RA3.1.4.3.5 - Sealing of All Accessible Leaks duct leakage verification protocol requires RA3.1.4.3.6 – Smoke Test of Accessible Duct Sealing to demonstrate that all accessible leaks have been sealed. By injecting theatrical fog into a duct system the HERS Rater confirms that smoke does not emanate from any accessible portion of the duct system. If smoke exits from any >accessible> portion of the system then the test fails. See definition of >accessible> under Work Scope Definitions.

Essentially, if the ducts can be accessed without causing damage to finish work in the dwelling and/or without putting the Installer at serious risk of physical harm then the ducts are considered accessible. Ducts located in an attic or crawlspaces are generally considered accessible because code requires access to those spaces. Access is usually gained by opening a door, hatch, or other moveable panel. If this can be done without causing damage that would need to be repaired, this is considered accessible. Somewhat counter intuitive is that ducts buried under insulation in an attic may be considered inaccessible. Essentially the benefit of pulling the ducts out of the insulation to reduce duct leakage is outweighed by the benefit of leaving them buried to reduce losses due to conduction of heat. Some judgment is required in determining if ducts are accessible or not. The local code enforcement agency will have the final say when it is not obvious. For example:

1. If a leak in the duct system is in too small a space between framing members for an average size person to be able to reach the joint to seal it, then this is probably not considered accessible;
2. If ducts are suspended far above the ground and reaching them would require scaffolding or special equipment other than normal ladders, then these are probably not considered accessible;
3. If a smoke test indicates multiple small leaks in ducts that are buried under insulation, and gaining access to those leaks would require substantially disturbing the insulation this is probably not considered accessible;
4. If sheet metal ducts are wrapped with insulation and a smoke test indicates multiple small leaks along the lengthwise seams in the ducts, it is probably not cost effective to remove the insulation to find and seal these leaks.

Note: for ducts buried under insulation or sheet metal ducts wrapped with insulation, if one or more locations shows a very obvious and substantial leak or disconnect, that location should be sealed.