Deadlegs

Ada beberapa definisi Deadleg yang disampaikan oleh para ahli korosi, diantaranya adalah :
1. "Any section of pipework or a vessel where the rate of flow is very low or zero"

2. "Section of pipe work or vessel which contain liquid under stagnant condition or where there is no measurable flow"

3. "Any unused length of pipe longer than six diameters of the unused pipe measured from the axis of the pipe in use"

4. "A pipe branch that under normal operating conditions does not experience operational flow"

Jadi intinya adalah bila fluida didalam suatu pipa tidak mengalir (diam) maka pipa tersebut dikatakan Deadleg.

deadlegs ini jika ditinjau dari sisi korosinya, tidak ada fungsinya karena aliran yg stagnant dan bila ada air dan temperatur dibawah 60oC, maka pada pipa deadleg tsb kemungkinan akan tumbuh bakteri yang menyebabkan korosi oleh bakteri (Microbial Induced Corrosion/MIC), bila ada deposit di pipa deadleg juga bisa menimbulkan corrosion under deposit (CUD).

Kemudian lokasi yang sering mengalami deadlegs diantaranya :
1. Drains pipework at the base of vessels

2. Bridle Pipework

3. Pipework sections that are used intermittently e.g. bypass lines and non-operating sections of spaded equipment

4. A section of pipework not in the normal flow, but which cannot be isolated from the normal flow e.g. obsolete lines

5. Pipework sections upstream or downstream of a closed valve where the intention is to keep the valve closed

6. Lowest sections of pipework runs where it is not possible to drain completely

7. Process pipework associated with a vessel, upstream of the first closed valve.

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