Quality Specifications
CSG COATING QUALITY SPECIFICATIONS
CSG coated glass consists of durable metallic coating applied directly to a float glass substrate. The coating is comprised of layers of metal, sequentially deposited in a vacuum by a process of magnetically sputtered vacuum deposition.
CSG coating quality specifications are in accordance with those specifications as established by ASTM C 1376-97 and are as follows:
SCOPE
1.1 This specification addresses blemishes related to the coating only. It does not address glass blemishes, applied ceramic frits, and organic films.
1.2 This specification covers the optical and aesthetic quality requirements for coatings applied to glass for use in building glazing.
1.3 The coatings covered are applied to the glass using either pyroltic or vacuum (sputtering) deposition methods and are typically applied to control solar heat gain, energy performance, comfort level, and condensation and enhance the aesthetic of the building.
1.4 Dimensional values are stated in inch pound units and are to be regarded as the standard units for this specification. The metric units given in parentheses are for information only.
REFERENCED DOCUMENTS
2.1 Reference t these documents shall be the latest issue unless otherwise specified by the authority applying this specification.
2.2 ASTM Standards: C 162 Terminology of Glass and Glass Products, C 1036 Specification for Flat Glass, C 1048-976 Specification for Heat- Treated Flat Glass – Kind HS, Kind FT Coated and Uncoated Glass, D2244 Test Method for Calculation of Color Differences from Instrumentally Measured Color Coordinates.
3. TERMINOLOGY
3.1 Definitions – Refer to Terminology C162, Specification C1036 or Specification C1048-976 as appropriate:
3.1.1 Blemishes in flat glass – refer to specifications C1036 or C1048-97b, as appropriate.
NOTE 1 – These definitions do not apply to in-service damage.
3.2 Definitions to Terms Specific to This Standard:
3.2.1 Banding – Linear non-uniformity that may be wide or narrow and occur anywhere on a lite.
NOTE 2 – The following terms are designed to guide the user to the appropriate inspection charts and requirements.
3.2.2 Coated overhead glass
Glass used in an installation in which the lower edge of the glass is more than 6 ft (1.8m) above (the viewer’s) floor level or cannot be approached within 10 ft (3.0m). The glass can usually, but not always, be viewed in both transmission and reflection. The glass is usually sloping in from the vertical plane, however, may also be vertical or sloping out from the vertical plane.
3.2.3 Coated spandrel glass
Glass used in an installation in which it is only viewed in reflection from the building’s exterior. The glass is usually installed vertically. However, may be at a slope to the vertical plane.
3.2.4 Coated vision glass
Glass used in an installation in which the lower edge of the glass is a maximum of 6ft (1.8m) above (the viewer’s) floor level. The glass can be viewed in transmission or reflection. The glass is usually vertical, however, may also be sloping in or out from the vertical plane.
3.2.5 Coating rub – a surface abrasion of appreciable width that has partial or complete removal of the coating, producing a hazy appearance.
3.2.6 Coating scratch – partial, or complete, removal of the coating along a thin straight or curved line.
3.2.7 corrosion – change in the color or level of reflected or transmitted light over all or part of the glass surface as a result of degradation of the coating from external sources.
3.2.8 crazing – a random conglomeration of fine lines or cracks in the coating.
3.2.9 cut size – flat glass sheets cut to specific dimensions.
3.2.10 edge to edge – gradient non-uniformity within a lite of glass.
3.2.11 lite to lite – non-uniformity between individual lites.
3.2.12 mark/contaminant – a deposit of foreign material on the glass surface.
3.2.13 mottling – splotchy or patchy non-uniformity (not to be confused with strain pattern inherent to heat-treated glass or in-service staining, or both, or damage of glass).
3.2.14 non-uniformity – obvious variation in reflected color of the coating within a lite of glass or between two lites of coated glass in the same building or both.
3.2.15 picture framing – perimeter non-uniformity.
3.2.16 pinhole – small area in which the coating is entirely or partially absent.
3.2.17 spot – a small, opaque blemish in the coating.
3.2.18 stock size – flat glass sheets cut to standard dimensions that will be cut to smaller sizes in future use.
