A lite kit installs into a prepared cutout in a commercial hollow metal door by securing a glazed vision panel between two frame halves (bezels) that clamp together through the door. This guide covers the standard installation method for lite kits in 1-3/4” commercial hollow metal doors, including cutout preparation, glazing, and frame assembly.
CDF Distributors supplies lite kits as part of complete door and frame assemblies from its Nashville, Tennessee headquarters. You can configure and order lite kits online using CDF’s ProBuilder tool at cdfdistributors.com. For assistance selecting the correct lite kit for your project, call (855) 769-9895 or email sales@cdfdoors.com.
What Is a Lite Kit?
A lite kit is a vision panel assembly designed to add a window to a commercial hollow metal door. Lite kits are also referred to as window kits or vision lite kits in the commercial door industry. Each lite kit consists of three primary components: the glass panel, the frame (also called a bezel or trim kit), and the glazing material (glazing tape or gaskets) that seals the glass within the frame.
Lite kits are available in standard sizes and custom configurations. Common standard sizes include narrow lite (6” x 27”), half lite (24” x 30”), and full lite (24” x 60”). The glass in a lite kit is tempered safety glass. Tempered glass is manufactured through a process of extreme heating and rapid cooling, making it significantly stronger than standard glass. If tempered glass breaks, it shatters into small granular pieces rather than large shards, reducing the risk of injury.
Lite kits serve functional and safety purposes in commercial buildings. They provide visibility through corridor doors, meet building code requirements for borrowed light, and allow occupants to see approaching traffic on the opposite side of a door. In fire-rated applications, lite kits must be listed and labeled to match the fire rating of the door assembly.
Installation Specifications
This guide covers the installation of a lite kit into a standard 1-3/4” commercial hollow metal door. The procedure applies to both new construction and retrofit installations where a prepared cutout exists in the door. Lite kit frame halves are typically secured with machine screws that pass through both bezels and clamp against the door face on each side. The glass is sealed using glazing tape or compression gaskets supplied with the kit.
At a Glance
Application | Vision panel (window) in commercial hollow metal door |
Door Thickness | 1-3/4” (commercial standard) |
Common Sizes | Narrow lite (6” x 27”), half lite (24” x 30”), full lite (24” x 60”) |
Glass Type | Tempered safety glass (standard); fire-rated glass where required |
Frame Material | Steel bezel (two halves, interior and exterior) |
Glazing Method | Glazing tape or compression gaskets |
Fire Ratings Available | 20-minute, 45-minute, 60-minute, 90-minute, and 180-minute |
Fasteners | Machine screws (supplied with kit) |
Tools and Materials
- Tape measure: for verifying cutout dimensions and lite kit size
- Safety glasses: required PPE when handling glass and metal components
- Work gloves: for handling glass panels and sharp metal edges
- Phillips screwdriver or drill with Phillips bit: for driving machine screws through bezel halves
- Glazing tape or gaskets: supplied with the lite kit; seals the glass within the frame
- Machine screws: supplied with the lite kit; fasten the two bezel halves together through the door
- Clean cloth: for cleaning glass and door surfaces before installation
- Utility knife: for trimming excess glazing tape if necessary
- Level: for verifying the cutout is square and the lite kit is aligned
- Deburring tool or file: for smoothing rough edges on the door cutout if needed
Step-by-Step Installation
Step 1: Verify the Door Cutout
Before handling the lite kit components, verify that the door cutout matches the lite kit dimensions.
- Measure the cutout width and height. Compare these measurements to the lite kit specifications. The cutout must match the kit’s required opening size, which is typically the glass size plus the overlap dimension specified by the manufacturer.
- Check that the cutout edges are clean and free of burrs. If the cutout has rough or sharp edges, smooth them with a deburring tool or file. Rough edges can damage glazing tape and prevent a proper seal.
- Verify that the cutout is square by measuring diagonally from corner to corner. Both diagonal measurements should be equal. An out-of-square cutout will cause the bezel frame to sit unevenly.
If the door was ordered from CDF with a lite kit, the cutout is factory-prepared to the correct dimensions during fabrication. For retrofit installations, confirm the cutout was made to the lite kit manufacturer’s specifications.
