Lites, commonly known as glass inserts, are a sought-after addition to doors, particularly in the realm of commercial door applications. To navigate the world of commercial lites effectively, it’s crucial to understand the three key measurements involved.
Order Size
The order size refers to the opening found within the door where the entire lite frame system is installed. It’s important to note that the glass doesn’t extend from edge to edge of the door but is instead 1/2″ shorter on each side. Consequently, the glass size is 1″ smaller than the order size. Furthermore, the lite frame extends past the edge of the glass by 1/2″. The visible lite size, also known as the exposed glass size, is 1″ smaller than the glass size, making it 2″ smaller than the order size.
Front View
Side View
Glass Types
There are three kinds of lite inserts which can be installed into a hollow metal or commercial flush wood door.
Clear Tempered Glass
Clear Tempered Glass is an excellent choice for lites. Importantly, it does not contribute to fire ratings. However, its strength surpasses that of regular glass, making it a safe choice. In case of breakage, tempered glass shatters into small granular chunks instead of sharp shards, enhancing safety.
Pyran F Glass (Clear Ceramic Safety Glass)
Pyran F Glass is ideal when fire ratings are a concern. The fire rating of the door hinges on the visible glass size. A door lite measuring 100 square inches or less will not affect the door’s fire rating. Pyran F glass features a heavy-duty 7 mil durable safety film with neutral colortation, providing both safety and protection.
Safe-Wire Fire Glass
Safe-Wire Fire Glass is another option for maintaining fire ratings. As with Pyran F Glass, the door’s fire rating depends on the size of the visible glass. A door lite measuring 100 square inches or less will not compromise the door’s fire rating. Safe-Wire Fire Glass boasts a 3/4″ x 3/4″ diamond pattern that preserves integrity even when fractured or subjected to a hose stream.
Lite Sizes
When considering lites for fire-rated doors, it’s crucial to understand how they impact the door’s fire rating. Installing a lite that covers more than 100 square inches on a fire-rated door will reduce its rating by 50%. The overall unit can only be rated as low as the lowest component. Here are a few examples:
- If a 22″ x 28″ Safe-Wire lite (measuring 616 square inches) is installed on a 90-minute fire-rated door, the door and lite together will maintain a 45-minute fire rating.
- However, if the same 45-minute rated lite is placed in a 20-minute rated door, the door and lite together will carry an overall 20-minute rating.
Standard Layout Options
100 Square Inches
4″ x 25″ Exposed Glass
6/8 Door: A = 12″
7/0 Door: A = 16″
5″ x 20″ Exposed Glass
6/8 Door: A = 15″
7/0 Door: A = 19″
10″ x 10″ Exposed Glass
6/8 Door: A = 12″
7/0 Door: A = 16″
B Always Equal
Over 100 Square Inches
22″ x 28″ Exposed Glass
6/8 Door: A = 6-1/2″
7/0 Door: A = 8-1/2″
B Always Equal
22″ x 58″ Exposed Glass
6/8 Door: A = 6-1/2″
7/0 Door: A = 8-1/2″
B Always Equal
| Glass Order Size | Exposed Glass Size | Safe-Wire Glass | Pyran F Glass | Clear-Tempered Glass | ||
|---|---|---|---|---|---|---|
| 90 Min Door | 20 Min Door | 90 Min Door | 20 Min Door | Non-Rated | ||
| 6″ x 27″ | 4″ x 25″ | Up to 90 mins. | Up to 20 mins. | Up to 90 mins. | Up to 20 mins. | Non-Rated |
| 7″ x 22″ | 5″ x 20″ | Up to 90 mins. | Up to 20 mins. | Up to 90 mins. | Up to 20 mins. | Non-Rated |
| 12″ x 12″ | 10″ x 10″ | Up to 90 mins. | Up to 20 mins. | Up to 90 mins. | Up to 20 mins. | Non-Rated |
| 24″ x 30″ | 22″ x 28″ | Up to 45 mins. | Up to 20 mins. | Special Order | Special Order | Non-Rated |
| 24″ x 60″ | 22″ x 58″ | N/A | N/A | N/A | N/A | Non-Rated |
Other options and styles may be available for special order though. Understanding these details will help you make informed decisions when enhancing doors with lites, whether for aesthetics, safety, or compliance with fire regulations.