[Retric]

Without surgery there is a significant risk she would have died.

I understand people get stuck on the 'coffee' aspect, but many acids cause similar levels of tissue damage. There is a huge difference between water at 140f and 190f.

To put things in perspective an autoclave at 134 °C for three minutes is as effective as 121 °C for 15 minutes. Steam at 134 °C can achieve in three minutes the same sterility that hot air at 160 °C can take two hours to achieve. Granted, 249.8F = 121 C, but water can transfer a lot of heat vary quickly.

[emn13]

The amount of liquid in a coffee cup is, however, limited. Furthermore, steam is a lot more dangerous due to the heat freed in condensation. Furthermore, there's a pretty large difference between 134 °C and 90. Finally, I don't think the mechanics of destroying infectious agents is really a great analogy for the mechanics of skin burns: the speed of reactions indeed increases non-linearly, yet the energy increases linearly. The energy in a coffee cup isn't nearly enough to damage the entire body; therefore the amount of damage is likely linked to the amount of energy released. Not that I'm volunteering for an experiment, admittedly.

You mention the amount of time needed for serious burns to occur, yet that amount of time is huge compared to the time needed for water (or coffee) will flow away off or for people will to react. For her to remain exposed to the full load of coffee for around 12-15 seconds requires a pretty odd set of circumstances. For those burns to be large enough to be life-threatening normally requires a large surface area to be burnt, and that requires a large amount of coffee for a long time. (The 12-15 number is from wikipedia which says her lawyers produced evidence that this is the duration t 82 degrees celsius that "may produce third-degree burns").

Of course, there's the complicating factor here that she was quite old; at 79 she would not have been as resilient as younger person. And while that's a terrible shame, it's unreasonable to blame macdonalds for aging. Reading, she weighed just 47kg before her injury, which is low. I don't believe that a healthy person would have sustained her injuries.

It sounds implausible that she could have managed to sustain those kind of injuries given the circumstances - unless some other factors played a role (such as frailty due to aging). It's terrible she suffered as she did, but I still don't see how that could have been reasonably foreseen by macdonalds (and therefore the verdict seems unreasonable).

The point of the lawsuit isn't (just) about what happened to her, but critically also about the degree to which MacDonalds' was taking unreasonable risks. And as wikipedia points out, there have been many, many similar lawsuits, that apparently were not successful. (And note that coffee is still served at that temperature).

[Retric]

Are you trying to argue that 3rd degree burns over 5+% of your body is not somehow a serious medical issue? Or that being younger or heaver somehow adds protection to your skin?

As to water vs steam, steam has effectively a much higher heat capacity but far lower density. 90c water can cause 3rd degree burns in as little as 2 seconds but clothing generally extends the exposure duration significantly.

PS: In the end it was a low cost lawsuit which was settled for presumably less than 600k and well within the cost of doing business. They changed cup design not temperature, but that's about it. As far as their concerned the issue was not the actual cost but discouraging people from suing in the future as it's been 20 years without a repeat.

[emn13]

I'm saying quite the opposite: that the very seriousness of her injury was likely due to her age, not that she didn't have serious injuries. Her age would have made the accident more likely, would have slowed down her response to the accident (her own trial lawyers' evidence suggested she must have remained in the hot coffee for at least 12-15 seconds, not the 2 seconds you mention), and would have hampered her recovery (pretty much any injury is more serious in the elderly, and indeed wikipedia mentions it for burns too).

She didn't just have any old minor burn; hers was huge - she stayed for months in the hospital and lost 20% of her body mass; that's not your typical scalding accident.

Such lawsuits have been repeated, they just haven't been so successful. The fact that it's been 20 years merely underlines how unusual her circumstances were - and perhaps how bad that original cup design was.

[DanBC]

> Or that being younger [...] somehow adds protection to your skin?

Well, that's a reasonable point. Children and old people do have more fragile skin and are going to suffer more severe scalds because of this.