1 The freezer time shown is for best quality only â foods kept constantly frozen at 0Â° F will keep safe indefinitely.  How long does baked ham last at room temperature? Bacteria grow rapidly at temperatures between 40 Â°F and 140 Â°F; baked ham should be discarded if left for more than 2 hours at room temperature.
Using this to calculate theoretical water-chilling capacity: 1 ton of refrigeration (12,000 BTUs per hour) will chill. 12,000 lbs. water/fish 1Â°F in 1 hour. Theoretically, then, a sample application to chill seawater and fish: 40 tons refrigeration (480,000 BTUs per hour) will chill. 120,000 lbs. water/fish 20Â°F in 5 hours.
You need to establish the correct number of BTUs per square foot for your house needed to either heat or cool it. The methods differ for heating and cooling and are described below. Many furnaces and air conditioners will be labeled BTU, but this is actually shorthand for BTU per hour (BTU/h). At a bare minimum, you can use a figure of 20 BTUs per hour per square foot and multiply this by the total square footage to be heated or cooled, but this does not take into account climate, the amount of insulation you have, or the way you live.