Coating Inspection & Quality Control

What we inspect and which type of inspection to choose

We inspect coatings on steel structures, tanks, piping, equipment and concrete, whether new, being applied or in service. Inspection is part of our industrial and protective coatings, our core business.

We carry out the inspections the specification calls for and record the readings. Where the specification requires a third-party certified inspector, we coordinate with the inspector appointed by the client: access, hold points and exchange of records. The type of assignment depends on the situation:

• Inspection built into our own work: every Induscoat painting or coating job includes its records. This is the most common case.
• Condition survey of an existing coating: to decide between spot repair, overcoat and full removal before repainting.
• Monitoring of another applicator's work, at the client's request: checking each step and its records against the specification.
• Coating failure analysis: when a coating blisters, peels or rusts early, to find the cause before the work is redone (coating failure modes and diagnosis).

The service is for industrial sites only. Readings are taken by our crews and qualified subcontractors.

Before the work: the starting condition

Pre-work inspection establishes the condition of the substrate and the existing coating, and it is what sets the preparation grade and the system. It is done at the survey, before quoting or at the start of the job.

• Degradation rating to ISO 4628 (blistering, rusting, cracking, flaking) and rust rating to ASTM D610, zone by zone, with photos.
• Adhesion of the existing coating, by pull-off or knife test, to find out whether it can be overcoated.
• Thickness and number of existing coats, which tell the history and how much load an overcoat will add.
• Lead in old paint, through laboratory analysis of collected samples. A positive result changes the method, the containment and the price (lead paint removal).
• Substrate condition: pitting, metal loss, welds, oil or salt contamination.

On concrete, moisture, laitance and surface soundness are also checked before the system is chosen.

During the work: conditions, preparation, thickness

During the work, conditions are checked before every coat, then thickness during and after application. A defect fixed at this stage costs far less than a repair after cure.

• Ambient conditions: air and substrate temperature, relative humidity and dew point, read at the start of the shift and for every coat (ISO 8502-4). Application only starts when the gap between substrate temperature and dew point meets the specification and the data sheet.
• Cleanliness and preparation grade: comparison with ISO 8501-1 or the SSPC visual guides, dust to ISO 8502-3.
• Surface profile: comparator to ISO 8503, or ASTM D4417 (comparator, depth micrometer or replica tape) (surface profile).
• Soluble salts: extraction to ISO 8502-6 and conductivity measurement to ISO 8502-9, against the limit set by the specification.
• Wet film thickness: comb gauge to ASTM D4414, during application, so it can be corrected on the spot.
• DFT measurement: to SSPC-PA 2 or ISO 19840, with the sampling plan the standard sets (dry film thickness). Areas out of tolerance are recoated.

Every reading carries the date, time, area and instrument used, with its calibration check.

After application: holidays, adhesion, cure

After application, we confirm that the film is continuous, bonded and cured before return to service. These tests are set by the specification; some are destructive and are done on selected areas or on test panels.

• Holiday testing (discontinuity detection): low-voltage wet sponge or high-voltage, depending on film thickness and coating type, to NACE SP0188 on steel and ASTM D4787 on concrete. It is the standard test for immersion linings (holiday test).
• Adhesion testing by pull-off: ASTM D4541 on metal, ASTM D7234 on concrete. The X-cut or cross-cut tape test (ASTM D3359) gives a quick indication, mainly on thin films.
• Cure: hardness, solvent rub or cure time, using the method on the data sheet, before filling or return to service.
• Final visual examination: runs, misses, inclusions and thin coverage on edges and welds.

Defects found are marked, repaired to the manufacturer's procedure, then tested again.

Hold points and the file you receive

Hold points are the steps where work stops until the readings are accepted. They are set with the client before the job, in an inspection and test plan, then followed in this order:

• Inspection plan: planned checks, standards, acceptance criteria, frequency and who is responsible for each check.
• Hold point after preparation: cleanliness, profile and salts accepted before the primer.
• Hold point between coats: thickness and recoat window checked before the next coat.
• Final hold point: holiday test, adhesion and visual examination accepted before return to service.
• File handed over: inspection plan, condition and thickness readings, test results, data sheets, batch numbers, non-conformances and their corrections, photos.

