Uncooked rice often contains the bacteria Bacillus cereus. These bacteria can form protective spores that survive the cooking process and if the rice is cooled slowly (and left between 5 Â°C and 60 Â°C for a long time), these bacteria spores can germinate, grow and produce a toxin (poison) that causes vomiting.
Obviously the colder a climate is, the more a furnace is required to run, and the shorter its life expectancy. With our relatively mild climate here in Seattle and the rest of the Puget Sound, the average life expectancy for a gas furnace is 15 to 20 years if well maintained, properly installed, and properly sized.
Older furnaces that were made with heavy metal heat exchangers, like cast iron, have been known to last 30 to 40 years, but they're also known for being energy drainers. Forced air furnace heat exchangers have an average life expectancy of 15 years, with a range typically between 13 and 20 years. Most heat exchangers used in models today today will last between 15 and 25 years and are usually made from aluminized or stainless steel. It's inevitable that the constant heating and cooling of a heat exchanger's metal will eventually cause it to crack, become corroded or otherwise fail.