standard guidelines and tolerances -...

Standard Guidelines and Tolerances

Flat/Curved Glass Products: Tempered, IGUs, Laminated (Annealed or Tempered), CurvaSmart XIR®, CurvaPrint,

and CurvaSpan

February 2017


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Please sign this page:__________

Table of contents 1. ASTM Applied Standards ................................................................................................................. 5

a) Acceptability .............................................................................................................................. 5

b) Mock Ups .................................................................................................................................. 5

2. All FLAT And CURVED Products Dimensional Tolerances ........................................................................ 6

a) Dimensions ................................................................................................................................ 6

b) Twisting / Squareness ................................................................................................................. 6

c) Edge Types................................................................................................................................. 7

d) Edge Straightness / Bow on FLAT and CURVED Heat Treated Glass ................................................. 8

e) Edge Alignment .......................................................................................................................... 9

f) Hole Alignment and Distance Tolerances ...................................................................................... 9

g) Thickness Tolerance .................................................................................................................. 10

h) Edge Color ............................................................................................................................... 11

i) Acute Corners .......................................................................................................................... 12

3. All CURVED Glass Products Specific Dimensional Tolerances (Annealed, Tempered, Laminated)............... 12

a) Twisting / Squareness ............................................................................................................... 12

b) Radial / Shape Tolerance ........................................................................................................... 12

c) Edge Straightness / Bow ............................................................................................................ 13

4. Heat Treated Products: Tempered, Heat Strengthened, CURVED Annealed, CURVED Tempered Tolerances ........................................................................................................................................................... 14

a) Distortion in FLAT Glass Products ............................................................................................... 14

b) Distortion in CURVED Glass Products ......................................................................................... 14

c) Roller Wave ............................................................................................................................. 15

d) Iridescence ............................................................................................................................... 15


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e) Birefringence ............................................................................................................................ 16

f) Heat Marks in FLAT Heat Treated Glass Products ......................................................................... 16

g) Heat Marks in CURVED Glass Products ....................................................................................... 16

h) Spontaneous Breakage ............................................................................................................. 17

i) Tempered Glass Breakage Pattern .............................................................................................. 17

5. IGUs: Tolerances And Considerations ................................................................................................. 18

a) Distortion, Surface Bow ............................................................................................................. 18

b) Standard Sealant Depth / Sightline ............................................................................................. 18

c) Sealant Depth Calculations Responsibility ................................................................................... 19

d) Primary Sealant Thickness ......................................................................................................... 19

e) Primary Sealant Creep In ........................................................................................................... 19

f) Deflection Related Guidelines .................................................................................................... 20

g) Edge Finish Aesthetics ............................................................................................................... 21

h) CURVED IGUs Spacer Straightness Tolerance .............................................................................. 22

i) Spacer Splices .......................................................................................................................... 23

j) Corners .................................................................................................................................... 23

k) Glazing Sealants Used ............................................................................................................... 23

l) Argon Filled Units ..................................................................................................................... 23

6. IGBUs (Insulated Glass Blind Units): Tolerances And Considerations ...................................................... 23

7. Soft Coated Low E Products: Tolerances ............................................................................................. 24

a) Shelf Life And Timely Ordering ................................................................................................... 24

b) Edge Deletion ........................................................................................................................... 24

I. APPEARANCE ...................................................................................................................... 25

II. DIMENSIONS ........................................................................................................................ 25

III. HUES ................................................................................................................................... 25

IV. SAMPLES ............................................................................................................................. 25

c) Color Uniformity ....................................................................................................................... 25


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d) Color Shift When Laminating ..................................................................................................... 26

e) Comfort ................................................................................................................................... 26

8. Laminated Glass: Tolerances .............................................................................................................. 26

a) Sealants To Use When Glazing .................................................................................................. 26

b) Grouting Materials for handrails ................................................................................................ 26

c) Translucent / Colored Interlayers Aesthetics Considerations .......................................................... 27

d) Edge Stability ........................................................................................................................... 27

e) Color Uniformity ....................................................................................................................... 27

9. CurvaSmart XIR® Laminated: Tolerances ............................................................................................ 27

a) CurvaSmart XIR® Edge Protection ............................................................................................. 27

b) Discoloration Of Interior Objects ................................................................................................ 29

c) Neutral Appearance .................................................................................................................. 29

d) Color Uniformity ....................................................................................................................... 29

e) CurvaSmart XIR® Specific Installation Guidelines ........................................................................ 29

10. CurvaPrint (Silk-Screened) And CurvaSpan (Spandrel Or Absolute Painted Glass: Tolerances) ................ 29

a) Mock Ups ................................................................................................................................ 29

b) Color Uniformity ....................................................................................................................... 30

c) CurvaPrint Inspection Guidelines ................................................................................................ 30

I. PINHOLES ............................................................................................................................ 30

II. PATTERN PARALLELISM ........................................................................................................ 31

III. PATTERN REGISTRY .............................................................................................................. 31

IV. INDEFINITE BORDER ............................................................................................................. 31

V. MOIRE PATTERN .................................................................................................................. 31

d) CurvaSpan Inspection Guidelines ............................................................................................... 31

I. OPAQUE AND NON-VISION AREAS BACKGROUND ................................................................. 32

II. PINHOLES ............................................................................................................................ 32

III. COLOR VARIATION ............................................................................................................... 32


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IV. INDEFINITE BORDER ............................................................................................................. 32

11. General Inspection Guidelines .......................................................................................................... 32

a) Bubbles ................................................................................................................................... 33

b) Blemishes ................................................................................................................................ 33

c) Edges And Chips ...................................................................................................................... 34

d) Scratches ................................................................................................................................. 34

12. Logos ............................................................................................................................................ 34

13. Receipt Of Goods ............................................................................................................................ 35

14. Storage And Handling ..................................................................................................................... 35

15. Installation ..................................................................................................................................... 36

16. Regular Care And Maintenance ........................................................................................................ 37

17. Warranties ..................................................................................................................................... 37


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1. ASTM Applied Standards

a) Acceptability Cristacurva’s flat and curved annealed laminated or flat and curved tempered laminated glass products offer superior optical qualities that meet or exceed the following industry-recognized standards as guidelines for acceptability:

1. ANSI Z97.1 – American National Standard for Glazing Materials Used in Buildings - Safety Performance Specifications and Methods of Test.

