Primary stresses resulting from primary loads (sustained)
- From external loading
- Not self-limiting and cause distortion
- Limit these loads to prevent plastic deformation
Examples of loads: Internal-pressure, Weight.
Sustained stresses must be less than sustained allowable stresses.
Secondary stresses resulting from secondary loads (expansion):
- By displacements constraints
- Self-limiting and cause no distortion
- Limit these loads to prevent fatigue failure
Examples of loads: Thermal load, Transient, Support-movement, Vibration.
Expansion stresses must be less than the thermal allowable stress range.
Peak stresses resulting from occasional loads (occasional)
- Cause the highest stresses but cause no distortion
- Limit these loads to prevent fatigue crack initiation
Examples of loads: Wind, Earthquake, Impact, Fluid-hammers.
Occasional stresses must be less than the occasional allowable stresses.
piping stress engineering
Piping stress engineering is the discipline of the piping engineering that deals with the assessment of the mechanical loads and deformation of the piping systems. The objectives of piping stress engineering are firstly to provide piping systems for safe operation in diverse conditions. Here are key aspects of piping stress engineering:Here are key aspects of piping stress engineering:
Load Analysis: Piping stress engineers determine the forces that are applied to a piping system; this comprises static forces such as pressure, weight, and thermal expansion; dynamic forces such as vibration, water hammer; and occasional forces such as earthquake forces, wind forces, etc.
Code Compliance: Modern piping stress engineers operate on the basis of certain guidelines set by the various industrial code and standards like ASME B31. 1 more specifically, called the Power Piping, and ASME B31. 3 (Process Piping). It is mandatory for piping systems to conform to these codes so as to achieve the desired safety and performance standards.
Modeling and Software: Designers employ pipe design software to design piping systems by using dimensions of the pipe, the type of material to be used, supports, and loads. These model assist in determining of stresses, displacements and other important variables.
Support Design: It is essential to consider some of the factors to avoid situations like sagging, too much movement or overloading on the pipes. Or piping stress engineers are responsible for pipe supports and restraints, in other words, they determine whether those supports and restraints are placed and designed properly for loads.
Thermal Analysis: Due to changes in temperature pipes also dilate and on the other hand they also contract. Depending on thermal expansion effects on the pipes, piping stress analysis provides provisions to contain such effects without causing over stressing or misalignment.
Flexibility Analysis: On the spot, flexibility assessment determines the capacity of the piping system to absorb thermal expansion and contraction loads and prevent imposition of undo stress on equipment or experience of related problems.
Stress Allowable Limits: Piping codes indicate maximum stress values for various types of material and services. Pressure design engineers collaboratively work with piping stress engineers to ensure that stress in some of the parts; namely, the piping components reach such limits in order to support the structure.
Fatigue Analysis: For the cyclic loads which include equipment start up and shut down, fatigue analysis is done to determine the ability of the equipment for fatigue failure.
Documentation and Reporting: The outcome of the piping stress analysis is in the paperwork containing the stress evaluation, structural reinforcement plans, advice on remedial measures, and reference to codes.
Review and Approval: Like all piping documents, piping stress analysis reports will be checked by certified engineers and may need the endorsement of the local authorities or company personnel.
Iterative Process: Stress analysis of pipes can very often be an iterative procedure. When the design or operating conditions of the system are altered, it may be necessary to rerun the models to determine if it is still adequately protected.
This person will be responsible for stress engineering in piping and this is very important in organizations where piping systems are exposed to pressures, temperature or any other difficult situation. When proper analysis is conducted it lessens the possibilities of failure and expenses for maintenance while increasing the duration of piping systems and contributing to the safety and efficiency for operation.
Piping stress engineering is a discipline of engineering that focuses on stress analysis of piping systems with an aim of providing suitable solution. Piping stress engineers use a variety of methods to analyze piping systems, including:Piping stress engineers use a variety of methods to analyze piping systems, including:
Hand calculations: DESIGN OF SIMPLE PIPING SYSTEMS Piping systems which are uncomplicated in nature can be assessed by hand calculations. Still, this method is not very precise and might take much time.
Finite element analysis: Finite element analysis is a more accurate method in any piping stress analysis. It applies a computer to partition the piping system into elements as a net. Subsequently, the stresses and strains in each element are calculated based on the known laws of physics in form of equations.
