Class 0 Is Dead: Why BS EN 13501-1 Class B s1 d0 Now Matters More Than Ever

The deadline has arrived! From 2nd March 2025, building materials such as fire retardant paints in England will no longer be permitted to use outdated national fire classification labels such as BS Class 0. The government’s amendments to Approved Document B remove the national classification system and replace it fully with the European standard: BS EN 13501-1.

This change isn’t just an update – it’s a complete shift in how fire performance is defined and verified. For contractors, specifiers, facilities managers and landlords, it means product selections must now meet more robust and clearly defined testing criteria. And for fire safety coatings, only those with the correct European classification will remain compliant.

Thermoguard was ahead of the curve. All of its core products – Wallcoat, Timbercoat, and Fire Varnish – have held BS EN 13501-1 Class B certification since 2014.

The End of BS Class 0: What’s Changing in Fire Regulations

Previously, many fire-resistant coatings were approved under BS 476 Parts 6 and 7, earning the now outdated “Class 0” rating. While Class 0 served as a benchmark for years, it lacked detail about smoke emissions and flaming droplets – both of which play a crucial role in real-life fire events.

Under the 2025 amendments to Approved Document B, the national system has been officially retired. Products will now be judged exclusively on the European BS EN 13501-1 system, which sets a clearer and more comprehensive standard.

From 2nd March 2025, using a Class 0-rated product alone will no longer satisfy building control requirements. Only BS EN 13501-1 classifications will be valid for proving compliance.

BS EN 13501-1: A Closer Look at the New Standard

The BS EN 13501-1 system breaks fire performance down into three key criteria:

1. Reaction to Fire Class (A1 to F)

This classification tells you how much a material contributes to fire growth. The categories range from A1 (non-combustible) to F (easily flammable):

A1 – Non-combustible: No contribution to fire at all
A2 – Limited combustibility
B – Very limited contribution to fire
C – Limited contribution
D – Medium contribution
E – High contribution
F – Easily flammable: No performance determined

Thermoguard’s Wallcoat, Timbercoat, and Fire Varnish systems are all Class B – offering very limited contribution to fire while still allowing for use on timber, painted walls, ceilings and other combustible surfaces.

2. Smoke Production Rating (s1, s2, s3)

Smoke is often the primary cause of death in fires. That’s why the European standard grades materials based on how much smoke they emit:

s1 – Little or no smoke
s2 – Average levels of smoke
s3 – High volume of smoke

Thermoguard Wallcoat and Timbercoat are certified s1, meaning they emit minimal smoke – crucial for evacuation and wayfinding under pressure. Thermoguard Fire Varnish is certified s2.

3. Flaming Droplets Rating (d0, d1, d2)

Flaming droplets can spread fire rapidly or cause injuries to those evacuating. Materials are rated for their droplet behaviour:

d0 – No burning droplets
d1 – Some droplets, slow dripping
d2 – High or intense dripping, which may ignite other materials

Thermoguard systems are rated d0. That means no burning droplets, adding another layer of protection in critical settings.

Beware Incomplete Ratings: The Hidden Risk of “Class B” Labels

Not all “Class B” products are created equal. Some coatings are sold as “Class B” without stating their smoke or droplet ratings. This creates dangerous ambiguity – especially when these products are actually Class B s3 d2. That combination means thick smoke and flaming droplets, which can turn an escape route into a death trap.

Thermoguard is fully transparent. Each of its systems is independently tested and certified to the complete Class B s1 d0 rating (B s2 d0 for Varnish) – meeting both current and future fire safety obligations without compromise.

Thermoguard Systems: Fire Protection with Proven Compliance

Thermoguard Wallcoat System

Specialist intumescent paint system for walls and ceilings. Applied in two coats over bare or previously painted surfaces – no need to strip back old layers. Designed for plasterboard, masonry, and more.

Thermoguard Timbercoat System

High-performance coating for timber cladding, ceilings and panels. Brings combustible wood surfaces into compliance with Class B s1 d0 in a straightforward application.

Thermoguard Fire Varnish System

A two-part clear varnish system for use on interior and exterior woodwork. Enhances the fire safety of timber while preserving the visual character. Ideal for commercial and heritage projects.

All three systems deliver fast-track compliance in just two coats, saving time, labour and disruption across new builds and refurbishments alike.

Built-In Support for Approved Document B Requirements

Using Class B systems from Thermoguard contributes to several core parts of Approved Document B:

Requirement B2 – Resists internal fire spread by surface linings
RB1 – Supports safe evacuation by minimising smoke emissions and flaming droplets
RB5 – Assists with emergency wayfinding by reducing smoke

These systems go beyond minimum compliance – they help actively support life safety strategies.

Why Thermoguard? Trusted, Tested, Transparent

Tested to BS EN 13501-1: Class B s1/s2 d0 since 2014
Member of the Association for Specialist Fire Protection (ASFP)
Backed by UKAS-accredited certification
No need for costly or invasive surface preparation
Expert technical support available for project-specific guidance

In an industry facing tighter scrutiny and stricter enforcement, Thermoguard provides the confidence of independent testing, full transparency, and decades of fire protection expertise.

The Deadline Is Fixed – Act Now

The 2nd March 2025 deadline marks a line in the sand. After that, products rated to BS Class 0 will no longer be accepted for demonstrating surface fire safety compliance. That includes many widely used paints, varnishes, and coatings on the market today.

Now is the time to check certifications, verify full EN ratings, and specify only the relevant Class B rated systems. Anything less may leave you non-compliant and exposed.

Ready to Upgrade to Compliance That Lasts?

Speak to the technical team today to confirm compatibility, coverage rates, and application guidelines for Thermoguard Wallcoat, Timbercoat, or Fire Varnish.

Don’t wait until the deadline. Choose systems that are ready – today – for the standards of tomorrow.