Loading...
HomeMy WebLinkAbout08 80 00 Glazing.DOCPEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 SECTION 08 80 00 - GLAZING PART 1 - GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section. 1.2 SUMMARY A. Section includes: 1. Glass for windows, doors and interior borrowed lites. 2. Glazing sealants and accessories. 1.3 DEFINITIONS A. Glass Manufacturers: Firms that produce primary glass, fabricated glass, or both, as defined in referenced glazing publications. B. Glass Thicknesses: Indicated by thickness designations in millimeters according to ASTM C 1036. C. IBC: International Building Code. D. Interspace: Space between lites of an insulating-glass unit. 1.4 COORDINATION A. Coordinate glazing channel dimensions to provide necessary bite on glass, minimum edge and face clearances, and adequate sealant thicknesses, with reasonable tolerances. 1.5 PRE-INSTALLATION MEETINGS A. Pre-installation Conference: Conduct conference at Project site. 1. Review and finalize construction schedule and verify availability of materials, Installer's personnel, equipment, and facilities needed to make progress and avoid delays. 2. Review temporary protection requirements for glazing during and after installation. 1.6 ACTION SUBMITTALS A. Product Data: For each type of product. B. Glass Samples: For each type of the following products; 12 inches square: 1. Coated glass. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 2. Insulating glass. C. Glazing Accessory Samples: For sealants and colored spacers, in 12-inch lengths. D. Glazing Schedule: List glass types and thicknesses for each size opening and location. Use same designations indicated on Drawings. E. Delegated-Design Submittal: For glass indicated to comply with performance requirements and design criteria, including analysis data signed and sealed by the qualified professional engineer responsible for their preparation. 1.7 INFORMATIONAL SUBMITTALS A. Qualification Data: For Installer, manufacturers of insulating-glass units with sputter-coated, low- E coatings, glass testing agency and sealant testing agency. B. Product Certificates: For glass. C. Product Test Reports: For tinted glass, coated glass, insulating glass and glazing sealants, for tests performed by a qualified testing agency. 1. For glazing sealants, provide test reports based on testing current sealant formulations within previous 36-month period. D. Preconstruction adhesion and compatibility test report. E. Sample Warranties: For special warranties. 1.8 QUALITY ASSURANCE A. Manufacturer Qualifications for Insulating-Glass Units with Sputter-Coated, Low-E Coatings: A qualified insulating-glass manufacturer who is approved by coated-glass manufacturer. B. Installer Qualifications: A qualified installer who employs glass installers for this Project who are certified under the National Glass Association's Certified Glass Installer Program. 1. Refer also to Specification Section 01 40 00 “Quality Requirements.” C. Glass Testing Agency Qualifications: A qualified independent testing agency accredited according to the NFRC CAP 1 Certification Agency Program. D. Sealant Testing Agency Qualifications: An independent testing agency qualified according to ASTM C 1021 to conduct the testing indicated. E. Mockups: Build mockups, if requested in writing by Architect, to demonstrate aesthetic effects and to set quality standards for materials and execution. 1. Install glazing in mockups to match glazing systems required for Project, including glazing methods. 2. Subject to compliance with requirements, approved mockups may become part of the completed Work if undisturbed at time of Substantial Completion. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 1.9 PRECONSTRUCTION TESTING A. Preconstruction Adhesion and Compatibility Testing: Test each glass product, tape sealant, gasket, glazing accessory, and glass-framing member for adhesion to and compatibility with elastomeric glazing sealants. 1. Testing is not required if data are submitted based on previous testing of current sealant products and glazing materials matching those submitted. 2. Use ASTM C 1087 to determine whether priming and other specific joint-preparation techniques are required to obtain rapid, optimum adhesion of glazing sealants to glass, tape sealants, gaskets, and glazing channel substrates. 