PPGI and PPGL Coil Sourcing for Roofing Panel Production
For coloured roofing panels, choose the complete substrate and coating system before approving the colour. This guide helps you define metallic coating, paint films and appearance separately, then test the actual stack through your forming line. Use the accepted flat and formed samples to compare the next coil offer with the same roofing requirement.
Specify the complete coloured-coil construction
If you form coloured roofing panels, choose the complete coating system before approving a colour chip or low coil price. Start with the substrate and metallic coating, then define pretreatment, paint system, front/back films and the forming and exposure requirements. PPGI and PPGL are different feedstock identities, not interchangeable labels. Relia manufactures plate and coil, while galvanizing and colour coating are agreed per order. Send the panel profile and coating specification so the actual offered stack can be checked by records and a representative formed sample before repeat production.
- Steel substrateName the grade and actual thickness required for the roofing profile.
- Metallic protectionSelect zinc or aluminium-zinc coating with its own designation and acceptance basis.
- Paint systemDefine front and reverse construction together with exposure and forming acceptance.
Selection context and decision detail
| Buyer requirement | Relia response | Evidence / condition |
|---|---|---|
| Defined roofing input | Manufactured plate/coil and selected rolling | One substrate and actual geometry |
| Complete protection stack | Coating responsibility agreed per order | Metallic layer, pretreatment and paint definition |
| Repeatable release | QC stages and corresponding batch records | Coil identity, layer evidence and forming sample |
Rolling and the coating stack need separate responsibility
Assign rolling, galvanizing and colour-coating responsibilities for the selected order, with records covering the actual supplied layers.
Relia performs selected hot or cold rolling in-house for plate and coil. Galvanizing and colour coating must be identified for the particular order. Incoming, in-process and final inspection and corresponding batch records are confirmed; they do not establish every pretreatment or paint line as in-house.
The colour-coil listing combines PPGI/PPGL, describes 0.2–5 mm and differing zinc fields, and offers 100–600 m by 600–2000 mm ranges. Requested 0.40/0.50 mm, 15/7 µm and title RAL colours are not separate actual options.
- Selected rollingRelia performs the selected hot or cold rolling for its steel plate and coil.
- Coating responsibilityIdentify galvanizing and colour-coating providers for the actual order rather than assuming ownership.
- Represented recordsAgree which staged inspection records cover the supplied substrate and coating construction.
A colour reference does not describe the protection system
Define substrate, metallic coating and paint system separately because colour alone cannot describe protection or adhesion.
Each layer has its own role
The substrate carries the panel; the metallic layer and the pretreatment/primer/topcoat system perform different roles. Cleaning and pretreatment support adhesion, and curing establishes the paint film condition. These are generic process relationships, not a declaration of the offered line's settings. Match the chosen system to exposure and forming rather than using colour alone as the specification.
- Structural substrateThe selected steel and its condition support the panel geometry during forming.
- Metallic layerDefine the protective coating separately from the visible paint colour and gloss.
- Pretreatment and paintIdentify the system supporting adhesion and the accepted cured paint-film condition.
Product references for your shortlist
Open the product details, then discuss the exact specification for your application.
Colour-coated roofing-coil enquiry
An enquiry reference for a selected painted steel construction evaluated against roofing exposure, appearance and roll-forming requirements.
Metallic-coated substrate enquiry
A separate substrate reference when reviewing the selected metallic-coating identity underlying a proposed painted roofing-coil construction.
Metallic coating chemistry and paint films use different bases
Keep metallic-coating chemistry and mass distinct from the thickness of front and reverse paint films.
State whether the substrate is zinc or aluminium-zinc coated and identify its designation and measurement basis. Define front and reverse paint films separately where required. Do not compare a metallic-coating mass directly with a paint-film thickness. The second coil listing also mixes AZ/Z wording and unitless gauge information; resolve those fields before treating it as the PPGL input.
- Metallic layerName zinc or aluminium-zinc chemistry and the applicable coating-mass designation and measurement basis.
- Paint filmsSpecify front and reverse paint-film thicknesses separately where required by the construction.
- Steel thicknessConfirm the actual substrate gauge and units before comparing the proposed coated input.
