What is the maximum operating pressure for PVC fittings?
At the maximum operating temperature for PVC - 140oF (60oC) - the strength is derated to approximately 20% of the strength at 73oF (23oC). Be aware that maximum operating pressures varies with the fittings design. Consult the manufacturing data. Engineering ToolBox - SketchUp Extension - Online 3D modeling!
What is the maximum pressure a compression fitting can withstand?
In combination with a high pressure tubing material like steel, large compression fittings can often be used at pressures in excess of 10,000 psig.
Can PVC pipe withstand high pressure?
PVC pipe often gets a bad rap because it cannot handle as much pressure as various types of metal pipe. However, smaller sizes of PVC pipe, especially schedule 80, can handle plenty of pressure for most home and business uses. Unlike tensile strength, burst pressure decreases as pipe size increases.
Why use compression fittings at high pressure?
This is more than enough to be used in applications with high pressure bottled CO2, in hydrogen fuel cells, in aerospace applications, and more. The key to using compression fittings at high pressure, especially with gases, is the integrity of the ferrule seal.
How much pressure can a compression fitting handle?
In combination with a high pressure tubing material like steel, large compression fittings can often be used at pressures in excess of 10,000 psig.
How much pressure can a 3/8 compression fitting hold?
3/8, 1/2: 200 psi.
Are PVC compression fittings reliable?
Although compression fittings are generally considered more reliable than threaded fittings, there are some potential problems. In general, compression fittings are not as resistant to vibration as soldered or welded fittings. Repeated bending may cause the ferrule to lose its grip on the tube.
How many PSI is PVC rated?
between 300-600 psiMost consumer air compressors compress air to 125-175 psi, which does not sound like much. Most smaller sizes of PVC pipe are rated for between 300-600 psi, but that is only if the pipes are new and the system is perfectly sealed.
What is the most common cause of leaking compression fittings?
If the nut is overtightened the ferrule will deform improperly causing the joint to fail. Indeed, overtightening is the most common cause of leaks in compression fittings.
Can you use compression fittings on plastic pipe?
A compression fitting works in the same way on a plastic pipe as it does on a copper pipe except that you need to put in a liner, which is there to keep the end of the pipe perfectly round.
Can compression fittings leak over time?
If the pipe gets bent back and forth, the compression fitting could eventually spring a leak. Another thing that'll you'll want to avoid is using a double compression fitting to lengthen a pipe unless you're using it under your kitchen sink. The reason being is because there's minimal movement and stress.
How do I stop my PVC compression fitting from leaking?
1:086:39FIX LEAKING COMPRESSION PIPE FITTING - Plumbing Tips - YouTubeYouTubeStart of suggested clipEnd of suggested clipTo be this way around like so okay then you can get your adjustable on the fitting like that andMoreTo be this way around like so okay then you can get your adjustable on the fitting like that and tighten it up give it an extra nip. Often that will stop a leak on a compression.
Why do compression fittings fail?
Unlike threaded fittings, compression fittings can seal properly but nevertheless slip out of position as a result of forces on a pipe. In this case, the plumbers failed to properly restrain the repaired pipe when using compression fittings.
Can PVC withstand high pressure?
Note that each material is pressure rated to 230 psi at 73°F (22.8°C). PVC has a derating factor of 0.31 at 130°F (54.4°C), making it pressure rated up to 71.3 psi at that temperature (230 psi x 0.31 = 71.3 psi).
What PSI is Schedule 40 PVC rated for?
For example, a 2” schedule 40 PVC pipe has a . 154” minimum wall and can handle up to 280 PSI.
What is the maximum pressure for Schedule 40 PVC?
Example: What's the Maximum Working Pressure of a 6” Schedule 40 pipe length at 110 degrees Fahrenheit? Answer: 180 PSI X .
What is compression fitting?
Compression fittings are one of the most common and versatile methods of connecting metal or hard plastic tubing. Particularly useful for their extreme temperature and pressure capabilities, and their compatibility with aggressive fluids, compression fittings can be seen in systems varying from gas lines in refineries, ...
How does metal tubing affect compression?
The way in which metal tubing is produced can have a significant effect on its performance with compression fittings. Tubing should be smooth and free of roughness or extrusion lines that can create a leak path past the ferrule. Furthermore, tubing that has been stored in coils can often have an asymetrical diameter, preventing even compression. While an elastomeric seal can deform to match these slight variations, the metal-to-metal seal of a compression fitting is less forgiving. It is also important that the end of each section be squarely cut, to allow the tubing to sit symmetrically in the fitting body.
