At Surface, we know efficient working practices are paramount during road and rail closures, and our highly experienced inspectors appreciate these constraints when working with you. But we don’t just ‘appreciate’ the constraints.  We work proactively with your contractor to get a depth of understanding that ensures we consistently provide optimum production without compromising quality. 

But what do we do? 

And, how do we ensure the ITP (Inspection Test Plan) has been followed to the letter to deliver a quality project?

Michael O’Neill, our Senior Coatings Inspector, takes you through a typical scope of work to demonstrate our rigorous process and how we never compromise on quality…


First things first, a pre-job conference will take place to discuss the scope of work and inspection duties. This is incredibly important as it helps us to fully understand specific requirements as well as set out the parameters of the job. 

A site-specific Inspection Test Plan (ITP) is developed outlining what will be inspected and how it will be assessed along with acceptance and rejection criteria being set.  The job then commences in alignment with the agreed plan. 


For an existing steel structure, “pre-cleaning” needs to take place. This involves High Pressure Fresh Water Washing, used to remove any surface contaminants and helps reduce or remove any soluble salts present on the surface.

Typical example of High Pressure washing

A test is usually specified at this stage for the presence of soluble salts to determine permissible level specified for acceptance. If the acceptance criteria are achieved, work is progressed to preparation stage.

Soluble Salt test being carried out
Sample assessed and result displayed

The Preparation stages 

The preparation stage typically involves abrasive blast cleaning, but this is specification specific. For example, the blasting standard SA 2.5 (a blasting standard that requires most of the mill scale rust, paint etc to be removed), will normally be specified this will also require climatic conditions during and after blasting to be closely monitored.  Further monitoring of the accepted or rejected criteria then takes place, and this is done by carrying out visual inspections.

Monitoring climatic conditions
Typical SA 2.5 standard achieved 

What happens once the cleaned surface is ‘accepted’?

Following the acceptance of the abrasive cleaned surface, further inspections are carried out to check the cleanliness before progressing to any coating application.  This ensures any deterioration or contamination of the prepared surfaces hasn’t taken place, these tests will again be contract specific but normally include dust and profile tests.

Typical profile testing – surface profile replica test (ISO 8503) / cleanliness tests (ISO 8501-1:  & ISO8502-3) 

Coating application stage

Once inspections are complete, the process will move to the coating application stage which again, is monitored as per the ITP with various inspections being carried out during the coating application including: 

  • Climatic conditions
  • Product specification
  • Paint batch numbers
  • Paint mixing 
  • Pre and post coating application 
Coating application underway – mixing
Application by airless spray
 Checking WFT during application

After a coating has been applied and before any subsequent coatings are applied, inspections are again carried out. 

This is to ensure the coating has cured and the correct thickness has been applied before assessing if the quality of finish expected has been achieved.  If all is found acceptable then further applications if specified can be applied or if any defects are found, these are rectified before progressing. 

Checking DFT application after ensuring curing has completed
Defect – example of non-compliant area highlighted for rework
Works and inspections complete ready for transport to site

What happens now the process has been completed?

When completed, the finished steel item or structure is then inspected with various ITP specific inspections, such as final Dry Film Thickness surveys (a measure of any cured coating condition) and visual inspections for quality checks ensuring any non-compliant areas are addressed, there are no discontinuities in the coating and the ITP has been followed to completion.

When the confirmation is received that the ITP has been followed to completion, it’s time to sign off.

If you would like any more information on our coating services, please don’t hesitate to contact us here.

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