Piping systems play an important role in industries like Gas, Marine, Oil & Gas, HVAC, Power Generation, and Manufacturing, as they are essentially the "backbone" of all those industries.
A piping system consists of pipes to carry fluids and gases, but it is the piping joints that combine all sections to form one complete system that can be expanded upon yet still maintain reliability. For many industrial environments, pipe length is restricted by transportation, installation or design constraints. Therefore, pipe joints are needed to create the ability to attach multiple lengths of piping together to create long, continuous piping systems that are safe to use.
Due to differences in pressure, temperature, and ways that the piping systems move, not all piping joint designs will work for all applications. Therefore, selecting the appropriate joint is critical for maintaining as much efficiency, safety, and sustainability as possible while minimising leakage, vibration and mechanical stress. This blog will detail what piping joints are, the various types of piping joints that are used in different industries, the criteria to use for selecting the proper joint and common mistakes to avoid.
See also: Maximizing Pipeline Efficiency: Exploring Different Types of Metal Expansion Joints
Piping joints (also referred to as connections) serve as the point where two or more pipes are connected together to form a continuous piping system (or network). At the junction of these pipes, liquids or gases can be transported safely through a piping network without compromising the structural integrity of the system due to the environmental conditions found in most industrial systems. Depending on the application, joints may be flexible or rigid (e.g., flared fittings) or be permanent or temporary.
The piping systems used in most industrial types will be subjected to various pressures, temperature fluctuations, vibrations, and in some cases chemicals. Therefore, the type of joint selected to connect the piping systems together should be done so based on the conditions that the piping systems will be subject to; therefore some types of pipe joints will allow for movement whereas others will allow for fixed, leak-proof connections. Failure to select pipe joints that are designed to meet the intended conditions may result in leaks, mechanical failure, or early wear.
As noted, many manufacturers such as Flexibel have developed innovative solutions for industrial piping systems that provide advanced piping joint solutions for complex industrial applications where movement, pressure, and reliability are paramount.
See also: Importance of Metal Hoses in Industrial Piping Systems
There are several types of piping joints, each designed for specific operating conditions and system requirements.
Welded Joints
Welded Joint refers to a type of permanent connection that is produced by joining the ends of two pipes through welding. Welded Joints can be found in many applications for high-pressure / high-temperature systems including Oil & Gas and Power Plants. They are strong, leak-proof joints but they do not permit movement and their installation must be performed by a qualified welder.
Flanged Joints
Flanged joints- which include gasketing and bolted flanges for pipe connections- make it simple to assemble and disassemble. This feature has made flanged joints a very popular option in maintenance-intensive applications such as marine and industrial piping systems.
Threaded Joints
Threaded joints consist of a pipe that has an internal (female) thread, and another pipe that has an external (male) thread. Due to their design, threaded joints are generally employed in applications with lower pressures than other methods of joining pipes, and are generally limited to the sizes of pipes used in many plumbing applications, compressed air systems, etc.
Expansion Joints
The design of expansion joints allows for the movement of pipe systems due to thermal expansion, vibration, or misalignment. The types fall into three categories: metallic expansion joints, rubber expansion joints, and fabric expansion joints. Each type has distinct characteristics and is suitable for different types of operating environments and applications.
Flexible Hose Joints
Metallic hose assemblies known as flexible hose joints allow for freedom of movement in the piping system yet allow for normal fluid flow through them. Flexible hose joints are generally used in vibration or movement (vibration isolation) applications where frequent vibrations are present.
Compensator Joint
A compensator joint is a flexible connection within the piping system that can accommodate the effects of thermal expansion and contraction of the piping system. It provides protection to the piping and associated equipment from excessive stresses and deformation.
See also: Your Guide to Metal Expansion Joints: Design, Uses, and Advantages
Before selecting a piping joint, you will need to decide your requirements. These requirements will determine what kind of piping you will use based on how much pressure will be placed upon the pipe or joint (High Pressure, Medium Pressure, or Low Pressure) and how you intend to use the piping system. For instance, if you have a piping system designed to operate above 1400 PSI, then the type of joining method that would be appropriate for that application would be completely different than a piping system that is rated to operate below 300 PSIG, where there are many different types of joining methods available.
In addition to pressure ratings, you should consider other factors, including:
Every pipe joint should have compatible materials, whether a metal expansion joint, a rubber expansion joint, or a fabric expansion joint, it should convey the fluids being transported, with ample space available for installation and maintenance over time. To ensure that your joint design has matched up with actual operating conditions, you should consult with an experienced manufacturer, such as Flexibel.
Piping connections in the gas industry are engineered to transport fluids without leaks under very high pressures and temperatures. The marine industry relies on flexible fittings to accommodate vessel movement and vibration.
Expansion joints are used by power plants to account for thermal expansion in steam and exhaust piping systems. Many HVAC (heating, ventilation, and air conditioning) systems utilize flexible piping joints to reduce noise and vibration from equipment operation. Corrosion-resistant couplings are very important for chemical and industrial plants that transport harsh liquids (corrosive).
A carefully selected combination of appropriate pipe joints should be used for optimal long-term dependability and safety of the remaining support and equipment in this industry.
While welded joints provide maximum strength, they do not allow pipe movement due to their rigid nature. Flanged joints allow for easy removal and replacement of piping components, but they take up more space than other types of joints and are also more complicated to seal.
Rubber expansion joints & fabric expansion joints are very effective at absorbing movement, but engineers need to ensure that the flexible joint can tolerate the pressure and the chemical used in piping applications. Similarly, metallic expansion joints are mainly used where extreme pressures or temperatures exist. Compared to other forms of flexible joints, they will have longer life spans; however, these joint types are generally more costly. Once an engineer comprehends the value of the various trade-offs in flexibility, the engineer may develop a piping system that meets a good balance between mechanical performance and efficiency.
Ignoring thermal expansion, which creates stress and the possibility of a pipe failure, is one example of a mistake commonly made when selecting a joint. In addition, a choice made solely on the basis of cost may be made at the expense of the design requirements for a particular application.
Improper installation, improper sizing, and neglect of maintenance, as well as selecting joints without accounting for potential system movement or future expansion, all contribute to reduced lifespan.
Consulting with knowledgeable manufacturers such as Flexibel will eliminate many of these costly mistakes.
The integrity and performance of piping systems depend heavily on piping joints. The variety of pipe joints is quite wide: rigid welded pipe joints, flexible expansion joints and more; each type serves a special need due to the varying pressures, temperatures, and types of movement experienced by piping systems.
When industries have knowledge of the types of pipe joints, their uses, and their selection criteria, they can create strong, efficient, and long-lasting piping systems. Having the appropriate types of pipe joints will protect both the piping and the equipment that is installed with the piping, thus protecting the entire piping system and the entire operational facility, as well.
