Those shelters are not without their limitations. I recently read the book: "The Thirtymile Fire: A Chronicle of Bravery and Betrayal" by John MacRae
http://www.amazon.com/Thirtymile-Fire-Chronicle-Bravery-Betrayal/dp/080507578XIt is a good read. Gives you a feeling for wildland fires, how they are handled, how things go wrong and how, in the end, luck and the smallest details of terrain and timing can decide who lives and who dies.
The biggest problem was that due to sloppy tactics and a lack of clear command structure a team of firefighters were put into danger where they were surrounded by and overrun by the fire.
And how by a lack of luck and understanding a subset of the group deployed their shelters in exactly the wrong spot. A location where the wind driven flames would concentrate heat and far exceed the capabilities of the shelters to protect the trapped firefighters.
The investigators observed that the effects of the fire in that location were highly variable. Where the people died the earth was baked hard and obliterated. Obviously exposed to extremely high temperatures. While only twenty feet away brush still had leaves. Had the shelter been deployed just a short distance away they would have had a good chance of living.
Better still would have been the larger group never being placed in enough danger to need shelters or, failing that, that everyone would have deployed where the other groups survived being overrun. The other groups ,made it even though they had fewer shelters than people. One brave firefighter made it through with three people under her shelter.
Unfortunately the book doesn't cover many of of the technical aspects of the shelters, a simple technical drawing and detailed description would have been a useful seeing as that so much of the action has to do with these devices, but it is still a good read without it.
Thanks for the link NightHiker. Haven't looked at it yet but perhaps the PDF will answer questions and fill in details left over from the book.
Hint to writers: If a story includes equipment or terrain as a central character be sure to include enough visual aids or detailed descriptions to make it all clear to the reader. It is old-hat to you but you can't assume any prior knowledge from the reader. Who may be reading the story a decade after the fact and half a world away.
OT:
For those who may be buying filter masks:
"I wish I had one with an exhaust valve to keep things cooler."
Amen to that. Even when it's cool the exhaust valve makes the mask a whole lot more comfortable and less tiring to wear. Your not re-breathing your own exhaust as much. There are some people who simply can't wear a filter mask because it brings up feelings of smothering. Some of these people can tolerate a mask with an exhaust valve because it feels more natural.
And, as you point out, when it gets hot and humid an exhaust valve is the only way to go. Big difference.
I didn't wish to hijack the thread but something to keep in mind when you buy filter masks. My advice is: spend the extra money. If and when you need to wear one you will consider that money well spent. Trust me on this one. Better yet, try one yourself. Wear one while exercising, as you may need to in a survival situation, and odds are the next ones you buy will have exhaust valves.
