ABSTRACT
Hydrotesting is the process by which installations, before commissioning, are lled with water, pressurized to 125% of their maximum allowable (or acceptable) operating pressure (MAOP) and examined and/or inspected for leaks (Figure 18.1).1-5 This is to ensure that they do not pose a signicant hazard to the surrounding environment and population. Pipelines in particular are tested, from owlines to large diameter transmission lines. Hydrotesting whole or sections of a pipeline is the rst stage of structural integrity measurement. For example, a pipeline with a designed operating pressure of 1000 psi (ca. 71 bar) will be tested to 1250 psi (ca. 89 bar). This is particularly challenging in the subsea environment where leak detection is usually by ultraviolet (UV) light, using remotely operated vehicles. The chemical dyes employed here are of particular relevance (see below).
