If you are specifying powder coating for architectural aluminium — windows, curtain wall, cladding panels, louvres, or shopfronts — the Qualicoat classification system is the single most important quality framework you need to understand. Class 1 and Class 2 are not grades of craftsmanship. They are defined weathering performance thresholds, and specifying the wrong class for a demanding environment is a mistake that can cost significantly more to remediate than the original coating.

What Is Qualicoat?

Qualicoat is an international quality label organisation founded in Switzerland in 1986. It sets and enforces technical standards for the lacquering and powder coating of aluminium for architectural applications. An applicator holding a Qualicoat licence has been audited and approved to apply powder coatings to Qualicoat Specifications, with regular third-party surveillance.

The Qualicoat Specifications define not only the coating performance requirements but also the pre-treatment process, the approved coating materials (products must be individually approved and listed in the Qualicoat approved products list), and the frequency of quality control testing required on the production line. It is a system-level quality framework, not just a product test.

Class 1 vs Class 2: The Core Distinction

Qualicoat

Class 1

Standard polyester powder coating
Minimum 40% gloss retention after 1000h artificial weathering (Xenon arc, ISO 16474-2)
Suitable for most European climates — northern and central Europe, most UK applications
Products must be Qualicoat-approved Class 1
Widest range of approved colours and products
Lower cost per unit than Class 2
10-year expected colour stability in moderate UV environments

Qualicoat

Class 2

Super-durable (PVDF-comparable) polyester powder coating
Minimum 50% gloss retention after 2000h artificial weathering (Xenon arc)
Mandatory for high UV-exposure environments — southern Europe, Middle East, coastal subtropical
Products must be Qualicoat-approved Class 2 — smaller approved list
Tighter colour stability: ΔE ≤ 2 after 1000h Florida exposure
Higher cost — super-durable resins command a premium
Expected 15–20 year colour stability in demanding environments

The Technical Requirements in Detail

Test / Requirement	Class 1	Class 2
Artificial weathering (Xenon arc)	1000 hours — ≥40% gloss retention; ΔE ≤ 3	2000 hours — ≥50% gloss retention; ΔE ≤ 2
Natural weathering (Florida)	1 year — ΔE ≤ 3, ≥40% gloss retention	3 years — ΔE ≤ 2, ≥50% gloss retention
Corrosion resistance (NSS)	1000 hours — max 1mm creep from scribe	1000 hours — max 1mm creep from scribe
Adhesion (cross-hatch)	GT0 (dry and wet after 24h immersion)	GT0 (dry and wet after 24h immersion)
Boiling water resistance	GT0 after 2h at 100°C	GT0 after 2h at 100°C
Impact (reverse)	No detachment at 80 cm·kg	No detachment at 80 cm·kg
Film thickness	Minimum 60 μm mean, no reading <40 μm	Minimum 60 μm mean, no reading <40 μm
Gloss tolerance	±5 GU of approved reference	±5 GU of approved reference

When to Specify Each Class

Qualicoat's own guidelines and accumulated field data provide a clear framework for matching class to environment. The key variable is UV intensity — specifically the annual UV dose (kJ/m²) experienced at the installation location.

Application / Location	Recommended Class	Rationale
UK residential windows and doors	Class 1	Moderate UV, temperate climate — Class 1 provides adequate 10–15 year performance
UK commercial facades and curtain wall	Class 1 or Class 2	Class 2 increasingly specified by demanding architects and specifiers on prestige projects
Southern Europe (Spain, Italy, Greece)	Class 2	High UV dose — Class 1 will show visible fading within 5–8 years
Middle East and North Africa	Class 2	Extreme UV and heat stress — Class 2 mandatory for meaningful service life
Coastal environments (salt-laden air)	Class 1 or 2 + Seaside approval	Qualicoat Seaside classification adds corrosion testing requirements for marine exposure
Industrial atmospheres	Class 1 minimum	Chemical resistance requirements dominate — also specify corrosion test performance

The Qualicoat Seaside Classification

Beyond Class 1 and Class 2, Qualicoat also administers a separate Seaside classification for coatings applied to aluminium in coastal environments within 3km of the sea. Seaside-approved products have passed additional corrosion testing in salt-laden atmospheres. If your project is near the coast, always specify Qualicoat Seaside in addition to the weathering class — Seaside products are available in both Class 1 and Class 2.

The Approved Products List

A critical aspect of Qualicoat that is often misunderstood: the classification applies to specific approved products, not to chemistry types in general. A powder coating manufacturer must submit their product for Qualicoat testing, pass the relevant tests for the class being sought, and be listed on the Qualicoat Approved Products List (published and updated regularly at qualicoat.net).

This means that not every polyester powder coating is automatically Class 1 compliant — only products that have been tested and listed can be used on Qualicoat-certified work. When specifying Qualicoat, it is entirely reasonable to ask your applicator which specific powder product they will be using and to verify it against the current approved list.

What About Class 3?

Qualicoat introduced a Class 3 classification for fluoropolymer (PVDF/FEVE) liquid and powder coatings. Class 3 products are primarily liquid fluoropolymer systems (such as Kynar-based coatings) and a small number of fluoropolymer-rich powder systems. They are specified for the most demanding architectural applications — iconic buildings, long-design-life facades in harsh climates — where a 30+ year colour stability expectation is required.

Class 3 products carry a significant cost premium and are relatively rarely used in standard UK construction. Most specifiers for UK commercial projects will find that Class 2 provides the performance they need at a considerably lower cost.

Specification Language to Use

When writing a specification, use precise Qualicoat language: Powder coating shall be applied to Qualicoat Specifications, Class 2, by a Qualicoat-licensed applicator. The coating material shall be listed on the current Qualicoat Approved Products List for Class 2. Pre-treatment shall conform to Qualicoat pre-treatment requirements for aluminium. The applicator shall provide a Qualicoat certificate of conformity for the completed work. This language is auditable, enforceable, and clearly understood across the supply chain.

Cost Difference Between Class 1 and Class 2

Class 2 super-durable powders typically cost 15–30% more than equivalent Class 1 products. On a typical commercial facade project, this translates to a relatively modest uplift in the overall coating cost — often 5–8% of the powder coating contract value — but the difference in service life can be 5–10 years of additional colour stability before remediation is needed. For a large or prominent building, that value is almost always worth capturing.

We are a Qualicoat-licensed applicator for both Class 1 and Class 2 powder coating on architectural aluminium. We can advise on the right classification for your project, source from the Qualicoat approved products list, and provide the certificates of conformity required by architects and clients. Contact our technical team to discuss your project requirements.

What's the Difference Between Class 1 and Class 2 Powder Coating?

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