Midwest Glass Fabricators

Specializing in all Commercial and Consumer Glazing needs

 

MWGF follows ASTM standards as a base line and in fact, uses stricter guidelines than those provided by the ASTM. 

Based on machine capabilities and our own quality standards.

These guidelines allow for certain defects and variations in fabricated and non-fabricated product.

  • The ASTM (American Society for Testing & Materials) sets standards for a variety of industries.​

    • The ASTM’s glass industry standards provide guidelines for allowable defects, quality, and how to visually inspect glass for:​

      • Flat glass​

      • Heat-strengthened and Tempered glass​

      • Laminated glass​

      • Insulated Glass​

  • Generally, use Quality 3 standards

Visual Standards

  • All visual inspections shall be made with 20/20 vision

  • View glass at 90° in daylight, but not direct sunlight

  • Stand at distance as specified by type of defect, focusing on the central area (center 80% of length and width) while looking through the glass and not directly at the surface.

  • For chips: View chips from 1' away, without magnification, using localized lighting.

Picture1.png
Picture2.png

Visual Standards - Bowing​

  • Use a "true straight edge, wire, string or monofilament fishing line."

  • Measure each of the 4 sides for overall bow on the concave portion of the glass within 1" of the glass edge and parallel to the edge.

  • Also check the approximate horizontal and vertical centerlines for overall bow.

Allowable Blemishes - Flat Glass

Point Blemish *

Blemish size: <1.2 (3/64")
Blemish size: ≥1.2 (3/64") < 2 (5/64") allowable w/ minimum separation between blemishes of 24"

Linear Blemish

Blemish intensity & size: Faint or Light & any size
Blemish intensity & size: Medium & ≤75 (3") allowable w/ minimum separation of 24"

Chip or Shell

Chip depth ≤ 50% of glass thickness
Chip width ≤ glass thickness or 6mm (¼"), whichever is greater
Chip length ≤ 2x the chip width

**v-chips not allowed in any circumstances

Intensity

Detection Distance:

130" - HEAVY

39" - MEDIUM

8" - LIGHT

<.2 - FAINT

* Values are for glass thickness ≤6mm (¼")

  •   Glass thickness >6mm (¼") ≤ 12mm (½") may contain proportionally larger blemishes for the same minimum distances.

  •   Allowable blemishes for glass > 12mm (½") shall be determined by agreement between the buyer and the seller.

Allowable Distortion

Please contact MWGF for information on this subject if needed.

Allowable Blemishes - Coated Glass

Picture3.png

Allowable Blemishes - Mirror

Mirror Glazing Quality (similar to Quality 3) for cut size

*Central area is considered center 80% of length and 80% of width centered on the lite. The rest is considered the outer area.

Point Blemish *

Blemish size: Central & outer area <0.3mm allowed
Blemish size: Central area ≥0.3mm < 0.5mm allowable w/ minimum separation between blemishes of 12"

Blemish size: Outer area ≥0.3mm < 0.8mm w/ minimum separation between blemishes of 12"

Blemish size: ≥0.8mm < 1.2mm w/ minimum separation between blemishes of 60" 

Linear Blemish

Blemish intensity & size: Faint allowed
Blemish intensity & size: Light ≤75mm (3") > 75mm allowable w/ minimum separation of 24"

Chip or Shell

Chip depth ≤ 25% of glass thickness
Chip width ≤ 25
% of mirror thickness or 1.6mm (1/16"), whichever is greater
Chip length ≤ 2x the chip width

**v-chips not allowed in any circumstances

Intensity

Detection Distance:

over 60" - HEAVY

24" - MEDIUM

8" - LIGHT

<8" - FAINT

HS and Tempered Glass

Bow

Deviation in flatness spanning the entire pane of glass. Commonly seen in tempered glass and IGUs. 

Allowed within reason. Not measurable on site or in an IGU. Positive and deflection is a natural occurrence with seasonal and barometric pressure cycling.

Distortion

Localized deviation in flatness that can look like ripples across the glass, or pockets of indentations. 

Allowed and very common in tempered glass. Not measurable on site or in an IGU.

Stain Pattern

AKA iridescence; An optical effect that results from the tempering process appearing as a pattern of dark spots on the glass. The intensity of the issue increases when viewed at steep angles to the glass and with polarized sun glasses. 

