Understanding REI Fire Resistance Ratings: What They Mean and How They Meet Safety Standards and UK Building Regulations
When planning fire protection for a building, understanding REI fire resistance ratings is essential. These ratings are more than just numbers, they are legal benchmarks for how long a structure can remain safe during a fire. If you’re an architect, surveyor, contractor or building manager, knowing the difference between REI and EI ratings can influence everything from design to compliance.
At Viper Fireproofing, we help you meet these exacting standards with systems that deliver certified load-bearing protection.
What Are REI Fire Resistance Ratings?
REI is a classification used in UK and European fire safety to define how a building component behaves in a fire:
R – Load-bearing capacity (how long it supports weight during a fire)
E – Integrity (how well it prevents flames/smoke from passing through)
I – Insulation (how long it prevents heat transfer)
For example:
REI 30 = 30 minutes of load-bearing, flame resistance, and insulation
REI 60 = 60 minutes of the same
These ratings apply to structural systems like steel beams, walls, floors, and ceilings, especially those that play a role in keeping a building upright during fire.
REI vs EI Classification: What’s the Difference?
REI includes the R (load-bearing) factor. This is essential for structural elements.
EI includes only E (integrity) and I (insulation). It’s used for:
Fire doors
Partition walls
Fire curtains
So, if you’re protecting structural steel or load-bearing walls, REI ratings are the correct standard.
At Viper, our services focus on REI-rated systems, especially intumescent fire protection for steelwork.
Typical REI Ratings and Use Cases
The higher the rating, the more time you provide for evacuation and emergency services and the longer your structure resists collapse.
How REI Ratings Fit into Passive Fire Protection
REI fire resistance is a cornerstone of passive fire protection. Rather than actively fighting flames (like sprinklers), passive systems contain the flame spread and maintain safety.
This includes:
Intumescent coatings on structural steel
Fire-rated boarding systems
Certified compartment walls and ceilings
For a building’s load-bearing components to meet REI ratings, they must be tested as full systems and applied correctly.
See How Intumescent Coatings Work
Why Are REI Ratings Required Under Building Regulations?
UK Building Regulations, specifically Approved Document B (Fire Safety), require that all structural elements within a building demonstrate adequate fire resistance to protect lives and allow for safe evacuation.
REI ratings are used to assess whether a structural element:
Maintains load-bearing capacity to prevent collapse (R)
Stops the passage of fire and smoke (E)
Prevents dangerous heat transmission (I)
Failure to meet these criteria can result in:
Rejection by building control
Delays in project approval
Legal liability in the event of fire-related damage or injury
In new builds and major refurbishments, REI ratings are critical for:
Escape route protection
Compartmentalisation
Protection of structural frames
All fire safety plans submitted for approval must include details of how REI performance is achieved, often through intumescent coatings, fire-rated boarding systems, and certified installation.
Certified Systems vs Standalone Products
Fire resistance ratings apply to tested systems, not just materials. A steel beam only achieves REI 60 when:
Coated with a certified intumescent system
Applied to specified thickness (dry film thickness)
Tested under BS 476 or EN 13381 standards
You cannot claim a rating based on a product alone. The whole system must be certified and correctly installed.
This is why Viper Fireproofing uses third-party approved materials and application methods.
How Viper Fireproofing Helps with REI Load-Bearing Protection
We help contractors, developers and asset owners in Manchester, Blackburn, Leeds and across the North West meet REI standards for structural safety.
Our services include:
Intumescent coatings for steel to achieve REI 30–120
Documentation and certification for building control
We work closely with architects and engineers to ensure specifications meet REI demands.
Frequently Asked Questions
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It means a structural element can retain its load-bearing ability, integrity, and insulation for 60 minutes during fire.
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REI includes structural performance (load-bearing), EI does not.
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Yes, for small residential and escape route protection, REI 30 is commonly specified.
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Yes. Certification from the coating manufacturer or fire engineer is usually required for compliance.
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Hospitals typically require REI 60 for key structural and escape route components.
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Yes. Timber elements can be protected with fire-retardant boards or intumescent coatings to meet REI requirements.
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Look for third-party certification, clearly labelled materials, and maintenance schedules for all fire-rated systems.
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Yes, in many cases. Intumescent coatings are often used in heritage buildings because they maintain appearance while delivering protection.
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Yes. For large, high-risk or high-occupancy industrial sites, REI 90 or REI 120 is typically recommended.
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Educational buildings usually need REI 60 for corridors, structural steel, and compartment walls.
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Yes. Shopping centres and retail parks require REI-rated structural and compartment systems, especially in multi-unit buildings.
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Yes, using fire-rated partition walls and ceilings. It’s important to combine REI-rated barriers with extract and suppression systems.
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Typically, an as-built fire strategy with REI rating declarations, application certificates, and third-party product certification is required.
Secure REI-Compliant Fireproofing
At Viper Fireproofing, we deliver fully certified solutions to help your building meet structural fire resistance targets.
CHAS Accredited
Specialists in REI-rated steel fire protection