Visually examining for a variety of surface flaws, such as corrosion, contamination, surface finish, and surface discontinuities.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global Standards
Inspection which identifies, without the use of access equipment or tools, those defects, such as missing bolts, which will be apparent to the eye.
Source: IEC 60079-17:2013, Explosive atmospheres – Part 17: Electrical installations inspection and maintenance, Edition 5.0, November 2013. Global Standards