When testing for gas leaks, what substance is commonly used?

When testing for gas leaks, a soap and water solution is commonly used because it effectively identifies escaping gas. When this solution is applied to joints, fittings, or connections in the gas line, any escaping gas will create bubbles as it escapes. This bubbling action provides a visual indication of a leak, allowing the technician to easily locate and address the issue before it leads to more serious safety concerns.

Using water alone may not provide the same clear indication of gas presence, as it would not bubble in response to the gas. Pure alcohol and powder-based solutions do not have the properties that would visually highlight a gas leak and are not standard practice in leak detection testing. Therefore, the soap and water solution is the most reliable and widely accepted method for identifying gas leaks in HVAC applications.