Step 2: Separate the Lite Kit Components
Unpack the lite kit and identify the components. A standard lite kit includes:
- Two bezel halves (interior frame and exterior frame)
- One tempered glass panel (or fire-rated glass if specified)
- Glazing tape or compression gaskets
- Machine screws for assembly
Inspect each component for damage before proceeding. Check the glass for chips or cracks, particularly along the edges. Tempered glass is strong across its face but is vulnerable at its corners and edges. Do not install damaged glass.
Labeled diagram showing: two bezel halves (interior and exterior), glass panel, glazing tape or gaskets, and machine screws. Cross-section view showing how components assemble through the door. This diagram requires CDF approval before inclusion in the production file.
Step 3: Apply Glazing Tape to the First Bezel Half
Glazing tape creates the seal between the glass and the bezel frame. Apply it before inserting the glass.
- Clean the bezel’s glass-contact surface with a clean cloth to remove dust, oil, or debris. Glazing tape adheres poorly to contaminated surfaces.
- Apply a continuous strip of glazing tape around the full perimeter of the bezel’s glass rabbet (the recessed ledge where the glass sits). Do not leave gaps at the corners.
- Press the tape firmly into place. The tape should sit flat against the bezel surface without bunching or overlapping.
If the lite kit uses compression gaskets instead of glazing tape, seat the gasket into the bezel channel according to the gasket profile. Compression gaskets snap or press into a dedicated groove in the bezel.
Step 4: Position the First Bezel and Glass on the Door
With glazing tape applied to the first bezel half:
- Hold the first bezel half against one face of the door, centered over the cutout. The screw holes in the bezel must align with the corresponding holes around the cutout perimeter.
- Place the tempered glass panel onto the glazing tape, centered within the bezel frame. The glass should rest flat against the tape with even margins on all sides.
- Press the glass gently but firmly into the glazing tape to create initial adhesion. Do not force or impact the glass.
Handle tempered glass with care. While tempered glass is significantly stronger than standard glass across its face, it is vulnerable at its corners and edges. Avoid striking the glass edges against the door or bezel frame during positioning.
Step 5: Apply Glazing Tape to the Second Bezel Half
Repeat the glazing tape application on the second bezel half, following the same procedure as Step 3. Clean the surface, apply a continuous strip of tape around the full perimeter, and press it firmly into place. If using compression gaskets, seat the gasket into the second bezel’s channel.
Step 6: Secure the Second Bezel Half
The second bezel half clamps against the opposite face of the door, sandwiching the glass between the two bezel halves.
- Position the second bezel half on the opposite side of the door, aligning it with the first bezel. The screw holes on both halves must align through the door.
- Insert the machine screws through the second bezel half and into the threaded holes or clips on the first bezel half.
- Tighten the screws in a star pattern (alternating opposite corners, then sides) rather than sequentially around the perimeter. This ensures even clamping pressure on the glass and prevents the bezel from shifting during assembly.
- Tighten each screw firmly but do not overtighten. Excessive torque can crack the glass, deform the bezel, or strip the screw threads. The bezel should sit flush against the door face on both sides with the glass held securely in place.
Step 7: Inspect the Completed Installation
After securing both bezel halves, perform a final inspection.
- Check that both bezel halves sit flush against the door face with no gaps.
- Verify that the glass is centered within the frame with even margins on all sides.
- Confirm all screws are secure and the bezel does not move or rattle when the door is operated.
- Inspect the glazing seal around the full perimeter. There should be no visible gaps between the glass and the bezel frame.
- Clean the glass on both sides with a clean cloth to remove fingerprints and installation residue.
For fire-rated lite kits, verify that all fire-rated labels are intact and visible after installation. Fire-rated labels must not be removed, covered, or painted over.
Common Mistakes to Avoid
Avoid these common errors during lite kit installation:
- Installing a non-rated lite kit in a fire-rated door. In fire-rated assemblies, the lite kit, glass, and glazing materials must all carry matching fire ratings. A non-rated lite kit voids the fire rating of the entire door assembly.
- Leaving gaps in the glazing tape. Incomplete tape coverage allows air and moisture infiltration and can cause the glass to rattle within the frame. Apply tape around the full perimeter without breaks.
- Overtightening the bezel screws. Excessive torque can crack tempered glass, deform the bezel frame, or strip screw threads. Tighten firmly to achieve a flush, secure fit without forcing the screws.
