What is propane?
Residential propane use
Propane is a liquefied petroleum gas also called LPG, GPL, LP gas or autogas. Propane is a byproduct of natural gas processing and crude oil refining. As you can see in the picture below, is often used as a source of energy for indoor heating (4), water heating (3), refrigeration (10), cooking (9), fireplaces (5), clothes drying (2), outdoor grills (6), outdoor lighting (1), or heating for pools (8) and spas (7).Some also use autogas as a source of fuel for cars (11). It is particularly practical in areas that are not connected to a natural gas supply. Propane is an alternative source of energy to electricity or fuel.
Propane is delivered in bulk and stored in a large tank outside your home. Depending on your preference, the tank can be aboveground or underground. It is convenient because these tanks require little maintenance and they last up to 40 years. Alternatively, if you do not need much propane (for example, if you only use it for barbecues), you can get smaller cylinders and refill them at your closest filling station when you need to. Using propane means you are not dependent on direct electricity or gas supply since your energy is on your property.
An underground tank, an aboverground tank and a propane grill
Propane is colorless, almost odorless and is not toxic. People choose propane because it is portable (easily transported, stored and used), clean (fewer greenhouse gas emissions than other fossil fuels), accessible (no infrastructure investment is necessary to use it), efficient (so cost-effective) and convenient (as seen above, it can be used for various purposes). There are hundreds of propane retailers in the United States and all the main dealers offer various options to make sure you do not run out of propane and find the arrangement that best suits your situation.
Propane usage regulation
For safety reasons (because it is highly flammable), the use of propane is highly regulated both at federal and state level. For example, there are mandatory distances between a propane tank and a propane appliance or a house. Propane companies use highly skilled staff and sophisticated material to transport propane to users. Such precautions mean that there are very few accidents related to propane.
Technically, propane is a three-carbon alkane (C3H8). Once crude oil and natural gas is refined and propane extracted it is stored in liquid form. When it is used it becomes a gas.
The propane circuit and how it gets to residential homes
Propane liquid and propane vapor
To begin with propane exists both in liquid and vapor forms. Both can be used to generate energy but they do not use the same systems. This means that propane vapor cannot be used in a system designed for propane liquid, for example. Indeed, the primary properties of propane liquid and propane vapor are very different: propane liquid depends on temperature whereas propane vapor depends on weight.
Propane is a liquid if it is below -44°F (boiling point) or if it is stored under pressure. Given its low temperature when it is a liquid it can be harmful to the human body. Above this boiling point, propane becomes a vapor and, just like water, it gives off steam when it boils. Because propane vapor is heavier than air, if there is a leak it will sink, collect as more propane leaks and can ignite if the right mix of air and vapor is reached. This is why indoor propane leaks can be dangerous and why propane (like any gas) needs to be monitored.