Specifications - City of Montpelier, Vermont

Title:Montpelier District HeatingCity of Montpelier, VT15891 – Metal Ductwork & AccessoriesIssue Date:September 28, 2012Page #:14 of 192.12 FLEXIBLE DUCTWORKA. General: Flexible ductwork may be used to provide minor alignment of branchducts with diffusers and grilles.B. Construction: Inner liner shall be a trilaminate of aluminum foil, fiberglass, andaluminized polyester reinforced with a mechanically attached galvanized steelhelix. The outer facing shall be a polyethylene material. A 1" thick fiberglassinsulation shall be factory installed between the liner and the outer facing. Theentire assembly shall conform to NFPA 90A, be constructed in accordance withUL 181, Class 1 Air Duct, and have a vapor barrier permeance of less than 1when tested in accordance with ASTM E96, Procedure A. Operating pressureshall be 12" w.g positive, 10" w.g. negative on sizes ≤12"∅, 12" w.g positive, 5"w.g. negative on sizes 14" & 16".C. Manufacturers: Provide flexible ductwork from one of the following:1. Buckley Associates – Flexmaster type 22. ACCOPART 3EXECUTION3.1 GENERALA. Inspection: Examine areas and conditions under which metal ductwork, air inletsand outlets and accessories are to be installed. Do not proceed with work untilunsatisfactory conditions have been corrected in manner acceptable to Installer.B. Coordination: It is the responsibility of the sheet metal contractor to coordinatethe work of his trade with all other trades prior to the commencement ofconstruction. Any conflicts must be brought to the attention of theArchitect/Engineer. Any work requiring removal and reinstallation due to thelack of coordination shall be the responsibility of the Contractors with noadditional cost to the Owner.C. Offsets: The HVAC duct drawings are schematic in nature and do not indicate allfittings. It is the responsibility of the Contractor to provide all necessary offsets,fittings, and transformations to provide a complete project at no additional cost tothe Owner.3.2 INSTALLATION OF METAL DUCTWORKMETAL DUCTWORK AND ACCESSORIES 15891 14