Pipe stress analysis software: Pipeline stress analysis software is available in different types out in the market. These packages can be utilized to do piping stress analysis for a complicated piping arrangement.
Therefore, the choice of which piping stress analysis method is to be used depends on the system complexity, and the degree of precision needed.
Piping stress engineers are responsible for:Piping stress engineers are responsible for:
Identifying potential problems in piping systems: Piping stress engineers utilize piping stress analysis results in order to determine possible problems in the piping systems, what may include overstressed piping, undersized piping, and improper pipework support.
Designing piping systems to be safe and reliable: Piping stress engineers are role players who possess adequate knowledge of piping stress analysis which enables them create the best piping systems.
Overseeing the construction of piping systems: Piping stress engineers who supervise the construction of piping systems that need to be constructed according to the design.
Maintaining piping systems: Piping stress engineers are responsible for the preservation of piping since they wish to guarantee that they are safe and secure.
Piping stress engineering is one of the best specialty areas in engineering that is quite-interesting and exciting. Piping stress engineers are responsible for the reliability of pipes in the companies and industries.
Here are some of the skills and knowledge that are required for a career in piping stress engineering:Continued here is a list of skills and knowledge that are considered relevant in piping stress engineering:
- Mechanical engineering: The piping stress engineers, should be able armed with mechanical engineering concepts like stress analysis, fluids mechanics, and thermodynamics.
- Finite element analysis: There will be a need for piping stress engineers to demonstrate an appreciation of finite element analysis software.
- Pipe stress analysis software: Pipe stress engineers have to also know about the software used for pipe stress analysis.
- Problem-solving skills: Furthermore, the piping stress engineers should have problem solving skills when it comes to piping systems problems.
- Communication skills: Any piping stress engineer should be in a position to present the findings of the analysis in form of reports to the engineers, technicians and other relevant personnel.
If you are interested in a career in piping stress engineering, there are a number of things you can do to prepare:If you are interested in a career in piping stress engineering, there are a number of things you can do to prepare:
- Get a degree in mechanical engineering: As a minimum qualification a piping stress engineer should possess a degree in mechanical engineering.
- Take courses in finite element analysis: As piping stress engineer and designer, the finite element analysis is also another important and valuable tool to be used.
- Get experience with pipe stress analysis software: Here are some of the pipe stress analysis software packages Pipe Stress Master®, PIPE-FLO® Analysis, PASCAL™, PEXA, Piping Stress, and Caesar IV. In essence, having practice with these software packages will make you be fit for an employer.
- Network with other piping stress engineers: Thus, communication with other piping stress engineers can be very useful to get informed about the field and ask for some recommendations concerning the further work.
Types of stress in piping
There are many types of piping stresses, but some of the most common include:There are many types of piping stresses, but some of the most common include:
- Axial stress: This is the stress that results due to the pressure of the fluid contained in the pipe.
Axial stress in piping
- Lateral stress: This is the stressing that is produced by the dead weight of the pipe and the contained fluid. It is applied in a direction that is transverse to the axis of the pipe.
Lateral stress in piping
- Torsional stress: This is the stress that is as a result of the torsion that is put on the pipe. It is directed along the circumference of the pipe.
Torsional stress in piping
- Bending stress: This is the stress which results from bending of the pipe.. It is directed along the radius of the pipe.
Bending stress in piping
- Shear stress: This is the stress that is caused by the relative motion of two adjacent parts of the pipe. It is directed parallel to the surface of the pipe.
Shear stress in piping
The type of piping stress that is most critical depends on the specific application. For example, axial stress is the most critical for pipes that are carrying high pressure fluids. Lateral stress is the most critical for pipes that are supporting a heavy load. Torsional stress is the most critical for pipes that are being twisted. Bending stress is the most critical for pipes that are being bent. With regard to pipes that are experiencing relative motion, shear stress is the most critical.
Piping stresses can be caused by a variety of factors, including:
- Internal pressure: The pressure of such a fluid within the pipe is recognized as the most usual type of piping stress.
- External loads: Other piping stress can be produced from the external loading, which may include the mass of the pipe as well as the fluid contained within the pipe.
- Supports: The force and support that carries or holds the pipe responsible for piping stresses.