2. ASTM C162 - Standard Terminology of Glass and Glass Products. 3. ASTM C1036 (Q3) - Standard Specification for Flat Glass. 4. ASTM C1048 - Standard Specification for Heat-Treated Flat Glass -- Kind HS, Kind FT Coated and

Uncoated Glass. 5. ASTM C1172 - Standard Specification for Laminated Architectural Flat Glass. 6. ASTM C1376 – Standard Specification for Pyrolytic and Vacuum Deposition Coatings on Flat Glass. 7. ASTM C1464- Standard Specification for Bent Glass 8. ASTM E2188 - Standard Test Method for Insulating Glass Unit Performance. 9. IGMA/IGCC Certification according to ASTM2190

The tolerances and specifications detailed herein should be considered as general guidelines for acceptability. At times, the specified tolerances may appear slightly exaggerated by the viewing angle. In some instances, it may be possible to reduce these tolerance levels. Special or unusual shapes may cause various tolerance levels to be increased. Any piece of glass manufactured by Cristacurva that falls within the tolerance levels explained in this document will be acceptable and will not be considered objectionable.

b) Mock Ups In order to make a better, more informed decision concerning any known limitations, tolerances or standards stated in this document, we strongly recommend installing real-size mock-ups at the job site. The mock-up should include those representative materials and/or lighting effects where the finished panels will actually be installed.


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2. All FLAT And CURVED Products Dimensional Tolerances

a) Dimensions Based on glass thickness according to ASTM C1036 – Standard Specification for Flat Glass, Table 2 (Dimensional Tolerance for Rectangular Shapes of Type 1 Transparent, Flat Glass):

Table 1.DimensionalTolerance

b) Twisting / Squareness ± 1/16” per 39” (2mm per 1m) (Figure1)

Figure 1

Glass Thickness

Tolerance

1/8” (3mm) ±1/16” (1.6mm)5/32” (4mm) ±1/16” (1.6mm)3/16” (5mm) ±1/16” (1.6mm)1/4” (6mm) ±1/16” (1.6mm)5/16” (8mm) ±5/64” (2.0mm)3/8” (9.5mm) ±3/32” (2.4mm)

1/2” (12.7mm) ±1/8” (3.2mm)5/8” (16mm) ±5/32” (4.0mm)3/4” (19mm) ±3/16” (4.8mm)


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c) Edge Types When the glass is cut:

i. The edges are sharp ii. They are not aesthetically pleasing iii. The rough finish may hide micro fissures that when heated inside the oven may

cause breakage.

To fix the mentioned situations we will finish the edge of the glass using the following processes (Figure 2):

Figure 2

For Polished Edge, without any further definition, the edge is executed with 45° chamfer (arris) on both sides; the dimensional tolerance for the chamfer width is ±1.5mm (Figure 3)

Seamed Edge

Ground Edge

Polished Edge for Rectangular

Shapes

Polished Edge For Non-rectangular

Shapes


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Figure 3

d) Edge Straightness / Bow on FLAT and CURVED Heat Treated Glass Based on glass measure and thickness according to ASTM C1048 – Standard Specification for Heat-Treated Flat Glass, Table 2 (Overall Bow and Warp, Maximum) . This table applies for flat glass, and due to the lack of a standard for curved glass on this matter, we have adopted the same tolerances for bent products as well (See Figure 4).

Table 2. Edge dimensions

Figure 4

0-50(0-20)

>50-90(>20-35)

>90-120(>35-47)

>120-150(>47-59)

>150-180(>59-71)

>180-210(>71-83)

>210-240(>83-94)

>240-270(>94-106)

>270-300(>106-118)

>300-330(>118-130)

>330-370(>130-146)

>370-400(>146-158)

Nominal ThicknessDesignation

mm (in.)3 (1/8) 3.0 (0.12) 4.0 (0.16) 5.0 (0.20) 7.0 (0.28) 9.0 (0.35) 12.0 (0.47) 14.0 (0.55) 17.0 (0.67) 19.0 (0.75) … … …

3 (1/8) Alternate Method* 2.0 (0.08) 2.0 (0.08) 2.0 (0.08) 3.0 (0.12) 5.0 (0.20) 6.0 (0.24) 7.0 (0.28) 8.0 (0.31) 10.0 (0.39) … … …

4 (5/32) 3.0 (0.12) 4.0 (0.16) 5.0 (0.20) 7.0 (0.28) 9.0 (0.35) 12.0 (0.47) 14.0 (0.55) 17.0 (0.67) 19.0 (0.75) … … …

5 (3/16) 3.0 (0.12) 4.0 (0.16) 5.0 (0.20) 7.0 (0.28) 9.0 (0.35) 12.0 (0.47) 14.0 (0.55) 17.0 (0.67) 19.0 (0.75) … … …

6 (1/4) 2.0 (0.08) 3.0 (0.12) 4.0 (0.16) 5.0 (0.20) 7.0 (0.28) 9.0 (0.35) 12.0 (0.47) 14.0 (0.55) 17.0 (0.67) 19.0 (0.75) 21.0 (0.83) 24.0 (0.94)

8 (5/16) 2.0 (0.08) 2.0 (0.08) 3.0 (0.12) 4.0 (0.16) 5.0 (0.20) 6.0 (0.24) 8.0 (0.31) 10.0 (0.39) 13.0 (0.51) 15.0 (0.59) 18.0 (0.71) 20.0 (0.79)

10 (3/8) 2.0 (0.08) 2.0 (0.08) 2.0 (0.08) 4.0 (0.16) 5.0 (0.20) 6.0 (0.24) 7.0 (0.28) 9.0 (0.35) 12.0 (0.47) 14.0 (0.55) 17.0 (0.67) 19.0 (0.75)

12 - 22 (1/2 - 7/8) 1.0 (0.04) 2.0 (0.08) 2.0 (0.08) 2.0 (0.08) 4.0 (0.16) 5.0 (0.20) 5.0 (0.20) 7.0 (0.28) 10.0 (0.39) 12.0 (0.47) 14.0 (0.55) 17.0 (0.67)

* Values apply to 3mm (1/8 in.) thickness only when alternative checking procedure in 10.7.2 used

Maximum Bow, mm (in.)

