DASMA TDS 158 - Glazing in Garage Doors

Garage door windows add curb appeal and natural light, but the glazing material matters for safety, energy performance, and in some jurisdictions, code compliance. DASMA TDS 158 describes the available glazing types and when each is appropriate.

What this data sheet says

TDS 158 covers the most common glazing materials used in sectional garage door window inserts and the relevant code provisions that apply to each.

"Garage door glazing materials must be selected to meet applicable building code requirements for safety glazing, thermal performance, and in windborne debris regions, impact resistance."

Key materials and considerations from TDS 158:

• Annealed (standard) glass is the least expensive option but breaks into large, sharp shards. It is not considered safety glazing and is generally not suitable for locations where a person could fall through or strike the glass.
• Tempered glass breaks into small, blunt granules rather than sharp shards. It is the standard safety glazing for most garage door applications where glass is within reach of occupants.
• Laminated glass holds together when broken due to a plastic interlayer. It provides impact resistance and is required in windborne debris regions where the door is not otherwise impact-rated.
• Polycarbonate is a plastic glazing that is highly impact-resistant and does not shatter. It is lightweight and often used as an alternative to glass in wind-sensitive applications.
• Insulated glass units (IGUs) consist of two panes separated by a sealed air or gas space. They improve thermal performance but add weight and cost.

When it applies

TDS 158 is relevant when selecting or specifying windows for a new or replacement garage door:

• Standard residential applications: tempered glass is the most common choice and satisfies safety glazing requirements in most jurisdictions.
• Windborne debris regions: IBC 1609.1.2 and 1609.2.2 require that glazed openings in garage doors either be impact-rated or protected by an approved impact-resistant covering. In these regions, laminated glass or polycarbonate may be required.
• Energy code compliance: if the jurisdiction enforces IECC provisions for garage doors, an insulated glazing unit improves the overall U-factor of a window-equipped door section.

Denver and the Colorado Front Range are not in a windborne debris region as defined by IBC 1609.1.2, so standard tempered glass satisfies requirements for most residential installations here. However, hail is a significant hazard, and polycarbonate windows are more hail-resistant than glass.

What this means for you

Choose tempered glass at minimum. Standard annealed glass is a safety hazard in a garage door. Any replacement insert or new window section should specify tempered or safety-rated glazing.

Polycarbonate is a good choice for hail-prone areas. On the Colorado Front Range, polycarbonate window inserts survive hail that would crack glass inserts. The trade-off is that polycarbonate can scratch and yellow over time.

Verify that added windows do not compromise the door's wind rating. Adding window inserts to a door that was not designed with them can reduce the section's structural integrity. Check with the door manufacturer or a technician before cutting into panels.

Weight increases with insulated units. If you upgrade to IGU windows, confirm that your spring system is recalculated for the added weight.

G Brothers can advise on glazing options for any door we sell or service and confirm whether a window upgrade requires spring rebalancing.

Full text and source

Download DASMA TDS 158 from the official TDS index at https://www.dasma.com/technical-data-sheets/.

This entry covers glazing in residential and commercial sectional garage door panels. Fire-rated door windows have separate requirements under NFPA 80 and are not addressed by TDS 158.