Which two methods can be used to determine the water level inside a steam boiler?

The two methods that can be effectively used to determine the water level inside a steam boiler are indeed the water column and the gauge glass. The water column is a vertical tube that provides a visual representation of the water level inside the boiler, while the gauge glass is a transparent tube that also shows the water level directly. This combination allows for clear observation and monitoring of the water level, which is crucial for safe boiler operation.

Using a gauge glass is particularly valuable because it provides a direct and easy-to-read measurement, allowing operators to assess the water level quickly. The water column, on the other hand, offers a more detailed indication of the water level, particularly in high-pressure boilers where pressure can affect readings. Together, these methods ensure that the operator has reliable information to prevent dangerous situations that can arise from low or high water levels in the steam boiler.

The other options, while they may touch on safety features (like alarms or automatic shutdowns), do not serve as primary methods to directly determine the actual water level in the system. Alarms and automatic shutdowns are crucial for safety, but they are secondary mechanisms that rely on measurements taken by methods like gauge glasses or water columns, rather than directly indicating water levels.