Edge Dimens ion, cm (in.)

Edge Straightness/Bow


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e) Edge Alignment (For laminated and IGU products): ± 1/8” (3mm) (Figure 5)

Figure 5

f) Hole Alignment and Distance Tolerances

Hole Placement: +/ 1/16”(1.5mm)

Hole Alignment (laminated prods) (Figure 6): ± 1/8” (3mm)

Hole Dimensions according to ASTM C1048 (±1mm)

Figure 6


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Hole Distance

Figure 7

g) Thickness Tolerance In monolithic products per ASTM 1036. For laminated or IGUs, the final overall thickness of the IGU is not something we can control. All glass has a +/- thickness tolerance that is generated by the primary glass manufacturer and accepted by ASTM 1036. In addition, the interlayers have a thickness variance due to the lamination process and the spacers have their own thickness tolerance. Cristacurva will offer the specified components and therefore any variance in unit thickness will not be a cause for rejection.

6T

2T or hole radius,wichever is largest

2T

T=3/16” - 5/8” (5mm-15mm)

6T

1 5/8” (42mm)

T=3/4” (19mm)

1 5/8” (42mm)Glass with Thicknesses

3/16” (5mm) - 5/8 ” (15mm) Glass with Thickness19mm

W

T=3/16” (5mm)

ØMax = W / 3

ØMin = 3/16” (5mm)

W

T=1/4” - 5/8” (6-15mm)

ØMax = W / 3

ØMin = E

W

T=3/4” (19mm)

ØMax = W / 3

ØMin = 7/8” (22mm)


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Nominal Designation Thickness Range

SI Designation

mm

Traditional Designation

mm in ±mm

min max min max

4 5/32 in. 3.78 4.19 0.149 0.165 1.6 5 3/16 in. 4.57 5.05 0.18 0.199 1.6 6 1/4 in. 5.56 6.2 0.219 0.244 1.6 8 5/16 in. 7.42 8.43 0.292 0.332 2 10 3/8 in. 9.02 10.31 0.355 0.406 2.4 12 1/2 in. 11.91 13.49 0.469 0.531 3.2 19 3/4 in. 18.26 19.84 0.719 0.781 4.8

Table 3. Thickness Tolerance

h) Edge Color The edges of the glass may exhibit different colors depending on many facturs, including the thickness, the size of the glass the lighting conditions, the edge finish type, and even materials within the glass composition. As the glass gets thicker and larger in dimensions, the green cast of the glass will become darker and practically black as shown in the chart below

Perceived edge color differences are therefore very likely to appear. This is something that is not possible to control and as such, a perceived edge color difference is not a cause to reject glass.

Figure 8


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i) Acute Corners Acute corners with angles smaller than 35° will require a flattened tip of about 3/8” to 5/8” to prevent Breakage during manufacturing or excessive surface bow and distortion. (Figure 10)

3. All CURVED Glass Products Specific Dimensional Tolerances (Annealed, Tempered, Laminated)

a) Twisting / Squareness ± 1/8” per 39”(3mm per 1m) (Figure 11)

Figure 11

b) Radial / Shape Tolerance ± 1/8” (3mm) (Figure 12)

± 1/8” (3mm)

Figure 10

39” (1m)


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±1/8" (±3mm)

±1/8" (±3mm)

Figure 12

* Radial/Bent glass may exhibit some flatter parts throughout its curvature, at the ends of the glass, while still remaining within the dotted lines representing the ± 1/8” tolerance. This slight lack of curve consistency is particularly noticeable when affixing two radial glass pieces end-to-end – such as with handrails. In curved tempered laminated glass products with holes, one hole will always be 1/8” larger in diameter than the other one. The customer needs to make sure that the smallest hole diameter drilled on the glass is at least 1/8” larger than the gasket going into it so that the hole alignment tolerance is correctly taken into account.

c) Edge Straightness / Bow Overall Edge Straightness and Flatness of the piece are determined by calculations using glass length and thickness in accordance with ASTM and/or ANSI guidelines for flat tempered products (Figure 13). These tolerances are listed in the chart listed in this document in Table 2, on page 7.

Figure 13


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4. Heat Treated Products: Tempered, Heat Strengthened, CURVED Annealed, CURVED Tempered Tolerances

a) Distortion in FLAT Glass Products Cristacurva’s internal standards for flatness in FLAT tempered glass products are limited to a 0.006” (0.15mm) differential as measured with a roller-wave gauge (Figure 14). There will be some roll distortion that exists in all heat-strengthened and tempered glass products, and the viewing angle will exaggerate these effects.

We apply the term ‘distortion’ to those specific dimensions and overall depths ranging from the height of the ‘peaks’ as measured to the lowest point in the ‘valleys’ on the finished glass surface that are created by the rollers of the tempering oven.

Figure 14

b) Distortion in CURVED Glass Products Cristacurva bent, tempered and laminated glass products offer great optical quality; however, roll distortion exists in all tempered glass products, and viewing angle will exaggerate distortion.

