New York Low Pressure Boiler COF Practice 2025 - Free Practice Questions and Study Guide

The recommended size for the outlet of the blowoff tank is indeed two times the diameter of the blowdown piping. This sizing guideline ensures that the discharge from the blowoff tank can adequately handle the flow rate generated during blowdown operations without causing excessive backpressure that could lead to operational issues.

Having an outlet that is two times the diameter of the blowdown piping allows for a sufficient escape for the water and sediment being purged from the system, reducing the risk of erosion or turbulence that could compromise the integrity of the tank and piping system. This sizing helps maintain efficient operation while adhering to safety and engineering standards.

Options suggesting larger outlet sizes, such as three, four, or five times the diameter, would unnecessarily increase the space requirements for the tank and might not offer any added benefits in terms of performance for the typical conditions found in low-pressure boiler operation. Thus, adhering to the guideline of two times ensures a balance between efficiency, safety, and practicality.