Which type of safety valve body is prohibited for installation in high temperature water boilers?

Cast iron safety valve bodies are prohibited for installation in high-temperature water boilers due to their brittleness and potential failure under extreme thermal stress. Cast iron, while strong and durable in many applications, has a lower tolerance for high-temperature environments when compared to other materials. When exposed to heat, cast iron can become frail, leading to cracks or breaks that could compromise the safety of the system.

In contrast, materials like steel and brass are more resilient and can withstand the high temperatures common in boiler systems without the same risks. Plastic is generally not used in high-temperature applications due to its susceptibility to deformation and degradation under heat. Therefore, selecting a safety valve body made from appropriate materials ensures the reliability and safety of high-temperature water boilers.