The Four Install Techniques for 3M Fire Barrier Duct Wrap 615+

There are four different grease duct installation techniques that are approved for 3M Fire Barrier Duct Wrap 615+.  The technique we see used most commonly is the Butt Joint on the first layer and Telescoping overlap on the second layer.  This blog post will show you how to properly install 3M Fire Barrier Duct Wrap with all four approved methods.

2A. Butt Joint Inner Layer with Telescoping Outer Layer 

With the Butt-Joint Inner Layer and Telescoping Outer Layer technique, the inner layer of blankets abut the adjacent pieces of blanket. The outer layer blankets each overlap one adjacent blanket, and then the exposed edge is covered by the next blanket as shown in Figure 2A. 

• 1a.  First layer of 3M™ Fire Barrier Duct Wrap 615+
• 1b.  Second layer of 3M™ Fire Barrier Duct Wrap 615+ 
• 2.    Steel banding 1/2"wide
• 3.    3" min. longitudinal overlap 
• 4.    Tightly butted joint

2B. Telescoping 3" Overlap Wrap

With the Telescoping Overlap Wrap method, each blanket overlaps one adjacent blanket, and each blanket has one
edge exposed and one edge covered by the next blanket as shown in Figure 2B.

• 1a.  First layer of 3M™ Fire Barrier Duct Wrap 615+
• 1b.  Second layer of 3M™ Fire Barrier Duct Wrap 615+
• 2.    Steel banding 1/2" wide
• 3.    3" min. longitudinal overlap

2C. Checkerboard 3" Overlap Wrap

With the 3" Checkerboard Overlap Wrap method, blankets with both edges exposed alternate with blankets with covered edges, as shown in Figure 2C.

• 1a.  First layer of 3M™ Fire Barrier Duct Wrap 615+
• 1b.  Second layer of 3M™ Fire Barrier Duct Wrap 615+
• 2.    Steel banding 1/2" wide
• 3.    3" min. longitudinal overlap

2D. Butt Joint with Collar

With the Butt Joint and Collar method, adjacent blankets are butted tightly together and 6" wide collar of duct wrap is centered over the joint, overlapping each blanket by 3" minimum as shown in Figure 2D. 

• 1a.  First layer of 3M™ Fire Barrier Duct Wrap 615+ 
• 1b.  Second layer of 3M™ Fire Barrier Duct Wrap 615+ 
• 2.    Steel banding 1/2" wide
• 3.    6" min. wide 3M™ Fire Barrier Duct Wrap 615+ Collar 
• 4.    Tightly butted joint

For securing the first layer if duct wrap, steel straps are not required as the steel straps on the second layer will secure both layers to the duct.  For the first layer, we recommend Reinforced Glass Filament Tape.