRick]

Are they the ones that release chlorine dioxide, instead of just chlorine? If so...

They most likely contain sodium chlorite and sodium dichloroisocyanurate dihydrate. Both are simple chemicals and neither are particularly unstable provided they are kept dry, dark and not too warm. Foil wrapping takes care of the first two. Water is the main thing that causes these compounds to decompose and release ClO[SUB]2[/SUB].

If they had decomposed to any great extent I would expect to see signs of that on the foil wrapping. Bubbling of the wrapper, obvious oxidation of the foil, white powdery residue, and thinning of the foil are the signs.

If the wrapping looks intact I personally would happily use them.

 

[Pandabean]

Wrapping is all intact and they have been in a cupboard for a few years so have been stored in a dry place. I was just wondering if there effectiveness would be reduced with age and if any possible issues might arise.

This is them here, but my ones have older labelling:
http://www.cotswoldoutdoor.com/lifesystems-chlorine-tablets-B5210003?channel_code=110&id_colour=180&product_code=73492251&utm_source=google&_$ja=tsid:45886&gclid=CjwKEAjwkf-gBRCd-b2m2aOo0EQSJABMeQDk93D0mtzmD6OxUfh4s6M4nMfOjRAfiiA__jkCzaPKPRoCeLPw_wcB&gclsrc=aw.ds

According to the Lifesystems website:
"Chlorine Tablets - An unopened tablet will last up to 3 years from date of manufacture."


I did find this interesting snippet on http://www.outdoorsmagic.com/forum/gear/water-purification-tabs/23146.html

Giles Cundell

Hi there, I am from the Lifesystems product development department and am happy to answer questions on this issue. We do state on the header card packaging that the tablets should be stored in a cool dry place and not kept for more than three years. This is a legal requirement for packaging, however this information is not duplicated on the plastic chlorine tub (although on Iodine we do state that the product should be used within a year of opening - again, a legal requirement). To be honest it is a bit of an ambiguous issue because chlorine tablets will only really break down if they are subjected to heat or moisture. We follow the HSE regulations that assume that after 3 years the product is likely to have fallen foul of one of these two things.

 

[oldtimer]

I'm following this thread with interest. I've been in the habit of carrying a few chlorine tablets in my wallet and in my possibles pouch in case my water bottle gets used up and I need to render potable water from a stream. They very seldom get used as I tend to boil or use water from a safe source when travelling. Thus I find they go past their use by date. Last time this happened I found it difficult to get a new supply without taking out a mortage. Single foil wrapped tablets like the ones you describe seem to have been phased out.

I don't use iodine as my wife is allergic to it and my son was dangerously ill after drinking from a welsh lake (he was only five and I only took my eyes off him for a moment!)

The outdoors magic link is helpful, but I remain confused, and look forward to seeing more replies to you useful question.

 

[FoxyRick]

The data I quickly looked at for the decomposition of the main component (sodium chlorite) gives a thermal decomposition temperature of 190 Celsius. That's not to say it does not happen below this (it's a statistics thing) but I can't imagine it would happen to any significant amount at normal room temperature. In other words, I think the tablets should be stable/undiminished for a long time. Three years isn't long.

Moisture is the main threat really, assuming the tablets aren't being kept on the dash of a car in the summer sun. If the foil is punctured then all bets are off with regards to how long the tablet remains effective.

I have Portable Aqua Chlorine Dioxide tablets secreted in various crannies and nooks in my kit. That has a stated four year shelf life and most of my tablets are probably around that now. They show no signs of any damage though and given the above, I would still use them; probably for several more years without worrying about it.

That said, if money is no object there's certainly no harm in swapping out old for new, if only for peace of mind. My money is, unfortunately, an object.

(I only keep the tablets for 'emergency' use as I normally carry a Katadyn pocket filter, now to be replaced by my new Sawyer )