GUIDE SPECIFICATION SECTION 230713-7
Revised 16 February 2016 Duct Insulation
SECTION 230713 - DUCT INSULATION
PART 1 GENERAL
RELATED DOCUMENTS
Drawings and general provisions of Contract, including General and Supplementary Conditions and Division1 Specification sections, apply to work of this section.
QUALITY ASSURANCE
Flame/Smoke Ratings: Provide composite duct insulation (insulation, jackets, coverings, sealers, mastics and adhesives) with flamespread index of 25 or less, and smokedeveloped index of 50 or less, as tested by ASTM E 84 (NFPA 225) method.
Exception: Outdoor HVAC ductwork insulation may have flame spread index of 75 and smoke developed index of 150.
SUBMITTALS
General: Submittals shall demonstrate compliance with technical requirements by reference to each subsection of this specification. Where a submitted item does not comply fully with each and every requirement of the Specifications, the submittal shall clearly indicate such deviations. Identification requirements for non-complying features of items are very specific. See Section 230210 for exact requirements.
Manufacturer's Data: Submit manufacturer's technical product data and installation instructions for each type of mechanical insulation. Submit schedule showing manufacturer's product number, kvalue, thickness, and furnished accessories for each mechanical system requiring insulation.
Samples: Submit, as requested by A-E, manufacturer's sample of each duct insulation type required. Affix label to sample completely describing product.
PART 2 PRODUCTS
INSULATION MATERIALS
Mineral Fiber Insulation: Insulation made up of fibers manufactured of glass, rock, or slag, processed from the molten state, with or without a binder.
Mineral Fiber Board Insulation: ASTM C 612, Type IA or IB, with factory-applied jacket. Insulation density shall be 3.0 pcf or greater and conductivity, k, tested in accordance with ASTM C 518 or C 177 at 75ºF mean temperature shall not exceed 0.25 Btu-in./(hr-sf-ºF).
Mineral Fiber Blanket Insulation: ASTM C 553, Type II, with factory-applied jacket. Insulation density shall be 1.00 pcf and conductivity, k, tested in accordance with ASTM C 518 or C 177 at 75ºF mean temperature shall not exceed 0.27 Btu-in./(hr-sf-ºF). The following insulation materials comply with ASTM C 553, Type II:
Manufacturer / Product ID /Owens Corning / SOFTR Type 100
Knauf / Friendly Feel
Certainteed / WideWrap Type 100
Johns Manville / Microlite XG Type 100
Factory-Applied Jacket for Mineral Fiber Insulation: Jacket and tape shall comply with ASTM C 1136, Type II, as follows:
FSP Jacket: Jacket consisting of aluminum foil, fiberglass-reinforced scrim with polyethylene backing.
FSK Jacket: Jacket consisting of aluminum foil, fiberglass-reinforced scrim with kraft-paper backing.
Jacket Tape: Seams and tears/damage to jacket shall be sealed with foil-face, vapor-retarder type tape matching the factory-applied jacket, with acrylic adhesive, 3" wide, and not less than 6.5 mils thick.
Polyisocyanurate Foam Board Insulation: Rigid board material manufactured from closed cell, polyisocyanurate foam between two aluminum foil facers, complying with ASTM C 1289 Type 1, Class 2, with Grade 2 minimum compressive strength.
//IF REQUIRED, INCLUDE THE FOLLOWING PARAGRAPH, BUT LIMIT THE USE OF DUCT LINER TO ABSOLUTE MINIMUM (TYPICALLY ONLY AT SUPPLY DUCT THRU-WALL PENETRATIONS WHERE EXTERIOR INSULATION CANNOT BE APPLIED).//
DUCT LINER
Duct liner shall be flexible closed cell flexible elastomeric that complies with ASTM C534 for sheeting, with the following physical properties:
Minimum thermal k value of 0.25 BTU - in./hr. - ft² - °F when tested according to ASTM C177 or C518 at 75°F mean temperature.
Water vapor transmission rate of 0.06 perm - inch or less when tested according to ASTM E96 (dry cup method).
Maximum water absorption rate of 0.2% (% by volume), when tested in accordance with ASTM C209.
Manufactured without the use of CFCs, HFCs, or HCFCs and be free of formaldehyde, fibers, and dust.
Meet the requirements of ASTM C411.
Meet the requirements of UL 181 Sections 11.0 and 16.0 for mildew and air erosion.
Minimum NRC of 0.55 when tested to ASTM C423 at a nominal 1” thickness.
Adhesives shall be water-based, low VOC type complying with ASTM C 916.
//TYPICALLY, NO JACKET IS REQUIRED ON DUCTWORK WITHIN MECHANICAL EQUIPMENT ROOMS, PLENUMS, OR OTHER CONCEALED SPACES. THE FOLLOWING SUBSECTION CAN BE DELETED IF NO EXPOSED INSULATED DUCTWORK IS PART OF THE WORK. EDIT TO SELECT JACKETS AS REQUIRED.//
JACKETING MATERIAL
Indoor Ductwork: Insulated indoor ductwork exposed to view in areas other than mechanical rooms shall have field-applied jacket as follows:
Type 1: Woven glass-fiber fabric "canvas" of approximately 8 oz./sq. yd. Cover fabric with one coat of fire retardant coating prior to finish painting.
