Thermally operated dampers are designed to do what if the bimetal fails?

Thermally operated dampers are designed to fail open in the event that the bimetal fails. This design is particularly important for safety reasons, especially in systems involving combustible gases or materials. When the bimetal, which is responsible for controlling the position of the damper in response to temperature changes, fails, allowing the damper to remain open ensures that there is an unobstructed airflow, preventing the build-up of harmful gases.

This characteristic plays a critical role in maintaining air quality and safety within HVAC systems. By allowing air to flow freely, it helps reduce the risk of dangerous situations that could arise if the damper were to fail closed, restricting airflow and possibly leading to hazardous conditions.

In contrast, other options like failing closed would create an unsafe environment by preventing proper ventilation, while staying in place might not allow for any adaptive response to temperature changes, which could result in inefficiency. Requiring manual intervention compromises the system's reliability, as it demands human action to resolve a potentially critical situation. Thus, failing open is designed to prioritize safety and functionality in case of a failure.