Fire-Rated Glass in the UK: Types, Ratings and Building Regulations

Fire safety and architectural transparency do not have to compete. In commercial interiors, fire-rated glazing can preserve natural light and visual connectivity while providing essential protection against fire. The challenge is selecting a system that meets the building’s fire-safety requirements without compromising the design. 

At GH Interior Glass, we approach fire-rated glazing as both a technical specification and a design decision. For architects, contractors and building owners across London, Essex, Kent and Surrey, understanding fire-resistance classifications is essential before specifying glazed partitions, screens or doors. 

What Is Fire-Rated Glass? 

Fire-rated glass is specialist glazing classified for its ability to resist fire for a defined period under specified test conditions. Depending on its classification, it can prevent flames and hot gases from passing through a barrier, limit heat transfer, or provide both forms of protection. 

Performance depends on the complete assembly, not simply the glass. Frames, seals, glazing beads, fixings and supporting construction must be compatible with the relevant test or classification evidence. 

This matters when designing contemporary glass partitions with slim profiles and expansive panels. A minimal aesthetic must not compromise the performance required for the installation. 

Understanding Fire-Rated Glass Performance Ratings 

Fire-resistance classifications describe performance under the relevant test and classification procedures. Two principal classifications are integrity (E) and integrity with insulation (EI). 

Integrity-only glass: E30, E60 and E90 

E denotes integrity: the ability to resist the passage of flames and hot gases. 

• E30: 30-minute integrity classification. 

• E60: 60-minute integrity classification. 

• E90: 90-minute integrity classification. 

Integrity-only glazing may be suitable where fire separation is required without an insulation classification, provided the application permits it. However, it does not offer the same protection against heat transfer as EI-rated glazing. 

Integrity and insulation glass: EI30 and EI60 

EI indicates that the system meets both integrity and insulation criteria. 

• EI30: Integrity and insulation classification for 30 minutes. 

• EI60: Integrity and insulation classification for 60 minutes. 

Insulation limits heat transfer to the unexposed side within the relevant test criteria. This can be important where people may need to pass or remain near the protected side of a barrier. 

E60 and EI60 are not interchangeable. The required classification and duration must be determined by the building’s fire strategy and applicable guidance. 

Types of Fire-Rated Glass 

Different glass constructions achieve fire resistance in different ways. Selection should reflect the required performance, panel dimensions, framing system and appearance. 

Wired glass 

Wired glass contains a metal mesh embedded within the glass. However, the presence of wire does not establish a fire-resistance rating. Suitability depends on the specific product, supporting system and performance evidence. Existing wired glazing should not automatically be assumed compliant during refurbishment. 

Specially toughened fire-resistant glass 

Ordinary toughened safety glass is designed to improve resistance to mechanical and thermal stresses and to break into relatively small fragments. It is not automatically fire-rated. 

Specialist fire-resistant products use particular compositions or manufacturing processes to achieve defined classifications. Always distinguish ordinary toughened glass from glazing tested and classified for fire resistance. 

Intumescent glass 

Intumescent glazing commonly incorporates specialist interlayers that react to heat and expand, helping form an insulating barrier. Depending on the construction, this can provide both integrity and insulation. 

For applications requiring EI-rated performance, intumescent glass may preserve daylight while limiting heat transfer. However, performance, thickness and permitted panel dimensions vary by product. The manufacturer’s evidence must support the proposed installation. 

When Do UK Building Regulations Require Fire-Rated Glass? 

In England, Approved Document B provides statutory guidance on meeting the fire-safety requirements of the Building Regulations. It addresses means of escape, compartmentation and internal fire spread. 

The requirement for fire-rated glazing depends on the building’s design and the function of the barrier. Approved Document B applies to England; Scotland, Wales and Northern Ireland have separate building standards and guidance. 

Commercial partitions and escape corridors 

A glazed partition may require fire resistance when it forms part of a compartment boundary or protected escape-route enclosure. For example, a screen separating an office corridor from adjoining accommodation may need to preserve the corridor’s protection. 

Not every office partition requires a fire rating. The specification must reflect the barrier’s function and the building’s fire strategy. 

Fire doors and glazed screens 

Where glazing forms part of a fire-resisting doorset or screen, the complete assembly must achieve the required performance. This includes the glass, frame, seals, hardware and installation details. 

Changing a vision panel or its dimensions without checking the relevant certification can compromise the doorset’s performance. A fire-rated pane does not automatically make an unsuitable door compliant. 

Atria and open-plan commercial spaces 

Atria connect multiple floors and can create complex fire and smoke-management challenges. Fire-resisting glazing may be required where it forms part of a compartment boundary or another protective enclosure. 

However, not every atrium requires fire-rated glass throughout. The fire strategy determines the necessary separation and its relationship with smoke control and escape arrangements. 

Retail shopfronts 

A retail shopfront does not automatically require fire-rated glazing. Requirements may apply when the frontage forms part of a fire-resisting boundary or serves a defined function in the building’s fire strategy. 

Its position relative to neighbouring premises, compartment walls and escape routes should be reviewed before the glazing specification is finalised. 

A Designer’s Note: Specify the Complete System 

GH Interior Glass tip: Confirm the required fire classification before finalising frame profiles, finishes or panel dimensions. Check the evidence for the complete system, including permitted sizes, glazing retention, seals and supporting construction. This helps prevent costly changes when a preferred design cannot meet the required performance. 

Common Misconceptions About Fire-Rated Glass 

• Toughened glass is fire-rated: Ordinary toughened safety glass does not automatically provide fire resistance. 

• E60 and EI60 are equivalent: E concerns integrity; EI requires integrity and insulation. 

• Any rated pane fits any frame: The complete assembly must be supported by relevant performance evidence. 

• Every commercial partition needs fire-rated glass: Requirements depend on its function and the fire strategy. 

• A certificate guarantees compliance: The product, installation, dimensions and supporting construction must match the approved configuration. 

Planning Your Fire-Rated Glazing Project 

A successful specification brings architectural intent and fire safety together from the outset. For commercial projects, GH Interior Glass can help you explore fire-rated glazing options suited to your design and project requirements. 

Whether you are planning an office partition, refurbishing a retail interior or coordinating a glazed screen with a wider fire strategy, we invite you to discuss your requirements with our team. Contact us to explore the available options.