New York Low Pressure Boiler COF Practice

When does a boiler require two bottom blow downs?

1. When the MAWP exceeds 50 psi

2. When the MAWP exceeds 75 psi

3. When the MAWP exceeds 100 psi

4. When the MAWP exceeds 150 psi

The correct answer is: When the MAWP exceeds 100 psi

The requirement for two bottom blowdowns in a boiler is tied to its Maximum Allowable Working Pressure (MAWP). When the MAWP exceeds 100 psi, regulations dictate that a boiler must be equipped with two bottom blowdown valves. This is because higher pressure boilers accumulate more sediment and sludge in the bottom, which can negatively affect the performance and safety of the system. The dual blowdowns facilitate better maintenance by ensuring that operators can effectively remove accumulated impurities and prevent potential malfunctions or hazards. Lower pressure boilers, such as those with an MAWP of 50 psi or 75 psi, typically do not require this additional blowdown capability because the conditions and risks associated with sediment buildup are less severe. Additionally, once the pressure exceeds 150 psi, special considerations might apply, but the specific requirement for two blowdowns is established at the 100 psi threshold. This regulation helps ensure the safe and efficient operation of high-pressure steam systems.