Thermal expansion and contraction of pipework is one of the largest dynamic forces acting upon piped services. Because piping systems often carry hot fluids, thermal expansion and the associated stresses must be carefully considered to avoid problems.
The forces created by the thermal expansion can be large enough to cause pipe bowing and buckling, damaged pumps, valves, pipe clamps and fixings and even fracturing of the pipe or damage to the steel or concrete structure of the building. In this blog, we will take a look at some of the factors that need considering when dealing with thermal pipe expansion, and also look at the basics of how to calculate the rate of thermal expansion within pipe systems, which is crucial to working out what products are required to deal with the problem.
Temperature changes cause an object or substance to change shape, area or volume. Pipes will generally expand when heated, and contract when cooled. This is caused by the molecular structure expanding due to the increased kinetic energy at a higher temperature — causing the molecules to move around more. As you can see, plastic pipe types usually expand significantly more than metal pipe types.
It is crucial that the expansion and contraction of pipework are addressed at the design stage of a project to avoid significant problems occurring. Problems such as snaking pipes or stress on pipe joints could eventually lead to leaks or burst pipes and all the related damage that a failure could cause.
It is often preferable to accommodate the expansion in a natural way using expansion loops, as expansion joints add considerable forces into the pipe system. Expansion loops accommodate thermal movements by installing sections of piping that run perpendicular to the piping system. Although these loops are semi-rigid, they do allow for some movement, thus reducing stress loads on the anchor points in the piping system.
A fixing point is used to ensure that the expansion is directed to the expansion loop where the force and movement is controlled.
When an expansion loop is being used, the distance between the first guiding clamp and the loop is important. The smaller the distance, the larger the force will be to bend the pipe.
This force is transferred to the fixing point. Expansion loops can take up a lot of room in the piping system layout so are most often used in outdoor systems.How To Connect Pex Pipe - Expansion Ring
In more confined spaces, flexible loops can be made which use corrugated metal hose assemblies for each leg of the loop. These flexible loops are more compact than pipe loops but require structural supports to prevent sagging. These kinds of loops are typically used where seismic protection is required. If there is no room for an expansion loop, then an expansion joint capable of axial movement should be used.These joints reduce stress, vibration, and noise in piping systems by providing a point of flexibility to absorb movement.
The flanged ends rotate for easy bolt hole alignment during installation. They mate with a same-size flat-surface Class flange without the need for a gasket. Joints have a flexible body that is reinforced with nylon for added strength. For technical drawings and 3-D models, click on a part number. These all-metal expansion joints can handle higher temperatures than rubber expansion joints.
They reduce stress, vibration, and noise in piping systems by providing a point of flexibility to absorb movement.
Joints are made of stainless steel for very good corrosion resistance. Flanges mate with a same-size flat-surface Class flange with a gasket sold separately.
Liners sold separately slide into the expansion joint to provide a smooth interior for unrestricted flow. These expansion joints have a double-bulb design for extra movement and vibration absorption.
The PTFE body on these expansion joints has a super-smooth surface that stands up to corrosive chemicals. Joints have a triple-bulb design that provides excellent vibration absorption, reducing stress on your piping system. The flanges mate with a same-size flat-surface Class flange without the need for a gasket. Limit rods are attached to the flanges to prevent overextension. Because the flanges are molded into the body for a wide sealing surface, these joints provide a tighter seal than other expansion joints.
Each flange is supported by a zinc-plated steel plate. Flanges mate with a same-size flat-surface Class flange without the need for a gasket. Joints reduce stress, vibration, and noise in metal piping systems by providing a point of flexibility to absorb movement. They have a flexible body that is reinforced with cord for added strength.
These joints reduce stress, vibration, and noise in plastic piping systems by providing a point of flexibility to absorb movement. Joints provide a tighter seal than other expansion joints because the flanges are molded into the body for a wide sealing surface. These joints weld to unthreaded pipe or another butt-weld fitting for a leak- resistant, permanent connection. They reduce stress, vibration, and noise in metal piping systems by providing a point of flexibility to absorb movement. These joints are designed for vertical use to reduce stress, vibration, and noise in drain, waste, and vent systems.
Slip them over the end of your pipe and tighten the band clamps for a secure hold.The same pump failed again.
A manufacturer experienced repeated failures on the same pump over and over, and even though the pump had been properly repaired, installed, and aligned, it still experienced chronic vibration issues.
A closer look determined that the vibrations were not being emitted from the pump, instead it was being affected by vibrations from other equipment as it travelled along the pipes. What can be done to stop rogue vibrations from affecting the pump? An expansion joint is installed in piping systems for a couple of reasons. Certain expansion joints are also designed for thermal expansion in very hot applications. Metal — Metal expansion joints are mostly used in applications where thermal expansion is an issue.
When the temperature of the pipe increases, the metal expansion joint compresses to compensate for the movement, taking stress off the anchors and the pipe. A metal expansion joint is a prime example of how to handle expanding hot pipes.
They also work as shock absorbers to minimize trauma caused by water hammerpressure surges, and seismic events not that we get a lot of earthquakes in Wisconsin….
Piping Flexibility Thermal Expansion of Pipe
Braided — Braided stainless hoses with flexible or metal liners aren't technically an expansion joint, more of a flexible connector. They work well in high pressure and temperature applications requiring vibration dampening or pipe misalignments. These are often used on pumps and other equipment to help eliminate thrust load on the equipment nozzles due to thermal expansion. Eliminating that load is critical to pump performance. We described some of the big reasons why expansion joints are helpful in piping systems already, but just to recap:.