GLASS

+0.006” (+ 0.15mm) Peak

-0.006” (- 0.15mm) Valley

GLASS


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Distortion is not a defect but a characteristic of the bending and tempering process and will not be considered objectionable.

c) Roller Wave In flat heat treated products, Cristacurva will orient roller wave parallel to the base or "width" where possible (Figure 15).

Figure 15

Pieces with a base or "width" dimension in excess of 130" (3.30m) will have roll wave distortion parallel to the height or perpendicular to the base/width (Figure 16).

Figure 16

d) Iridescence Please note that according to ASTM C1048 “A strain pattern also known as iridescence is inherent in all heat-strengthened and fully tempered glass. This strain pattern may become visible under certain lighting conditions. It is a characteristic of heat-treated glass and should not be mistaken as discoloration or non-uniform tint or color, or a defect on the glass. The strain pattern does not affect any physical properties or performance values of the glass.” (ASTM C1048)

Roller Rotation Direction

Under 130” (3.30m)

Flip

Base or“Width”

Base

or“

Wid

th”

Base

or“

Wid

th”

Base or“Width”

Roller Rotation Direction

Over 130” (3.30m)

Base or“Width” Base or“Width” Base or“Width”


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e) Birefringence “A rainbow-type strain, or pattern known as birefringence, might be visible on heat treated glass (tempered, heat strengthened) or on any laminated product including CurvaSmart XIR® Laminated even when annealed, under certain types of indirect lighting or when viewing the glass at an angle approximately 45° or more. This phenomenon occurs very rarely but all heat-treated glass will show it under specific lighting conditions. It is not considered a defect, discoloration or a non-uniform tint or color, but is characteristic of this type of glass.”

f) Heat Marks in FLAT Heat Treated Glass Products The heat treating process will cause certain small marks on the glass surface. They are very similar to fine salt grains (Photo 1) and they usually will show when viewing the glass at an angle and/or against a bright background. They are more visible in thicker and larger pieces of glass, especially when they weigh more than 300 pounds (140Kg). Glass 3/4” thick will always show these marks.

Photo 1

g) Heat Marks in CURVED Glass Products Tiny marks are a distinctive characteristic of the bending and tempering process. They are accentuated in 3/8” and 1/2” glass with radii below 79” (2.00m). They appear along the edges as a particular pattern and may spread along the glass surface. They should not be mistaken with edge chips. Handrails using 1/2” glass will always show these marks, even in the central area of the glass. In addition, marks, similar to “salt grains” (Photo 2) will be visible when viewing the glass against a bright background and/or at an angle. These are not defects but characteristics of the bending and tempering process.


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Photo 2

h) Spontaneous Breakage Tempered glass may suffer spontaneous breakage due to nickel sulfide inclusions. Such a defect originates at the float glass manufacturing process and cannot be controlled or detected by the primary glass producers or Cristacurva. Therefore, in applications where safety is critical such as skylights and handrails, we recommend the use of tempered LAMINATED glass. As a way to reduce the possibility of spontaneous breakage, but never eliminate it, we offer the Heat Soak Test to any tempered glass type at an additional cost. The customer specifically needs to request this process.

i) Tempered Glass Breakage Pattern Tempered glass, like other glass, can break for various reasons, including damage to the glass during installation of the glass into a framing system, installation of the framing system in a way which places undue stress on the glass, damage from an impact of some kind, and other reasons. These circumstances can sometimes cause glass to break after a period of time, not immediately. In addition, while tempered glass typically breaks into small, dice-like pieces, when following the breaking procedure described in 16 CFR 1201, it is possible that some longer, thinner pieces will be present, as the procedure indicates the following: “When breakage occurs, what appear to be the 10 largest particles shall be selected within 5 minutes subsequent to the test and shall weigh no more than the equivalent weight of 10 square inches (64 square centimeters) of the original specimen” Therefore a breakage pattern with some longer, thinner pieces does not necessarily indicate a problem with the glass itself or the tempering process. This is particularly accentuated when the glass is laminated.


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5. IGUs: Tolerances And Considerations

a) Distortion, Surface Bow The air sealed within an insulated glass unit will respond to the gas laws of physics the moment the unit is sealed. These laws govern the volume of gas as it relates to changes in temperature and pressure. As the sealed-in air is heated or cooled, it expands or contracts in volume. As the barometric pressure falls and rises, it likewise expands and contracts. This causes the two lites of glass to bow away from and toward each other. As a result, objects viewed in reflection will be distorted. The amount of distortion depends upon the amount of deviation from flatness and the pattern of movement of the objects viewed. There is no known method by which the identical internal volume, air temperature and pressure can be achieved in each and every insulated unit for a specific project and still have the advantages of a sealed unit. Distortion will also be evident in the units with heat-treated glass and from unequal glazing pressures around the perimeter (reference GANA glazing manual-11 design considerations) An IGU that is composed of heat treated laminated lites will in most cases enhance the glass substrate surface to accentuate levels of bow or warp and roller distortion that in non-laminated IGUs may not be considered objectionable.

b) Standard Sealant Depth / Sightline Our standard sealant depth in IGUs is 4mm (5/32”) to 6mm (1/4”). The customer is responsible to inform Cristacurva if they will install the glass in a structural application, where there might be a need for a thicker secondary sealant (silicone) to prevent the glass from pulling apart from each other. The depth of the secondary sealant may need to vary from our standard depth to increase the strength of the sealant and be able to keep the glass unit bonded together. Standard Spacer Depth/Sightline (IGUs only): The sightline is the measure from the edge of the glass to the end of the spacer as shown below (Figure 17). The sightline will include the measure of the silicone depth plus the width of the spacer. Our standard tolerance is 3/8” – 1/2” (10 – 12mm)* *It is the customer’s responsibility to inform Cristacurva if they will install an IGU in a structural application. The depth of the secondary sealant may need to vary from our standard in structural applications. Sightline

Standard tolerance 3/8" (10mm) - 1/2" (12mm) or +/- 1/8" (3mm) when a special spacer depth is required


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Figure 17

c) Sealant Depth Calculations Responsibility Cristacurva will calculate this depth only when the customer formally informs us in writing that they will structurally install the glass. Failure to indicate this fact will void our warranty.

d) Primary Sealant Thickness

Figure 18

e) Primary Sealant Creep In

Minimum primary sealant thickness 1/8” (3mm)

Maximum primary sealant “creep in” 3/32” (2mm). The “creep in” may not necessarily follow a continuous or even line or pattern, it may show up in spots.


