Pipeline Vs Piping Comparison

This article is intended to throw light on the differences between pipeline engineering and piping engineering, which are important organs of any engineering firm active in oil and gas sector. Pipeline and piping engineering do not only sound similar but share a lot of common activities. Both the engineering department belong to mechanical disciplines and deals primarily with pipes. Various codes have defined the battery limits for pipeline and piping activities, however, there has always been a contest between Pipeline and Piping disciplines regarding the division of scope in various types of projects. Therefore we have tried to highlight the differences between both the engineering disciplines for onshore systems and offshore systems separately.

Note:We do not claim that all companies follow the exact division of activities between pipeline and piping disciplines. However, we are trying to broadly differentiate between the two. Pipeline vs piping

1 Design Codes
  • ASME B31.4 : Pipeline Transportation Systems for Liquids and Slurries
  • ASME B31.8 : Gas Transmission and Distribution Piping Systems
  • ASME B31.3 : Process Piping
2 Scope
Outside plant boundary
Cross-country (i.e. villages, fields, river, canal, railway, highway, cities, deserts, forests, hills, ghats etc.)
Within plant boundary
(upto all nozzles/ equipment terminal points)
3 Type of pipe
Line pipes as per following code:
Assorted pipes as per following code:
  • ASTMs
  • BS
  • API 5L
4 Valves
Valves are procured as per following code:

  • API 6D: Specification for Pipeline and Piping Valves

Full Bore (FB) Ball Valves are used for smooth passage of pigs.
Valves are procured as per following code:
  • BS
  • API Standard
Full bore (FB) and Reduced bore (RB) both types of valves are used as per respective valve standards. There is no requirement for pigging.
5 Welding
Welding code:
  • API Std. 1104: Welding of Pipelines and Related Facilities

Type of welding:
Automatic / Semi-Automatic/ Manual
Welding code:
  • ASME Sec. IX: Standard for Welding and Brazing Procedures, Welders, Brazers and Welding and Brazing Operators
Type of welding:
Manual (mostly)
6 Weld joint inspection (NDT requirements)
100% by Automatic UT or RT (by using X-Ray) 5% to 100% (mostly by using gamma ray source)
7 Analyses
- Wall Thickness Analysis
- Elastic Bend Radius Analysis
- Stability Analysis for Water Bodies/ Marshy Areas
- Horizontal directional drilling design analysis
- Railroad/ Highway Crossing Analysis
- Casing Pipe Analysis for Crossings
- Seismic Analysis
- Piping wall thickness calculation [as input to Piping Material Specification (PMS)]
- Piping Stress Analysis (by Caesar II). Following analyses are performed on CAESAR II
  • Static Analysis
  • Dynamic Analysis
  • Wind Analysis
  • Flange Leakage Analysis
  • Seismic Analysis
8 Installation
Buried (mostly) Above ground/ On rack/ slippers/ T-postal etc.
9 Special Installations
Across rivers Across road/ rail/ highway
  • Auger boring/ jacking boring method
  • Shallow HDD
Ghats/ Hills – Special equipments used
Special fabrication methods:
  • Modular installations
  • Finning
  • Studding
  • Jacketing
  • Spooling inside warehouse
  • U/G piping for cooling water
10 Special Equipments
  • Sectionalizing Valves (Remote operated)
  • Insulating Joints
  • Scraper Launcher/ Receiver
  • Stem Extended Valves (for buried valves)
  • Flow Tee
  • Long Radius bends (R=6D)
  • Cold field bends (R = 30D or 40D)
  • Expansion Joints
  • Motor Operator Valves (MOV)
  • Cryogenic Valves
  • Springs
11 Survey
  • Topographical Survey (all along the pipeline route)
  • Geotechnical investigation (all along the pipeline route)
  • Soil resistivity survey (all along the pipeline route)
  • Hydrological Survey for water bodies (for scour depth calculation)
  • Cadastral Survey (for RoU acquisition)
  • Wind profile from meteorology
  • Seismic study of plot
12 Corrosion Protection Coating
  • Three Layer Polyethylene (3LPE) coating
  • Three Layer Polypropylene (3LPP) coating
  • Fusion bonded epoxy (FBE) coating
  • Coal tar enamel (CTE) Coating
  • Painting
13 Cathodic Protection System
  • Impressed Current Cathodic Protection (ICCP) system
  • Sacrificial Anode (limited locations)
  • Not applicable
14 Hydrostatic testing
Gauge Plate run of 95% of ID of highest thickness of pipes

Test Pressure
  • 1.25 times of Design Pressure (for liquid pipelines)
  • 1.25 to 1.5 times of Design Pressure (for gas pipelines)
  • Pressure equivalent to Hoop stress of 95% of SMYS of pipe material
Hold period: 24 hours (generally)

Selection of hydrostatic test section based on elevation difference of ground profile
No gauge plate run is done. Generally card-board blasting is done to clean the piping.

