New York Low Pressure Boiler COF Practice

If a gauge reads 175 psi and it is 45 feet below the boiler, what is the true reading?

1. 155.5 psi

2. 175.0 psi

3. 195.0 psi

4. 210.0 psi

The correct answer is: 155.5 psi

To determine the true pressure reading in a system where a gauge reads 175 psi and is located 45 feet below the boiler, it's important to consider the relationship between pressure, elevation, and the weight of the water column above the gauge. The pressure reading on the gauge indicates the pressure relative to the atmospheric pressure at the location of the gauge. As you go deeper in a fluid, the pressure increases due to the weight of the fluid above. Specifically, the pressure increase due to the water column can be calculated using the following relationship: For every foot of vertical depth in water, the pressure increases by approximately 0.433 psi. Therefore, to find the additional pressure created by a 45-foot water column, you would multiply the height by this value: 45 feet * 0.433 psi/foot = 19.485 psi. Since the gauge is reading a pressure of 175 psi, and there is additional pressure from the water column, the true pressure at the boiler level is actually higher than what the gauge indicates. You would add the pressure due to the water column to the gauge reading: 175 psi + 19.485 psi ≈ 194.485 psi. When rounding this value for practical purposes, it can be approxim