A2 vs B1 Fire-Rated ACP: What the Numbers Actually Mean

If you've ever asked "which fire-rated panel do I need?" you've probably walked away from the conversation more confused than when you started. A2, B1, B2, Class A, Class 1, FR — the alphabet soup of fire ratings is real, and getting it wrong has serious consequences. This article clears it up.

The short version

Both A2 and B1 are considered "fire-rated" classifications under major international standards, but they perform very differently in a real fire. The difference comes down to what is in the core of the panel.

• A2 — practically non-combustible. The core is mineral-based (often aluminum hydroxide). It does not burn, does not release toxic gases, and does not produce flaming droplets.
• B1 — flame-retardant. The core is a low-smoke, fire-resistant polyethylene. It will not easily ignite, and flame spread is slow.

How each rating is measured

The two main international standards you will encounter are:

• EN 13501-1 (European): rates construction products as A1, A2, B, C, D, E, F based on a single-flame-source test (SBI) plus a small-flame test, plus smoke (s1, s2, s3) and burning droplets (d0, d1, d2). ALUCOVERBOND A2 panels are classified as A2-s1, d0 — the best possible rating short of "non-combustible" (A1).
• GB 8624-2012 (Chinese): uses A1, A2, B1, B2, B3 — a similar scale, but with different test conditions. Our A2 panel is A2 here too; our B1 panel is B1.

For a 50,000 m² commercial facade, choosing B1 where A2 is required can mean re-cladding the entire building. Specifying the right rating up front is the cheapest decision you'll make on the project.

Which rating do I need?

It depends on your local code, the building's height and its use. The general pattern is:

• High-rise residential or commercial (above ~24m in most markets): A2 is usually required
• Mid-rise commercial, hospitals, schools: A2 or B1, depending on local code
• Low-rise commercial, interior partitions, shopfitting: standard PE-core (B2) is usually acceptable

The mineral core difference

Standard PE-core ACP is rated as "B2 — normal flammable" under GB 8624. The plastic core melts and burns in a fire. To upgrade to B1, we add flame retardants to the PE compound. To upgrade to A2, we replace the plastic core entirely with a mineral-based compound (aluminum hydroxide + fillers).

That A2 core is roughly 50% heavier than PE-core, and the price per m² is about 1.8–2.2×. But it is the only choice for projects where the local code requires non-combustible cladding.

What we can provide

ALUCOVERBOND supplies both A2 and B1 panels, with current test reports from:

• EN 13501-1 (A2-s1, d0) — EU-notified body
• GB 8624-2012 (A2 and B1) — National Center for Building Materials Testing, China
• ASTM E84 (Class A) — for North American projects

Send us your project location, building height and the relevant local code — we will specify the right panel and provide the test certificates.