SSPC-PA 2

Introducing SSPC-PA 2 – Industrial Physics

SSPC-PA 2 is the widely specified standard for determining whether a coating meets its dry film thickness (DFT) requirements. Its full title is “Procedure for Determining Conformance to Dry Coating Thickness Requirements,” and it answers a question that the measurement-method standards do not: not just how to measure coating thickness, but how many readings to take, where, and how to judge whether the result passes.

It applies to coatings on both ferrous and non-ferrous metal substrates, and it works hand in hand with the gauge-use practice ASTM D7091. This gives quality, R&D, and operations experts a consistent, defensible way to accept or reject a coated structure – in the shop or in the field.

What SSPC-PA 2 Covers

SSPC-PA 2 defines a procedure for determining shop or field conformance to a specified DFT range, using the non-destructive coating thickness gauges described in ASTM D7091. Key elements of the standard include:

• A defined measurement hierarchy – gage reading, spot measurement, and area measurement – so results are built up consistently
• The frequency of measurements: how many readings and spots are required across a given area
• Rules for determining whether coating thickness conforms to the specified minimum and maximum
• Two gauge types, as in ASTM D7091: Type 1 (magnetic pull-off) and Type 2 (electronic)
• Appendices covering specific situations (such as different structure types and restriction levels), some of which become mandatory when invoked by the project specification

The measurement hierarchy is worth understanding: a gage reading is a single reading; a spot measurement is the average of at least three readings taken within a small (about 4 cm / 1.5 inch) circle; and an area measurement is the average of five spot measurements over each roughly 10 m2 (100 ft2) of coated surface.

The current version is SSPC-PA 2-2022, published by AMPP. The standard was first issued in 1973 and has been revised several times since. It references ASTM D7091 and ISO 19840. It’s worth confirming the current revision at the time of publishing.

Why Measurement Frequency and Conformance Matter

Coating thickness can vary widely across a single surface, so a handful of readings in the wrong places can give a misleading picture – passing a structure that is actually under-coated in parts, or rejecting one that is fine. SSPC-PA 2 exists to remove that ambiguity. By fixing how many readings to take, how to group them, and how to judge the result, it turns a scatter of individual readings into a clear, defensible accept or reject decision.

A consistent conformance procedure helps quality, R&D, and operations experts to:

• Judge whole structures fairly, not just convenient spots, using a defined sampling approach
• Settle accept or reject decisions with agreed rules rather than opinion or dispute
• Meet project specifications that call up SSPC-PA 2 by name
• Reduce costly rework, disputes, and coating failures caused by inconsistent inspection
• Produce auditable inspection records for contract and warranty purposes

Because coating thickness is easy to dispute when it is measured inconsistently, a standardised conformance procedure like SSPC-PA 2 protects the integrity of both the coating and the customer relationship – particularly across protective coatings on steel structures, and in marine, oil and gas, and heavy industrial work.

How SSPC-PA 2 Testing Works

First, the coating thickness gauge is calibrated, verified, and adjusted following ASTM D7091 – SSPC-PA 2 relies on those gauge-use steps rather than redefining them. Then measurements are built up through the standard’s hierarchy: several individual gage readings are averaged into a spot measurement, and a set of spot measurements is averaged into an area measurement, taken across each defined area of the structure.

The resulting spot and area measurements are compared against the specified minimum and maximum thickness using the standard’s conformance rules, giving a clear pass or fail. Where the project specification invokes particular appendices or restriction levels, those add further conditions. Measuring and judging the coating this way – to a set frequency, with defined acceptance rules – is what makes the outcome consistent and defensible.

SSPC-PA 2 Testing Equipment

Industrial Physics offers a coating thickness gauge from TQC Sheen that supports SSPC-PA 2 dry film thickness measurement and conformance testing.

TQC Sheen PosiTector 6000 Coating Thickness Gauge

The TQC Sheen PosiTector 6000 is a rugged, fully electronic coating thickness gauge that suits SSPC-PA 2 work particularly well. The Advanced model includes a dedicated SSPC-PA 2 compliance mode, which helps build up gage readings, spot measurements, and area measurements the way the standard requires – and it measures on both ferrous (magnetic method) and non-ferrous (eddy-current method) substrates, automatically recognising the substrate.

Typical features include:

• A built-in SSPC-PA 2 compliance mode on the Advanced model, plus ISO 19840 and PSPC 90/10 modes
• Magnetic and eddy-current measurement, with automatic recognition of ferrous and non-ferrous substrates
• Scan modes for fast, repeated readings when building up spot and area measurements
• Rugged, weatherproof design with built-in temperature compensation for reliable readings in the field
• WiFi and Bluetooth connectivity and real-time graphing on the Advanced model for straightforward inspection reporting

The PosiTector 6000 conforms to a wide range of national and international standards, including SSPC-PA 2, ISO 19840, and the ASTM D7091, B499, and B244 methods it relies on. If you’re not sure which model or probe best fits your structures and coatings, our experts can help guide you to the right choice.

Your Global Test and Measurement Partner for SSPC-PA 2

Industrial Physics supports quality, R&D, and operations experts around the world with the paint and coating test and measurement expertise needed to work confidently with standards like SSPC-PA 2. Whether you’re inspecting a coated steel structure, settling an accept or reject decision, or producing inspection records for a contract, we can help you achieve accurate, repeatable, and reliable dry film thickness results.

Get in touch to talk through your dry film thickness measurement and conformance requirements.