Meaning of 水洗式 other than flush toilet

Question

In an article about penetrant testing (浸透探傷検査) I found the following sentence:

浸透液は水洗式でハケ塗りとし，極力溶接部以外に浸透液が付着しないようにすること．

In this kind of test, a penetrant liquid is used on a surface (in this case a weld area, 溶接部) to check if it has defects.

Here I read that 水洗式 refers to a flush toilet, but in this context it doesn't make much sense to me. Could it refer to a drainage outlet or something similar? I mean something used during the test to collect the dripping of penetrant liquid?

Thank you for your help!

Answer 1

水洗式 does not refer to a flush toilet itself, but it refers to a method/system.

• 水: water
• 洗: wash / clean
• 式: -type

So 水洗式 (literally "water-wash type") can refer to anything that can be washed, flushed or wiped with water. In layman terms it usually refers to a type of toilet, but in this case, it describes a type of 浸透液. The Wikipedia article you linked has a good explanation for this:

The excess penetrant is then removed from the surface. The removal method is controlled by the type of penetrant used. Water-washable, solvent-removable, lipophilic post-emulsifiable, or hydrophilic post-emulsifiable are the common choices.

So:

浸透液は水洗式でハケ塗りとし、
The penetrant must be water-washable and applied with brushes, ...