What is deadleg Integrity Management System?

Deadlegs can be defined as locations in piping circuits containing idle, stagnant or intermittently flowing fluids. Corrosion in deadlegs represents a significant threat to the integrity of hydrocarbon production facilities.Deadlegs include components of piping that normally have no significant flow. If a piping circuitcontains a deadleg, then the likelihood of thinning activity at this location will be higher and accordingly, the risk of failure for that specific piping circuit will be increased.

Deadlegs can be divided into three main categories:

  • – Permanent or Physical Dead legs (Normally No Flow Dead Legs)

Examples are Drains, Vents, Instrument Connections (IC), Purge Connections (PC), Sample Points Level Transmitters (LT), Level Bridles (LB) and Lines with one end blanked.

  • – Operational Dead legs (On/off Flow Dead Legs)

Examples are spare pump piping, by-pass lines, relief valve inlet & outlet and lines normally closed. Lines only used for start up or shut down (These are locations or sections of plant that are stagnant for operational reasons.

  • – Temporary dead legs

Examples are Mothballed or equipment temporarily removed from service.

DeadLeg Corrosion Mechanisms

Two key causes of corrosion in deadlegs are:

  1. Microbiologically Induced Corrosion (MIC).
  2. Under Deposit Corrosion.

DeadLeg Inspection Techniques

  • Thermography
  • Profile Radiography
  • Scanning Ultrasonic Test or Radiography Teston larger diameter deadlegs
  • Electromagnetic Acoustic Transducers (EMAT)

Deadleg Corrosion Mitigation methods

  • Deadlegs removal or isolation
  • Flushing of deadlegs with fluids that contain appropriate biocides to inhibit microbial growth
  • Using more corrosion-resistant alloys
  • Altering the process environment to reduce corrosivity
  • Using corrosion inhibitors

Deadleg Integrity management process

Deadleg Integrity management process includes following main steps:

  • – Deadleg Identification
  • – Deadleg register
  • – Deadleg risk assessment and prioritize
  • – Definition of mitigation plans
  • – Developing Inspection plans

Please contact us if you want to know how we can manage dead legs integrity.

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