What is the importance of the shape of the ferrule and the mating angle of the fitting body?
The shape of both the ferrule and the mating angle of the fitting body are critical factors in the reliability of a compression seal. Both components must be tapered in a manner that allows the ferrule to compress properly as the nut is tightened, while maintaining axial alignment with the tubing.
What is the radial compression of a ferrule?
It is this radial compression that creates the leak tight seal between the fitting, ferrule, and tubing, and gives the compression fitting its name. ...
Why is PTFE tubing used?
PTFE tubing is a popular material choice for tubing because it is resistant to most chemicals, handles relatively high pressure, is low out-gassing, and is more flexible than metallic tubing. One key design factor when using this kind of tubing is its tendency to “cold flow”, or deform away from a compressive load. This can cause leaks to develop over time, as the tubing wall begins to creep (cold flow) away from the ferrule. The cold flow issue is exacerbated when the tubing is exposed to high temperatures, and can occur even when fittings are properly installed and initially leak free.
Is compression fitting elastomeric or metal?
While an elastomeric seal can deform to match these slight variations, the metal-to-metal seal of a compression fitting is less forgiving. It is also important that the end of each section be squarely cut, to allow the tubing to sit symmetrically in the fitting body.
Is tighter or tighter better?
Tighter is Not “Better”. Often when assembling fittings, assemblers and engineers assume that “tight er is better”.
How to measure tensile strength of PVC pipe?
PVC pipe tensile strength can be measured by hanging weight from the pipe until it bends or cracks.
What is the crush strength of PVC pipe?
Collapse pressure (or PVC pipe crush strength) is the amount of outside pressure a pipe can take before it starts collapsing inwards. This is an important measurement when burying pipe for subterranean applications. To test this type of strength, you can place weight on a pipe until it starts buckling. As with burst pressure, the amount of collapse ...
Why is PVC pipe bad?
PVC pipe often gets a bad rap because it cannot handle as much pressure as various types of metal pipe. However, smaller sizes of PVC pipe, especially schedule 80, can handle plenty of pressure for most home and business uses. Unlike tensile strength, burst pressure decreases as pipe size increases.
What is burst pressure?
Burst Pressure. Burst pressure is basically what it sounds like: the amount of internal pressure pipe can take before it fails. It is a measurement that should be taken into consideration anytime you are pumping any kind of fluid through a piping system.
Is PVC pipe stronger than metal?
In conclusion, PVC is not as strong as metal, but is often the perfect choice, especially when you are on a budget! Shop Schedule 80 PVC Pipe. Shop Schedule 40 PVC Pipe.
Does burst pressure decrease with pipe size?
Unlike tensile strength, burst pressure decreases as pipe size increases. The smaller pipes are far less likely to fail due to internal pressure problems. If you look closely you will notice that 2.5" pipe has a slightly higher burst pressure rating than 2", oddly.
Introduction to Compression Fittings
Ferrules
- The ferrule is the primary sealing component of a compression fitting assembly, and they can be found in a wide variety of materials ranging from stainless steel to graphite. The majority of ferrules in the marketplace however, are manufactured from metals. Metal ferrules are attractive because they are stable over a wide temperature range, and they can bear compressive loads wi…
Tubing
- Compression fittings are most commonly used with hard tubing because the tubing wall must be rigid enough to resist the compression forces applied by the ferrule. Common choices include metallic tubing (such as stainless steel or copper) and stiff plastic tubing (such as PEEK, nylon, Teflon®, Kynar®, or polyethylene). The use of softer tubing (such as polyurethane or vinyl) is no…
Installation
- Installation instructions for compression fittings vary depending on the manufacturer and the specific fitting design. Care should be taken to follow the assembly procedures recommended by the manufacturer. There are however, several common elements to the installation procedure for nearly all compression fittings:
Application Considerations
- Compression fittings are often selected for reasons beyond just leak-free sealing and ease of use. In many applications, high pressures and temperatures necessitate the use of hard tubing, which is incompatible with many other types of fittings. In other applications, such as laboratory instruments, concerns over contamination make the sterility and low out-gassing properties of s…
Conclusion
- Compression fittings are widely used across a number of industries, and can be an asset in almost any fluid power design. Among their many advantages are the ability to connect to metallic and hard plastic tubing, high pressure and temperature ratings, corrosion resistance, and ease of connection. While there are many challenges associated with compression fittings as w…