What is the maximum pressure at which cast iron fittings can be used to carry steam?

Cast iron fittings are known for their strength and durability, but they have specific limitations when it comes to pressure applications, especially with steam systems. The maximum allowable working pressure for cast iron fittings used to carry steam is typically recognized to be up to 250 pounds per square inch gauge (psig).

This standard is set to ensure safety and reliability, as pressures above this threshold can compromise the integrity of the cast iron material. The reason that 250 psig is the upper limit is due to the inherent brittleness of cast iron, which can lead to failures under excessive stress or exposure to high temperatures commonly associated with steam systems.

Using cast iron fittings in applications that exceed this pressure threshold increases the risk of failure, which can lead to dangerous situations, including leaks or ruptures that could result in steam burns or property damage. Thus, the specification of 250 psig is crucial for maintaining safe operational conditions in steam piping systems utilizing cast iron fittings.