Red Seal Gasfitter — Class A Practice Exam

What is the safe working pressure range for residential gas appliances?

1. 1 to 3 inches water column

2. 3.5 to 10 inches water column

3. 10 to 15 inches water column

4. 15 to 20 inches water column

The correct answer is: 3.5 to 10 inches water column

The safe working pressure range for residential gas appliances typically falls between 3.5 to 10 inches water column. This range is appropriate because it suits the operational requirements of most household gas appliances, ensuring they operate efficiently and safely. Gas appliances, such as furnaces, water heaters, and stoves, are designed to function within this pressure zone, allowing for reliable ignition and consistent performance. On the lower end, 3.5 inches water column is adequate for many types of gas appliances, particularly those that require lower gas flow rates. The upper limit of 10 inches water column ensures that the appliances receive enough gas to function correctly without risking overpressure conditions that could lead to safety hazards. Appliances exceeding this pressure range could potentially malfunction or create unsafe situations, such as gas leaks or combustion issues. Thus, maintaining the pressure within 3.5 to 10 inches water column is crucial for both performance and safety in residential settings.