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3/4” (19mm)

Figure 19

In color PIBs, particularly gray, the creep in tolerance is 1/8” (3 mm) with the possibility of seeing it grow through time.

f) Deflection Related Guidelines Using large glass panes in IGUs may result in the two pieces of glass bowing and touching each other if the proper glass and/or spacer thickness is not used (Figure 20). When the two pieces of glass touch, the glass will show white abrasion marks (Photo 3).

Figure 20 Photo 3


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In addition, if the glass bows more than L/175 or ¾” (19mm), whatever is less, the spacer sealants will be stressed unnecessarily and will be more prone to break as time goes by (Figure 21). Cristacurva is able to recommend the thickness of the glass and spacer to prevent this situation only when the customer specifically requests it and sends all the necessary information, including the wind load that the glass will be subject to and the installation system. It is the customer’s responsibility to specifically request this service. Simply sending specifications does not cover our requirement to specifically request that we calculate the deflection of the unit. Cristacurva will not guarantee any units that experience failure due to excessive deflection if the customer has not requested that Cristacurva run calculations and specify the glass and spacer thickness.

Figure 21

g) Edge Finish Aesthetics The sealant prevents the IGU from condensation and structural failure; it is not intended to be an aesthetically pleasing product. We do not recommend the use of IGUs with the edges exposed or in a

3/4” (19mm)


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special visual edge requirement application. The primary and secondary sealant may show small spots or stains along its surface, particularly noticeable when using gray sealants. Silicone may also exhibit areas with slightly different hues due to the application process, particularly noticeable when the depth of the sealant is above ¼”. Both conditions do not compromise the structural performance of the silicone. In addition, the aesthetic qualities of the edge finish of IGUs will be those that are consistently manufactured by our equipment and may vary in uniformity of edge finish and appearance. None of the above described aesthetic conditions are considered defects and therefore will not be a cause for rejection.

h) CURVED IGUs Spacer Straightness Tolerance In curved IGU´s the tolerance for straightness or waviness of the spacer is +/- 3/32” (2.5 mm) every 1’ (300 mm) with a maximum tolerance of 1/4” (6 mm) (Figure 22). The waviness will usually be concentrated in the first 4” close to the corner.

Figure 22


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i) Spacer Splices The spacer in an IGU will not be a continuous bar; the metal spacer in an IGU will be spliced at different positions. The number of joints or splices will differ from unit to unit and cannot be predetermined. The splices are a part of the process of making an IGU and therefore are not a reason to reject any unit.

j) Corners If a stainless steel spacer or other special spacers are specified, all corners of the unit will have a splice and a joint, instead of a continuous bent shape.

k) Glazing Sealants Used Our IGUs are sealed with Dow Corning 982, General Electric IGS3723/IGS3733 silicone, or Sika Sikasil IG-25. The customer is responsible for insuring that the setting blocks, flashing or roofing membranes, building sealants, gaskets, and any other elements that will be in contact with the silicone in the installation system specified or used are compatible with the above-mentioned sealants. Lack of compatibility may result in stained or damaged IGU silicone seal. Laminated and Decorative glass requires the use of compatible silicones for installation in order to guarantee the life of the unit. Please read “Installation” guidelines listed at the end of this document.

l) Argon Filled Units Cristacurva offers argon filled IGUs. Adding argon to an IG unit is an additional process that is supposed to increase the insulation values of the IGUs. At this moment, there is no posted and recognized standard that indicates how much percentage of argon needs to be in an IGU for it to be considered “argon filled” and overtime it is possible that the seals of the IGU allow for migration of it. Therefore, while Cristacurva has the best available equipment to perform this process and will in good faith search to achieve the highest possible filled rates, we cannot warrant an “argon filled” percentage in any of our IGUs.

6. IGBUs (Insulated Glass Blind Units): Tolerances And Considerations Controluz products (IGBUs), from the “Matic Line” (Automatic Blinds) with measurements less than 750mm wide and/or greater than 1900mm high will emit a very faint, high-pitched sound when the


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blinds are raised or lowered. This sound is not a result of a manufacturing defect nor does it affect the function or life of the unit.

Units that are more than 1900mm in height may allow slight visibility from interior to exterior from certain viewpoints. It is mandatory to follow instructions for handling and pressure control detailed in the label.

7. Soft Coated Low E Products: Tolerances

a) Shelf Life And Timely Ordering Please note Soft-Coat Low-E products have a shelf life of approximately 3 months. Therefore, if Cristacurva orders these products to store and be ready to manufacture the customer’s order in a timely basis, and the customer does not send Cristacurva the final glass sizes according to the mutually agreed schedule for any reason, the integrity of the glass will be altered and therefore considered damaged. In any of these events, the customer will be liable and pay for the glass that is reflected unusable and no good for fabrication.

b) Edge Deletion Soft coated Low E glass products will have an “Edge Deletion” around the edges (Photo 4). The purpose of the edge deletion is to remove the Low E coating from the glass creating a barrier to the coating, keeping it free of damage caused by environmental conditions. It cannot be eliminated.


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Photo 4

I. APPEARANCE The edge deletion will be uneven in appearance, showing scratched areas and different uneven patterns, not necessarily aesthetically pleasing.

II. DIMENSIONS It will have an estimated standard depth dimension of 3/8” – 1/2” (10-12mm). The edge deletion is allowed to infringe the sightline up to 1/8”(3mm). It is visible at close inspection, as the glass will show to be clear where the edge deletion occurred.

