Visual testing (VT) is the first examination on almost every job. A qualified inspector examines parts, welds and assemblies directly, or remotely where the eye cannot reach, and judges what is found against the acceptance criteria that apply. Many problems are caught here, before any other method is set up.
- Finds
- Surface cracks, undercut, porosity, weld profile, corrosion, mechanical damage
- Typical use
- In-process weld inspection, construction, receiving inspection, CWI sign-off
What visual inspection finds
- Surface cracks and porosity
- Undercut, overlap and incomplete fusion at the surface of a weld
- Weld size, profile and misalignment
- Corrosion, erosion and pitting
- Wear, deformation and mechanical damage
- Missing parts, markings and workmanship problems
Direct and remote visual examination
Direct visual examination is done with the eye close to the surface under adequate light, sometimes with magnifiers and gauges. Remote visual examination uses optical aids, such as borescopes, fiberscopes or cameras, to see inside pipes, vessels and assemblies that cannot be reached directly. Either way, the procedure states the lighting, the viewing conditions and what has to be recorded.
For welds, checking fit-up, joint preparation and cleanliness before a weld is covered up is the cheapest way to prevent defects. Where the job calls for a Certified Welding Inspector, see certified weld inspection.
Where it’s used
- In-process and final weld inspection in construction and fabrication
- Receiving inspection of parts and material
- Bridges, structures and maritime work
- API in-service inspection of vessels, piping and tanks
- Crane hooks and lifting gear and amusement rides
Codes and standards
- ASME Boiler and Pressure Vessel Code, Section V, Article 9, visual examination
- AWS D1.1 and the other AWS structural welding codes, which set visual acceptance criteria for welds
- API 510, API 570 and API 653, where external and internal visual inspection is central to in-service inspection
- ASME B30 standards for cranes, hooks and rigging
- Customer and prime-contractor specifications
Who does the work
Every Midgard technician who performs visual testing holds current certification in that method, issued under a written practice. For most industrial work the written practice follows ASNT’s SNT-TC-1A; for aerospace and defense work it follows NAS410. A Responsible Level III oversees the program: approving procedures and technique sheets, examining and certifying technicians, and answering the technical questions that come up on the job.
If your contract calls for a different scheme, such as ANSI/ASNT CP-189 or NAVSEA requirements, tell us when you ask for a quote.
Training in visual testing
Midgard also trains in visual testing, along with all the other major methods. Instruction is given at Level I, II and III by certified Level III instructors, to SNT-TC-1A, CP-189, NAS410, NAVSEA or whichever code you certify to, with general, specific and practical examinations at your facility or ours. It suits new hires working toward first certification as well as technicians due for re-examination. See training and certification, or ask about a class.
Common questions
What is the difference between visual testing and a CWI inspection?
Visual testing is an NDT method, and a technician is certified in it under the employer’s written practice. A Certified Welding Inspector is certified by the American Welding Society and covers more than the visual examination: welding procedure and welder qualification records, and compliance with the welding code. Many codes and contracts name the CWI specifically.
What is remote visual inspection?
Visual examination with optical aids, such as borescopes, fiberscopes or cameras, used where the eye cannot get close to the surface, such as inside pipe, vessels and assemblies.
What does a visual weld inspection check?
Cracks, porosity, undercut, overlap and incomplete fusion at the surface, weld size and profile, misalignment, arc strikes and spatter, all compared with the acceptance criteria of the welding code that applies.
Tell us what needs examining, whether it can be reached directly, and the code or specification you work to. Call 1-844-MIDGARD, email contact@midgardscientific.com, or use the contact page.