When an inspector appointed by the client attends the hold points, we pass on the readings as we go and wait for release before continuing.

Site conditions and safety

Inspection follows the same safety rules as the work, plus a few measures of its own. They are settled in the quote and with the site's health and safety department.

• Confined spaces: inspecting tanks, cells and ducts follows the site's entry procedure (permit, atmosphere monitoring, attendant outside, ventilation).
• High-voltage holiday testing: barricaded area, personnel informed, never with solvent vapour or a flammable atmosphere present.
• Work at height: scaffolding, lifts or rope access, often the same as for the work itself.
• Lockout of equipment before any internal inspection.
• Winter: readings are taken inside the heated enclosure, where the coating is applied and cures.

Pricing: by quote

Coating inspection is priced by quote, because the cost depends on the number of checks and how much time on site is required. Five factors drive it:

• The type of assignment: inspection built into our work, condition survey, monitoring of another applicator or failure analysis.
• The area and the number of zones, which set the number of readings under the sampling plan.
• The tests required, laboratory analyses in particular.
• Access and safety requirements: confined space, height, remote site.
• The number of hold points and the time spent on site.

Send the specification, photos and the location with your quote request: we reply within 24 business hours.

Where we work

Induscoat provides coating inspection in Montreal, across Quebec and in Ontario, working from LaSalle. Each regional page sets out the sectors and exposure conditions specific to that territory:

• Montreal and Montérégie
• Quebec, for the province as a whole
• Abitibi-Témiscamingue
• Côte-Nord
• Saguenay–Lac-Saint-Jean
• Mauricie–Centre-du-Québec
• Ontario

When an inspection is not enough

An inspection is not enough when the problem is known and keeps coming back: it records the condition, it does not always explain why the coating failed. If the same system blisters or peels from one shutdown to the next, a root cause analysis is needed (specification, preparation, application conditions, compatibility, service conditions), which falls under our strategic advisory service.

If the inspection reveals metal loss, cracks or deteriorated concrete, the substrate is repaired before any new coating, through our maintenance and rehabilitation service. And if the coating has to be redone, industrial painting or tank lining takes over, with the same inspections.

Typical Problems We Solve

• Coatings that blister or peel early with no readings to show what went wrong
• Film thickness too low or too high, found only after cure
• Holidays in immersion linings that become corrosion points in service
• Uncertainty whether an existing coating can be overcoated or must be removed

What You Receive

• Inspection and test plan with hold points, standards and acceptance criteria
• Ambient condition, profile, soluble salt and film thickness readings, dated and located
• Holiday, adhesion and cure test results, with defects marked and retested
• Close-out file with data sheets, batch numbers, non-conformances, corrections and photos

Timeline

Standards & Certifications

• ISO 8501-1 and ISO 8502-3, -4, -6, -9: cleanliness, dust, dew point and soluble salts
• ISO 8503 and ASTM D4417: surface profile measurement
• SSPC-PA 2, ISO 19840 and ASTM D4414: dry and wet film thickness
• NACE SP0188, ASTM D4787, ASTM D4541, D3359 and D7234: holiday and adhesion testing

Industries We Serve

• Energy and hydroelectric: penstocks, tanks, structures, piping
• Mining and metallurgy: tanks, thickeners, flotation cells, structures
• Water and wastewater: basins, tanks, concrete structures
• Chemical and petrochemical: storage tanks, containment areas, pipe racks

Service FAQ

Technical guides

• Coating failure modes and diagnosis
• NACE No. 2 / SSPC-SP 10 surface preparation
• Epoxy coating service life
• Maintenance painting of steel structures

Related applications

Concrete industrial use cases where this service is applied.