Corrosion Test Panel Rating Record Sheet: Rust, Blister, Creep

The record sheet covers coated test panels rated after accelerated or atmospheric exposure, mainly on steel and other nonporous substrates. It does not reproduce the pictorial references of ASTM D610, ASTM D714 or ISO 4628, which the rater needs beside the panel, and it does not rate cracking, flaking, filiform corrosion or pit depth.

What does a corrosion panel evaluation record sheet capture?

A corrosion panel evaluation record sheet captures one row per panel per inspection: which panel, which coating system and pretreatment, which exposure test and how many hours, and then the three ratings most coating specifications ask for, which are rust, blistering and creep at the scribe. Every row also carries the acceptance criterion the rating is read against and the judgment, so that ratings from different panels, inspections and laboratories can be compared on the same terms.

The three ratings come from three methods. ASTM D610-25 is a practice that quantifies the amount and distribution of visible surface rust (ASTM D610-25, section 3.1). ASTM D714-25 is a test method that describes blister size and density so that comparisons of severity can be made (ASTM D714-25, section 3.1). ASTM D1654-24e1 is a test method for evaluating coated specimens after exposure for corrosion, blistering associated with corrosion and loss of adhesion at a scribe mark (ASTM D1654-24e1, section 1.1). ISO 4628 covers the same defects in its own parts: blistering in part 2, rusting in part 3 and the scribe in part 8.

Published claims use the same three criteria. One coating maker's example reads: "No more than 1/32-inch rust creepage at scribe after 10,000 hours of exposure." (Tnemec, accessed 2026). A record sheet that holds all three ratings per panel and hour is what lets a reader check a claim like that against the panels behind it.

Which columns does a corrosion panel record sheet need?

A corrosion panel record sheet needs 26 columns, grouped as panel identity, exposure, the three ratings, evidence and the criterion with its judgment. The table below previews every column of the corrosion panel evaluation record so ratings from different panels, inspections and labs can be compared against the same criteria; every example value is illustrative.

The key row is the acceptance criterion: each rating is written beside the criterion frozen before exposure, so the judgment column can be checked by anyone reading the log.

Three groups of columns are easy to leave out and hard to rebuild later. The control panel ID ties each test panel to the reference system exposed beside it, which is what makes a judgment on the test panel readable. The exposure test with its edition and the cabinet ID tell a later reader which conditions the hours refer to, because hours from different tests or chambers are not interchangeable. The photo reference keeps the evidence for each rating, so a disputed grade can be rated again from the photo rather than from memory. Keep one row per panel per inspection; a new inspection is a new row, never an edit of the old one. If the plan rates to ISO 4628 rather than ASTM, fill the ISO 4628 column, leave the ASTM rating columns blank instead of converting, and say so in Notes. Add any extra column to the right of Notes, so every file keeps the same column order for import.

How do you record rust grade, blister size and density, and scribe creep per panel?

You record rust grade, blister size and density, and scribe creep per panel by rating each panel at each inspection against the standard's own pictorial references, writing each grade exactly as the standard designates it, and measuring creep at the scribe in millimetres. Write the method edition in the row, because a rating made to a superseded edition reads against a different text.

The table below lists the edition of each method this sheet uses that was in force on 2026-10-23, as shown in its catalogue entry.

The key row is ISO 4628-3:2024, because its 2016 edition was withdrawn and older records may cite it.

Rust goes first. ASTM D610-25 evaluates the degree of rusting on a zero to ten scale based on the percentage of visible surface rust, and classes the distribution as spot, general, pinpoint or hybrid (ASTM D610-25, sections 3.2 and 3.3). Its visual examples form part of the standard, and in a dispute the written definition prevails (ASTM D610-25, section 1.1).

Blistering comes second. ASTM D714-25 uses photographic reference standards, and states: "When the reference standards are used as a specification of performance, the permissible degree of blistering of the paint system shall be agreed upon by the purchaser and the seller." (ASTM D714-25, section 1.1).

The scribe comes last. ASTM D610-25 excludes rust propagation around a scribe (ASTM D610-25, section 1.1), so creep is rated under ASTM D1654-24e1 or ISO 4628-8:2012. In one public study, the Federal Highway Administration traced creepage twice per panel and reported the mean creepage distance (FHWA-HRT-12-044, 2012). Record mean and maximum in millimetres; a criterion may name either. A coatings patent that rates to D714 and D1654 gives the scribe rating as "rating 0-10 where 10 shows zero loss of adhesion at the scribe and 0 is a complete failure of the coating" (US 7,169,862 B2, 2007). It cites earlier editions; check against your copy.

How do you set each corrosion panel rating against the fixed acceptance criteria?

You set each corrosion panel rating against the fixed acceptance criteria by reading every rating beside the criterion written before exposure began, then recording one judgment per criterion: met, borderline, not met or unassessed. ASTM D714-25 requires the permissible degree of blistering to be agreed between purchaser and seller when its references are used as a specification (ASTM D714-25, section 1.1), and the same order holds for rust and creep: agree the limit first, rate second.

