Pipeline Construction: Miscellaneous

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The following is a summary listing of typical issues that have been identified by PHMSA inspections of new pipeline construction projects. Identified problems have primarily been due to a failure to implement existing industry standards, manufacturer’s recommendations, and federal regulations. Some of these issues are discussed in more detail on other Pipeline Construction web pages, but are repeated here in order to provide a consolidated list.


Pipe and Miscellaneous Issues
Pipe
  • Pit defects in the pipe body
  • Laminations
  • Pipe sizing issues and variability/damage to pipe ends
  • Low tensile strength and/or thin wall in some pipe

Hydrostatic Testing
  • Poor test in winter due to freezing of pressure equipment
  • Cracks discovered in girth welds during hydro test
  • Improper pressure maintenance during hydro test
  • Long seam failure

Design
  • Incorrect pipe wall thickness for class location
  • Inadequate testing documentation for pipeline components

Bending
  • Ripples out of tolerance
  • Pipe seam not in neutral axis
  • Inadequate construction specification
  • Not using internal mandrel when required by procedures
  • Not following procedures

Lowering
  • Inadequate boom spacing per the ECA requirements
  • Unrepaired coating defects at lowering

Operation - Insufficient line markers

Inadequate Operator Qualification Documentation If Applicable

Post Construction Documentation

End Facing

Stringing - Long seam alignment/orientation

Coating
Fusion Bonded Epoxy Issues
  • Coating over mud or rust
  • Application temperature too hot or cold
  • Heat damage to the factory FBE coating
  • Failing to follow manufacturer's instructions
  • Sand blast technique - no correct bevel / no overlap at factory coating
  • Coating in high wind with blowing dirt
  • Water in the pipe during heating – does allow for uniform heating
  • Coating specifications not available to inspectors
  • Girth weld coating not fully bonded to pipe

Melt Stick
  • Failing to follow manufacturer's instructions
  • Not adequately heating pipe before application
  • Inadequate surface preparation - abrasion
  • Use on defects larger than 0.5 in2
  • Application over two part epoxy
  • Improper accelerated drying by patting
  • Use on bare metal

Electronic Defect Detectors (Jeeping)
  • Failing to follow manufacturer's instructions
  • Low voltage setting on holiday detector
  • Inadequate training of inspectors and contractors
  • Jeeping over tape and fiberboard stuck to the pipe
  • Failing to adequately clean the pipe before jeeping
  • Failing to visually inspect pipe for coating defects
  • Using damaged (bent) detector springs
  • High resistance in electrical circuit
  • Jeeping at too fast a speed per the spec or manufacturer
  • Jeeping over coating repairs before they are dry
  • Detector failing to identify defects
  • Detector not calibrated per manufacturer

Two Part Epoxy Issues
  • Failing to follow manufacturer's instructions
  • Inadequate surface prep - abrasion
  • Application after epoxy starts to set
  • Inadequate mixing of the epoxy
  • Applying above or below recommended temp - or not pre-heating pipe
  • Using unapproved IR temperature sensors

Welding
Mechanized Welding
  • Coating damage caused by welding band
  • Incomplete weld procedure qualification
  • Pre-heat crew not using Tempilstiks
  • Pipe size - Hi-Lo alignment issues
  • NDT falling behind main gang
  • Lack of padding between pipe and skids
  • Incorrect or inadequate placement of skid cribbing
  • Lack of inspector oversight
  • Not following procedures
  • Incorrect pre-heat or interpass temp
  • Improper use of Tempilstik - too near weld
  • Amps and Volts measured at machine not weld (only long leads)
  • Moving pipe during root bead welding
  • Initial high defect rates
  • Inadequate defect repair tracking
  • Inadequate quality and documentation of MUT
Manual Welding
  • Not following procedures
  • Lack of inspector oversight
  • Early clamp release
  • Arc burns due to poor welding practices
  • Incorrect pre-heat or interpass temp
  • Inadequate visual weld inspection
  • Improper storage of low hydrogen rods
  • Welding inspectors not in possession of welding procedures
  • Use of 'hinging' technique to aid with pipe line-up
  • Pipe size - Hi-Lo alignment issues
  • Improper gas flow rate for gas shielded processes
  • Inadequate defect repair tracking
  • Incomplete qualification documents for welders
  • Amps and Volts measured at machine not weld (for long leads)
  • Inadequate defect removal on repair welds
Excavation
  • Inadequate use of rock shield, padding machines or selective backfill
  • Insufficient burial depth( to code or waiver)
  • Ditch profile not matching pipeline causing inadequate support
  • Dents caused by placing pipe on rocks
  • Erosion of cover at streams
  • Insufficient pipeline weights
  • Excavating over the pipe without adequate protection from rocks, etc.
  • Not reviewing as-built drawings for parallel pipelines
  • No One-Call notifications
Nondestructive Testing
  • Essential wire or hole not visible on radiograph
  • Testing to achieve only the minimum requirements of 192 or 195
  • Poor radiographic technique - not meeting 1104 requirements
  • Not meeting the minimum 10% NDT requirements
  • NDT records not adequate or up to date
  • Incomplete qualification documents for technicians
  • Inadequate interpretation of radiographic results
  • Film density not in spec