What is the flame failure response time for HSI systems rated 400 MBH or less?

The flame failure response time for Hot Surface Ignition (HSI) systems rated 400 MBH or less is established to be 90 seconds. This duration is critical as it ensures the safety and reliability of gas-fired appliances by allowing enough time for the system to identify whether the flame has been successfully established. If the flame does not ignite within this designated time frame, the system will automatically shut off the gas supply to prevent the risk of unburned gas accumulating in the combustion chamber, which could lead to hazardous situations such as explosions or gas leaks.

Understanding the importance of this safety standard is crucial for maintaining compliance with building codes and ensuring safe operation of heating systems. The specified response time is a regulatory requirement designed to protect both the appliance and the inhabitants of the space it serves.