How many safety valves are required for a high pressure boiler with over 500 square feet of water heating surface?

For a high-pressure boiler that has over 500 square feet of water heating surface, the regulations require at least two safety valves. This requirement is in place to ensure that if one safety valve were to fail or become inoperable, the second valve could still function and provide protection against overpressure conditions. Safety valves are critical components of boiler systems, as they help prevent the potential hazards associated with excessive pressure, which can lead to catastrophic failures.

Having two safety valves is a standard safety measure that enhances the reliability of the boiler system's ability to relieve pressure. This redundancy is essential for maintaining safe operations in high-pressure environments, where the risks are significantly elevated due to the potential for explosive releases of steam and water if the pressure exceeds safe limits. Therefore, the requirement of at least two safety valves for a high-pressure boiler is aligned with the best practices in boiler safety and regulatory standards.