603.10 Joints and Seams of Ducts
Joints and seams and reinforcements for factory-made air ducts and plenums shall comply with the conditions of prior approval in accordance with the installation instructions that shall accompany the product. Closure systems for sealing factory made air ducts and plenums shall be listed and labeled in accordance with UL 181A or UL 181B, and marked in accordance with Table 603.10.
TABLE 603.10 CLOSURE MARKINGS
|TYPE OF DUCTWORK||STANDARD||TYPE OF CLOSURE SYSTEM||MARKING|
|Rigid Metallic or Rigid Fiberglass||UL 181A||Pressure Sensitive Tape||181A-P|
|Rigid Metallic or Rigid Fiberglass||UL 181A||Mastic Tape||181A-M|
|Rigid Metallic or Rigid Fiberglass||UL 181A||Heat Sensitive Tape||181A—H|
|Flexible Air Ducts||UL 181B||Pressure Sensitive Tape*||181B-FX*|
|Flexible Air Ducts||UL 181B||Mastic*||181B-M*|
* Mechanical fasteners shall be used in conjunction with a listed pressure sensitive tape or mastic in accordance with UL 181. Nonmetallic mechanical fasteners shall be listed and labeled in accordance with UL 181B and labeled "181B-C".
Lmax = CLP0.65
|Lmax||=||maximum permitted leakage, (ft3/min)/100 square feet [0.0001 (m3/s)/m2] duct surface area.|
|CL||=||six, duct leakage class, (ft3/min)/100 square feet [0.0001 (m3/s)/m2] duct surface area at 1 inch water column (0.2 kPa).|
|P||=||test pressure, which shall be equal to the design duct pressure class rating, inch water column (kPa).|