Yesterday, I began using a propane torch (which I won in a raffle; Yay!) for browning the tops of foods. My quandary is: where do I store the torch? The instructions say not to store it in your living space, and not to store it in a place which will get overly hot. That rules out the cabinet under the sink, and the backyard shed. I don't have a garage. 
Most recommendations about storing propane tanks outside are assuming you're storing quite a large amount of it (eg, 20lb tanks for a grill).  Odds are a hand-torch has a 1-lb tank or smaller, which isn't quite as much of a problem, as be less likely to reach the concentrations to be explosive.  (that's not to say it wouldn't be flamible ... just not explosive without the proper fuel-air ratio).  I still wouldn't store it inside, as should there be a leak in the tank, many homes have ignition sources such as pilot lights, and LP will travel into basements, being denser than air.  If your shed isn't air tight (especially if there's a poor seal well along the bottom of the door), and it doesn't get too hot in the summer time, it should be okay in there.  Personally, I keep my propane tanks under a table on my deck, so they've got lots of airflow, but they're out of direct sun and weather.  update : another word of caution : always store the canister so the relief valve is up.  This typically means don't store it on its side unless you can prevent it from rolling.  If you don't, and it gets warm, it will release propane (and then possible sieze up and then burst if it gets hot) 