piping

Piping Engineering Overview

Pipe and Tube Definitions

• Pipe: Specified by nominal bore, outer diameter (OD), and wall thickness (referred to as schedule).

• Tube: Specified by OD and wall thickness according to Birmingham Wire Gauge (BWG).

Piping Manufacturing Methods

1. Extrusion: Converts raw plastic material into a continuous tubular melt using an annular die.

   • Example: PVC pipe.

2. Spiral Welded Pipes: Formed by twisting strips of metal into a spiral shape and welding the edges.

3. Electrical Resistance Welded Pipes (ERW): Made from a steel coil with a welded seam running parallel to the pipe circumference. The diameter of the coil matches the pipe's circumference.

   • Key Difference: Seamless pipes are produced without welds, whereas ERW pipes are welded.

Piping Codes

• ASME Standards:

  • ASME B31.1: Power Piping

  • ASME B31.3: Process Piping

Pipe Size Notations

• Nominal Pipe Size: Identified by a nominal diameter; varies with OD above certain sizes.

• Size Conversion Examples:

  • 1/4 inch pipe OD: 1.315 inch

  • 14 inch nominal size has the exact OD of 14 inch.

Steel Types

• Carbon Steel:

  • High Carbon: 0.61 - 1.50%

  • Medium Carbon: 0.26 - 0.60%

  • Low Carbon: 0.05 - 0.25%

• Alloy Steel:

  • Contains elements like magnesium, molybdenum, and sulfur.

Piping Insulations

• Used to prevent freezing in domestic water supply pipes and reduce heat loss.

• Insulation Types:

  • Fibreglass

  • Foam

  • Mineral Wool

  • Rubber

  • Phenolic

Pipe Fittings

• Components used to interconnect pipes.

• Types of Fittings:

  • Elbows: Modifies direction (90° and 45°).

  • Reducers: Changes pipe diameter (concentric and eccentric).

  • Tee Fittings: For branch connections.

  • Couplings: Connects two pipes (Types: Full, Half, Reducing).

  • Olets: Used for branching in high pressure applications (Types: Weldolet, Elbowlet, Sockolet).

  • Flanges: Connect various piping system components.

    • Types include:

      • Weldneck Flanges

      • Blind Flanges

      • Spectacle Blinds

      • Socket Flanges

Special Devices in Pipelines

• Blinding: Closing a pipe using blind flanges for maintenance.

• Spectacle Blinds: Used to block flow in pipelines during maintenance.

Gasketing in Piping

• Purpose: Prevents fluid escape under extreme pressures.

• Types of Gaskets:

  • Metallic: e.g., oval rings.

  • Non-metallic: e.g., rubber, ceramic.

  • Composite: e.g., spiral wound gaskets.

Piping Specifications and Classes

• Piping Specification: Details components used in different fluids and conditions.

• Pipe Class: Describes component types based on pressure, temperature, and corrosion environment.

• Examples of Pipe Classes:

  • Class 150, Class 300, Class 600, up to Class 2500.

Piping Insulation Types

• Hot Insulation: Applied on hot surfaces to conserve energy.

• Cold Insulation: Used on cold surfaces to avoid heat gain or condensation.

Pipe Supports

• Essential for avoiding vibration, sagging, and damage.

• Common Support Types:

  • Shoe support

  • Clamp support

  • Saddle support

  • Trunnion support

  • Spring supports

Pipeline Pigging

• Involves using devices (pigs) for cleaning and inspecting pipelines.

Valves in Piping Systems

• Crucial for controlling flow, isolating systems, and protecting equipment.

• Types of Valves:

  • Isolation Valves: Gate, Butterfly, Knife valves.

  • Flow Control Valves: Glove, Diaphragm, Needle valves.

  • Safety Valves: Low lift, Full lift, Conventional, Pilot-operated.

  • Pressure Relief Valves (DPRV): Protect systems from overpressure.

ASME Codes and Standards

• Various sections govern piping materials, welding qualifications, and testing standards, including:

  • ASME Section IX: Covers welding and brazing qualifications.

  • ASME B31.1 and B31.3 for power and process piping codes.

Piping and Instrumentation Diagrams (P&IDs)

• PFDs: Graphical representation of processes and tasks.

• PIDs show piping, equipment, and instrumentation.

Joint Numbering System

• Joints: Modified by suffixes to denote work done (e.g., Rwo for rewelded joints).

Ultrasonic Testing and Magnetic Particle Testing

• Ultrasonic Testing: Non-destructive testing using sound waves to detect defects (e.g., acoustic impedance, back wall echo).

• Magnetic Particle Testing: Detects surface defects on ferromagnetic materials using magnetic fields.

Key Definitions in Piping Engineering

• Gasket: Sealing material between flanges for static seals.

• Pigging: Maintenance and inspection processes using pipeline pigs.

• Fillet Weld: A triangular type of weld.