Forming can reveal an adhesion or flexibility mismatch
Retain flat and formed samples to distinguish substrate fracture, coating failure and tool-induced surface scoring.
Run the intended profile with identified coil, tooling and settings. Inspect demanding bends for substrate fracture, coating cracking or paint delamination, and inspect contact zones for tool-induced scoring. Those observations have different causes. Keep a flat input reference and the formed sample so an incoming-system mismatch can be distinguished from line damage.
- Flat inputRetain identified starting material and coating alongside the actual tooling and line settings.
- Demanding bendsInspect substrate fracture, coating cracking and paint delamination at the critical profile radii.
- Contact zonesLocate tool-induced scoring separately so incoming coating behavior is not confused with line damage.
Colour and gloss need controlled comparison
Compare colour, gloss and texture under controlled viewing conditions rather than accepting an attractive isolated chip.
Compare appearance under agreed conditions
Compare the approved surface under agreed lighting and orientation. Colour designation, gloss and visible texture describe different appearance characteristics. A colour chip does not demonstrate film thickness, adhesion or long-term weathering. If panels are installed together, define the accepted appearance variation and preserve the relevant lot references rather than mixing attractive but unmatched samples.
- Colour referenceUse the retained approved sample and the selected colour designation together.
- Gloss and textureAssess these characteristics separately rather than treating a colour match as complete approval.
- Panel groupingPreserve lot references and the appearance limits for panels intended to be installed together.
QC records should follow each layer and the represented coil
Connect layer-specific records and methods to the represented coil without treating laboratory results as a universal roof-life guarantee.
Connect substrate identity, dimensional basis and agreed coating results to the offered coil. Confirm which incoming/process/final records cover the actual rolling and coating scope. No particular film gauge, accelerated test or inspection frequency is presumed. A laboratory result needs its method and represented sample; it does not automatically become a roof-life warranty.
- SteelGrade and actual thickness
- Metallic layerChemistry and mass basis
- PaintFace/reverse system and tests
- TraceabilityRepresented coil and approved revision
Packing should prevent avoidable wetness and rubbing
Specify protection and support around the transport route, documenting wetness and rubbing before the forming line starts.
Preserve the surface before forming starts
Define protection and coil support against the actual handling and transport route. Trapped moisture and movement can affect appearance before the forming line starts. Record wrapper condition, coil identity and damage location at receipt. A wrapped-coil illustration is not a contractual packing specification or evidence of corrosion-life performance.
- Coil supportAgree support and protection for the actual transport, unloading and handling route.
- Wrapper conditionRecord wetness or damage when the package arrives with its coil identity.
- Surface locationLocate rubbing or other marks before processing changes the original delivery context.
Repeat orders preserve the full approved stack
Preserve every approved layer, appearance reference and package detail as one repeat-order construction revision.
Retain substrate, metallic coating, paint system, front/back films, colour/gloss reference and package as one revision. Review a proposed change to any layer, not just the visible colour. Include the successful forming conditions and records used for release. A repeated colour name is not proof that the underlying product is unchanged.
- ApproveComplete construction and retained colour sample
- RepeatSpecify the same accepted revision
- TraceConnect delivered coils to formed panels
Define the roofing coating stack
Send the profile and layered coating brief so the actual PPGI or PPGL offer can be defined coherently.
Share the profile and exposure with a layered coating brief so we can discuss a defined coil construction and the records and samples needed for release.
Qingdao Relia Industries Co., Ltd.
Contact address: Shuyuan Road, Qingdao, Shandong, China
- Substrate grade and thickness basis
- Metallic coating identity and mass convention
- Front and reverse paint requirements
- Colour gloss and appearance sample
- Profile coil limits and trial quantity
Enquiry scope and supporting detail
Send selected substrate, actual thickness, width and coil limits together with metallic-coating identity, paint system, face/reverse requirements and colour reference. Add the exposure and formed-panel acceptance. We can then review a defined PPGI or PPGL offer, assign coating responsibility and agree useful records and commercial terms without relying on mixed catalogue labels.
- ProjectExposure and coating approval requirements
- CoilSubstrate, paint, colour and dimensions
- LineHandling limits, sample trial and quantity