III. HUES In some conditions, the edge deletion may show a purplish/reddish iridescent like hue or pattern. This is an intrinsic result of the process, not a defect in the unit.

IV. SAMPLES In some instances, our samples will not have an edge deletion; this does not mean that the end product will not be edge deleted.

c) Color Uniformity The scientific nature of controlling gas flow, electrical charges, and coatings and interlayer densities requires production tolerances for light transmittance, reflectance, and color of interlayers and coated fenestration products. Glass and film products that are coated and produced well within allowable production tolerances, such as Low E or CurvaSmart products may unexpectedly yield slight differences as reflected in color or intensity of light transmittance or reflectance or both. Such minor, almost unperceivable, differences are not immediate cause for rejection.

Non-uniformity in coated and/or laminated glass products can be defined by using DE*CMC as defined in ASTM Test Method D 2244 for CMC. Allowable DE* CMC for exterior reflectance shall be less than four and a half (4.5) within a lite or between adjacent lites to a reference target sample by using the aforementioned industry standards as outlined in Measuring Color Uniformity Guidelines.

Design professionals and building owners should be aware that certain fenestration glazing products incorporating coated glass and or film products will yield minor color differences when used in adjacent vision and spandrel area conditions and when used in laminated glass constructions or on different glass thickness.


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d) Color Shift When Laminating When using a Low-E or reflective coating embedded within a laminate and placed in contact with the interlayer, the refractive index of the coating is changed and will result in a perceived color shift that generally is reddish/purplish.

e) Comfort Soft coated Low E products and CurvaSmart XIR® laminated glass will considerably lower the amount of incoming solar heat into a building while allowing a great amount of visible light in. This does not mean that by using these types of glass, the incoming heat will be completely eliminated. In order to have a comfortable room temperature, depending on what comfort means to each person, air conditioning or proper air ventilation may be required.

8. Laminated Glass: Tolerances

a) Sealants To Use When Glazing Neutral silicones are typically compatible with laminated glass. If further details are required as to which silicone to use, please contact your sealant supplier or reach out to us. The use of any unauthorized sealant will void all written, verbal and/or implied warranties.

b) Grouting Materials for handrails It is a common practice to use different grouting materials like Portland cement-based grouts or other aggressive ones to secure glass baluster panels. The industry has found these types of aggressive grouting materials when used to secure laminated glass, particularly in exterior applications, will very likely lead to glass fracture or delamination of the glass. It is always necessary to use sealants, gaskets and wedges that are compatible with laminated glass and do not promote corrosion of the base channel. In addition to preventing the use of aggressive grouting materials, weeping systems in the base channel are very important to correctly evacuate water penetration, prevent moisture from accumulating thus damaging the installation system or the laminated glass itself. Cristacurva will offer technical support only when specifically and in writing the customer requests installation details revisions. However, the use of any grouting materials and Portland cement-based grouts will void any warranty.


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c) Translucent / Colored Interlayers Aesthetics Considerations When flat or curved heat treated glasses (FT or HS) are laminated with colored interlayers, they may show some bands of dark or clear color, it is not a defect but a characteristic of this product as long as the color differential is not larger than the allowed DE* 4.5

d) Edge Stability Laminated glass with exposed edges may develop small air pockets over time. They are not considered defects if they stay at less than 8mm (5/16”) from the edges.

e) Color Uniformity Non-uniformity in coated and/or laminated glass products can be defined by using DE*CMC as defined in ASTM Test Method D 2244 for CMC. Allowable DE* CMC for exterior reflectance shall be less than four and a half (4.5) within a lite or between adjacent lites to a reference target sample by using the aforementioned industry standards as outlined in Measuring Color Uniformity Guidelines. Perceived color or lighting transmission differences when placing the glass in front of lights and using it as a lighting device will not be subject to reject the product. The only accepted method to measure color uniformity is by using a colorimeter or spectrophotometer under lighting conditions as described in ASTM 1048 or 1172.

9. CurvaSmart XIR® Laminated: Tolerances

a) CurvaSmart XIR® Edge Protection In order to protect the heat-reflecting characteristics of the metal-sputtered surface on the CurvaSmart-XIR® film against moisture and oxidation, the units will have an edge deletion called “Kiss Cut” (Figure 23) or “Cut Back” (Figure 24). This edge deletion characteristic will be present along all glass edges, including notches and holes in order to seal the film and protect it against the elements. The width tolerance of the “Cut Back” ranges from ¼” to 5/16”on glass pieces smaller than 10sqft. For pieces that are larger than 10sqft, the Cut Back width tolerance will range from 5/16” to ½”.Both the “Kiss Cut” or “Cut Back” will not be perfectly straight varying in size and width according to the following drawings:


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KISS-CUT

Figure 23

CUT-BACK

Figure 24


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b) Discoloration Of Interior Objects PVB, SGP and CurvaSmart XIR® Laminated glass filter up to 99% of UV light, one of the main causes of material discoloration; however, depending on the type of product and pigments, other elements such as oxygen, humidity, natural light, contamination, heat, and normal use, also contribute to the fading process.

c) Neutral Appearance CurvaSmart XIR® Laminated glass offers a very neutral appearance; however, it is necessary to point out that it does have a slight tint that, when compared to plain clear glass or glass with the same color composition, will have a minor difference in appearance.

d) Color Uniformity Non-uniformity in coated and/or laminated glass products can be defined by using DE*CMC as defined in ASTM Test Method D 2244 for CMC. Allowable DE* CMC for exterior reflectance shall be less than four and a half (4.5) within a lite or between adjacent lites to a reference target sample by using the aforementioned industry standards as outlined in Measuring Color Uniformity Guidelines.

e) CurvaSmart XIR® Specific Installation Guidelines Please take a minute to read carefully the following installation guidelines that are required to install CurvaSmart XIR® correctly. 1. We recommend installing the glass within a week following glass reception. 2. Keep glass stored in a clean and dry place. 3. Install the glass face with the label towards the inside of the building. 4. It is necessary to only use sealants approved by Southwall glass: Dow Corning 795, 983, 993 and 995, General Electric Silicone II (a.k.a. G.E. Silicone 4000) and Silglaze II.

