What does a specifier check before approving a coating system?
They check the whole system rather than a single product: surface preparation, primer, intermediate and topcoat, with dry film thickness for each and a corrosion category the system is rated for. A single-product page cannot be specified, because coatings are approved as systems.
A corrosion engineer is writing a protective coating specification that has to survive a consultant's review and twenty years of service.
Reviewed 4 August 2026
Scope and specifications
- Product type and binder chemistry
- Epoxy, polyurethane, alkyd and zinc-rich differ in everything that matters.
- System build-up
- Primer, intermediate and topcoat with dry film thickness for each.
- Corrosion category and durability
- The classification a specification will reference.
- Surface preparation required
- Determines whether the applicator can achieve it on site.
- Volume solids and theoretical spreading rate
- How the buyer costs the job.
- Overcoating window and pot life
- Application planning depends on it.
- Colour system and finish
- Standard fan decks and gloss levels.
Documents buyers may need
| Document | What it proves | Where it belongs |
|---|---|---|
| Technical Data SheetAsked at: specification stage | System build-up, film thickness, spreading rate and application limits | Publish it |
| Safety Data SheetAsked at: before site use | Hazard, handling and ventilation requirements | Publish it |
| Corrosion test reportAsked at: specification and approval | Salt spray, cyclic or immersion performance under a named standard | Publish it |
| Certificate of AnalysisAsked at: each delivery | Batch conformance for the delivered material | Per shipment |
| Volatile organic compound declarationAsked at: regulatory review | Compliance with the destination market's limits | Publish it |
| Approved applicator or warranty termsAsked at: before specification is locked | What is covered, for how long, and under what application conditions | Publish it |
| Reference project listAsked at: risk assessment | That the system has performed in comparable exposure | Publish it |
Details for a useful enquiry
- Substrate and its current condition
- New steel and maintenance repaint are different systems.
- Exposure environment
- Determines the corrosion category required.
- Required durability
- Drives the number of coats and the chemistry.
- Area to be coated
- The basis of both quantity and price.
- Application method and site conditions
- Spray, brush and roller change the product choice.
- Project location and timing
- Freight, shelf life and weather windows.
Questions suppliers ask
Should we publish a full system specification for each environment?
Yes. A specifier's job is to select a system for an exposure, so a page organised by exposure environment rather than by product does their work for them. It also reduces the misapplication that damages your reputation when a single product is used alone.
How should warranty be presented?
State what is covered, the conditions that must be met, and who must apply it. Coating warranties nearly always depend on surface preparation and applicator approval, and a warranty presented without those conditions will be read as either misleading or worthless.
Are colour cards worth putting online?
Yes for the standard ranges, with the colour standard named. Screen colour is never accurate and everyone knows it, but the range and the reference system tell a buyer whether their required colour is a stock item or a special.
Check which documents and standards your buyer needs; requirements vary by market, customer and contract.
Plact Research. Plact's editorial desk for buyer-evidence research. Industry standards, documents and buyer questions are researched and drafted with Plact's AI tools, then reviewed by Praveen Kavuri before publication. Every claim cites the standard, regulation or public source it rests on.
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