Type 2: Corrugated aluminum jacket 0.016" thick in accordance with ASTM B209, 3003 alloy, H-14 temper, banded on 8” centers. Where aluminum jacket is installed outdoors, it shall have a 3-mil thick heat bonded polyethylene and kraft-paper moisture barrier.
Type 3: PVC jacket, glossy finish, 20-mil high impact UV-resistant type meeting the requirements of ASTM D 1784, Class 16353-C. Jackets shall have integral colors as required by Section 230553.
Outdoor Ductwork Additional Weather Jacket: Insulation on outdoor ductwork shall be protected by a covering with minimum 20 gauge aluminum complying with ASTM B 209, Alloy 3003, Temper H-14 arranged so that sides are flashed under the top and the bottom is flanged, turned down, and mechanically attached to the sides. All transverse joints shall be made with a minimum ½” standing seam, mechanically closed and caulked watertight with flexible mastic. See Drawings for construction details.
PART 3 EXECUTION
INSULATION APPLICATION
Indoor ductwork shall be insulated as follows:
Ductwork exposed to view in mechanical equipment rooms, etc. shall be insulated with 2” thick mineral fiber board insulation.
Concealed ductwork shall be insulated with 2” thick mineral fiber blanket insulation except 6” wide board insulation at trapeze hangers.
Outdoor ductwork shall be insulated with 3" thick polyisocyanuarate insulation. Mineral fiber insulation shall not be applied to outdoor ductwork.
Insulate the following ductwork and plenums:
Supply air, including back side of air outlets
Return air
Relief air
Outside air
Exhaust air located in unconditioned spaces, including attics, crawl spaces, basements, mechanical rooms, etc.
Exceptions: Do not insulate the following:
Flexible connections at fans or equipment
Factory-insulated flexible ductwork
GENERAL INSTALLATION REQUIREMENTS
Install insulation materials, accessories, and finishes with smooth, straight, and even surfaces; free of voids throughout the length of ducts and fittings.
Install insulation materials, vapor barriers or retarders, jackets, and thicknesses required for each item of duct system as specified in insulation system schedules.
Install accessories compatible with insulation materials and suitable for the service. Install accessories that do not corrode, soften, or otherwise attack insulation or jacket in either wet or dry state.
Install insulation with longitudinal seams at top and bottom of horizontal runs.
Install multiple layers of insulation with longitudinal and end seams staggered.
Keep insulation materials dry during application and finishing.
Install insulation with tight longitudinal seams and end joints. Bond seams and joints with adhesive recommended by insulation material manufacturer.
Install insulation with least number of joints practical.
Where vapor barrier is indicated, seal joints, seams, and penetrations in insulation at hangers, supports, anchors, and other projections with vapor-barrier mastic.
Install insulation continuously through hangers and around anchor attachments. Extend insulation on anchor legs from point of attachment to supported item to point of attachment to structure. Taper and seal ends at attachment to structure with vapor-barrier mastic.
Install insert materials and install insulation to tightly join the insert. Seal insulation to insulation inserts with adhesive or sealing compound recommended by insulation material manufacturer.
Apply adhesives, mastics, and sealants at manufacturer's recommended coverage rate and wet and dry film thicknesses.
Install insulation with factory-applied jackets as follows:
Draw jacket tight and smooth.
Cover circumferential joints with 3-inch-wide strips, of same material as insulation jacket.
Secure strips with adhesive and outward clinching staples along both edges of strip, spaced 4 inches o.c.
Overlap jacket longitudinal seams at least 1-1/2 inches. Clean and dry surface to receive self-sealing lap. Staple laps with outward clinching staples along edge at 2 inches o.c. Tape laps with 3" wide foil tape.
For below ambient services, apply vapor-barrier mastic over staples.
Cover joints and seams with tape, according to insulation material manufacturer's written instructions, to maintain vapor seal. Apply vapor-barrier mastic on seams and joints and at ends adjacent to duct flanges and fittings.
Cut insulation in a manner to avoid compressing insulation more than 75 percent of its nominal thickness.
Finish installation with systems at operating conditions. Repair joint separations and cracking due to thermal movement.
Repair damaged insulation facings by applying same facing material over damaged areas. Extend patches at least 4 inches beyond damaged areas. Adhere, staple, and seal patches similar to butt joints.
INSTALLATION AT PENETRATIONS
Roof Penetrations: Install insulation continuously through roof penetrations.
Seal penetrations with flashing sealant.
For applications requiring only indoor insulation, terminate insulation above roof surface and seal with joint sealant. For applications requiring indoor and outdoor insulation, install insulation for outdoor applications tightly joined to indoor insulation ends. Seal joint with joint sealant.
Extend jacket of outdoor insulation outside roof flashing at least 2 inches below top of roof flashing.
Seal jacket to roof flashing with flashing sealant.