10. CurvaPrint (Silk-Screened) And CurvaSpan (Spandrel Or Absolute Painted Glass: Tolerances)

a) Mock Ups In order to make a better, more informed decision concerning any known limitations and color matching possibilities regarding the use of CurvaPrint/CurvaSpan Glass, we recommend installing a real-size mock-up at the job site. The mock-up should include those representative materials and/or lighting effects where the finished panels will actually be installed. This is of special importance with innovative, intricate, or complex designs, including graduated and stochastic ones, where the dots may become very small, tight, and randomly scattered. These may be prone to create special visual effects that nobody


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can anticipate and that will only be visible once the unit is in its final place and under the special lighting conditions related to it.

b) Color Uniformity In both CurvaPrint and CurvaSpan, color, as well as opacity of the ceramic frit pattern may vary slightly due to minor variations in paint thickness and/or viewing angles. Non-uniformity in colored printed glass can be defined by using DE*CIELAB as defined in ASTM Test Method D 2244 for CIELAB Allowable DE* CIELAB for exterior reflectance shall be less than four and a half (4.5) within a lite or between adjacent lites to a reference target sample. When applying the same color frit to different glass thicknesses, the frit may exhibit color differences greater than the allowed DE 4.5. This differential will also happen between curved and flat glass that use the same color frit. The difference tends to happen more easily with reds, blues, yellows, and greens. This will not be considered a defect. The customer needs to be aware of it and use mock ups to evaluate this design driven situation. Perceived color or lighting transmission differences when placing the glass in front of lights and using it as a lighting device will not be subject to reject the product. The only accepted method to measure color uniformity is by using a colorimeter or spectrophotometer under lighting conditions as described in ASTM 1048 or 1172.

c) CurvaPrint Inspection Guidelines Industry standards detail that the finished glass should be viewed from a distance of 10 feet (3m) and under natural daylight conditions (Figure 25).

Figure 25

I. PINHOLES Tiny, reflected pinholes and minute scratches are not considered defects at this distance.


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Pinholes larger than 1/16" (2mm) are not allowed if noticeable from a distance of 10 feet (3m) or greater.

II. PATTERN PARALLELISM Patterns may be up to 1/8" (3mm) off parallel from edges. A difference in the size of the printed pattern of ± 1/32” 0.8mm is acceptable.

III. PATTERN REGISTRY Pattern Registry: Maximum variation of ±1/32" (1mm) in dot, line or hole location is acceptable.

IV. INDEFINITE BORDER A print definition of 1/8" (3mm) indefinite border is acceptable.

V. MOIRE PATTERN When using silk-screened patterns in architectural building and design applications, there may be a potential to see a Moiré pattern develop in the glass when viewed in certain light conditions and at specific solar angles. Moiré is an optical phenomenon that presents itself as a "wavy, rippled or circular" pattern under some conditions. The Moiré image is a pattern formed when two regularly spaced patterns "overlap," but are not aligned, and is not controllable by our process. This is not a defect but a characteristic of the printed pattern.

d) CurvaSpan Inspection Guidelines Industry standards detail that the finished glass should be viewed from a distance of 15 feet (4.6m) and under natural daylight conditions. (Figure 26)


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Figure 26

I. OPAQUE AND NON-VISION AREAS BACKGROUND Spandrel, absolute or back-painted glass applications provide nearly unmatched uniform color and scratch resistant qualities which are intended to cover walls and/or other solid objects. These panels are not intended for use in applications that are positioned against incoming light transmission, as the light and any pinholes, lack of paint uniformity, or other inherent qualities of the ceramic frit product will be noticeably visible.

II. PINHOLES When viewing CurvaSpan under the conditions described above, reflected pinholes and scratches are not considered defects if they are unobtrusive.

III. COLOR VARIATION Color and reflectance may vary when viewed under a uniform, opaque background. This is not considered a defect unless the color variance is above 4.5 DE as explained at the beginning of this section.

IV. INDEFINITE BORDER A print definition of 3/16" (5mm) indefinite border is considered acceptable.

11. General Inspection Guidelines Industry standards (ASTM) clearly specify that the finished monolithic, laminated, or insulated glass units are to be visually inspected from a distance of 10 ft. (3m) and at a viewing angle of 90 degrees to the said glass product (Figure 27), which has been placed against a bright and uniformly colored opaque background and viewed in a natural daylight setting.


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Figure 27

Once this criteria is in place, standards for acceptability with respect to flat/curved tempered/annealed laminated glass, IGUs, are as follows:

a) Bubbles Per ASTM 1172 Table 1, if there should appear an air bubble or other such impurity that is readily apparent, then the following criteria applies in determining acceptability: Air bubbles larger than 1/4" (6mm) in diameter are not allowed in any part of the glass area. Blow in or short interlayer larger than 1/4" (6mm) is not allowed, unless the glass is captured by more than ¼” (6mm).

b) Blemishes Per ASTM 1172 Table 1, blemish is a defect found on the glass surface between the laminate and the glass. Blemishes up to 1/32” (1.0mm) are allowed unless there is blemish accumulation. In 80 percent of the central glass area, up to three blemishes no larger than 3/16” (5mm) per 10sqft (1.0m2) are allowed, unless there is blemish accumulation. In the outer 20 percent, up to four blemishes no larger than 3/16” (5mm) per 10sqft (1.0m2) are allowed.

