Gas Fitter Practice Test

A one cubic foot test dial on a natural gas meter makes one revolution every 22 seconds. Approximately how many Btuh are being generated?

1. 164 MBtuh

2. 41 MBtuh

3. 75 MBtuh

4. 82 MBtuh

The correct answer is: 41 MBtuh

To determine the correct answer, we start by calculating the flow rate of gas in cubic feet per hour (CFH). Since the meter makes one revolution every 22 seconds, we can convert this to an hourly rate. There are 3600 seconds in an hour, so the number of revolutions in an hour can be calculated by dividing 3600 seconds by 22 seconds per revolution: 3600 seconds / 22 seconds per revolution ≈ 163.64 revolutions per hour. This means that approximately 163.64 cubic feet of gas flow through the meter each hour. Next, we need to convert cubic feet per hour into British thermal units per hour (Btuh). The conversion factor is that one cubic foot of natural gas generates approximately 1,000 Btus when burned. By multiplying the flow rate in cubic feet per hour by 1,000 Btus per cubic foot, we find: 163.64 CFH × 1,000 Btuh/CF ≈ 163,640 Btuh. To express this in MBtuh (which is Mega British thermal units per hour), we divide by 1,000,000: 163,640 Btuh ÷ 1,000,000 ≈