- Expansion and contraction: Temperature variations also cause piping stress due to the change in the dimension of the pipe from expansion and or contraction.
- Fatigue: Fatigue is the repeated loading and unloading on the pipe results in piping stress.
- Creep: Piping stress is the deformation under constant load and creep is the gradual deformation of the pipe.
Piping stresses can lead to a variety of problems, including:Piping stresses can lead to a variety of problems, including:
- Failure: If the piping stresses are greater than the piping capacity, then the pipe eventually bursts.
- Leaks: Injury of the pipe can damage severely and also increase the chances of producing a leak through the piping stresses.
- Deformation: Piping stresses can cause the pipe to deform.
- Fracture: Piping stresses can cause the pipe to fracture.
Piping stresses can be minimized by:Piping stresses can be minimized by:
- Using the correct size and type of pipe: The pipe should be of right size and type which should be capable enough to bear the concerned stress.
- Using proper supports: The pipe should be supported properly to minimize the stresses.
- Designing the pipe for expansion and contraction: This pipe structure should be made in a way that when pressure is applied and exerted the stresses are at its lowest.
- Using fatigue-resistant materials: The pipe should be of construction materials that do not fatigue to fail in service.
- Using creep-resistant materials: For this reason the pipe should be materials that possess high creep resistance characteristics.
Piping stress analysis is defined as the procedure to find the forces and stresses to which a piping system will be subjected. It is used to guarantee that the piping system is secure then undertaking functions perfectly. There are several ways through which piping stress analysis can be done, these include; manual calculations, use of finite element analysis and through pipe stress analysis tools.
piping stress calculation
The objective of piping stress evaluation varies according to the nature of stress to be determined.
Here are some of the formulas for calculating the most common types of piping stresses:Here are some of the formulas for calculating the most common types of piping stresses:
Axial stress:
σa = P/A
where:
σa is the axial stress (Pa)
P is the internal pressure (Pa)
A is the cross-section area of pipe in m2
Lateral stress:
σl = W/A
where:
σl is the lateral stress (Pa)
And W is the weight of the pipe and the fluid in the pipe in Newton (N).
A is the cross-sectional area of the pipe which is in meter square [m2].
Torsional stress:
τ = T/J
where:
τ is the torsional stress (Pa)
T is the torque applied to the pipe (N)
J is the polar moment of inertia of the pipe (m4)
Bending stress:
σb = Mc/I
where:
σb is the bending stress (Pa)
M is the bending moment applied to the pipe (N m)
c is the distance from the neutral axis to the outer surface of the pipe (m)
I is the moment of inertia of the pipe cross-section (m4)
Shear stress:
τ = F/A
where:
- τ is the shear stress (Pa)
- F is the shear force applied to the pipe (N)
- A is the cross-sectional area of the pipe (m2)
These are just some of the formulas for calculating piping stresses. The specific formula that is used depends on the specific application.
Piping stress analysis can be performed using a variety of methods, including hand calculations, finite element analysis, and pipe stress analysis software.
Hand calculations are the simplest method of piping stress analysis, but they are also the least accurate. Finite element analysis is a more accurate method of piping stress analysis, but it is also more complex and time-consuming. Pipe stress analysis software is a convenient and efficient way to perform piping stress analysis.
The choice of piping stress analysis method depends on the complexity of the piping system and the accuracy that is required.
Piping stress calculation involves determining the stresses and displacements within a piping system to ensure its safe and reliable operation. The calculation process is complex and typically involves the following steps:
Piping System Modeling:
- Prepare full-spectrum, comprehensive 3D model of the network with reference to the pipe sizes, materials, supports, restraints and all gadgets (valves, fittings, etc.). For this purpose, specialized pipings design and analysis software are frequently applied.
Load Analysis:
- Identify and analyze all loads acting on the piping system. These loads include:
- Pressure Load: Calculate the internal and external pressure loads on the pipes.
- Weight Load: Consider the weight of the pipes, fluid, insulation, and any attached equipment.
- Thermal Load: Reason for thermal change and explain what should be done in case of expansion or contraction to its maximum.
- Dynamic Loads: Analyse dynamic loads like – vibration, water hammer effect and seismic force.
- Nozzle Loads: Determine the forces and moment acting at the nozzles of equipment through connected piping.
