§ 2.1. Duct System  

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  • 2.2. When the space under, above, behind or beside duct systems must be regularly cleaned, a clear space of at least six (6) inches for cleaning or maintenance shall be provided.

    2.3. Where materials may accumulate in an approximately horizontal duct and thereby reduce the system's efficiency significantly below design requirements, access openings for cleaning shall be provided therein at least every ten (10) feet in ducts smaller than one hundred and ninety (190) square inches in cross sectional area and at least every twenty (20) feet in larger ducts.

    2.4. Cleanout openings shall be at least as large as the duct they serve or one hundred and ninety (190) square inches, whichever is the smaller.

    2.5. Cleanout openings in the duct or fan shall provide ready access to the fan housing and blade.

    2.6. Suitable shut-off devices or caps shall be installed on all openings to the system which are not intended and used for ventilation and such openings shall be kept closed except when in actual use for access or maintenance.