Which classification of penetrant is based on the method of removing excess penetrant?

The classification of penetrant that is based on the method of removing excess penetrant is indeed water-washable. In this context, water-washable penetrants are designed to be removed from surfaces using water. This allows for an effective cleaning process without the need for solvents or other chemicals, making it a convenient option for non-destructive testing procedures.

Water-washable penetrants typically have properties that enable them to be easily washed off with water, making them ideal for situations where environmental considerations are important or where solvents may introduce contamination. This classification directly influences how operators handle the inspection process, from application to removal.

In contrast, non-water removable penetrants require the use of solvents for removal, which can complicate the inspection process and require additional safety considerations. Solvent-removable penetrants involve a different methodology entirely, focusing on cleaning with solvents, while other-removable refers to alternative methods that do not fall under the standard classifications.