What type of piping is prohibited from using cast iron fittings?

Cast iron fittings have specific applications and limitations in piping systems due to their material properties and vulnerability to certain types of substances. In the context of oil piping systems, the use of cast iron fittings is prohibited primarily because oil can lead to corrosion and degradation of cast iron over time. Additionally, oil can cause the fittings to fail, which can result in leaks and safety hazards.

On the other hand, water, gas, and steam systems can commonly utilize cast iron fittings, as these substances do not typically react adversely with cast iron in the same way that oil does. Understanding the compatibility of materials with the substances being transported is a crucial aspect of maintaining safe and efficient piping systems in HVAC applications. This knowledge helps ensure long-term reliability and reduces the risk of equipment failure or environmental issues.