- Tightening screws sequentially instead of in a star pattern. Sequential tightening creates uneven clamping pressure that can shift the glass off-center or cause the bezel to sit unevenly against the door face.
- Installing damaged glass. Tempered glass with chips or cracks at the edges is compromised and may fail under thermal stress or impact. Inspect all glass before installation.
- Failing to deburr the door cutout. Rough edges on the cutout can damage glazing tape, prevent proper bezel seating, and create an inconsistent seal.
- Using an incorrect cutout size. A cutout that is too small prevents the lite kit from seating properly. A cutout that is too large leaves the glass unsupported at the edges. Always verify cutout dimensions against the lite kit specifications before installation.
Configure Your Assembly
CDF’s ProBuilder tool allows contractors and facility managers to configure complete door assemblies with lite kits online. During configuration in ProBuilder, lite kit size, glass type, and fire rating are selected as part of the full door and frame assembly. ProBuilder displays compatible options and provides instant pricing.
For assistance selecting the correct lite kit for your project, call (855) 769-9895 or email sales@cdfdoors.com. CDF’s sales team is available Monday through Friday, 7:30 AM to 4:30 PM CT.
Frequently Asked Questions
What sizes are available for lite kits in hollow metal doors?
Standard lite kit sizes include narrow lite (6” x 27”), half lite (24” x 30”), and full lite (24” x 60”). Custom sizes are also available. The lite kit size is determined by the cutout in the door, which must be prepared to the exact dimensions specified by the lite kit manufacturer. CDF’s ProBuilder displays all available lite kit sizes for each door configuration.
What type of glass is used in lite kits?
Standard lite kits use tempered safety glass. Tempered glass is manufactured through extreme heating and rapid cooling, making it significantly stronger than standard glass. If tempered glass breaks, it shatters into small granular pieces rather than large sharp shards. For fire-rated applications, lite kits use fire-rated glass such as ceramic glass or wired glass, depending on the required fire rating.
What are the fire rating options for lite kits?
Fire-rated lite kits are available in 20-minute, 45-minute, 60-minute, 90-minute, and 180-minute ratings. In a fire-rated door assembly, the lite kit, glass, frame, and glazing materials must all carry ratings that meet or exceed the rating of the door. Fire-rated lite kits use fire-rated glass and listed frames. All fire-rated labels must remain intact and visible after installation. Verify all requirements with project specifications and the Authority Having Jurisdiction (AHJ).
Can I add a lite kit to an existing hollow metal door?
Yes, lite kits can be installed in existing hollow metal doors if a properly sized cutout is made. The cutout must be made to the lite kit manufacturer’s exact specifications. For fire-rated doors, adding a lite kit in the field requires that the modification be performed in accordance with NFPA 80 and that the completed assembly, including the lite kit, glass, and glazing, is listed and labeled for the required fire rating. Consult the AHJ before modifying a fire-rated door.
Do I need glazing tape or gaskets for a lite kit?
Yes. Glazing tape or compression gaskets are required to seal the glass within the bezel frame. Without proper glazing, the glass can rattle, shift, or allow air and moisture infiltration. Most lite kits ship with the appropriate glazing material included. For fire-rated lite kits, only the glazing material specified by the listing can be used.
What is the difference between a lite kit and a storefront door?
A lite kit is a vision panel assembly that adds a window to a hollow metal door. A storefront door is a full glass-and-aluminum door assembly typically used in retail entrances and commercial storefronts. Storefront doors have aluminum frames with large glass panels that make up most of the door surface. Lite kits are components installed into hollow metal doors, while storefront doors are complete door units.
How do I know if my lite kit is installed correctly?
A correctly installed lite kit has both bezel halves flush against the door face, all screws secure, the glass centered with even margins, and a continuous glazing seal with no visible gaps. The glass should not rattle or shift when the door is operated. For fire-rated installations, all fire-rated labels must be intact and visible.
About This Guide
This installation procedure reflects CDF Distributors’ standard specifications for lite kit installation in commercial hollow metal doors. CDF fabricates door assemblies with factory-prepared lite kit cutouts at its Nashville, Tennessee facility, ensuring precise fitment between the door and lite kit components.
For questions about lite kit installation or to order a door assembly with a lite kit, contact CDF at (855) 769-9895 or sales@cdfdoors.com. Configure your assembly online at cdfdistributors.com using ProBuilder.