90°

45°45°

10ft (3m)


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Per ASTM 1172 Table 1, areas of concentrated lint or interlayer scuff/streak are allowed when they are barely noticeable at 3ft (1m). Hair is allowed if not noticeable at 11ft (3.3m) Blemish accumulation happens when more than ten blemishes are located within a circle no larger than 8” (200mm) in diameter.

c) Edges And Chips The edges must be free of excess PVB. Our tolerance for edge PVB cleanliness is a maximum 1/16” (2mm) PVB protuberance. SGP or PVB interlayer cleanliness around the edges of the holes that do not interfere with the fittings. Chips on the edges are allowed when the edges will be captured and the chips are not visible through the glass surface once the glass is installed. When the edges are not captured, one chip per every 3 feet (1.0m) measuring less than 3/8” (10mm) in length and 1/16” (2mm) in width is allowed if it is not visible through the glass surface.

d) Scratches Per ASTM C1036 (Q3), all glass products are to be inspected from a distance of 10 ft. (3 m). Visible scratches of up to 3"(75mm) in length, visible from this distance, are allowed with a minimum separation of 24” (600mm). Concentrated scratches or abraded areas are not allowed. Any scratch that is not visible from 10ft. (3m) even if larger than the mentioned sizes will not be a cause for rejection.

12. Logos A non-removable, white/frost ceramic frit Cristacurva logo is printed on all heat treated glass that we manufacture in order to comply with ASTM and other international codes (Figure 28). This includes curved annealed, flat and curved heat strengthened, and tempered glass. We may be able to accommodate special logo requests; however, failure to place and/or write the logo exactly as specified, even printing it when it was not required, will not be a cause to reject the glass.


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Figure 28

13. Receipt Of Goods Within five (5) consecutive days from delivery reported by the freight company of the glass panels, every individual lite included in that delivery must be carefully inspected. This is to ensure that the pieces were manufactured according to the specifications detailed in the Cristacurva Order Confirmation. Cristacurva will not accept claims after this period.

14. Storage And Handling Laminated Glass and Decorative glass products must be stored in a secure, low-moisture/dry location, preferably a controlled climate environment. In regard to all glass products care should also be taken to immediately clean off any foreign materials, liquids or gasses that may happen to spill, fall or otherwise come into contact with the glass. Liquids, even water or water vapor will stain the glass if not cleaned quickly. This may even occur during transit so it is very important to review glass carefully upon receipt. Also, at no time should any metal hardware or tools, any sharp objects or hard, sticky substances be allowed to scratch, mark or otherwise be in prolonged contact with the glass, or with any part of the sealant at the perimeter. Please note that Cristacurva does not recommend storing any glass outdoors and the customer is responsible to follow industry common storage practices. Cristacurva will not be held liable for any damage resulting from refusal to follow such storage practices developed by the industry or listed in our


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“Glass Cleaning and Maintenance Guidelines”. This guide is available upon request and can be found at http://www.cristacurva.com

15. Installation Glass installation, measurements (dimensions), shop drawings, and structural calculations are the sole responsibility of the customer. Cristacurva is solely responsible in manufacturing its products according to the Cristacurva order confirmation and Cristacurva drawings provided. Cristacurva is not responsible for any design, calculations, specifications, measurements, and installation details, knowledge of product final application and proper use, details, and effects of prior designs other than its own manufacturing processes. Cristacurva will perform glass calculations and project revisions only when the customer specifically requests in writing for these. If this is not the case, Cristacurva will not perform any project revisions or glass calculations and will manufacture the order understanding that the customer comprehends that it is their sole responsibility to perform structural and load calculations, and install the glass in a way that will serve its intended purpose safely and long lasting.

The actual frame where the glass is to be installed must be clean and free of liquids and debris, equipped with functioning weep holes to allow for excess moisture drainage and should be well-finished according to the manufacturer’s original standards. The frame should also be properly supported, fastened and entirely square, or flush with the intended and adjoining architecture according to plan and must also allow for specified tolerances. Neutral silicones are typically compatible with laminated glass. If further details are required as to which silicone to use, please contact your sealant supplier or reach out to us. The use of any unauthorized sealant will void all written, verbal and/or implied warranties. Failure to comply with any of these guidelines will void our warranty b. Creanza® Frost And CurvaFrost Specific Sealant Warning Regarding Glazing Sealants on our Creanza® Frost and CurvaFrost Decorative Glass, such as Acid Etched, Frosted or Etched Glass: If at any time during the application of glazing sealants, the sealant is in contact with the decorative surface, please remove the sealant residue from the surface as quickly as possible by following the proper cleaning methods available in our “Glass Cleaning & Maintenance” Document. If this is not removed in a timely manner or if it is done using the wrong methods/tools, the decorative surface may be permanently damaged. Cristacurva will not be held liable for any damage resulting from not following the proper cleaning methods. This guide is available upon request and can be found at http://www.cristacurva.com

http://www.cristacurva.com/



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16. Regular Care And Maintenance Glass Panels should be cleaned regularly with any of the following: A mixture of mild soap and water Commercial glass cleaner A solution of ½ Isopropyl Alcohol (IPA) and ½ Water Regular cleaning and maintenance will help conserve the brilliance of the glass, maximize heat-reflecting properties and provide greater, long-term value. For additional information, please ask for our “Glass Cleaning and Maintenance Guidelines”. Cristacurva will not be held liable for any damage including scratches, rubs, stains, abrasion, or other, created by any type of cleaning practices performed by the customer or any contracted cleaning company, whether they are professionals or amateurs, certified or non-certified, after the product has been received. The customer must not attempt to sandblast, etch or acid wash any type of processed glass, this will cause it to break. Processed glass includes laminated, curved annealed, curved and flat tempered or heat strengthened glass.

17. Warranties Standard warranties on all of our products are available upon request. They are valid from the date the product is manufactured or shipped, whatever happens first.

Please contact our Sales Team regarding any specific design criteria or quoting considerations you may have:

Toll-Free: 1.866.827.6049 e-mail: [email protected]

www.cristacurva.com

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