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. 

  • 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

  • Using the naked eye, 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)

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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

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 Blemishes - Coated Glass

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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

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.

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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

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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.

Hole and Notch Guideline

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HOLE LOCATION:

 

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

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HOLE DIMENSION:

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”)

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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

  • Per MWGF policy, ½ the thickness of the glass is Midwest Glass normal tolerance.​

  • Customers can request hold tolerance​ for a fee

  • Paid hold tolerance for glass <1/4 and >5/8 will be 1/16”

  • Hold Tolerance for 5/8” and 3/4" glass will be 3/16”

HOLD TOLERENCE ON SHAPES SHOULD BE DISCUSSED WITH MIDWEST BEFORE ORDERING, SHAPES OUTSIDE OF RECTANGLES AND SQUARES MAY HAVE LOWER HOLD TOLERANCE CONTACT MIDWEST WITH ANY QUESTIONS IF REQUESTING HOLD TOLERANCE ON SHAPES

Sources

  • MWGF Terms & Conditions​

  • ASTM​

  • ASTM C1036​

  • ASTM C1048​

  • ASTM C1172​

  • ASTM C1376​

  • “When is a Defect Not a Defect? ASTM Glass Standards for General Contractors”​

  • Dynamic Architectural Windows & Doors​

  • Abridged Inspection Criteria​

  • ASTM C1048 Tempered Glass; Hole and Notch Guidelines​

  • https://fgiaonline.org/pages/glass-standards-and-guidelines ​

 

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

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