A glazed fire door must use fire-rated glass, fitted as part of that door’s specification — ordinary glass is not enough. Vizat lists many 1G to 29G layouts, with clear, frosted and, on many styles, Georgian wired options described as fire rated. This guide sets out those published styles and the general UK rules, without telling you that a particular pane is acceptable in a particular opening.
This article is general guidance, written with England in mind, and is not legal advice. Fire door requirements depend on the building, its use, the fire strategy and the fire risk assessment. Rules in Scotland, Wales and Northern Ireland can differ. If you are unsure, take advice from a competent fire safety professional before you buy or fit a door.
The basic rule for glazed fire doors
If a fire door has glass in it, that glass has to do the same job as the rest of the door for the required period. In England, Approved Document B deals with fire-resisting construction, including fire-resisting glazing. The practical buying rule is simple: only use glass and glazing beads or systems that belong with that door’s fire door specification. Do not glaze a fire door with ordinary glass, and do not assume that a pretty layout is automatically suitable for a given opening.
This is general guidance, not a design manual. Maximum pane sizes, bead details and whether insulated (integrity and insulation) or integrity-only glass is needed all come from the tested or assessed specification and the fire strategy for the building.
Glazing options listed by Vizat
On glazed Vizat fire doors, the product descriptions say: “All our glazing options are fire rated including: Clear (C730) Pyro glass; Georgian Wired Polished Plate (GWPP) glass; Frosted glass (sandblasting one face of the C730 glass).”
The selectable options on many doors are Georgian Wired Glass, Clear Glazed and Frosted Glass. That is not true of every style. The Oak Veneer 20G Glazed FD30 Internal Fire Door lists all three. The oak veneer 19G FD30 door lists Clear Glazed and Frosted Glass only. Always read the options on the page you are ordering from.
Vizat glazing styles (1G to 29G)
The table below repeats the pane descriptions published on the oak veneer FD30 product pages for each style, as they stood on 12 November 2026. Other finishes use the same style codes. Some descriptions note that the setting can depend on the door size. Check the product page if you need exact dimensions for a particular width.
| Style | Pane description published on the oak veneer FD30 page |
|---|---|
| 1G | 450 mm × 450 mm glass panel, setting in 127 mm down, central |
| 2G | 700 mm × 450 mm glass panel, setting in 127 mm down, central |
| 3G | 700 mm × 150 mm glass panel, setting in 127 mm down and in |
| 4G | 450 mm × 150 mm glass panel, setting in 127 mm down and in |
| 6G | 450 mm × 450 mm glass panel |
| 7G | 914 mm × 150 mm glass panel, setting in 127 mm down and in |
| 8G | 914 mm × 508 mm glass panel, setting in 127 mm down, central |
| 10G | 245 mm × 245 mm glass panel, 5 panes, setting in 127 mm down, even mid-rail |
| 16G | 150 mm × 775 mm (top) and 150 mm × 770 mm (bottom), setting in 127 mm down and in, 200 mm mid-rail |
| 18G | 1150 mm × 150 mm glass panel, setting in 406 mm down and 127 mm in |
| 19G | 1654 mm × 508 mm glass panel, setting in 127 mm down, central |
| 20G | 1440 mm × 150 mm glass panel, setting in 127 mm down and in |
| 22G | 245 mm × 245 mm glass panel, 4 panes, setting central (door size dependent) |
| 23G | 400 mm × 200 mm glass panel, 3 panes, setting central (door size dependent) |
| 24G | 200 mm × 400 mm glass panel, 3 panes, setting central (door size dependent) |
| 25G | 1440 mm × 150 mm glass panel, setting in central, 127 mm in |
| 26G | 245 mm × 245 mm glass panel, 4 panes, setting door size dependent, 127 mm in |
| 27G | 300 mm × 200 mm glass panel, 4 panes, setting door size dependent, 127 mm in |
| 28G | 400 mm × 200 mm glass panel, 3 panes, setting door size dependent, 127 mm in |
| 29G | 1440 mm × 150 mm glass panel, setting in central |
Non-glazed fire doors are listed separately in Non-Glazed Fire Doors.
Choosing a style without over-claiming
A narrow side pane (for example 3G, 4G, 7G or 20G) is often used where you want borrowed light but less view through the door. A central square (1G, 6G) or a larger pane (8G, 19G) gives more vision. That is a design choice. It does not tell you whether that door is acceptable on a particular flat entrance, stair or kitchen door — that is a specification question.
FD30 and FD60 versions are listed for these glazed styles. The presence of a 60-minute product in a style does not mean every pane option is interchangeable. Choose the rating first, then the layout and glass type on that product page.
Frequently asked questions
Can any glass be used in a fire door?
No. Glazing in a fire-resisting door must be fire-rated glass, fitted in a way that matches the tested or assessed specification for that door. Ordinary decorative or untested glass should not be used. Vizat’s glazed fire door pages state that the listed glazing options are fire rated.
What glazing options does Vizat list?
On many glazed fire doors the options are Georgian Wired Glass, Clear Glazed and Frosted Glass. Product descriptions name these as Clear (C730) Pyro glass, Georgian Wired Polished Plate (GWPP) glass, and frosted glass made by sandblasting one face of the C730 glass. Some styles do not list every option — for example the oak veneer 19G FD30 door lists Clear Glazed and Frosted Glass only. Check the product page.
What do 1G, 20G and similar style codes mean?
They are Vizat’s glazing layout codes. Each style has its own pane size and position, described on the product page. Collections such as 1G, 3G and 20G group those layouts. There is also a non-glazed range if you do not need glass.
Is a glazed fire door allowed in an HMO or on a flat entrance?
Sometimes, if the glass and the door as a whole meet the fire resistance (and, where required, smoke control) needed for that opening. A large pane is not automatically unacceptable, and a small pane is not automatically acceptable. The fire risk assessment and the door’s specification decide this, not the style code alone.
Can I add a vision panel to a solid fire door later?
Only if the door’s documentation allows it and the work is done with a compatible, fire-rated vision panel kit, by someone competent to do it. Cutting a fire door without an assessed method can undermine it. Vizat lists some vision panels separately; those product pages include their own limits (for example, some are described as suiting 44–45 mm doors and not for exterior doors).
Does fire-rated glass shatter like ordinary toughened glass?
Do not assume that. Fire-resistant glasses are different products. Vizat’s general FAQs page describes safety glass on doors in broad terms; the fire door product pages describe C730 Pyro glass and Georgian wired glass instead. Use the wording on the fire door product you are buying.
Related guides and products
You may also find these Vizat guides useful:
- FD30 vs FD60 fire doors: what's the difference?
- Fire door sizes in the UK
- Choosing a fire door for an HMO or flat
- Fire door ironmongery: closers, hinges and seals
- How to measure and fit a fire door
Existing Vizat articles on regulations and upkeep:
For product questions, contact Vizat Doors on the contact page, email info@vizatdoors.co.uk or call 0116 319 1940.