Test Pressure
  • 1.5 × Design Pressure × Temperature Factor
  • based on line schedule
Hold period: 2 - 6 hours

15 Preservation
Preservation of pipeline with corrosion inhibited water or by filling of inert gas (N2) Not applicable
16 Communication System
Telecom/ SCADA Not applicable
17 Pigging
Intelligent Pigging Not applicable
18 Machines/ Equipments required for installation
  • Trencher
  • Backhoe/ Excavator
  • Side Boom
  • Cold field bending machine
  • Holiday Detection Machines
  • Pneumatic/ Hydraulic Internal Clamps
  • Crane/ Hydra

SL. NO. Offshore PIPELINE Offshore PIPING
1 Design Codes
  • DNVGL-ST-F101 : Submarine pipeline systems
  • API RP 1111 : Design, Construction, Operation and Maintenance of Offshore Hydrocarbon Pipelines (Limit state design)
  • ASME B31.3 : Process Piping
2 Installation
Subsea (in water on seabed or buried in seabed) Deck Platform Piping (similar to plant)
3 Survey (Subsea)
  • Geophysical survey/ Bathymetric Survey by using side scan sonar, sub-bottom profiler and echo-sounder
  • Met-Ocean data collection
  • Geo-technical data of the pipeline route
Not Applicable
4 Pipes
Line pipes are utilized as per following specs:

Assorted Pipes are utilized as per following specs:

  • ASTM Standards
5 Valves
Full bore Valves for smooth passage of intelligent pigs are utilized as per spec:
  • API 6D SS : Specification on Subsea Pipeline Valves
Reduced bore valves are utilised (as there is no requirement for pigging) as per spec:
  • BS/API standards
6 Analyses
  • Wall thickness Analysis
  • On-bottom Stability
  • Span Analysis
  • Global Buckling – Lateral and Upheaval
  • Pipeline Expansion Analysis
  • Riser Design (Span , Stress & Flexibility Analysis)
  • Riser Clamp Design
  • Pipeline Crossing Design and Analysis
  • Installation Analyses such as :- Pipelay Analyses in OFFPIPE, Shore approach installation design & Analyses, Riser/ Expansion Spool installation analyses, Hoses lifting & installation analyses
  • Deck piping stress analysis using CAESAR II
7 Environmental Loads (Met-ocean Parameters)
Wave, current and external pressure and buoyancy Wind load
8 Corrosion Protection Coating
Coatings such as:–
  • Coal Tar Enamel Coating (CTE)
  • Three layer polyethylene coating (3LPE)
  • Three layer poly-propylene coating (3LPP)
  • Double layer fusion bonded epoxy coating (DLFBE)
9 Cathodic Protection System
Sacrificial Anodic Cathodic Protection (SACP) system Not Applicable
10 Welding
Welding is performed as per specification:

Mostly automatic welding on pipelay barge.
Welding is performed as per specification:

  • ASME Sec. IX : Standard for Welding and Brazing Procedures, Welders, Brazers and Welding and Brazing Operators
Manual welding at fabrication yard.
11 Weld joint inspection (NDT requirements)
100% by Automatic UT Mostly by using gamma ray source.
12 Special Equipments
  • Subsea Isolation Valve (SSIV)
  • LR Bends
  • Flow tee
  • Pipeline End Manifold (PLEM)
  • Single Point Mooring (SPM) system
  • Submarine hoses
  • Floating hoses
  • Cables and umbilical installation
  • Piggy-back pipelines
Not Applicable
13 Installation Equipment
  • Pipelay Barge
  • Derrick Barge
  • Diving support vessel
  • Dynamic Positioning (DP) barge (for deepwater)
  • Pre-fabricated deck piping
14 Installation Methods
  • S-lay Method (for shallow water installation)
  • J-Lay Method (for deep water installation)
  • Shore pull/ barge pull near Land Fall Point (LFP)
  • Along with deck structure
15 Hydrostatic testing
Gauge Plate run of 95% of ID of highest thickness of pipeline.
Test Pressure
  • Minimum : 1.25 times x Design Pressure
Hold period
  • 24 hours
No gauging is done.
Test Pressure
  • Maximum : As per line schedule
Hold period
  • 2 hours
16 NDT requirements
100% weld joints by RT or AUT Varies from 10% to 100% depending upon service.
17 Intelligent Pigging
Compliant Not applicable