10 December 2007

Ask the rubber librarian: what happens to condoms in a cold snap?

Talk of your cold! through the parka's fold it stabbed like a driven nail.
— Robert Service, The Cremation of Sam McGee

It's a bit of a stretch calling myself a rubber librarian, although I feel I can make some modest claim to the title. As a student I once endured an excruciating presentation on "Rubber Librarianship" given with a straight face by the corporate librarian at Goodyear, who was so completely devoid of a sense of humour that she banged on in earnest about "rubber research" and "rubber bibliography" over the unsuppressible tittering of my classmates. As fate would have it, I now find myself acting as the unofficial information specialist for Winnipeg public health workers; so I have to know the latest on latex and other prophylactic materials. One has to be flexible you know. Last August a by-the-way question led me to a lengthy search on the efficacy of plastic wrap for oral sex. The outcome? It isn't and you probably shouldn't, but it's better than nothing, especially if you're in prison. Last week I was given another stumper: Do condoms retain their integrity when shipped or stored in extremely cold temperatures?

This is not a frivolous question. This is Winnipeg in wintertime. Like Bratsk, Irkutsk and Krasnoyarsk, Winnipeg is in the running to be The World's Coldest City. This year I think we're winning. Plunked down on flat parkland at the edge of the boreal vastness, we are a congealed place of block heaters and balaclavas, frost bite and flannel sheets. For nearly a month now we have experienced what is appropriately called an "Arctic outbreak," a dome of fiercely frigid air that squats on the middle of North America like an invisible glacier. The result: intense cold — blubber-cracking, tooth-splitting cold. The slightest breeze is a scimitar slicing through the sinuses, trees crack like gunfire, and the hard snow crunches loudly underfoot. Similes and metaphors barely suffice: So cold the wolves are eating the sheep just for the wool. Cold as a sled-dog's snout. Cold as a cocked trigger. Cold as a cruise missile. Cold as a bailiff's heart. A cold so brutal the liquid crystal displays on parking metres wink out, neon signs fade to a sickly glimmer, iPods sputter and die, and cars start, if they start at all, with a juddering, cranking lurch. Even teenagers are known to zip up their jackets and thrust their hands further into their jeans.

So when we ask about the viability of condoms stored in sub-zero temperatures we're not just whistling Dixie. They are still our best defence against STIs. If leaving condoms in the cold degrades their quality, this is something people should know about. So I started my rubber literature search confident that the answer was out there. Unfortunately, like my fruitless investigations into cling wrap, I found virtually nothing on my topic. I pressed on, plumbing the depths of dube-ology, with little to show for it.

There was much technical analysis of the viscoelastic properties of polymers, time-temperature superposition, inspissation, diffusion-limited oxidation, thermogravimetry, Arrhenius behaviour, degradation parameters, tensile elongation, modulus, density, and decay compressive force. In these forbidding thickets of jargon I think I gained a basic understanding that extreme temperatures are bad for condoms, as is air, especially polluted air (3). Condoms should be packaged in impermeable, flexible aluminium foil packaging with a recommended minimum thickness of 8 micrometres (6,9). There are several studies on condom storage in excessive heat (1,2,5,6,7). Research has demonstrated, so says the World Health Organization, that properly packaged, good-quality condoms do not deteriorate when stored at average temperatures found in tropical climates. Air conditioning is not necessary if the condoms are properly packaged and stored in a clean, dry, well-ventilated environment. They must not come into contact with oil, petrol, water or ultraviolet light (9).

About condoms in the cold, however, the literature is silent, except for a 16-year-old article in German on the safety of condoms in outdoor vending machines (4), which I have not been able to obtain. Even if it turns up, I can't be sure its findings would be relevant to the daunting conditions of a Canadian winter. The best that authorities can say is that research is continuing to find better ways to predict accurately the stability of a condom as it ages (8).

Chapter 5 of the online monograph on latex condoms by McNeill et al. (8) offers a useful description of how variations in temperature might affect condoms:

Latex rubber is known as a "viscoelastic" material; i.e., it has a "viscous" or damping component and an "elastic" or springy component. . . . The response of these components changes with the frequency of vibration and with temperature. For example, the children's toy called Silly Putty, which is a silicone rubber, becomes solid if it is very cold but flows under its own weight in a warm room. If pulled quickly, it fractures; if pulled slowly, it stretches. Analogous phenomena occur in latex rubber.
In Winterpeg, in a cold snap, no one in their right mind is going to try playing with Silly Putty outside. The same goes for condoms. But if you watch the cars creeping through the freezing exhaust fog at Portage and Main, you can bet that many of them will have a few condoms stashed in the glove compartment. Probably not a good idea. But having diligently applied all my rubber learning to the matter of how condoms fare in extreme cold, I regret to say I can produce little more than a few undocumented warnings. Canadiancondom.com advises against prolonged storage of its products in temperatures above or below 15-30 degrees Celsius. Similar instructions can be found on manufacturers' websites and on packages on the store shelf. Here is a piece of advice from Go Ask Alice:
Question: I'm not wrong when I say condoms can freeze, right? I had some condoms in my car when the temperature outside was definitely below freezing. They were only out in the cold for about thirty minutes. Would it be safe to still use them? Or, should I discard the condoms and get new ones. The box says to keep it below 100-degree temperature, but doesn't say anything about keeping them above a certain temperature. Safe or not?

