PVDF Aluminum Coil for Facade and Rainscreen Cladding: Specification Notes.

Why does PVDF come up on facade and rainscreen projects?

Because a facade asks the coating to hold color and surface condition through years of sun, rain and cleaning. PVDF is a fluoropolymer. The Fenestration and Glazing Industry Alliance (FGIA) groups AAMA 2603, 2604 and 2605 as its "good, better, best" category of aluminum finishes; AAMA 2605 is titled Superior Performing Organic Coatings (see FGIA: finishes documents (AAMA 2603, 2604, 2605)). A specification tier describes a performance bar, not a guarantee of service life.

For how PVDF compares with PE and HDPE, and for where AAMA 2605 sits in the picture, see the PE vs PVDF comparison.

What does 70:30 mean on a PVDF specification?

It describes the resin binder: 70 parts PVDF resin to 30 parts acrylic resin by weight. Ask the coating supplier for the resin content and the specification tier the system is tested to. Pigment and the other coating components are in addition to the binder.

State the PVDF content your specification names. A 70:30 PVDF ratio does not by itself show compliance with a performance specification such as AAMA 2605. That is shown by test reports.

How does color retention show up on a facade?

As slow change, not sudden failure: chalking, fade and loss of gloss develop with sun and weather exposure. A coating that holds its color and gloss changes less between the day the panels go up and years later, and the difference is visible where panels from different elevations are seen side by side.

Gloss and color change are measured by methods such as ASTM D523 and ASTM D2244. A specification should say which measurement and which exposure it relies on, rather than asking for color retention in general terms.

How do I specify panel-to-panel consistency?

Treat it as a written requirement. State the color by RAL reference or an approved physical sample, agree a color difference tolerance in delta E, and name the formula and the measurement basis. ASTM D2244 describes how the difference is calculated from measured color coordinates. Decide before ordering which panels will come from which production quantity, because if one elevation is ordered months after another, the tolerance is what protects the match.

Metallic and textured finishes should be approved as physical samples, viewed in the light the facade will see, since they can look different from a flat solid color as the light changes. Orbit coats in any RAL or custom color, in solid, metallic, woodgrain, brushed, matte or gloss, and textured finishes. Availability by coating system, color and volume is confirmed through an RFQ.

How does coastal exposure change the specification?

It raises the demand on the coating and on the warranty. Orbit's warranty on coated coil runs 5 to 20 years by application and environment, with coastal exposure the more demanding case, and the term is confirmed for your specification. State the exposure in the RFQ, including how close the building is to the shoreline. Coastal performance also depends on pretreatment, cut edges, maintenance and installation, not the resin alone.

Treat the alloy as a separate decision. Two alloys used for cladding, 3003 and 5052, are compared in 3003 vs 5052 aluminum for outdoor coil coating.

How does panel type, ACP or single-skin tray, change the coating question?

The coating family is the same, but it is stressed in different places. An ACP skin is coated coil that is later laminated to a core, so the coating has to survive lamination and fabrication as well as weather. The ACP specification post covers the coil side of that.

A single-skin tray or cassette is formed from coated material, so the coating has to survive the bends at corners and returns without cracking, which a T-bend result indicates. Tell the supplier which panel type the coil is going into so that coating, alloy and temper are confirmed together.

What should I ask any coil coater to put in writing?

These are questions for any supplier, not statements about Orbit. Get the answers in writing:

• Coating resin: which resin is the topcoat, and for PVDF, what share of the binder is PVDF resin?
• Pretreatment: ask the supplier to state the pretreatment applied to the substrate.
• Substrate: which alloy, temper and gauge does the quoted coating system apply to?
• Color tolerance: which delta E tolerance applies, by which formula and measurement basis?
• Forming requirements: which bend radius or T-bend result does your panel type need the coating to survive?
• Test reports: ask the supplier to state which tests were run, to which standards, on which substrate and coating system.
• Warranty terms: what term applies, under which exposure conditions, and what does it cover?

What should a facade coating inquiry include?

• Exposure: inland or coastal, with the distance from the shoreline if coastal
• RAL or custom color and finish, including gloss level
• Panel type and the forming operation
• Alloy, temper, gauge and width
• Total quantity, phasing and destination
• Warranty requirement, and any coating standard your specification cites

Orbit's confirmed certifications are ISO 9001, ISO 14001 and ISO 45001. Coated coil is up to 1.60 mm thick and 1350 mm wide, so check that your gauge and panel width fit that range. Fire performance is set by the panel system and local building regulations and is outside this post. We respond to RFQs within one business day.

Common questions

References

• FGIA: finishes documents (AAMA 2603, 2604, 2605): FGIA lists the AAMA 2603, 2604 and 2605 finishes documents and calls them "good, better, best".