Quick answer: Choose a coating thickness method for the actual coating and substrate. Then identify the required standard edition, sampling procedure and acceptance limits in the project documents. A standard that describes a measurement method does not automatically certify an instrument or define a universal acceptable film thickness.
Common questions about standards and compliance
Which standard applies to magnetic measurement?
ISO 2178:2016 covers magnetic measurement of nonmagnetizable coatings on magnetizable base metals. Confirm both materials: “steel” alone is not enough to establish that a particular substrate is suitable for a magnetic method.
Which standard applies to eddy-current measurement?
ISO 2360:2017 covers amplitude-sensitive eddy-current measurement of nonconductive coatings on nonmagnetic conductive base metals. Aluminum with an appropriate nonconductive coating is a typical combination. The scope is not a blanket rule for every metal or coating.
What does ISO 2808 cover?
ISO 2808:2019 describes methods for determining paint-film thickness, including wet film, dry film and uncured powder. Select the method suited to the job rather than treating all methods as interchangeable. Roughness, geometry and the condition of the coating matter.
Does ASTM D7091 set the acceptable thickness?
The ASTM D7091-22 catalog describes a practice for nondestructive dry-film measurement on specified metal substrates, including calibration, verification and adjustment of gauges. Do not use its method scope as a universal acceptance limit. Obtain the applicable sampling and acceptance requirements from the coating specification, contract or cited inspection procedure.
What about a coating on a nonmetallic substrate?
Ordinary magnetic and eddy-current coating gauges require the appropriate metal substrate. ASTM D6132-13(2022) addresses ultrasonic measurement of organic coatings over a dissimilar substrate. Whether an ultrasonic instrument works on a particular stack depends on its specifications, acoustic interfaces and validation on representative samples; the standard’s title does not guarantee every material combination.
Is coating thickness the same as wall thickness?
No. The measurand must be explicit. A coating method concerns a film or coating system; a wall-thickness measurement concerns the underlying component. Specify which quantity is required before choosing the method and reporting a result.
Does “measured according to a standard” mean a product is certified?
No. A documented measurement procedure, calibration evidence, an inspection result and product certification are distinct things. Claim only what the actual documents support. Do not describe an instrument as ISO-certified merely because its operating principle corresponds to a method standard.
Which edition should the report cite?
Use the edition required by the contract and check the publisher’s current catalog. The source links below identify ISO 2178:2016, ISO 2360:2017, ISO 2808:2019, ASTM D7091-22 and ASTM D6132-13(2022), checked October 6, 2026. These public scope pages do not replace the full normative text or the project’s requirements.
What to record before issuing a compliance conclusion
| Record | Purpose |
|---|---|
| Coating, substrate and measured quantity | Establish whether the method fits the job. |
| Standard identifier and edition | Make the referenced procedure traceable. |
| Gauge, probe and verification evidence | Document the measurement conditions. |
| Locations, individual readings and sampling rule | Explain what was inspected. |
| Acceptance document and limits | Support the pass/fail conclusion. |
Use our inspection-record guide and measurement checklist to keep the evidence together.
Publisher sources
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