The ACP sheet core is the middle layer in the sandwich construction. It helps create a relatively thick, lightweight panel from thin metal skins, but its effect must always be assessed as part of the complete panel.
A typical aluminium composite panel is built as a bonded stack. The exact coating system, adhesive, metal specification and ACP sheet core vary by product grade and intended use.
We group ACP core choices into polyethylene-based and mineral-filled fire-retardant families. The best choice depends on application, fire strategy, building height, occupancy, panel grade and project approvals.
Virgin or recycled describes polymer feedstock origin, not the complete quality of an ACP sheet core. Virgin LDPE can offer higher strength and flexibility than recycled LDPE in comparable formulations, while finished-panel consistency still depends on formulation, cleanliness, extrusion, moisture control, bonding, lamination and testing.
| Particulars | Virgin LDPE core | Recycled LDPE core |
|---|---|---|
| Feedstock | New polymer resin with controlled origin. | Recovered polymer that requires segregation and contamination control. |
| Consistency | May offer more predictable formulation when processed correctly. | Can be consistent when source, blending and filtration are tightly controlled. |
| Fabrication | Can offer higher strength and flexibility than recycled LDPE in comparable formulations. | Fabrication response depends on source control, blending, extrusion, bonding and finished-panel performance. |
| Commercial effect | Usually carries a higher polymer-input cost. | Can support a more economical PE-core grade. |
| Buyer check | Ask for the exact grade, both skin thicknesses, core declaration, panel weight where relevant, bond quality and approved application. Do not accept a feedstock label as the only evidence. | |
A fire-retardant ACP sheet core contains a polymer binder and inorganic mineral fillers. The formulation is designed to lower heat release and flame development compared with a polyethylene-rich core, but classification belongs to the tested panel construction.
| Category | Classification reference | What it means in practice | What buyers must verify |
|---|---|---|---|
| FR0 / FR-O / FRO | BS 476 Part 6 & 7 Class 0 (legacy terminology) | A legacy reaction-to-fire category; it is not equivalent to DIN 4102 B1 or an EN 13501-1 classification. | Project acceptance and a matching, valid product test or classification. |
| FR B1 | DIN 4102 Class B1 | Aludecor FRB1 is a mineral-filled fire-retardant core with a nominal density of 1,550 kg/m³, used in panel configurations classified DIN 4102 B1. | Exact grade, panel build-up, current classification and project acceptance. |
| FR B | EN 13501-1 B-s1,d0 | Aludecor FRB uses about 72% inorganic content with a nominal core density of 1,650 kg/m³. The B-s1,d0 classification applies to the tested panel configuration. | Matching report for thickness, skins, alloy, coating, core and production configuration. |
| FR A2 | EN 13501-1 A2-s1,d0 | Aludecor FRA2 uses more than 90% mineral content with a nominal core density of 1,800 kg/m³. The A2-s1,d0 classification applies to the tested panel configuration. | Current A2-s1,d0 evidence and separate review of the complete façade assembly. |
MDH and ATH are mineral flame-retardant fillers used in engineered fire-retardant core formulations. Their presence alone does not establish a fire class; percentage, particle dispersion, binder content, panel build-up and test results all matter.
MDH absorbs heat as it decomposes and releases chemically bound water as vapour. In a properly formulated ACP sheet core, this can help cool the material and reduce flame development.
ATH, also called aluminium hydroxide, also releases bound water when heated. It can help reduce heat build-up and dilute combustible gases in a properly engineered formulation.
