The __________ is a device that measures the volume of gas entering a building.

The device that measures the volume of gas entering a building is called a gas meter. It is specifically designed to keep track of the amount of gas being consumed by the building, typically measured in cubic feet or cubic meters. Gas meters are crucial for utility companies to bill customers accurately based on their gas usage.

In contrast, a pressure gauge measures the pressure of the gas within the system, not its volume. A flow sensor can measure the flow rate of gas or liquids and could provide information about how quickly the gas is moving, but it does not measure total volume consumed over time like a gas meter does. A vacuum meter measures the vacuum pressure in systems, which is not related to the measurement of gas entering a building. Thus, the gas meter is the appropriate choice for tracking gas volume specifically.