Rate the control panel before judging any test panel. ASTM D5894-21 says its cyclic test should not be used for a pass or fail approval after a set exposure period unless performance is compared with a control material exposed at the same time, or test variability is rigorously quantified (ASTM D5894-21, section 5.5). If the control behaves outside its known range, the run is in question before any panel is judged. Write each judgment with its inspection hour: a panel that met the criterion at 500 hours and failed it at 1000 hours (illustrative hours) has two rows and two judgments.

The table below decides what to do with each kind of reading of a corrosion panel against its criterion.

The key row is the third one: a control that fails with the test panels points to the run, not the coating. ISO 4628-3:2024 states that its rusting assessment is an estimate of the affected area and that edges are not included (ISO 4628-3:2024, scope).

How do you fill in and import the corrosion panel log?

You fill in the corrosion panel log by entering panel identity and the frozen criterion before the panels go into exposure, then adding one row per panel at every inspection, never overwriting an earlier row. The editable Word sheet, Excel log and CSV file are at the end of this page.

The Excel workbook has three sheets. The Instructions sheet repeats the rules on this page. The Log sheet has a frozen header row with the unit in each column name, so no rating loses its unit. The Example sheet holds illustrative rows only and is marked as such; enter real data on the Log sheet.

The CSV file holds the Log sheet header row only, saved as UTF-8 with a byte order mark, for systems and work logs that import CSV but not Excel. Save your filled Log sheet as CSV in the same way before importing it.

The Word sheet is a printable version for rating at the cabinet: run details and frozen criteria, a panel table with checkbox fields for rust distribution and judgment, a run check, and a separate illustrative example page. Transfer its entries to the Log sheet the same day.

Three habits keep the log usable. Write hours as exposure hours, not calendar dates alone. Photograph each panel at every rating, under the same light, and put the file name in the row. Leave a rating blank and write the reason in Notes rather than guessing a value.

Common mistakes when rating corrosion test panels

Common mistakes when rating corrosion test panels are rating without the standard's pictorial references at hand, mixing ASTM and ISO scales in one column, comparing panels from different runs or cabinets, rating edges, and changing the criterion after seeing the panels. Each one makes the log unreadable to the next person.

The ASTM and ISO scales are numbered differently. ISO 4628-2:2016 shows blister sizes 2 to 5 in quantities 2 to 5 (ISO 4628-2:2016, scope), while ASTM D714-25 uses its own designations, so a number cannot be copied from one column to the other. The withdrawn ISO 4628-3:2016 gave a correlation between its rust scale and ASTM D610 in Annex B (ISO 4628-3:2016, note 2); check the current edition before relying on any conversion.

Comparing across runs misleads too. ASTM D5894-21 says the practice is best used to compare materials tested at the same time in the same exposure device (ASTM D5894-21, section 5.5). ASTM B117-26a notes that variability has been observed when similar specimens are tested in different fog chambers under nominally similar conditions, and says sufficient replicates should be included (ASTM B117-26a, section 3.3).

A criterion relaxed after the panels are seen is a new criterion, and the panels already rated under the old one stay judged under the old one. Rating under changing light, or by a new person each time with no second rating, adds variation the log cannot separate from the coating; record the rater in every row.

What does a corrosion panel record sheet not tell you?

A corrosion panel record sheet does not tell you how long the coating will last in service, how two different exposure tests compare, or why a panel failed; it tells you how each panel rated against its criterion at each hour of one exposure. Field life needs field data or correlated long-term exposure.

ASTM B117-26a is direct about the limit: "Prediction of performance in natural environments has seldom been correlated with salt spray results when used as stand-alone data." (ASTM B117-26a, section 3.2). ASTM D5894-21 says that calculating an acceleration factor relating laboratory hours to months outdoors is not recommended, because materials and formulations can have significantly different acceleration factors (ASTM D5894-21, section 5.4). ISO 9227:2022 states that its salt spray methods are not intended for ranking materials against each other or for predicting long-term corrosion resistance (ISO 9227:2022, scope). ISO 12944-6:2018 presents its laboratory test results as an aid in selecting paint systems and not as exact information for determining durability (ISO 12944-6:2018, scope).

The log also does not explain a failure. A creep rating out of limit shows where to look, such as pretreatment, film thickness or adhesion, and the cause needs its own checks on retained panels and production records. In Lubinpla, a trial result evaluation reads per-panel results written beside the fixed criteria and judges each criterion as met, borderline or not met, marking one without a valid result as not judged.

Key takeaways

• Rate rust, blistering and scribe creep per panel and per inspection hour, each with its method and edition.

• Write every rating beside the criterion frozen before exposure, and judge the control panel first.

• Keep ASTM and ISO ratings in separate columns, and keep the pictorial references beside the panel.

• Treat the log as a comparison within one run, not a prediction of field life.