The grade code represents a complete product configuration. It combines total thickness, aluminium skin thickness, alloy, coating and available core options. The ACP sheet core must therefore be read as one part of the grade, not as the grade itself.
| Grade code | Total panel thickness | Top and bottom aluminium skin | Nominal core thickness | Core options listed |
|---|---|---|---|---|
| AL312 | 3 mm | 0.12 mm each | 2.76 mm | LDPE |
| AL32 | 3 mm | 0.20 mm each | 2.60 mm | LDPE / FR B1 |
| AL3C | 3 mm | 0.20 mm each | 2.60 mm | LDPE / FR B1 |
| AL33 | 3 mm | 0.25 mm each | 2.50 mm | LDPE / FR B1 |
| AL33D | 3 mm | 0.30 mm each | 2.40 mm | LDPE / FR B1 / FR B |
| AL43 | 4 mm | 0.25 mm each | 3.50 mm | LDPE / FR B1 |
| AL43D | 4 mm | 0.30 mm each | 3.40 mm | LDPE / FR B1 / FR B |
| AL445 | 4 mm | 0.45 mm each | 3.10 mm | LDPE / FR B1 / FR B |
| AL4E | 4 mm | 0.50 mm each | 3.00 mm | LDPE / FR B1 / FR B |
| AL45 | 4 mm | 0.50 mm each | 3.00 mm | LDPE / FR B1 / FR B / FR A2 |
| AL45D | 4 mm | 0.50 mm each | 3.00 mm | LDPE / FR B1 / FR B / FR A2 |
| AL4C | 4 mm | 0.20 mm each | 3.60 mm | LDPE / FR B1 |
| AL63 | 6 mm | 0.25 mm each | 5.50 mm | LDPE / FR B1 |
| AL65 | 6 mm | 0.50 mm each | 5.00 mm | LDPE / FR B1 / FR B |
These are standard grade-to-core combinations for the listed grade codes. Separately, Aludecor FireWall Class A2 is manufactured in 3 mm and 4 mm thicknesses, so this table should not be read as the complete list of FireWall A2 configurations. Confirm the exact product build-up before specification or order.
FR B1, FR B and FR A2 cores use mineral-filled formulations and generally require tighter formulation control, greater core mass, specialised processing and fire-performance documentation. The price premium must be compared against the exact classification and panel build-up.
A lower quote may use thinner skins, another alloy, a different coating, a different ACP sheet core, a smaller size, different commercial inclusions or no matching fire documentation. Normalize the specification before comparing rates.
LDPE may be considered where the project permits it and where fire, occupancy and circulation requirements do not demand an FR grade. Public and critical interiors may require a mineral-filled option.
Check panel size, skin thickness, flatness, routing, exposure and local fire requirements. The selected grade may use LDPE or an FR core depending on risk and specification.
Core choice must be reviewed with wind load, panel size, aluminium alloy, skin thickness, coating, height, occupancy, cavity design and fire strategy.
Use project-specific façade and fire-engineering review. Depending on the applicable code and project fire strategy, a tested B-s1,d0 or A2-s1,d0 panel may be specified. The core label alone does not approve the complete façade system.
Confirm reaction-to-fire, smoke, mechanical, impact, vibration, fabrication and maintenance requirements with the relevant authority and consultant.
Confirm whether the required core is available with the chosen coating, colour, width, length, alloy and minimum order. Changing the core may change the approved product configuration.
Through our 205 Tests approach, we encourage buyers, architects, façade consultants and project teams to look beyond colour, weight, thickness labels and unverified sales claims. The ACP sheet core must be checked together with the complete grade, both aluminium skins, coating system, bond quality and applicable classification documents.
For fire-retardant applications, verify the exact panel construction represented in the report. A core description alone cannot establish the performance of the finished panel, and panel-level evidence does not replace evaluation of the complete façade system, including cavities, insulation, barriers, sub-frame, fixings and workmanship.
Learn how complete ACP panels are constructed, finished and used across façades, signage and interiors.
Review our fire-retardant panel solutions, classifications and specification considerations.
Understand how thickness, skin, coating, finish, core and commercial scope influence price.
Learn how complete ACP panels are constructed, finished and used across façades, signage and interiors.
Review our 3 mm ACP panel price and current project documentation requirements.
Review our 4 mm ACP sheet price and current project documentation requirements.
Check out our Zinc Composite panel and Zinc Solid Panel pricing details.
Understand how Aluminium Honeycomb Panel skin, coating, finish, core influence the price.
Share the application details, location, building height for recommended specification.