SECTION M1601  DUCT CONSTRUCTION
Pursuant to the UCC, delete Exception #3 of Section M1601.4.1, and replace as follows:
   R-M1601.4.1 Joints, seams and connections.
   Exceptions:
      3.   For ducts having a static pressure classification of less than 2 inches of water column (500 Pa), additional closure systems shall not be required for continuously welded joints and seams and locking-type joints and seams. This exception shall not apply to snap-lock and button-lock type joints and seams that are located outside of conditioned spaces.