AMPP CAS-2 key terms

The microscopic roughness pattern created on a substrate by abrasive blasting or other surface preparation, measured as peak-to-valley height. It gives the coating a mechanical key to grip the steel surface.

A surface preparation method that propels grit, shot, or other media at high velocity against a substrate to remove rust, mill scale, old coatings, and contaminants while creating a roughened profile.

A joint standard describing near-white blast cleaning, in which at least 95 percent of the surface area is free of visible residues, with only slight staining permitted on the remaining 5 percent.

A joint standard for commercial blast cleaning, requiring removal of all visible oil, grease, dirt, mill scale, rust, and old coatings so that at least two-thirds of the surface is free of residues.

A photographic or physical reference, such as SSPC-VIS 1, used to compare a prepared substrate against a defined cleanliness grade so inspectors can judge conformance consistently.

A reference disc, plate, or replica with known roughness values that an inspector places against the prepared substrate to estimate anchor profile depth by touch and sight.

All operations performed on a substrate before coating application to make it suitably clean, dry, and rough, including solvent cleaning, blasting, and power tooling. It largely determines coating service life.

Removal of oil, grease, and similar soluble contaminants using solvents, emulsions, or alkaline cleaners before mechanical preparation. It prevents contaminants from being driven into the surface during blasting.

Ionic contaminants such as chlorides and sulfates left on a substrate after preparation. They draw moisture through a coating and promote osmotic blistering and underfilm corrosion if not removed.

A field method that measures the electrical conductivity of water used to wash a surface, indicating the concentration of soluble salts present and whether cleaning is adequate.

The temperature at which moisture in the air begins to condense on a surface. Coating should not be applied when the substrate is at or near dew point, typically within 3 degrees Celsius.

The amount of water vapor in the air expressed as a percentage of the maximum it could hold at that temperature. It affects drying, curing, and the risk of condensation on the substrate.

The temperature of the substrate itself, which governs coating wetting, cure, and condensation risk. It must be measured directly rather than assumed from ambient air temperature.

The combined ambient factors of air temperature, humidity, dew point, and substrate temperature that must be within the coating manufacturer's limits before and during application.

An extra coat brushed into welds, edges, corners, fasteners, and other hard-to-reach areas before or after the main coat, ensuring adequate film thickness where spray tends to thin out.

The thickness of the cured coating measured after the film has dried, usually with a magnetic or eddy current gauge. It is the primary acceptance criterion for coating thickness specifications.

The thickness of a coating measured while still wet, often with a comb gauge, allowing applicators to adjust spray passes and estimate the resulting dry film thickness.

An instrument, commonly magnetic or eddy current based, used to measure dry film thickness non-destructively on steel or other substrates after the coating has cured.

The percentage of a coating's liquid volume that remains as solid film after solvent evaporates. It is used to calculate expected dry film thickness from wet film thickness.

A discontinuity, pinhole, or thin spot in a coating film that exposes the substrate or leaves insufficient protection. Holidays are located with visual inspection or high-voltage detection equipment.

A device that applies a voltage across a conductive substrate and a coating to reveal breaks in the film, indicated by a spark or audible alarm at the defect.

A tiny hole through a coating film, often caused by solvent escape, air entrapment, or surface contamination, that leaves a path for moisture to reach the substrate.

Lifting of a coating film into dome-shaped blisters caused by water and soluble salts drawing moisture through the film by osmosis, usually traced to inadequate surface cleaning.

Release of trapped air, solvent, or gas from a porous substrate or weld during coating cure, which can create bubbles or pinholes in the applied film.

Bonding of a coating to a substrate through physical interlocking into a roughened surface profile, as opposed to chemical or polar bonding at the interface.

A test such as pull-off or cross-cut that measures how strongly a coating bonds to the substrate or to an underlying coat, used to verify application quality.

An adhesion test in which a loading fixture is glued to the coating and pulled perpendicular to the surface until failure, reporting the stress at which the coating detaches.

Verification and adjustment of an inspection instrument against a known reference, such as foils for a thickness gauge, so measurements are accurate and traceable.

A stage in an inspection and test plan where work must stop and be verified or approved by the inspector before the next activity can proceed.

A documented schedule defining the inspection activities, acceptance criteria, and hold or witness points required at each stage of a coating project.

The planned inspection, testing, and documentation activities used to confirm that surface preparation and coating work meet the specified standards before acceptance.

The usable working time of a mixed multi-component coating before its viscosity rises so much that application quality suffers. Exceeding it can cause poor flow and incomplete cure.

The waiting period after mixing two or more coating components and before application, allowing chemical reactions to begin so the product performs as formulated.

The specified proportion of base and hardener or catalyst that must be combined for a multi-component coating to cure correctly, usually given by volume.

The minimum and maximum time allowed between applying successive coats of a coating system, within which the next coat will bond properly without solvent entrapment.

An enclosed or partially enclosed area with limited entry and exit that is not designed for continuous occupancy, such as a tank interior, requiring atmospheric testing and attendant monitoring.

Testing of the air in a work area for oxygen content, flammable gases, and toxic vapors before entry and continuously during work to confirm it is safe.

The minimum concentration of a flammable vapor in air at which ignition can occur. Work is typically stopped well below this level, often at 10 percent of the LEL.

Supplying fresh air and removing contaminated air from a work area to control solvent vapor, dust, and oxygen deficiency, especially in confined spaces.

Gear such as respirators, gloves, eye protection, and protective clothing worn to shield workers from coating chemicals, abrasives, and physical hazards during surface preparation and application.

A standardized document providing hazard, handling, storage, and first-aid information for a coating or chemical product, required to be available to workers.

Carbon-based solvents and other substances that evaporate from coatings and can contribute to air pollution and worker exposure. Regulations often cap their content in coatings.