14E-6-640 Audio signal processing, amplification, and reproduction equipment.
The provisions of Article 640 of NFPA 70 are adopted by reference with the following modifications.
1.   Revise subsection 640.3(B) to read, with no exceptions or notes:
"Ducts, Plenums, and Other Air-Handling Spaces. Section 300.22(B) shall apply to circuits and equipment installed in ducts specifically fabricated for environmental air. Section 300.22(C) shall apply to circuits and equipment installed in other spaces used for environmental air (plenums)."
2.   Revise subsection 640.23 to read:
"Conduit or Tubing. The number of conductors permitted in a single conduit or tubing shall not exceed the percentage fill specified in Table 1, Chapter 9."
3.   Revise subsection 640.24 to read:
"Wireways, Gutters, and Auxiliary Gutters. The use of metallic wireways, gutters, and auxiliary gutters shall be permitted for use with audio signal conductors and shall comply with applicable articles with respect to permitted locations, construction, and fill."