Is PEX made of polyethylene?
Cross-linked Polyethylene (PEX) is a plastic material made from medium- or high-density polyethylene that is modified to have improved properties such as enhanced heat resistance and long term strength and stability that make it an excellent choice for use in service lines, hot- and cold-potable water distribution ...
Is polyethylene tubing the same as PEX tubing?
PEX tubing is made of cross-linked polyethylene for extra strength and is suited for hot or cold drinking water.
Is PEX better than polyethylene?
One advantage that PEX has over PB is its greater tolerance to high pressures. Different manufacturers may have different numbers, but PEX will always have greater pressure limits than PB. So if you will be pumping water, or the pipes will be exposed to the cold, PEX is a better option than PB.
What type of material is PEX?
PEX pipe is made from cross-linked HDPE (high density polyethylene). The HDPE is melted and continuously extruded into a tube to form a high-performing pipe suitable for a variety of potable and non-potable plumbing applications.
How can you tell PEX from Poly B?
Polybutylene pipe was commonly used from 1978 – 1995 and is a gray flexible pipe. PEX is a plastic flexible pipe that comes in white, blue, orange, red and a translucent milky white clear. This piping came about to replace polybutylene plumbing.
What is another name for PEX?
Cross-linked polyethylene, commonly abbreviated PEX, XPE or XLPE, is a form of polyethylene with cross-links.
Is PEX a polypropylene?
PEX-a uses a polyethylene starting material with a linear backbone having no branching. In contrast, both polypropylene (PP-r) and polyethylene raised temperature (PE-RT) pipes contain short-chain branches along the backbone, decreasing the chemical resistance of the polymer chains.
Is polypropylene the same as PEX?
Polypropylene is a durable, rigid plastic with less likelihood of chemical leaching compared to PEX. Heat can be used to join polypropylene pipes, instead of chemical solvents or leaded joint materials.
Can sharkbite fittings be used on polyethylene pipe?
0:231:31Polybutylene Pipe Fittings - SharkBite Conversion Coupling - YouTubeYouTubeStart of suggested clipEnd of suggested clipThe sharkbite conversion coupling will convert poly butylene to any cts pipe size such as copperMoreThe sharkbite conversion coupling will convert poly butylene to any cts pipe size such as copper pegs or CPVC. The poly butylene pipe end can only be used on poly butylene pipe remove.
Why is PEX not allowed?
Rodent Risk Factors While pest experts don't know whether rodents chew through PEX to get to the water inside or simply because it's there, PEX and rodents can be a dangerous combination. Local building codes in some communities may not permit the installation of PEX if rodent infestations are common.
What are the three types of PEX?
So What are the Differences between PEX types?PEX A is made using the Peroxide, or Engel, method.PEX B is formed using Silane, or Moisture Cure, method. This is the most common PEX pipe type out there.PEX C is created using the Electronic Irradiation, or Cold, method of cross-linking.
What is a PEX fitting made of?
PEX fittings are most commonly made up of one of three different types of materials: Plastics, Brasses, or Stainless Steel. Alternatively, a push fit fitting uses a combination of these materials.
Can you use PEX fittings on poly pipe?
The SharkBite PEX barb polybutylene adapter is made of a lead-free DZR brass, and is an easy to install, low-cost solution to connect PEX tubing to polybutylene pipe. SharkBite PEX barb fittings are compatible for potable water distribution and hydronic heating applications.
Is polypropylene the same as PEX?
Polypropylene is a durable, rigid plastic with less likelihood of chemical leaching compared to PEX. Heat can be used to join polypropylene pipes, instead of chemical solvents or leaded joint materials.
What is polyethylene tubing?
Poly tubing, often referred to as PE tubing or polyethylene tubing is a flexible, lightweight, durable and corrosion resistant plastic that can be used for a wide range of liquid, gas and fluid transfer applications.
Can you use SharkBite fittings on polyethylene tubing?
Sharkbite push-to-connect fittings are only approved with PEX, copper, CPVC, and PE-RT piping.
How is polyethylene classified?
Polyethylene is classified by its density and branching. Its mechanical properties depend significantly on variables such as the extent and type of branching, the crystal structure, and the molecular weight. There are several types of polyethylene:
Where does the name polyethylene come from?
The name polyethylene comes from the ingredient and not the resulting chemical compound, which contains no double bonds. The scientific name polyethene is systematically derived from the scientific name of the monomer. The alkene monomer converts to a long, sometimes very long, alkane in the polymerization process.
What is the most common plastic in the world?
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly (methylene)) is the most common plastic in use today. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including bottles, etc.). As of 2017.
What are the different grades of polyethylene?
With regard to sold volumes, the most important polyethylene grades are HDPE, LLDPE, and LDPE.
How are radicals generated in polyethylene?
In each method, a radical is generated in the polyethylene chain (top center), either by radiation (h·ν) or by peroxides (R-O-O-R). Then, two radical chains can either directly crosslink (bottom left) or indirectly by silane compounds (bottom right).