Answer: The condoms in your car are probably okay to use considering the brief period of time (thirty minutes) they were out in the freezing cold. For longer-term condom storage, keep them in a regulated and constant environment. Ideally, condoms need to be kept in a cool, dry storage space, and away from direct sunlight, to prevent deterioration. Think of certain fruits and vegetables — once they are frozen or cooked, their texture and consistency are permanently changed. The same holds true for condoms. If they've been exposed to a very cold or a very hot climate long enough to freeze or heat up, then cut them in half (so that no one else can use them) and throw them away. Why? After spending a considerable amount of time in these temperature extremes, latex can become brittle, weakening it as a form of adequate protection against pregnancy and most sexually transmitted diseases (STDs). When warmed up or cooled down to room temperature, even if they look okay, these condoms will be less resilient and effective than before.
So take it from Alice: don't hide your condoms in the freezer, under the hookah in the back porch, or in your glove compartment during a Winnipeg winter.

In a frosty December on the Canadian Prairies you can almost feel the planet's uncaring tilt away from warmth. The poor sun can barely lift itself past eye level before dropping out of sight behind smoking chimneys and brittle trees. The remorseless winds empty out the streets, leaving only hunched smokers shivering and stomping in doorways. During this festive time of tipsy indiscretions at office parties and family fisticuffs over the placement of decorations, Winnipeggers brave the unreal cold to go shopping, elbowing their way through hangar-sized emporiums for trinkets and treats, while the latest tattooed crooner roasts chestnuts from scratchy loudspeakers. In one of these mega-stores — was it Krazy Keester's, or Frostco, or The Haggle Hutch? — I attracted not a few cold stares as I rummaged through condom packages squinting at the storage instructions. The rubber librarian gets no respect.


References:

1. Bo MC, Gerofi PJ, Visconte LLY, Nunes RCR. Prediction of shelf life of natural rubber male condoms—a necessity. Polymer testing. 2007 May;26(3):306-14.

2. Bo MC, Lopes L, Visconte LLY, Nunes RCR. Thermal degradation of natural rubber male condoms. Macromolecular symposia, 245-246. 2006:668-76.

3. Clark LJ, Sherwin RP, Baker RF. Latex condom deterioration accelerated by environmental factors: I. Ozone. Contraception 1989 Mar;39(3):245-51

4. Dahmen HG. [Storage and safety of condoms with reference to the effect of high and low temperaturesdispensers in the open]. Lagerfähigkeit und Sicherheit von Kondomen im Hinblick auf die Einwirkung hoher und niedriger Temperaturen - Automaten im Freien. Offentl Gesundheitswes. 1991 Feb;53(2):97-8. [Note: Article in German. The title as translated in the Scopus database has "outside slot machines" instead of "dispensers in the open." The term should be translated as "outdoor vending machines." I was unable to review the text of this article.]

5. Free MJ, Srisamang V, Vail J, Mercer D, Kotz R, Marlowe DE. Latex rubber condoms: predicting and extending shelf life. Contraception 1996 Apr;53(4):221-9

6. Free MJ, Hutchings J, Lubis F, Natakusumah R. An assessment of burst strength distribution data for monitoring quality of condom stocks in developing countries. Contraception 1986 Mar;33(3):285-99

7. Guigon P, Breton D, Mendes-Oustric AC, Pech A, Clair P. [In vitro studies of factors possibly influencing the performance of latex condoms]. Etude en laboratoire de facteurs pouvant influencer la qualité des préservatifs masculins. Med Trop (Mars) 2005 Nov;65(6):575-9

8. McNeill ET, et al. The Latex Condom: Recent Advances, Future Directions [Internet]. Family Health International; 2006. [cited 8 Dec 2007]. Available from: http://fhi.org/en/RH/Pubs/booksReports/latexcondom/index.htm

9. World Health Organization. The male latex condom: specification and guidelines for condom procurement : 2003. Geneva: Dept. of Reproductive Health and Research, Family and Community Health, World Health Organization; 2004.

3 comments:

Pat said...

Now those are Friday questions - I've had some good ones over the years, but nothing quite like that.

My current favorite is whether bees or butterflies can get inebriated on fermenting fruit - which they can. There are even invertebrate models of drug addiction.

Carol Cooke said...

Loved this one Mark!

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