Gary Nelson at the Dry Climate Forum 2014 presenting TEC's Ring 4 for the Duct Blaster. Someone has cleverly named this photo Ductilupigus after Gary demonstrated how to inspect the flex duct before use.
Combustion Appliance Zone Testing (CAZ) Made Easy (March 24, 2016)
-Adapting to the new BPI standard
-RESNET testing requirements
-NFPA testing requirements
-Best practices for best results