Final answer:
The standard propane gas building line pressure for a single-family residence is typically around 11 inches of water column. Pressure gauges can measure the propane tank pressure, which can fluctuate with temperature according to Gay-Lussac's Law.
Step-by-step explanation:
Normal propane gas building line pressure for a single-family residence is generally around 11 inches of water column (approximately 27.4 millibars or 0.4 psi). This pressure is sufficient to operate household appliances such as a furnace, water heater, and stove. However, during certain applications like with propane tanks used for barbecue grills, pressure gauges are necessary to measure the pressure inside the tank, which varies depending on the temperature due to Gay-Lussac's Law. Hot days will show higher pressure readings than colder days, making it essential to consider air temperature when determining how much propane is left.