- Occasional Loads: Consider transient loads from start-up, shut-down, or other non-standard conditions.
Support and Restraint Design:
- Design and analyze pipe supports, hangers, and restraints to ensure they are appropriately located and designed to handle the loads and constraints.
- Conduct a flexibility analysis to determine the insulation system’s capacity to handle thermal expansion and contraction loads without exerting high stress on the adjacent equipment or developing problems related to stress.
Stress Calculations:
- Calculate the stresses at various points along the piping system using the appropriate stress equations and principles. Stresses include axial, bending, hoop, and shear stresses.
Stress Allowable Limits:
- Subtract the calculated stresses from or add to them the allowable stress limits defined by ASME B31 and other codes and standards. 1 Standard for Class 1 (Power Piping), or ASME B31. 3 (Process Piping).
Fatigue Analysis:
- If the system experiences cyclic loading, conduct fatigue analysis to assess the potential for fatigue failure over time.
Thermal Expansion Analysis:
- Review the expansion and thermal stress of the piping system to guarantee that it does not overload the systems’ components beyond the permitted level.
Review and Recommendations:
- Check the results of stress calculations and stress analysis to define some issues and stress concentrations.
Documentation:
- Document the piping stress analysis in a comprehensive report that includes all calculations, assumptions, load data, support design, and compliance with relevant codes and standards.
Review and Approval:
- The piping stress analysis report should be reviewed and approved by qualified engineers and may require approval from regulatory authorities or internal stakeholders.
The piping stress analysis report should be reviewed by some qualified engineers and may be required to have endorsements by the regulation’s body or other internal users.
Stress analysis of piping is one of the vital parameters in piping design and is mandatory when the safety of a piping system and its efficiency is a key factor in industries.
piping stress calculation
The calculation of piping stress depends on the type of stress being calculated.
Here are some of the formulas for calculating the most common types of piping stresses:
Axial stress:
σa = P/A
where:
σa is the axial stress (Pa)
P is the internal pressure (Pa)
A is the cross-sectional area of the pipe (m2)
Lateral stress:
σl = W/A
where:
σl is the lateral stress (Pa)
W is the weight of the pipe and the fluid in the pipe (N)
A is the cross-sectional area of the pipe (m2)
Torsional stress:
τ = T/J
where:
τ is the torsional stress (Pa)
T is the torque applied to the pipe (N)
J is the polar moment of inertia of the pipe (m4)
Bending stress:
σb = Mc/I
where:
σb is the bending stress (Pa)
M is the bending moment applied to the pipe (N m)
c is the distance from the neutral axis to the outer surface of the pipe (m)
I is the moment of inertia of the pipe cross-section (m4)
Shear stress:
τ = F/A
where:
- τ is the shear stress (Pa)
- F is the shear force applied to the pipe (N)
- A is the cross-sectional area of the pipe (m2)
These are just some of the formulas for calculating piping stresses. The specific formula that is used depends on the specific application.
Piping stress analysis can be performed using a variety of methods, including hand calculations, finite element analysis, and pipe stress analysis software.
Hand calculations are the simplest method of piping stress analysis, but they are also the least accurate. Finite element analysis is a more accurate method of piping stress analysis, but it is also more complex and time-consuming. Pipe stress analysis software is a convenient and efficient way to perform piping stress analysis.
The choice of piping stress analysis method depends on the complexity of the piping system and the accuracy that is required.
Piping stress calculation involves determining the stresses and displacements within a piping system to ensure its safe and reliable operation. The calculation process is complex and typically involves the following steps:
Piping System Modeling:
- Create a detailed 3D model of the entire piping system, including pipe dimensions, materials, supports, restraints, and all components (valves, fittings, etc.). Specialized piping design and analysis software is often used for this purpose.
Load Analysis:
- Identify and analyze all loads acting on the piping system. These loads include:
- Pressure Load: Calculate the internal and external pressure loads on the pipes.
- Weight Load: Consider the weight of the pipes, fluid, insulation, and any attached equipment.
- Thermal Load: Account for thermal expansion and contraction due to temperature changes.
- Dynamic Loads: Analyze dynamic loads, such as vibration, water hammer, and seismic forces.
- Nozzle Loads: Assess the forces and moments applied to equipment nozzles through connected piping.
- Occasional Loads: Consider transient loads from start-up, shut-down, or other non-standard conditions.
