Definition(s)
Tightness Test
A pressure test that is conducted on pressure vessels after maintenance or repair activities to indicate that the equipment is leak free and is conducted at a test pressure determined by the owner/user that is not higher than the MAWP.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global Standards