ACP cladding and fire performance: the core is the whole decision

An Aluminium Composite Panel is two thin aluminium skins bonded to a core. The skins are typically half a millimetre each. Everything else in the thickness is core.

That matters because the aluminium contributes very little to how the panel behaves in a fire. The core is the fuel, and the core is what the approval process is actually interested in.

Three core types, three different conversations

Polyethylene (PE) core. Unmodified PE is a thermoplastic with a high calorific value. In a façade cavity it can contribute significantly to vertical fire spread. Its use on buildings in the UAE has been progressively restricted, and specifying it on a new build is generally a non-starter. Assume it is not an option unless a competent fire engineer has specifically justified it for the application.

Fire-retardant (FR) core. Mineral-filled to reduce combustibility. This is a broad category, not a single product, and the level of mineral loading varies considerably between manufacturers. The classification on the datasheet and the supporting test evidence matter more than the letters "FR" on a label.

Limited-combustibility (A2) core. Very high mineral content with minimal organic binder. Where the building's fire strategy calls for a non-combustible or limited-combustibility façade, this is the category. It is heavier and costs more, and on a high-rise it is frequently the only thing that will be approved.

The requirement does not come from the supplier

This is the point that gets lost most often. No supplier — including us — determines what fire performance your façade needs.

That is set by the building's approved fire strategy, by the UAE Fire and Life Safety Code of Practice, and by the authority having jurisdiction. Building height, occupancy, cavity design and the proximity of other buildings all feed into it. A residential tower and a single-storey warehouse are not the same conversation.

The supplier's job is to supply against the approved specification and hand over the manufacturer's test documentation for what was actually delivered. Anyone offering to tell you what rating you need, rather than asking what rating was approved, is the wrong supplier.

Why substitution is the expensive mistake

ACP is often value-engineered late, when the cladding package is priced and the core looks like an easy saving. It is not.

Fire performance evidence attaches to a specific product from a specific manufacturer, tested in a specific system. Swapping to a different core — even one the label calls FR — means the documentation submitted for approval no longer describes what is on the building.

That is usually discovered at inspection, after the panels are installed. At that point the options are remedial testing, a fresh submission, or stripping and re-cladding. All three cost multiples of the saving that prompted the substitution.

If a core change genuinely is necessary, it goes back through approval before fabrication, not after installation.

Documentation to insist on

At order stage, ask for and keep:

• Manufacturer name, product name and the exact core designation
• Fire classification and the standard it was tested to
• Test certificates from a recognised laboratory
• Any local authority approval or listing for the product
• Coating warranty for the finish, which is a separate matter from the core

Keep these with the project record. They will be asked for at handover, and quite possibly again years later during a refinancing, an insurance review or a sale.

Two things unrelated to fire, worth getting right anyway

Flatness holds the whole appearance together. ACP's advantage over solid aluminium sheet is that a large panel stays genuinely flat. A panel that oil-cans under sun makes expensive cladding look cheap from across a car park. Panel size, thickness and the cassette fixing method all affect this.

Coating is not core. PVDF and polyester coatings behave very differently under Gulf UV. The coating governs how the façade looks in year eight; the core governs whether it is approved in year zero. They are separate specifications and both belong in the enquiry.