American Society of Mechanical Engineers (ASME) Practice Exam 2025 - Free ASME Practice Questions and Study Guide

In boiler operation, particularly at pressures of 100 psig or greater, safety and effective management of water quality are paramount. The requirement for blowdown valves is guided by the need for both operational efficiency and safety measures in the event of a malfunction or operational issue.

Having two blowdown valves in such applications serves specific purposes: one valve is typically used for regular blowdown, which is important for controlling the concentration of impurities in the boiler water, thus ensuring that the boiler operates efficiently and safely over time. The second valve serves as a backup, providing assurance that the system can still be drained in an emergency or during maintenance, even if the primary valve is stuck or malfunctioning.

This redundancy enhances safety, as it ensures that the boiler can be effectively managed under various conditions, which is critical in high-pressure systems where the risks associated with failure can be significant.

While a single valve may sometimes be deemed sufficient in lower pressure systems, the increased risks associated with higher pressures necessitate a more robust setup, highlighting the importance of two blowdown valves in boilers operating at 100 psig or greater.