What's the Difference Between Class 1 and Class 2 Powder Coating?
Understanding Qualicoat classifications and what they mean for your architectural aluminium project
By Azfar ·Technical Director 30April 2026 6 min read
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
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
The
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
Technical Requirements in Detail
4/30/26, 3:33AM
Test / Requirement
Artificial weathering (Xenon arc)
Natural weathering (Florida)
Corrosion resistance (NSS)
Adhesion (cross-hatch)
1000 hours — ≥40% gloss retention; ΔE ≤ 3
1 year — ΔE ≤ 3, ≥40% gloss retention
1000 hours — max 1mm
creep from scribe
GT0 (dry and wet after 24h immersion)
Boiling water resistance
Impact (reverse)
Film thickness
Gloss tolerance
GT0 after 2h at 100°C
2000 hours — ≥50% gloss retention; ΔE ≤ 2
3 years — ΔE ≤ 2, ≥50% gloss retention
1000 hours — max 1mm
creep from scribe
GT0 (dry and wet after 24h immersion)
GT0 after 2h at 100°C
No detachment at 80 cm·kg No detachment at 80 cm·kg
Minimum 60 μm mean, no
reading <40 μm
±5 GU of approved reference
When to Specify Each Class
Minimum 60 μm mean, no
reading <40 μm
±5 GU of approved reference
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 /
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
Southern Europe (Spain, Italy, Greece)
Middle East and North Africa
Coastal environments (salt-laden air)
Class 1 or Class 2
Industrial atmospheres
Class 2
Class 2
Class 1 or 2 + Seaside approval
Class 2 increasingly specified by demanding architects and specifiers on prestige projects
High UV dose — Class 1 will show visible fading within 5–8 years
Extreme UV and heat stress — Class 2 mandatory for meaningful service life
Qualicoat Seaside classification adds corrosion testing requirements for marine exposure
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 specificapprovedproducts, 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: Powdercoating shallbeappliedtoQualicoatSpecifications, Class2, byaQualicoat-licensed applicator. ThecoatingmaterialshallbelistedonthecurrentQualicoat ApprovedProductsListforClass2. Pre-treatmentshallconformtoQualicoat pre-treatmentrequirementsforaluminium. Theapplicatorshallprovidea Qualicoatcertificateofconformityforthecompletedwork 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.
WeareaQualicoat-licensedapplicatorforbothClass1andClass2powdercoatingon architecturalaluminium Wecanadviseontherightclassificationforyourproject, sourcefromtheQualicoatapprovedproductslist, andprovidethecertificatesof conformityrequiredbyarchitectsandclients. Contactourtechnicalteamtodiscussyour projectrequirements
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