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Pipe stress analysis is the key to safe piping systems
20. august 2025
In industrial facilities, piping systems play a central role in transporting liquids and gases under high pressure and varying temperatures. The design of these systems involves a number of technical challenges that requires precise calculations.
One of the key challenges in piping system design is ensuring that the system can withstand the loads it is exposed to during operation. Pipe stress analysis is a vital tool in this process, as it evaluates both thermal and mechanical loads (such as temperature and pressure), external forces (including pipe weight, supports, vibrations, seismic activity and wind), and movement from connected components (such as pumps, valves and vessels).
Piping systems like steam lines, oil pipelines, and district heating pipes are particularly exposed to high stress levels at bends, supports and pump flanges due to thermal expansion and significant pressure variations. These types of loads are commonly found in power plants, chemical facilities, refineries and district heating networks – and are often subject to the Pressure Equipment Directive (PED).
Pipe stress analysis is essential for ensuring the operational reliability of a plant. It allows engineers to identify weaknesses and optimize the design, ultimately extending the service life of the piping system. As part of the analysis, Pressure Equipment Directive (PED) is consulted to determine the PED classification of the system. This classification indicates the extent to which the system must be calculated and documented. The assessment is based on design pressure, volume, and fluid group - in other words, the mechanical loads inside the pipes. PED applies when the pressure exceeds 0.5 barg. In such cases, the system is subject to specific legal requirements, including CE marking. This makes pipe stress analysis closely linked to proper certification of the installation. In addition, thermal forces acting on the piping system must also be considered, as they influence pipe displacement. If these loads are not accounted for, they can ultimately lead to material damage - or in the worst case, personal injuries.
Stress analysis of a piping system with 100 meters of steam pipe
At Process Engineering, we carry out a wide range of pipe stress analyses. Most recently, we worked on a project involving TIE INS – connection of new piping to an existing steam line transporting steam at very high temperature (350 C) and pressure (25 barg). The connection was made using a special valve setup: a double block & bleed system that allowed both heating and draining of the steam line. This ensured a completely sealed system before further work could be carried out. The piping system consisted of more than 100 meters of steam pipe, and we performed stress analysis on the entire system. Since the pressure exceeded 0.5 barg, the system was subject to the Pressure Equipment Directive (PED), and we also handled the regulatory compliance.
Regulatory handling and documentation are a significant part of the pipe stress analysis process. The team at Process Engineering works with design, analysis and documentation ensuring that the piping system complies with relevant standards and regulations.
You can read more about our expertise and services in pipe stress analysis here.