What do the fire rating classes mean?

People often use “fire rating” as one term, but in practice it can refer to two different things: Reaction to Fire, and Fire resistance. 

1) Reaction to fire (RtF) 

This describes how much a product contributes to a fire (ignition, flame spread, heat release), plus classifications for smoke and flaming droplets. 

In the Euroclass system: A1 is the best class (non-combustible), followed by A2, then B, C, D, E, and F. 

Then there are added indicators: 

• s1 / s2 / s3 = smoke production (s1 is the lowest)  

• d0 / d1 / d2 = flaming droplets/ (d0 is best) 

Examples of classifications therefore include: 

• A1 (non-combustible – no smoke/droplet classification needed) 

• A2-s1,d0 (very limited contribution to fire, very low smoke, no flaming droplets) 

Many Rockfon products achieve A1 or A2-s1,d0 classifications due to their stone wool core, which is a non-combustible material. The exact classification can vary depending on surface finishes, coatings, or product design, so the specific fire class should always be checked in the product datasheet or Declaration of Performance (DoP). 

In many building regulations, Class B-s1,d0 is often the minimum requirement for interior surfaces. Products rated A1 or A2-s1,d0 therefore exceed these requirements, which is why these classes are commonly considered “best in class”. 

These classifications are defined under the European framework, using reference test methods such as EN 13823 (SBI) and EN ISO 11925-2 (ignitability).  

2) Fire resistance (e.g., EI30, EI60) 

This describes how long a complete building installation, acting as a barrier, can resist fire exposure while maintaining its structural integrity. In this rating system: 

• E = integrity (prevents flames/hot gases passing through) 

• I = insulation (limits heat transfer) 

• and the number (e.g., 30, 60) is the time in minutes.  

These ratings apply to complete constructions or installations, not just individual materials. 

For suspended ceilings this often means a combination of tiles or panels, a suspension grid, fixings and clips, integrations, possibly even the structural deck above the ceiling. 

A common misunderstanding is assuming a high reaction-to-fire class automatically means a ceiling provides EI30/EI60. It doesn’t. EI ratings are about the full installation/assembly, not just a single tile.  

If you’re unsure which “fire rating” you need to take into account (Euroclass vs EI), contact us and we’ll help you understand the requirements for your project.