According to ASME high-pressure boiler code, how many square feet of heating surface requires the installation of two or more safety valves?

The requirement for the installation of two or more safety valves according to the ASME high-pressure boiler code is triggered when the boiler has a certain amount of heating surface area. When the heating surface exceeds 500 square feet, it is necessary to have multiple safety valves. This is to ensure adequate safety measures are in place for pressure relief in larger installations, where single safety valves may not provide sufficient pressure regulation or redundancy.

In high-pressure systems, having more than one safety valve improves overall safety, as it reduces the risk of valve failure during operation. Ensuring that there is a reliable means to vent excess pressure is critical in maintaining safe boiler operation, especially as the heating surface area increases. This requirement reflects the general engineering principle of providing additional safety features in systems that operate under higher pressures and capacities.