Support and Restraint Design:
- Design and analyze pipe supports, hangers, and restraints to ensure they are appropriately located and designed to handle the loads and constraints.
Flexibility Analysis:
- Perform flexibility analysis to assess the ability of the piping system to absorb thermal expansion and contraction without imposing excessive loads on connected equipment or causing stress-related issues.
Stress Calculations:
- Calculate the stresses at various points along the piping system using the appropriate stress equations and principles. Stresses include axial, bending, hoop, and shear stresses.
Stress Allowable Limits:
- Compare the calculated stresses to the allowable stress limits specified in industry codes and standards, such as ASME B31.1 (Power Piping) or ASME B31.3 (Process Piping).
Fatigue Analysis:
- If the system experiences cyclic loading, conduct fatigue analysis to assess the potential for fatigue failure over time.
Thermal Expansion Analysis:
- Analyze the thermal expansion and contraction of the piping system to ensure that it remains within allowable limits and does not overstress components.
Review and Recommendations:
- Review the results of the stress calculations and analysis to identify any areas of concern or stress concentrations. Provide recommendations for corrective actions or design modifications if necessary.
Documentation:
- Document the piping stress analysis in a comprehensive report that includes all calculations, assumptions, load data, support design, and compliance with relevant codes and standards.
Review and Approval:
- The piping stress analysis report should be reviewed and approved by qualified engineers and may require approval from regulatory authorities or internal stakeholders.
Piping stress calculation is a critical aspect of piping engineering and is essential for ensuring the safety, reliability, and performance of piping systems, especially in industries where safety and operational efficiency are paramount.
what is piping stress analysis
Piping stress analysis is a branch of engineering that deals with the understanding and determining the stress and deformation of pipings subjected to any loading condition. The prime goals of piping stress analysis are to prove that stresses and deformations in the piping system are successfully within the allowable ranges.
Load Analysis: Piping stress analysts consider various types of loads that act on the piping system, including:
- Pressure Load: Internal and external pressure due to the transported fluid or surrounding environment.
- Weight Load: The weight of the pipe, fluid, insulation, and attached equipment.
- Thermal Load: The change in the sizes of pipes due to changes in temperature.
- Dynamic Load: Temporary loads including – vibrations, water hammer, horse and other seismic loads.
- Nozzle Loads: Forces and moments applied to equipment nozzles through connected piping.
Modeling and Software: They will then apply special software to model the whole piping system right from the pipe sizes and material, supports, and restraints up to all the components of the model.This model serves as the basis for stress calculations and analysis.
Support and Restraint Design: Considering the loads that are to be supported and the constraints that are expected to be imposed on the piping system, right design and analysis of these supports, hangers, and restraints are very important.
Flexibility Analysis: Figure 3 – Flexibility analysis – This determines the capacity of the piping system to allow provisions for change in thermal expansion and contraction without straining the connected equipment and or give rise to stress related complications.
Stress Calculations: Stress equations and some principles applied by piping stress analysts are axial stresses, bending stresses, hoop stresses, and shear stresses at several points in the piping system.
Stress Allowable Limits: These calculated stresses are then compared with the allowable stress limits with the help of codes and standards such as ASME B31. pipelines and ASME STD 1 (Power Piping) or ASME B31. 3 (Process Piping).
Fatigue Analysis: When the load application is (or expected to be) cyclic in nature (e.g., equipment start-ups, shut-down, etc.), it is also common to perform the fatigue analysis to diagnose the probability of fatigue crack failure.
Thermal Expansion Analysis: Checking and calculating of the thermal stresses, which occurs to the piping system due to thermal expansion and contraction, show that the stresses are within allowable limits so that overstressing the components does not occur.
Documentation: The piping stress analysis report is in electronic format and has standard format reporting check list, calculated data, assumed data, loading data, support design data and code / standards checklist.
Review and Approval: Both the piping stress analysis reports are usually prepared for the engineering assessment and may be subjected to approval by the regulatory bodies or the client.
Piping stress analysis is required when piping systems are to operating at high pressures, or temperatures or at operating conditions which could be considered adverse such as the oil and gas, petrochemicals, power, or chemical. This ensures that the functionality of piping components is optimally maintained thus increasing the service time of the piping and safety.