Aboveground Exterior Wall Penetrations: Install insulation continuously through wall penetrations.
Seal penetrations with flashing sealant.
For applications requiring only indoor insulation, terminate insulation inside wall surface and seal with joint sealant. For applications requiring indoor and outdoor insulation, install insulation for outdoor applications tightly joined to indoor insulation ends. Seal joint with joint sealant.
Extend jacket of outdoor insulation outside wall flashing and overlap wall flashing at least 2 inches.
Seal jacket to wall flashing with flashing sealant.
Interior Wall and Partition Penetrations, Not Fire Rated: Install insulation continuously through walls and partitions.
Fire-Rated Wall, Partition, and Floor Penetrations: Terminate insulation at fire damper sleeves for fire-rated wall and partition penetrations. Externally insulate damper sleeves to match adjacent insulation and overlap duct insulation at least 2 inches. Comply with requirements 230210 for firestopping and fire-resistive joint sealers.
INSTALLATION OF MINERAL FIBER INSULATION
Blanket Mineral Fiber Insulation Installation: Secure with adhesive and insulation pins, as follows:
Apply adhesives according to manufacturer's recommended coverage rates per unit area of duct and plenum surfaces.
Apply adhesive to entire circumference of ducts and to all surfaces of fittings and transitions.
Install either capacitor-discharge-weld pins and speed washers or cupped-head, capacitor-discharge-weld pins on sides and bottom of horizontal ducts and sides of vertical ducts. Adhesive secured pins are prohibited. Pins shall be installed as follows:
On duct sides with dimensions 18 inches and smaller, place pins along longitudinal centerline of duct. Space 3 inches maximum from insulation end joints, and 16 inches o.c.
On duct sides with dimensions larger than 18 inches, place pins 16 inches o.c. each way, and 3 inches maximum from insulation joints. Install additional pins to hold insulation tightly against surface at cross bracing.
Pins may be omitted from top surface of horizontal, rectangular ducts and plenums.
Do not overcompress insulation during installation.
Impale insulation over pins and attach speed washers.
Cut excess portion of pins extending beyond speed washers or bend parallel with insulation surface.
Cover exposed pins and washers with 3" long piece of 3" wide foil continuous vapor barrier tape.
For ducts and plenums with surface temperatures below ambient, install a continuous unbroken vapor barrier. Create a facing lap for longitudinal seams and end joints with insulation by removing 2 inches from one edge and one end of insulation segment. Secure laps to adjacent insulation section with 1/2-inch outward-clinching staples, 1 inch o.c. Install vapor barrier consisting of factory- or field-applied jacket, adhesive, vapor-barrier mastic, and sealant at joints, seams, and protrusions.
Repair punctures, tears, and penetrations with tape or mastic to maintain vapor-barrier seal.
Install vapor stops for ductwork and plenums operating below 50 degF at 18-foot intervals. Vapor stops shall consist of vapor-barrier mastic applied in a Z-shaped pattern over insulation face, along butt end of insulation, and over the surface. Cover insulation face and surface to be insulated a width equal to two times the insulation thickness, but not less than 3 inches.
Overlap unfaced blankets a minimum of 2 inches on longitudinal seams and end joints. At end joints, secure with steel bands spaced a maximum of 18 inches o.c.
Install insulation on rectangular duct elbows and transitions with a full insulation section for each surface.
Install insulation on round and flat-oval duct elbows with individually mitered gores cut to fit the elbow.
Insulate duct stiffeners, hangers, and flanges that protrude beyond insulation surface with 6-inch-wide strips of same material used to insulate duct. Secure on alternating sides of stiffener, hanger, and flange with pins spaced 6 inches o.c.
Board Mineral Fiber Insulation Installation: Secure with adhesive and insulation pins in accordance with the requirements for blanket insulation above, with the following modifications:
For ducts and plenums with surface temperatures below ambient, install a continuous unbroken vapor barrier. Create a facing lap for longitudinal seams and end joints with insulation by removing 2 inches from one edge and one end of insulation segment. Secure laps to adjacent insulation section with 1/2-inch outward-clinching staples, 1 inch o.c. Install vapor barrier consisting of factory- or field-applied jacket, adhesive, vapor-barrier mastic, and sealant at joints, seams, and protrusions.
Install insulation on rectangular duct elbows and transitions with a full insulation section for each surface. Groove and score insulation to fit as closely as possible to outside and inside radius of elbows. Install insulation on round and flat-oval duct elbows with individually mitered gores cut to fit the elbow.
Insulate duct stiffeners, hangers, and flanges that protrude beyond insulation surface with 6-inch- wide strips of same material used to insulate duct. Secure on alternating sides of stiffener, hanger, and flange with pins spaced 6 inches o.c.
INSTALLATION OF POLYISOCYANURATE INSULATION
Polyisocyanurate Board Insulation Installation: Secure with adhesive and insulation pins:
Apply adhesives according to manufacturer's recommended coverage rates per unit area of duct and plenum surfaces.
Apply adhesive to entire circumference of ducts and to all surfaces of fittings and transitions.