Where must the bottom of the gage glass be positioned on a water tube boiler?

The correct positioning for the bottom of the gage glass on a water tube boiler is set at a specific height related to the Low Safety Water Level (LSWL). Specifically, the bottom of the gage glass must be situated 2 inches above the LSWL. This standard ensures that the water level indicated by the gage glass is always above the safety threshold, preventing the danger associated with operating the boiler when the water level is too low, which could lead to overheating and potential damage to the boiler components.

Positioning the gage glass in this manner provides an important safety margin to ensure that operators can confidently monitor the water level without the risk of exposing the boiler’s heating surfaces, which could occur if the water level were to drop below the LSWL. This practice aligns with both safety norms and operational guidelines found in various boiler codes and standards, reinforcing the importance of maintaining a safe working environment in industrial settings.