What is the melting point of polyethylene?
For common commercial grades of medium- and high-density polyethylene the melting point is typically in the range 120 to 130 °C (248 to 266 °F). The melting point for average commercial low-density polyethylene is typically 105 to 115 °C (221 to 239 °F).
When was polyethylene first used?
The first industrially practical polyethylene synthesis (diazomethane is a notoriously unstable substance that is generally avoided in industrial application) was again accidentally discovered in 1933 by Eric Fawcett and Reginald Gibson at the Imperial Chemical Industries (ICI) works in Northwich, England.
What is PEX pipe?
Cross-linked Polyethylene (PEX) is a plastic material made from medium- or high-density polyethylene that is modified to have improved properties such as enhanced heat resistance and long term strength and stability that make it an excellent choice for use in service lines, hot- and cold-potable water distribution systems, residential fire-sprinkler systems and hydronic heating applications. Pipes made from these materials are produced to meet the requirements of ASTM F876, ASTM F877, AWWA C904 and/or CSA B137.5.
How is PEX produced?
The tubing is produced by blending this grafted compound with a catalyst which can be done using either the Sioplas method or by using a special extruder it can be done using the Monosil method. After extrusion the tubing is exposed to either steam or hot water to induce the final cross-linking reaction in the tubing.
Why is PEX crosslinked?
PEX results from chemically joining individual polyethylene molecules in order to improve the performance of the original base resin in higher temperatures. The primary reason for cross-linking polyethylene (PE) is to raise the thermal stability of the material under load. This substantially improves environmental stress crack resistance and resistance to slow crack growth.
What is PEX tubing used for?
PEX tubing is also widely used for heat transfer applications - both low-temperature (radiant floor heating and/or cooling, snow melting, turf conditioning and permafrost protection), as well as distribution piping for temperatures up to 200°F (hot-water baseboard, convectors, radiators, etc.) and some is approved for use in residential fire-sprinkler systems.
How is PEX tubing manufactured?
PEX tubing is manufactured by extrusion in sizes from ¼"-3" nominal diameter. It is controlled to OD controlled to (Outside Diameter) dimensions in what is commonly called CTS (copper tube size). The wall thickness is based on a Standard Dimension Ratio 9 (SDR 9), meaning that the ratio of the OD to the wall thickness of the tubing is 9:1. It is available in coils of various lengths and straight lengths.
How many methods are there for PEX tubing?
There are three primary methods for producing PEX tubing.
What are the benefits of PEX?
A significant benefit of PEX and other plastic pipe is its small environmental impact compared to other materials used for similar applications. To learn more click here .
How is PEX formed?
PEX is a polymeric material formed by the chemical joining of individual polyethylene molecules in a process called cross-linking. Cross-linking alters the performance of the original polyethylene polymer improving several key properties. The primary reason for cross-linking polyethylene (PE) is to increase the material's elevated temperature performance under load. In addition, cross-linking substantially improves the pipe's environmental stress crack resistance (ESCR), resistance to slow crack growth, chemical resistance, toughness and abrasion resistance.
When was Pex used?
Pex (Cross-Linked Polyethylene): PEX was first used for hot-water radiant heating in the early 1970's, and today is a reliable solution around the world for hot- and cold water plumbing, radiant heating and cooling, outdoor snow and ice melting, residential fire protection, hydronic (hot-water) building services piping, and other demanding applications such as natural gas piping (outside of North America).
How is PEX pipe connected?
PEX pipe is typically connected using either a copper crimp ring or expansion fittings with outer expansion rings . In the crimping method, a copper crimp ring is put over the pipe near the end, a copper fitting is inserted into the pipe end, and a crimping tool is used to crimp the ring over the pipe and fitting. In the expansion fitting method, an expansion tool is used to open the diameter of the pipe, into which an expansion fitting is inserted.
How much elongation is required for a 100ft PEX pipe?
Elongation (linear expansion): Typical elongation is anywhere from 1" to 2.5" for every 100ft of PEX pipe at a 10°F temperature rise. Since PEX expands and contracts with temperature changes, it should be secured so as to provide sufficient space for expansion to occur.
When was PEX pipe first used?
It was first introduced in North America in the early 1980s and is widely used for plumbing, water service, fire protection, hydronic heating and cooling, snow and ice melting and ground source geothermal piping systems. PEX is approved in all model plumbing and mechanical codes across the United States and Canada, and some PEX pipe is listed for use in fire sprinkler systems as defined in NFPA standard 13D.
What is the pressure rating of PEX tubing?
PEX tubing is SDR9 with standard hydrostatic pressure ratings of 160 psi at 73°F (1105 kPa at 23°C) and 100 psi at 180°F (690 kPa at 82°C). Consult the specific PEX manufacturer's literature and listings for appropriate pressure ratings. PEX tubing and pipe are sold in coils and straight lengths.