Your entire process is intertwined, each piece affects the next. Having a reliable piping system is key to a process that maximizes uptime. Carefully managing your piping system not only keeps the pipes in great working condition, but also extends the life of the equipment attached to it.
His experience in sanitary and industrial processes makes him the go-to guy for many of Crane Engineering's customers. Join your peers! Subscribe to our blog for more tips, tools, and troubleshooting advice delivered right to your inbox. A piping expansion joint might help.
What is a piping expansion joint? Expansion joints allow pipes to move in three different ways: Axial compression or extension Lateral offset Angular deflection They typically come in three different materials to cover a variety of applications. They also absorb vibration rather well. Why would I need one? We described some of the big reasons why expansion joints are helpful in piping systems already, but just to recap: Thermal expansion of piping Solve initial piping misalignment and settlement lateral offsets Pump and equipment vibration Shock and bending loads Your entire process is intertwined, each piece affects the next.
Previous Next. Blog Search. Subscribe by email.
Always pay attention to plastic pipes and tubes when temperature varies. Expansion of the pipe can be calculated as. Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro.
We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.
Privacy We don't collect information from our users. Citation This page can be cited as Engineering ToolBox, Temperature Expansion Coefficients of Piping Materials. Modify access date. Scientific Online Calculator. Make Shortcut to Home Screen?Expansion joints for piping systems are flexible connectors, made out of PTFE, natural or synthetic elastomers, with combinations of rubber, fabric and metal reinforcement.
Expansion joints installed into piping systems will help solve problems such as:. To select the proper piping expansion joint, it is critical to understand the media compatibility with the materials selected, full temperature, pressure and vacuum ranges, movements required, and dimensions between pipe flanges. Available for Style and Style designs. Available for StyleStyleand Style designs. For more information, please see our EJ Materials Guide. Industry standard abrupt arch design for vacuum and pressure applications.
Rubber pipe connectors designed to absorb noise and vibration in air-conditioning, heating, and industrial piping systems. Style S-type has been developed specifically for submarine service. Other styles are available per application. Read More. Submit an Idea. Skip to main content. Search form Search. Contact a Representative Request a Quote. Expansion Joints for Pipes.
Style Narrow Arch Expansion Joint. Eliminates media buildup and reduces fluid turbulence in high-pressure applications. Molded spherical bellows design for general service applications. Style S-Type.
This tutorial includes advice on different methods and full calculations. All pipes will be installed at ambient temperature. Pipes carrying hot fluids such as water or steam operate at higher temperatures.
It follows that they expand, especially in length, with an increase from ambient to working temperatures. This will create stress upon certain areas within the distribution system, such as pipe joints, which, in the extreme, could fracture.
How to deal with thermal pipe expansion and contraction
The amount of the expansion is readily calculated using Equation Alternatively, the chart in Figure Using Figure For this example an approximate expansion of mm is indicated. The pipework system must be sufficiently flexible to accommodate the movements of the components as they expand. In many cases the flexibility of the pipework system, due to the length of the pipe and number of bends and supports, means that no undue stresses are imposed.
In other installations, however, it will be necessary to incorporate some means of achieving this required flexibility. An example on a typical steam system is the discharge of condensate from a steam mains drain trap into the condensate return line that runs along the steam line Figure Here, the difference between the expansions of the two pipework systems must be taken into account.
The steam main will be operating at a higher temperature than that of the condensate main, and the two connection points will move relative to each other during system warm-up. The total amount of expansion is first calculated for each section between fixed anchor points. The pipes are left short by half of this amount, and stretched cold by pulling up bolts at a flanged joint, so that at ambient temperature, the system is stressed in one direction.
When warmed through half of the total temperature rise, the piping is unstressed. At working temperature and having fully expanded, the piping is stressed in the opposite direction.
In practical terms, the pipework is assembled cold with a spacer piece, of length equal to half the expansion, between two flanges. When the pipework is fully installed and anchored at both ends, the spacer is removed and the joint pulled up tight see Figure The remaining part of the expansion, if not accepted by the natural flexibility of the pipework will call for the use of an expansion fitting.
In practice, pipework expansion and support can be classified into three areas as shown in Figure Roller supports Figure One major requirement in piping design is to provide adequate flexibility for absorbing the thermal expansion of the pipe. However, due to lack of quick method of checking, pipings are often laid-out to be either too stiff or too flexible. In either case, valuable time and material are wasted.
Piping Expansion Joints
This article presents some of the quick methods for checking piping flexibility. These methods include visual, hand calculation, and micro computer approaches. They are all quick and easy for designers to use in planning their layouts.
Once the designers have taken care of the flexibility problem, the iterative procedure between the stress engineers and the designers become simpler. The project schedule can also be improved. As the pipe temperature changes from the installation condition to the operating condition, it expands or contracts.
In the general term, both expansion and contraction are called thermal expansion. When a pipe expands it has the potential of generating enormous force and stress in the system. However, if the piping is flexible enough, the expansion can be absorbed without creating undue force or stress. Providing the proper flexibility is one of the major tasks in the design of piping system.
Piping is used to convey a certain amount of fluid from one point to another. It is obvious that the shorter the pipe is used the lesser the capital expenditure is required. The long pipe may also generate excessive pressure drop making it unsuitable for the proper operation. However, the direct shortest layout generally is not acceptable for absorbing the thermal expansion. Figure 1 shows what will happen when a straight pipe is directly connected from one point to another.
First, consider that only one end is connected and the other end is loose. However, since the other end is not loose, this expansion is to be absorbed by the piping.
Take a 6-inch standard wall carbon steel pipe for instance, an increase of temperature from 70F ambient to F operating creates an axial stress of psi and an axial force of lbs in the pipe.