3. Test no fewer than eight Samples of each type of material, including joint substrates, shims, sealant backings, secondary seals, and miscellaneous materials. 4. Schedule enough time for testing and analyzing results to prevent delaying the Work. 5. For materials failing tests, submit sealant manufacturer's written instructions for corrective measures including the use of specially formulated primers. 1.10 DELIVERY, STORAGE, AND HANDLING A. Protect glazing materials according to manufacturer's written instructions. Prevent damage to glass and glazing materials from condensation, temperature changes, direct exposure to sun, or other causes. B. Comply with insulating-glass manufacturer's written instructions for venting and sealing units to avoid hermetic seal ruptures due to altitude change. 1.11 FIELD CONDITIONS A. Environmental Limitations: Do not proceed with glazing when ambient and substrate temperature conditions are outside limits permitted by glazing material manufacturers and when glazing channel substrates are wet from rain, frost, condensation, or other causes. 1. Do not install glazing sealants when ambient and substrate temperature conditions are outside limits permitted by sealant manufacturer or are below 40 deg F. 1.12 WARRANTY A. Manufacturer's Special Warranty for Coated-Glass Products: Manufacturer agrees to replace coated-glass units that deteriorate within specified warranty period. Deterioration of coated glass is defined as defects developed from normal use that are not attributed to glass breakage or to maintaining and cleaning coated glass contrary to manufacturer's written instructions. Defects include peeling, cracking, and other indications of deterioration in coating. 1. Warranty Period: 10 years from date of Substantial Completion. B. Manufacturer's Special Warranty for Insulating Glass: Manufacturer agrees to replace insulating-glass units that deteriorate within specified warranty period. Deterioration of insulating glass is defined as failure of hermetic seal under normal use that is not attributed to glass breakage or to maintaining and cleaning insulating glass contrary to manufacturer's written instructions. Evidence of failure is the obstruction of vision by dust, moisture, or film on interior surfaces of glass. 1. Warranty Period: 10 years from date of Substantial Completion. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 PART 2 - PRODUCTS 2.1 MANUFACTURERS A. Manufacturer: Subject to compliance with requirements, provide product indicated in glass schedules or comparable product by one of the following: 1. Cardinal Glass Industries. 2. Guardian Industries Corp. 3. Oldcastle BuildingEnvelope. 4. Pilkington North America Inc. 5. PPG Industries, Inc. 6. Saint-Gobain Corporation. B. Source Limitations for Glass: Obtain from single source from single manufacturer for each glass type. C. Source Limitations for Glazing Accessories: Obtain from single source from single manufacturer for each product and installation method. 2.2 PERFORMANCE REQUIREMENTS A. General: Installed glazing systems shall withstand normal thermal movement and wind and impact loads (where applicable) without failure, including loss or glass breakage attributable to the following: defective manufacture, fabrication, or installation; failure of sealants or gaskets to remain watertight and airtight; deterioration of glazing materials; or other defects in construction. B. Delegated Design: Engage a qualified professional engineer, as defined in Section 014000 "Quality Requirements," to design glazing. C. Structural Performance: Glazing shall withstand the following design loads within limits and under conditions indicated determined according to the IBC and ASTM E 1300. 1. Design Wind Pressures: As indicated on Drawings. 2. Design Snow Loads: As indicated on Drawings. 3. Maximum Lateral Deflection: For glass supported on all four edges, limit center-of-glass deflection at design wind pressure to not more than 1/50 times the short-side length or 1 inch, whichever is less. 4. Differential Shading: Design glass to resist thermal stresses induced by differential shading within individual glass lites. D. Windborne-Debris-Impact Resistance: Exterior glazing shall comply with basic-protection testing requirements in ASTM E 1996 for appropriate wind zone when tested according to ASTM E 1886. Test specimens shall be no smaller in width and length than glazing indicated for use on Project and shall be installed in same manner as glazing indicated for use on Project. E. Safety Glazing: Where safety glazing is indicated, provide glazing that complies with 16 CFR 1201, Category II. F. Thermal and Optical Performance Properties: Provide glass with performance properties specified, as indicated in manufacturer's published test data, based on procedures indicated below: 1. For monolithic-glass lites, properties are based on units with lites of thickness indicated. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 2. For insulating-glass units, properties are based on units of thickness indicated for overall unit and for each lite. 3. U-Factors: Center-of-glazing values, according to NFRC 100 and based on LBL's WINDOW 5.2 computer program, expressed as Btu/sq. ft. x h x deg F. 4. Solar Heat-Gain Coefficient and Visible Transmittance: Center-of-glazing values, according to NFRC 200 and based on LBL's WINDOW 5.2 computer program. 5. Visible Reflectance: Center-of-glazing values, according to NFRC 300. 2.3 GLASS PRODUCTS, GENERAL A. Glazing Publications: Comply with published recommendations of glass product manufacturers and organizations below unless more stringent requirements are indicated. See these publications for glazing terms not otherwise defined in this Section or in referenced standards. 1. GANA Publications: "Glazing Manual." 2. IGMA Publication for Insulating Glass: SIGMA TM-3000, "North American Glazing Guidelines for Sealed Insulating Glass Units for Commercial and Residential Use." B. Safety Glazing Labeling: Where safety glazing is indicated, permanently mark glazing with certification label of the SGGC. Label shall indicate manufacturer's name, type of glass, thickness, and safety glazing standard with which glass complies. C. Insulating-Glass Certification Program: Permanently marked either on spacers or on at least one component lite of units with appropriate certification label of IGCC. D. Thickness: Where glass thickness is indicated, it is a minimum. Provide glass that complies with performance requirements and is not less than the thickness indicated. 1. Minimum Glass Thickness for Exterior Lites: 6 mm. 2. Thickness of Tinted Glass: Provide same thickness for each tint color indicated throughout Project. E. Strength: Where annealed float glass is indicated, provide annealed float glass, heat- strengthened float glass, or fully tempered float glass as needed to comply with "Performance Requirements" Article. Where heat-strengthened float glass is indicated, provide heat- strengthened float glass or fully tempered float glass as needed to comply with "Performance Requirements" Article. Where fully tempered float glass is indicated, provide fully tempered float glass. 2.4 FABRICATION OF GLAZING UNITS A. Fabricate glazing units in sizes required to fit openings indicated for Project, with edge and face clearances, edge and surface conditions, and bite complying with written instructions of product manufacturer and referenced glazing publications, to comply with system performance requirements. B. Clean-cut or flat-grind vertical edges of butt-glazed monolithic lites to produce square edges with slight chamfers at junctions of edges and faces. C. Grind smooth and polish exposed glass edges and corners. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 2.5 GLASS PRODUCTS A. Clear Annealed Float Glass: ASTM C 1036, Type I, Class 1 (clear), Quality-Q3. 1. Thickness: 6.0 mm. B. Tinted Annealed Float Glass: ASTM C 1036, Type I, Class 2 (tinted), Quality-Q3. 1. Thickness: 6.0 mm. C. Fully Tempered Float Glass: ASTM C 1048, Kind FT (fully tempered), Condition A (uncoated) unless otherwise indicated, Type I, Class 1 (clear) or Class 2 (tinted) as indicated, Quality-Q3. 1. Fabrication Process: By horizontal (roller-hearth) process with roll-wave distortion parallel to bottom edge of glass as installed unless otherwise indicated. 2. Thickness: 6.0 mm. D. Heat-Strengthened Float Glass: ASTM C 1048, Kind HS (heat strengthened), Type I, Condition A (uncoated) unless otherwise indicated, Type I, Class 1 (clear) or Class 2 (tinted) as indicated, Quality-Q3. 1. Fabrication Process: By horizontal (roller-hearth) process with roll-wave distortion parallel to bottom edge of glass as installed unless otherwise indicated. 2. Thickness: 6 mm. 2.6 INSULATING GLASS A. Insulating-Glass Units: Factory-assembled units consisting of sealed lites of glass separated by a dehydrated interspace, qualified according to ASTM E 2190. 