3.2.19 vacuum deposition – term used to describe a method of manufacture for a coating. The process applies the coating in a vacuum chamber to flat glass.
3.2.20 vacuum sputtering – see vacuum deposition.
4. SIGNIFICANCE AND USE
4.1 This specification groups coated glass according to application. These groups are: vision, spandrel/non-vision, and overhead. Similar but unique quality tolerances and inspection guidelines have been outlined for each application. The glass to be coated shall comply with the applicable provisions of Specification C 1036 and Specification C 1048-97b
4.2 Coating blemishes may be an inherent part of the glass-coating process. In addition, coatings can be damaged as a result of improper transportation, storage, handling, fabrication, installation, and application guidelines.
4.3 Individual manufacturers should be contacted for recommended handling, fabrication, installation, and application guidelines.
5. CLASSIFICATION
5.1 kinds – Coated flat glass furnished under this specification shall be of the following kinds, as specified:
5.1.1 Kind CV – Flat transparent glass conforming to the applicable requirements of Specification C 1036 or Specification C 1048-97b or both, and having a coating applied to one or more of the glass surfaces which further conforms with the requirements hereinafter specified for coated vision glass.
5.1.2 Kind CO – Flat transparent glass conforming to the applicable requirements of Specification of C1036 or Specification C1048-97b or both, and having a coating applied to one or more of the glass surfaces which further specified for coated overhead glass.
5.1.3 Kind CS – Flat glass conforming to the applicable requirements of Specification of C1036 or Specification C1048-97b or both and having a coating applied to one or more of the glass surfaces that further conforms with the requirements herein-after specified for coated spandrel glass.
NOTE 3 – Coated spandrel glass may have additional material designed to opacify the glass that is not included in the scope of this specification.
6. REQUIREMENTS
6.1 Blemishes for Coated Vision Glass – The type and number of blemishes shall be no greater than those specified in Table 1.
6.2 Blemishes for Coated Overhead Glass – The type and number of blemishes shall be no greater than those specified in Table 2.
6.3 Blemishes for Coated Spandrel Glass – The type and number of blemishes shall be no greater than those specified in Table 3.
6.4 Non-uniformity for Coated Glass – The phenomenon of non-uniformity in coated glass may be visible within an individual lite, or between lites of glass, in a particular building or curtain wall. Consultation with suppliers and viewing full size mock-ups under typical site conditions and surrounding landscape is highly recommended before construction.
6.4.1 The scientific nature of controlling gas flow, electrical charges, and coating layer densities require production tolerances for light transmittance, reflectance and color of coated glass products. Glass within allowable production tolerances may yield differences in reflected color or intensity of light transmittance or reflectance or both. Perceivable differences are not immediate cause for rejection.
6.4.2 Glass should be viewed as installed and from the exterior of the building for uniformity comparison. Coating non-uniformity may occur from lite to lite in a building. It may also occur within a lite in the form of edge-to- edge gradation, banding, mottling, or picture framing.
6.4.3 Non-uniformity is defined using AE*ab as defined in Test Method D 2244 for CIE 1976 L*a*b, illuminant D65, and 10o Observer. Allowable AE*ab for exterior reflectance shall be less than five within a lite or between adjacent lites to a reference target sample established by the manufacturer.
QUALITY SPECIFICATIONS FOR CUT SIZE COATED VISION GLASS
Blemish Central Area, in. (mm) Outer Area, in. (mm)
Pinhole 1/16” (1.6mm) max 3/32” (2.4mm) max
Spot 1/16” (1.6mm) max 3/32” (2.4mm) max
Coating scratch 2” (50mm) max length 3” (75mm) max length
Mark/contaminant 2” (50mm) max length 3” (75mm) max length
Coating rub none allowed length plus width not to exceed ¾” (19mm)
Crazing none allowed none allowed
Corrosion none allowed none allowed
A. These specifications apply to cut size glass only. For specifications of stock size glass, contact the manufacturer.
B. The glass shall be inspected, in transmission, at a distance of 10ft (3.0m) at a viewing angle of 90o to the specimen against a bright uniform background. If a blemish is readily apparent under these viewing conditions, the above criteria applies.
