Piping Systems: All you need to know about thermal expansion and contraction

Author: Judith Morrison

It is natural for piping materials to compress or expand with fluctuations in temperatures (lower or greater) than the installation condition. The pipe expands as the temperature of the pipe material rises due to fluid temperature or sun radiation. And when it decreases, pipe contracts. Thermal contraction and expansion of the piping system are some of the largest dynamic forces acting upon pipes. This pipe expansion or contraction alters depending on the pipe materials. This factor needs to be considered while designing the piping system to avoid unnecessary costs in the future by ensuring the safety and reliability of the system.

This article will explore the essentials to deal with thermal expansion and contraction of the piping systems.

Identifying Thermal Expansion & Contraction

Let’s have a look at the parameters to determine how much a pipe will expand or contract during its functioning

  • Thermal expansion coefficient in./in.°F (C): Every material used in a pipe has a coefficient of linear thermal expansion. It represents how every degree of temperature change result in a specific amount of linear expansion.
  • Pipe Length (L): The longer the pipe, the more will be its expansion or contraction
  • Temperature Change (?T): The distinction between the base and most extreme temperature of the pipe will be exposed to (°F) for the duration of its service life.

    • The amount of thermal pipe expansion /contraction can be defined based on the following equation:

    • L = L C?T

    Factors to Handle Generated Stress

    It is essential to understand the following material qualities to design an efficient piping system

  • Working stress: The maximum amount of stress that a pipe material can handle while operating
  • Modulus of elasticity: Denotes pipe stiffness
  • Outer pipe diameter: The pipe outside diameter, which affects the ability of the pipe to deflect stress

    • Pipe Systems Design Considerations for Thermal Expansion and Contraction

    The piping expansion and contraction practices need to be dealt with during the design phase to avoid substantial problems at a later stage. The four deflection techniques that are widely used to assist the thermal expansion inside the pipeline system without losing integrity and reliability include;

  • Directional Change: The corner elbow at the end of the pipe, with the adjacent pipe, can allocate a certain extent of movements. If the adjacent pipe is lengthy enough, thermal expansion and contraction are often accounted to put a hanger or guide a defined distance away from the elbow.
  • Expansion Offsets: Expansion offsets are generally placed in the center of a pipe run. Each elbow including the vertical length of pipe accounts for some degree of deflection. Offsets are preferably used to absorb a small quantity of thermal expansion or contraction pipe.
  • Expansion Loops: It can easily accommodate large pipe deflections. Piping systems employ different types of expansion loops. Anchors are placed on both sides of the expansion loop to direct the pipe expansion inside the loop.
  • Expansion Joints: A specialized assembly that can absorb pipe thermal expansion or contraction. Expansion joints are mostly used in tight, enclosed areas where expansion loops or offsets do not fit well.

    • Are you looking for piping stress and flexibility analysis services for your industrial plant? If yes, consider outsourcing a reliable engineering partner that adheres to the latest international standards and codes.