1. Sealing System: Dual seal, with manufacturer's standard. 2. Spacer: Manufacturer's standard spacer material and construction. 3. Desiccant: Molecular sieve or silica gel, or a blend of both. 2.7 INSULATING-GLASS TYPES A. Glass Type: Low-e-coated, clear insulating glass: 1. Overall Unit Thickness: 1 inch. 2. Thickness of Each Glass Lite: 6.0 mm. 3. Outdoor Lite: Fully tempered float glass. 4. Inter-space Content: Air. 5. Indoor Lite: Fully tempered float glass. 6. Low-E Coating: Pyrolytic on second surface. 7. Visible Light Transmittance: 70 percent minimum. 8. Winter Nighttime U-Factor: 0.29 maximum. 9. Summer Daytime U-Factor: 0.27 maximum. 10. Solar Heat Gain Coefficient: 0.38 maximum. 11. Provide safety glazing labeling. B. Glass Type: Low-e-coated, clear insulating glass: 1. Overall Unit Thickness: 1 inch. 2. Thickness of Each Glass Lite: 6.0 mm. 3. Outdoor Lite: Heat strengthened float glass. 4. Inter-space Content: Air. 5. Indoor Lite: Heat strengthened float glass. 6. Low-E Coating: Pyrolytic on second surface. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 7. Visible Light Transmittance: 70 percent minimum. 8. Winter Nighttime U-Factor: 0.29 maximum. 9. Summer Daytime U-Factor: 0.27 maximum. 10. Solar Heat Gain Coefficient: 0.38 maximum. 11. Provide safety glazing labeling. 2.8 FIRE-RESISTIVE SAFETY GLASS UNITS A. Fire-rated Glazing Units: Laminated ceramic, .75 inch thick. 1. Manufacturers: a. Pilkington Sales (North America) Ltd. b. Product: Pyrostop. 2.9 GLAZING SEALANTS A. General: 1. Compatibility: Compatible with one another and with other materials they contact, including glass products, seals of insulating-glass units, and glazing channel substrates, under conditions of service and application, as demonstrated by sealant manufacturer based on testing and field experience. 2. Suitability: Comply with sealant and glass manufacturers' written instructions for selecting glazing sealants suitable for applications indicated and for conditions existing at time of installation. 3. Field-applied sealants shall have a VOC content of not more than 250 g/L. 4. Sealants shall comply with the testing and product requirements of the California Department of Public Health's (formerly, the California Department of Health Services') "Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions from Indoor Sources Using Environmental Chambers." 5. Colors of Exposed Glazing Sealants: As selected by Architect from manufacturer's full range. B. Glazing Sealant: Neutral-curing silicone glazing sealant complying with ASTM C 920, Type S, Grade NS, Class 50, Use NT. 1. Products: Subject to compliance with requirements, provide one of the following: a. Dow Corning Corporation; 791. b. GE Advanced Materials - Silicones; SilPruf NB SCS9000. c. Polymeric Systems, Inc.; PSI-641. d. Sika Corporation U.S.; Sikasil WS-295. e. Tremco Incorporated; Spectrem 2. 2.10 GLAZING TAPES A. Back-Bedding Mastic Glazing Tapes: Preformed, butyl-based, 100 percent solids elastomeric tape; non-staining and non-migrating in contact with nonporous surfaces; with or without spacer rod as recommended in writing by tape and glass manufacturers for application indicated; and complying with ASTM C 1281 and AAMA 800 for products indicated below: 1. AAMA 804.3 tape, where indicated. 2. AAMA 806.3 tape, for glazing applications in which tape is subject to continuous pressure. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 3. AAMA 807.3 tape, for glazing applications in which tape is not subject to continuous pressure. B. Expanded Cellular Glazing Tapes: Closed-cell, PVC foam tapes; factory coated with adhesive on both surfaces; and complying with AAMA 800 for the following types: 1. AAMA 810.1, Type 1, for glazing applications in which tape acts as the primary sealant. 2. AAMA 810.1, Type 2, for glazing applications in which tape is used in combination with a full bead of liquid sealant. 