What is PEX pipe?
Cross-linked polyethylene (PEX), a type of flexible plastic, is currently replacing traditional copper and galvanized steel as water supply lines in both new construction and remodeling projects. You’ve probably seen rolls of blue and red PEX pipe in the plumbing aisle of your local home improvement store, but might not know that this colorful tubing now makes it possible for enthusiastic DIYers to replace their own leaky water lines instead of calling a pro. Read on to learn more about PEX—what it is, where it can be used, and all the pros and cons of this popular plumbing material.
What color is PEX?
Water flows silently through PEX, eliminating the “water hammer” noise associated with metal piping. Color-coding (red and blue) make it simple to distinguish hot and cold supply lines. PEX can be connected to existing metal supply lines with the correct fittings.
What type of fittings are used for PEX?
Hundreds of types of fittings, usually brass, are available for connecting PEX to existing copper or steel pipes, and for making connections to fixtures. Fittings are also available for connecting pipes of different sizes. The following five methods are used for making the connections watertight. Photo: amazon.com.
What is PEX tubing?
Choose the tubing best suited to your needs: PEX-A is manufactured using peroxide. This type of PEX is the most flexible of the three types and is suitable for use in all home water-supply plumbing needs.
What is the advantage of PEX pipe?
PEX has a distinct advantage over these materials because of its flexibility, which allows one end of PEX pipe to connect to a PEX manifold (the main water control system) and then wind through walls and floors—uninterrupted—all the way to an individual fixture.
What type of PEX pipe is used for hot water?
Blue PEX pipe carries cold water. White PEX pipe can be used for either hot or cold water. Gray PEX pipe, like white, can be used for either hot or cold water (although not all DIY centers carry gray).
How long is a PEX pipe?
PEX is available in a variety of lengths, from short 10-foot pieces (for small repairs) to rolls over 500 feet long, which are used to install a home’s entire water supply system. PEX pipe ranges from 3/8- to 1-inch in diameter and its color-coding makes it a snap to identify what a specific pipe is used for. Although there are three types of PEX (see Label Lingo, below), the different colors don’t connote the distinctions; they simply make it easy for the installer to identify which lines carry hot water and which carry cold.
Why don't you consider PEX?
Freeze thaw is why you don't consider PEX, because it is a phenomenon (frost and heave) that can bring pipe to the surface, where it is exposed to sunlight.
Is crosslinked polyethylene good for outdoor use?
Cross-linked Polyethelene meets ASTM standards for heat, cold, pressure, etc etc, certified for outdoor use, cold weather, etc, etc, seems far superior to poly. What am I missing here?
Is there a saddle for Pex?
Ease of installing fittings. I've never seen a saddle for pex.
Overview
Classification
Polyethylene is classified by its density and branching. Its mechanical properties depend significantly on variables such as the extent and type of branching, the crystal structure, and the molecular weight. There are several types of polyethylene:
• Ultra-high-molecular-weight polyethylene (UHMWPE)
History
Polyethylene was first synthesized by the German chemist Hans von Pechmann, who prepared it by accident in 1898 while investigating diazomethane. When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the white, waxy substance that he had created, they recognized that it contained long −CH2− chains and termed it polymethylene.
The first industrially practical polyethylene synthesis (diazomethane is a notoriously unstable su…
Properties
The properties of polyethylene can be divided into mechanical, chemical, electrical, optical, and thermal properties.
Polyethylene is of low strength, hardness and rigidity, but has a high ductility and impact strength as well as low friction. It shows strong creep under persistent force, which can be reduced by addition of short fibers. It feels waxy when touched.
Manufacturing process
The ingredient or monomer is ethylene (IUPAC name ethene), a gaseous hydrocarbon with the formula C2H4, which can be viewed as a pair of methylene groups (−CH 2−) connected to each other. Typical specifications for PE purity are <5 ppm for water, oxygen, and other alkenes contents. Acceptable contaminants include N2, ethane (common precursor to ethylene), and metha…
Joining
Commonly used methods for joining polyethylene parts together include:
• Welding
• Fastening
• Adhesives
Adhesives and solvents are rarely used because polyethylene is nonpolar and has a high resistanc…
Environmental issues
Polyethylene is produced from ethylene, and although ethylene can be produced from renewable resources, it is mainly obtained from petroleum or natural gas.
Moreover, the widespread usage of polyethylene poses difficulties for waste management if it is not recycled. Polyethylene, like other synthetic plastics, is not readily biodegradable, and thus accumulates in landfills. Recycling is mad…
Chemically modified polyethylene
Polyethylene may either be modified in the polymerization by polar or non-polar comonomers or after polymerization through polymer-analogous reactions. Common polymer-analogous reactions are in case of polyethylene crosslinking, chlorination and sulfochlorination.
In the low pressure process α-olefins (e.g. 1-butene or 1-hexene) may be added, which are incorporated in the polymer chain during polymerization. These copolymers introduce short sid…