Pressure gauge connections are required to be made of non-ferrous material when the connection size is less than what dimension?

Pressure gauge connections need to be made of non-ferrous materials when the connection size is less than 1 inch to prevent corrosion and ensure the integrity of the gauge system. Non-ferrous materials, such as brass or bronze, resist oxidation and corrosion, which is particularly important in environments where moisture or chemicals may be present.

Using non-ferrous materials for smaller connections helps to maintain accurate pressure readings over time, as ferrous materials can corrode and alter the connection's integrity, potentially leading to leaks or incorrect readings.

In this context, the size threshold of 1 inch is significant because it reflects industry standards designed to promote safety and reliability in pressure gauge installations. Larger connections can often tolerate ferrous materials since they may not be as susceptible to the degradation factors affecting smaller connections.