2.11 MISCELLANEOUS GLAZING MATERIALS A. General: Provide products of material, size, and shape complying with referenced glazing standard, with requirements of manufacturers of glass and other glazing materials for application indicated, and with a proven record of compatibility with surfaces contacted in installation. B. Cleaners, Primers, and Sealers: Types recommended by sealant or gasket manufacturer. C. Setting Blocks: Elastomeric material with a Shore, Type A durometer hardness of 85, plus or minus 5. D. Spacers: Elastomeric blocks or continuous extrusions of hardness required by glass manufacturer to maintain glass lites in place for installation indicated. E. Edge Blocks: Elastomeric material of hardness needed to limit glass lateral movement (side walking). F. Cylindrical Glazing Sealant Backing: ASTM C 1330, Type O (open-cell material), of size and density to control glazing sealant depth and otherwise produce optimum glazing sealant performance. 2.12 FABRICATION OF GLAZING UNITS A. Fabricate glazing units in sizes required to fit openings indicated for Project, with edge and face clearances, edge and surface conditions, and bite complying with written instructions of product manufacturer and referenced glazing publications, to comply with system performance requirements. 1. Allow for thermal movements from ambient and surface temperature changes acting on glass framing members and glazing components. a. Temperature Change: 120 deg F, ambient; 180 deg F, material surfaces. B. Clean-cut or flat-grind vertical edges of butt-glazed monolithic lites to produce square edges with slight chamfers at junctions of edges and faces. C. Grind smooth and polish exposed glass edges and corners. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 PART 3 - EXECUTION 3.1 EXAMINATION A. Examine framing, glazing channels, and stops, with Installer present, for compliance with the following: 1. Manufacturing and installation tolerances, including those for size, squareness, and offsets at corners. 2. Presence and functioning of weep systems. 3. Minimum required face and edge clearances. 4. Effective sealing between joints of glass-framing members. B. Proceed with installation only after unsatisfactory conditions have been corrected. 3.2 PREPARATION A. Clean glazing channels and other framing members receiving glass immediately before glazing. Remove coatings not firmly bonded to substrates. B. Examine glazing units to locate exterior and interior surfaces. Label or mark units as needed so that exterior and interior surfaces are readily identifiable. Do not use materials that leave visible marks in the completed Work. 3.3 GLAZING, GENERAL A. Comply with combined written instructions of manufacturers of glass, sealants, gaskets, and other glazing materials, unless more stringent requirements are indicated, including those in referenced glazing publications. B. Protect glass edges from damage during handling and installation. Remove damaged glass from Project site and legally dispose of off Project site. Damaged glass includes glass with edge damage or other imperfections that, when installed, could weaken glass, impair performance, or impair appearance. C. Apply primers to joint surfaces where required for adhesion of sealants, as determined by preconstruction testing. D. Install setting blocks in sill rabbets, sized and located to comply with referenced glazing publications, unless otherwise required by glass manufacturer. Set blocks in thin course of compatible sealant suitable for heel bead. E. Do not exceed edge pressures stipulated by glass manufacturers for installing glass lites. F. Provide spacers for glass lites where length plus width is larger than 50 inches. 1. Locate spacers directly opposite each other on both inside and outside faces of glass. Install correct size and spacing to preserve required face clearances, unless gaskets and glazing tapes are used that have demonstrated ability to maintain required face clearances and to comply with system performance requirements. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 2. Provide 1/8-inch minimum bite of spacers on glass and use thickness equal to sealant width. With glazing tape, use thickness slightly less than final compressed thickness of tape. G. Provide edge blocking where indicated or needed to prevent glass lites from moving sideways in glazing channel, as recommended in writing by glass manufacturer and according to requirements in referenced glazing publications. H. Set glass lites in each series with uniform pattern, draw, bow, and similar characteristics. I. Set glass lites with proper orientation so that coatings face exterior or interior as specified. J. Where wedge-shaped gaskets are driven into one side of channel to pressurize sealant or gasket on opposite side, provide adequate anchorage so gasket cannot walk out when installation is subjected to movement. K. Square cut wedge-shaped gaskets at corners and install gaskets in a manner recommended by gasket manufacturer to prevent corners from pulling away; seal corner joints and butt joints with sealant recommended by gasket manufacturer. 