Texas CNG(Compressed Natural Gas) Driver Practice

Can cast iron shutoff valves be used in CNG systems?

1. Yes, all types of cast iron valves can be used

2. No, with specific exceptions

3. Only if they are ANSI certified

4. Yes, but only with a special coating

The correct answer is: No, with specific exceptions

The use of cast iron shutoff valves in CNG systems is primarily governed by safety standards and material compatibility with natural gas. CNG systems require components that can withstand high pressures and are resistant to corrosion. Cast iron, while durable, is not recommended for use in all contexts within CNG systems due to potential issues such as brittleness and the risk of failure under high-stress conditions. However, there are specific exceptions where cast iron could be utilized safely, such as in low-pressure applications or in specific configurations where the manufacturer provides guidance that complies with industry standards. This distinction underscores the importance of adhering to regulatory guidelines and manufacturer recommendations to ensure safety and reliability in CNG operations. Understanding the limitations and suitable applications for cast iron valves is critical for ensuring the integrity of the CNG system.