VISUAL INSPECTION (VT)

What Is Visual Testing?

Visual testing (VT) is the first and most widely used NDT method on any site. A trained inspector examines a surface, weld or component directly and reaches a judgement about its condition before any instrument is switched on. It is easy to underrate because it looks straightforward, but a good visual inspection sets up everything that follows. In practice most other NDT only happens after the surface has passed a visual check, since there is little point running a more sensitive method over a weld that already shows obvious problems to the eye.

Direct vs Remote Visual Testing

Direct visual testing is carried out with the eye, helped along by gauges, mirrors and good lighting so the inspector can measure a weld profile or check a fit-up against the drawing. Remote visual testing extends that reach. Borescopes, cameras and drones let us get inside the bore of a vessel or a run of piping, or up to high steelwork and stacks, without scaffolding or rope access. The same trained judgement applies in both cases; the equipment only changes how the inspector gets eyes on the surface. Where a structure is tall or awkward, a drone inspection often gives a clearer and safer view than working at height.

What Visual Inspection Finds

A careful visual goes a long way on welds, picking up undercut, overlap, spatter and surface cracking, along with poor profile and weld toe issues that lead to fatigue later. Away from the weld it catches corrosion and coating breakdown before they get a foothold, mechanical and impact damage, misalignment, and missing or wrong components. None of this needs a probe or a film, yet it is the sort of thing that takes equipment out of service if it is missed. When a surface indication needs confirming, VT is usually backed up with a method such as magnetic particle inspection to size and characterise the flaw.

What Makes a Valid Visual Inspection

A visual result is only as good as the conditions it was taken in. There has to be adequate lighting and illuminance at the surface, a viewing angle and working distance that actually let the inspector see the feature, and physical access to the area. On top of that the inspection has to be done by a qualified inspector who knows what an acceptable weld or surface should look like. Drop any one of those and the report cannot be relied on, which is why we record the conditions as part of the job rather than treating the look as a formality. The same discipline carries through to internal work such as pressure vessel inspection, where access and lighting inside the shell are often the hardest part.

Standards & Qualification

APEC performs visual inspection to the relevant standards for the work in front of us. Fusion-welded joints are examined to ISO 17637, general visual inspection and inspector requirements follow AS 3978, and where a job runs to the ASME code we work to ASME Section V, Article 9 for visual examination. Our inspectors hold a recognised visual testing (VT) qualification, such as ISO 9712, so the assessment carries weight. APEC is a NATA-accredited inspection body staffed by AINDT-certified technicians.

Why Choose APEC Inspection for Visual Inspection

Visual is where a sound inspection programme starts, and it pays to have it done by people who do it every day rather than as an afterthought. We bring the right access method to each job, whether that is direct viewing with gauges and lighting or a borescope and drone for the parts you cannot reach, and we tie the visual in with the wider NDT your assets need. We mobilise across Newcastle, the Hunter and nationally. To talk through a job or request a quote, get in touch with the team.