C. No more than two readily apparent blemishes are allowed in a 3”(75mm) diameter circle, and no more than five readily apparent blemishes are allowed in a 12” (300mm) diameter circle.
D. The central area is considered to form a square or rectangle defined by the center 80% of the length and 80% of the width dimensions centered on a lite of glass. The remaining area is considered the outer area.
QUALITY SPECIFICATIONS FOR CUT SIZE COATED OVERHEAD GLASS
Blemish Central Area, in.(mm) Outer Area, in.(mm)
Pinhole 3/32” (2.4mm) max 1/8” (3.2mm) max
Spot 3/32” (2.4mm) max 1/8” (3.2mm) max
Coating scratch 3” (75mm) max length 4” (100mm) max length
Mark/contaminant 3” (75mm) max length 4” (100mm) max length
Coating rub length plus width <3/4”(19mm) length plus width < ¾” (19mm)
Crazing none allowed none allowed
Corrosion none allowed none allowed
A. These specifications apply to cut size glass only. For specifications of stock size glass, contact the manufacturer.
B. The glass shall be inspected, in transmission, at a distance of 15ft (4.6m) at a viewing angle of 90o to the specimen against a bright uniform background. If a blemish is readily apparent under these viewing conditions, the above criteria applies.
C. No more than two readily apparent blemishes are allowed in a 3”(75mm) diameter circle, and no more than five readily apparent blemishes are allowed in a 12” (300mm) diameter circle.
D. The central area is considered to form a square or rectangle defined by the center 80% of the length and 80% of the width dimensions centered on a lite of glass. The remaining area is considered the outer area.
QUALITY SPECIFICATIONS FOR CUT SIZE COATED SPANDREL GLASS
Blemish Range Number 1, in. (mm) Range Number 2, in. (mm)
Pinhole 1/8” (3.2mm) max 5/32” (4.0mm) max
Spot 1/8” (3.2mm) max 5/32” (4.0mm) max
Coating scratch 3” (75mm) max length 6” (150mm) max length
Mark/contaminant 3” (75mm) max length 6” (150mm) max length
Coating rub none allowed length plus width <3/4” (19mm)
Crazing none allowed none allowed
Corrosion none allowed none allowed
A. These specifications apply to cut size glass only. For specifications of stock size glass, contacts the manufacturer.
B. The glass shall be inspected, in reflection, at a distance equal or greater than 15ft (4.6m) at a viewing angle of 90o to the specimen under uniform lighting conditions. If a blemish is readily apparent under these viewing conditions, the above criteria apply.
C. No more than two readily apparent blemishes are allowed in a 3”(75mm) diameter circle, and no more than five readily apparent blemishes are allowed in a 12” (300mm) diameter circle.
D. The specifications separate glass by the distance that it will be viewed when installed. Range No. 1 is for all glass within a viewing distance of 15 ft (4.6m) or less, and Range No. 2 is all glass viewed from a distance greater than 15ft (4.6m)
NOTE 4 – Design professionals and building owners should be aware that certain coated glass products will yield color differences when used in adjacent vision and spandrel area conditions and when used in laminated glass constructions or on different glass thickness.
NOTE 5 – Refer to manufacturer for blemishes not listed in this specification.
7. KEYWORDS
7.1 blemishes; coated glass; coatings; glazing; non-uniformity; overhead glass; spandrel glass; sputtered coatings; vacuum deposition coating; vision glass
ASTM C 1036-91 Standard Specification for Flat Glass.
ASTM C 1048-97B Standard Specification for Heat-Treated Flat Glass – Kind HS, Kind FT Coated and Uncoated Glass.
The information contained in this and other SGC Architectural Glass publications are offered for your assistance in the application of products supplied by SGC Architectural Glass, BUT DOES NOT CONSTITUTE A WARRANTY OF MERCHANTABILITY, NO WARRANTY THAT THE MATERIAL IS FIT FOR ANY PARTICULAR PURPOSE OR USE, NO WARRANTY AGAINST GLASS BREAKAGE OF ANY TYPE.
WARRANTY, EXPRESSED OR IMPLIED. Actual performance may vary in particular applications. Contact SGC general office in Clinton,Los Angeles, California concerning particular product applications.
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