Allowed. This optical issue is characteristic of tempered glass and cannot be completely controlled. It will vary from pane to pane.

Picture4.png

Laminated Glass

ASTM provides only basic guidelines for laminated glass – UNITS WITH TWO OR MORE LAYERS MAY CONTAIN MORE ALLOWABLE BLEMISHES

CONTACT MWGF FOR SPECIFIC QUESTIONS RELATED TO LAMINATED GLASS

Picture5.png

Lami Length & Width Tolerances

  • Tolerances include cutting and fabrication of the individual lites and mismatch of the lites after lamination.

  • For any piece over 75ft² please contact MWGF for length and width tolerances.

Lami Thickness Tolerance

  • Always consult MWGF directly for lami thickness questions and concerns.

  • Basic ASTM guidelines are as follows:

Lami Bowing

Insulated Glass

Stain Patter

An optical effect that results from the tempering process appearing as a pattern of dark spots on the glass. The intensity of the issue increases when viewed at steep angles to the glass

Allowed. This optical issue is characteristic of tempered glass and cannot be completely controlled. It will vary from pane to pane.

Fringes

An optical effect that appears as a faint, random, pattern resembling an oil stain. 

Allowed. This is the result of having exactly matched thickness of glass panes in an IGU (less than 0.0001" difference in thickness).

Newton Rings

This is an optical issue that appears as concentric rings of rainbow colors near the center of an IGU that has its panes touching each other.

There is no industry standard covering this issue. Contact the manufacturer.

Color Uniformity

Readily apparent glass color variation from window to window, or within a window. It can be the result of the glass tint or glass coating.

Allowed within reason. Can be measured with special instrumentation if needed. Consult with manufacturer.

Fogging

A moisture or chemical deposit between the panes of an IGU.

Not allowed. Indicates seals have failed or outgassing of materials has occurred.

Sightline Infringement

An extension into the daylight opening of an IGU by the sealant, spacer, or area of coating deletion. 

1/8" maximum 

ASTM provides only basic guidelines for Insulated Glass, please contact Midwest Glass for special requests or more information

IG THICKNESS CAN VARY +/- 1/16 please call if you need to consult on your IG.

IG Thickness Tolerance

  • MWGF generally follows Guardian's guidelines for IG thickness.

    • However, after testing MWGF tolerance for annealed & tempered is +/- 1/32"

Bevels

•Based on machine capabilities

•Bevel width tolerance is +/- 3/32”

•Bevel corner tolerance on 1 ¼" and above is +/- 3/16"

Hole and Notch Guideline

Picture6.png

LOCATION (See FIG. 1):

 

Min. distance from edge of glass: 6 mm (¼”) or 2x glass thickness, whichever is greater

Min. distance between holes: 10mm (3/8”) or 2x glass thickness, whichever is greater

Picture8.png
Picture7.png

DIMENSION (See FIG. 2 - 4):

Min. diameter of circular holes: 6mm (1/4”) or the thickness of the glass, whichever is greater

Any other holes: Required to have fillets. Fillet radius must be equal to or greater than the glass thickness

Hole Dimensional Tolerance: ±1.6mm (1/16”)

Picture9.png

Notch & Cutout Dimensional Tolerance:

  • ±1.6mm (1/16”) for glass thickness less than ½”

  • ±3mm (1/8”) for glass thickness ½” or greater

Hold Tolerance

  • ​Customers can request hold tolerance​ for a fee

  • For customer-supplied patterns, call MWGF if hold tolerance is required.

  • MWGF does not accept partial patterns.

*Fabricated material is always ​+ 0, - overall size

*All tolerances are up to the size noted.

Sources

 
 
 
 
 
 
 
 
 
 
 

Contact Midwest Glass Fabricators

For all quotes, orders or inquires:

Sales - sales@mwgf.com

248-889-7900

For all issues with existing orders:

Customer Service - csr@mwgf.com

248-889-7900

We accept quotes and orders by mobile text:


 

248-431-0895

OUR ADDRESS

Midwest Glass Fabricators

100 Transfer Dr. 

Highland, MI 48357

AR Billing Address:

Midwest Glass Fabricators

PO Box 1509

Highland, MI 48357

CONTACT MWGF

Contact Us

Thanks for submitting!

Or call Midwest Glass Fabricators 800-245-5457 

 
 
Glass_social media_member_1-8.png