3.4 TAPE GLAZING A. Position tapes on fixed stops so that, when compressed by glass, their exposed edges are flush with or protrude slightly above sightline of stops. B. Install tapes continuously, but not necessarily in one continuous length. Do not stretch tapes to make them fit opening. C. Cover vertical framing joints by applying tapes to heads and sills first, then to jambs. Cover horizontal framing joints by applying tapes to jambs, then to heads and sills. D. Place joints in tapes at corners of opening with adjoining lengths butted together, not lapped. Seal joints in tapes with compatible sealant approved by tape manufacturer. E. Do not remove release paper from tape until right before each glazing unit is installed. F. Apply heel bead of elastomeric sealant. G. Center glass lites in openings on setting blocks, and press firmly against tape by inserting dense compression gaskets formed and installed to lock in place against faces of removable stops. Start gasket applications at corners and work toward centers of openings. H. Apply cap bead of elastomeric sealant over exposed edge of tape. 3.5 GASKET GLAZING (DRY) A. Cut compression gaskets to lengths recommended by gasket manufacturer to fit openings exactly, with allowance for stretch during installation. B. Insert soft compression gasket between glass and frame or fixed stop so it is securely in place with joints miter cut and bonded together at corners. PEDCOR SQUARE; BUILDING 5 08 80 00 - PEDCOR SQUARE Issue Date 12.18.15 GLAZING PEDCOR SQUARE; BUILDING 5 C. Installation with Drive-in Wedge Gaskets: Center glass lites in openings on setting blocks, and press firmly against soft compression gasket by inserting dense compression gaskets formed and installed to lock in place against faces of removable stops. Start gasket applications at corners and work toward centers of openings. Compress gaskets to produce a weathertight seal without developing bending stresses in glass. Seal gasket joints with sealant recommended by gasket manufacturer. D. Installation with Pressure-Glazing Stops: Center glass lites in openings on setting blocks, and press firmly against soft compression gasket. Install dense compression gaskets and pressure- glazing stops, applying pressure uniformly to compression gaskets. Compress gaskets to produce a weathertight seal without developing bending stresses in glass. Seal gasket joints with sealant recommended by gasket manufacturer. E. Install gaskets so they protrude past face of glazing stops. 3.6 SEALANT GLAZING (WET) A. Install continuous spacers, or spacers combined with cylindrical sealant backing, between glass lites and glazing stops to maintain glass face clearances and to prevent sealant from extruding into glass channel and blocking weep systems until sealants cure. Secure spacers or spacers and backings in place and in position to control depth of installed sealant relative to edge clearance for optimum sealant performance. B. Force sealants into glazing channels to eliminate voids and to ensure complete wetting or bond of sealant to glass and channel surfaces. C. Tool exposed surfaces of sealants to provide a substantial wash away from glass. 3.7 CLEANING AND PROTECTION A. Immediately after installation remove nonpermanent labels and clean surfaces. B. Protect glass from contact with contaminating substances resulting from construction operations. Examine glass surfaces adjacent to or below exterior concrete and other masonry surfaces at frequent intervals during construction, but not less than once a month, for buildup of dirt, scum, alkaline deposits, or stains. 1. If, despite such protection, contaminating substances do come into contact with glass, remove substances immediately as recommended in writing by glass manufacturer. Remove and replace glass that cannot be cleaned without damage to coatings. C. Remove and replace glass that is damaged during construction period. D. Wash glass on both exposed surfaces not more than four days before date scheduled for inspections that establish date of Substantial Completion. Wash glass as recommended in writing by glass manufacturer. End of Section 08 80 00