Cold outside temperatures not only freeze lakes, streams and fingers, they affect propane tanks. Propane or liquefied petroleum gas commonly provides the fuel for a backyard barbecue grill or house furnace. Metal cylinders or tanks store this fuel source that originates from the refining of natural gas and crude oil. The storage container uses pressure to keep propane in a liquid form. Propane appliances might not function correctly if the outside temperature surrounding a propane tank becomes too cold.
Similarities Between Propane and Water
Liquid propane and water act similarly when temperature drops, but their boiling points differ. At sea level, propane begins to boil at a temperature of -44 degrees Fahrenheit and produces propane vapor, while water boils at 212 degrees F and produces water vapor. As the temperature drops below 212 degrees F, water stays in liquid form, it doesn't change to a vapor. Similarly, as the temperature outside the propane tank drops and approaches -44 degrees F, less propane boils inside the storage tank producing less vapor and a lower pressure.
As the pressure inside the propane tank drops, it eventually becomes too low to light a furnace or other appliance. At -44 degrees F or lower, propane stays as a liquid, there is little vapor and propane appliances won't function properly. Therefore, for appliances to work correctly, a propane tank must usually be kept in an area with a temperature greater than -44 degrees F.
In climates where the temperature may drop to well below 0, small, insulated frame shelters house propane tanks. Applying a heat tape specifically designed for propane tanks may keep the tank above -44 degrees. Sometimes propane tanks are buried to protect them from cold temperatures.
Cold Weather and Propane Delivery
Many propane tanks contain a tank gauge to show the percentage of propane in the tank. During propane deliveries in cold weather, the gauge may show less propane delivered based on the beginning and ending gauge readings than is actually delivered. However, the meters used to measure the amount of propane delivered include a volume correction device that takes into account cold temperatures. Therefore, an accurate measurement is possible in cold as well as warm temperatures.
Other Cold Weather Problems
When heavy snow and ice accompany cold temperatures, additional precautions become necessary. Ice and snow must be cleared from the propane tank regulators, vents, piping and valves to prevent damage that could cause a gas leak. Ice and snow must also be removed from any appliance vents, flues and chimneys to allow the gas to vent properly. To find the tank in heavy snow, a flag, pole or stake next to the tank shows the location. Propane is flammable when mixed with oxygen. Be sure to turn off the main gas supply if an appliance fails to light or if a gas leak is detected.