What is the maximum natural gas or propane gas pressure allowed inside a one- or two-family dwelling?

The maximum gas pressure allowed inside a one- or two-family dwelling is 11 inches of water column (WC). This pressure is specified for safety and operational efficiency, ensuring that appliances function correctly without the risk of leaks or operational hazards associated with excessive pressure.

In typical residential applications, lower pressures facilitate proper combustion in appliances such as furnaces, water heaters, and stoves. The use of 11" WC strikes a balance between providing sufficient gas flow for appliances and maintaining safety standards to prevent issues like backdrafting or increased risk of gas leaks.

Understanding the importance of maintaining appropriate pressure levels is crucial for any gas technician, as exceeding these limits could lead to adverse effects on appliance performance and safety. Therefore, 11" WC is recognized as the standard maximum for residential settings involving natural or propane gas.