Gedanken Experiment - Portapotty Etiquette

Now that we're back in the racing groove, we're getting reused to all of the finer points of the bike game that fade from memory in the offseason. Things like number pinning, 6am DunkinDonuts meetings, and of course the early-morning use of freezing portapotties.

This post is about portapotties. Perhaps I am a bit of a nancyboy, but putting my bare arse on chilly plastic just gets my goat. So much so that I've put a considerable amount of time into thinking of ways to make the whole experience more pleasant. Way too much time.

I used Newton's Law of Cooling to model heat transfer, because Isaac Newton could beat up your dad. The equation works like this:

After the Romeo and Juliet ordeal, I will not bother explaining this in any detail. You get it or you don't.

The idea here is that your derierre will warm the plastic toilet. The longer you sit, the closer the toilet gets to the temperature of your posterior. Then, when you stand up, the cold air will chill the toilet, and its temperature will approach that of the environment, i.e. nipples-could-cut-glass cold.

I'll assume the following things:

• everybody weighs the same (haha, you wish, Willis, you fatty mcfatfat)
• everybody's butt-skin is the same temperature, 80* F
• everybody takes the same amount of time on the toilet
  
• everybody takes the same amount of time to doff and don clothing
  
• no males are using the portapotty to pee (on pains of death, or at least cussing)

Certainly there are a lot of potential problems here. The womens need the portapotties to urinate, spending less time on the toilet but just as much time messing with clothing. The biggest assumption has to be the bit about clothing. Some people visit the portapotties before getting into their kits, and their turnaround time is rather fast, while others are already in bibshorts/jerseys or skinsuits and have multiple layers to deal with... which should immediately foreshadow one of my conclusions.

Rather than choose my r values in a manner that even approaches scientific rigor, I'm just going to arbirtrarily choose them. We'll assume that the ambient temperature is 33* F. Let's further assume that the first poor schmuck to arrive at the venue will use a toilet with the same temperature as the air. If, after 5 minutes, the toilet has almost reached butt-skin temperature, then the temperature of the toilet will look like this

and the r value for butt-to-toilet (rb) will be 0.05 (sec^-1). One last assumption... let's assume that the r value for air-to-toilet (ra) is 3/4 as big as ra. It makes sense, I think.

So if everybody takes 5 minutes to do their bizness on the toilet, and 2 minutes to take off, then put on, all their clothing, then the temperature of the toilet will look like this

Notice that the peaks are near 80*, but the valleys are a chilly 60*. Your buttocks will not be pleased.

If, however, there is only 1 minute of not-on-potty time allotted per person, then the valleys will be closer to 70*, as in the following...

Rather than rush the whole disrobing/re-robing process (you don't want to snag your skinsuit!), we could just spend longer on the toilet. 8 minutes of "on" time doesn't look much different than 5, but if we bump the time up to 15 minutes, we buy ourselves an extra 30sec of "off" time without losing too much temperature.

If you take 15 minutes in the portapotty before my race, though, I will be forced to kill you. No jury would convict me.

In conclusion, get the hell out of the portapotty. Do your business, and then get out. Try to go while still in jeans, but if you're already in your kit, futz with the top layers after getting the hell out. The longer you take in there, letting the toilet seat get all cold, the more I want to hurt you. Some people may think that a pre-warmed toilet seat is creepy, but it is a valuable commodity on a cold morning. So GET OUT.

Some people write blog posts about the events of their day. Others write race reports. Some geeks write about the mathematics of aerodynamics and power. I write about toilets.