Polyethylene Pipe and Fittings Manufacturing part 1

Scope
This chapter describes the production of extruded solid wall and profilewall pe pipe and the molding and fabrication of pe fittings. Qualityassurance and control tests that are required under typical ASTM specificationswill also be discussed.

Introduction
The principles of pipe and fitting production are to melt and conveypolyethylene into a particular shape and hold that shape during the coolingprocess. This is necessary to produce solid wall and profile wall pipe as well asinjection molded fittings.
The smaller diameters of solid wall polyethylene pipe are continuouslyextruded through an annular die. For large diameter profile wall pipes, the profileis spirally wound onto a mandrel and sealed along the seams.
Solid wall polyethylene pipe is currently produced in sizes ranging from1/2 inch to 63 inches in diameter. Spirally wound profile pipe may he made up to10 feet in diameter or more. There are several specification standards that governthe manufacturing processes for polyethylene pipe, but the main standards forsolid wall and profile pipe include:

ASTM D2239 Standard Specification for Polyethylene (PE) Plastic Pipe(SIDR-PR) Based on Controlled Inside Diameter
ASTM D2447 Standard Specification for Polyethylene (PE) Plastic Pipe,Schedules 40 and 80, Based on outside Diameter
ASTM D2513 Standard Specification for Thermoplastic Gas PressurePipe, Tubing, and Fittings
ASTM D3035 Standard Specification for Polyethylene (PE) Plastic Pipe(SDR-PR) Based on Controlled Outside Diameter
ASTM F714 Standard Specification for Polyethylene (PE) Plastic Pipe(SDR-PR) Based on Outside Diameter
ASTM F894 Standard Specification for Polyethylene (PE) LargeDiameter Profile Wall Sewer and Drain Pipe
Generally, thermoplastic fittings are injection molded, fabricated using sections ofpipe, or machined from molded plates. Injection molding is used to produce fittings upthrough 12 inches in diameter, and fittings larger than 12 inches are normally fabricatedfrom sections of pipe. The main ASTM specifications for injection molded fittingsinclude:

ASTM D2683 Standard Specification for Socket-Type PolyethyleneFittings for outside Diameter-Controlled Polyethylene Pipe and Tubing
ASTM D3261 Standard Specification for Butt Heal Fusion Polyethylene(PE) Plastic Fittings for Polyethylene (PE) Plastic Pipe and Tubing
ASTM F1055 Standard Specification for Electrofusion-TvpePolyethylene Fittings for Outside Diameter-Controlled Pipe and Tubing

Currently, there is not an ASTM specification for fabricated fittings, but an ASTM task group is working on this matter. The industry recognizes the need for thisnew specification due to the rapid growth of demand for large diameter pipe.
All of these standards specify the type and frequency of quality control tests thatare required. There are several steps during the manufacturing process that are closelymonitored to ensure that the product complies with these rigorous standards. Some ofthese steps are discussed in the section of this chapter on quality control and assurance.

History of PVC

Polyvinyl chloride was discovered late in the nineteenth century. Scientists observing the newly created chemical gas, vinyl chloride,also discovered that when the gas was exposed to sunlight, itunderwent a chemical reaction (now recognized as polymerization) resulting in an off-white solid material. But, the solid material was so difficult to work with that it was cast aside in favor of other materials. Years later in the 1920s, rubber scientist Waldo Semon was hired by BFGoodrich to develop a synthetic rubber to replace increasingly costly natural rubber. His experiments eventually produced polyvinyl chloride. Although product developers began to use PVC in a variety of ways ? in shoe heels, golf balls, and raincoats, to name just a few ? its application increased significantly during World War II.PVC turned out to be an excellent replacement for rubber insulation in wiring and was used extensivelyon U.S. military ships. After 1945, its peace-time usage exploded.

PE Water Service, Pipe and Tube Installation Guide

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PE products FAQ - part 2

Are PE pipe and fittings safe for use in homes? *Reference ASTM and NSF performance and health standards.
Yes, PE is safe for use in the home. As answered above it is a polymer composed of only carbon and hydrogen atoms. PE is commonly used for food containers (milk bottles, plastic food bags, etc.) when the plastic has received approval to NSF International's standards health effects applications by a third party certifying agency. Examples of such standards are NSF 14 and NSF 61.
What is ASTM?
ASTM (American Society for Testing & Materials) is an independent, not-for-profit standards writing organization. It promulgates standards in many diverse technical disciplines. ASTM is the forum for a majority of standards in the USA, especially those related to plastic materials and products testing. ASTM writes standards and conducts educational training seminars (Specifications, Test Methods and Guides. ASTM does not conduct testing, listing, certifying, or enforcement of its standards.
What is NSF?
NSF (NSF International) is an independent, private, not-for-profit, 3rd party certification, testing, and standards writing organization. NSF is accredited by ANSI, (the American National Standards Institute), RvA, (the Dutch Raad voor Accreditatie), and SCC, (the Standards Council of Canada) for its testing, standards writing, and certification programs. NSF writes consensus standards for product, material, and system assessment. NSF provides an array of testing services to many different industries. NSF provides the plumbing industry services for items such as pipes, fittings, valves, pumps, water heaters, sinks, showers, toilets, faucets, controllers, filters, materials, and ingredients. NSF does conduct testing, listing, certifying, and enforcement of its standards.
What is PPI?
PPI (a.k.a. the Plastics Pipe Institute) is a trade organization whose members include plastic manufacturing companies, plastic piping product manufacturing companies, related equipment and chemical suppliers and educators and consultants to the plastic pipe industry.
What is ASTM D 3350?
This is an ASTM Standard which provides a cell classification method for classifying plastics. When classified under D 3350 the plastic material receives an alphanumeric designation, which identifies its mechanical and chemical properties. It is a shorthand method for describing a plastic material.
What is NSF Standard 14?
ANSI/NSF Standard 14 Plastic Piping System Components and Related Materials is a consensus standard promulgated by NSF International. This standard enables comprehensive assessment of plumbing system products, materials, and ingredients for health effects, quality control, quality assurance, marking, material property requirements, long term strength evaluation via PPI TR-3, and short term product performance to various standards such as ASME, ASTM, ASSE, etc.
What is NSF Standard 61?
ANSI/NSF Standard 61 Drinking Water System Components-Health Effects is a consensus standard promulgated by NSF International. This standard enables in depth assessment of a variety of drinking water system products and materials for health effects. This standard is used to evaluate a product for health effect concerns only.
What is PPI TR3?
(Plastic Pipe Institute's Technical Report 3) PPI TR3 is a standard published by PPI which describes, in depth the testing, calculations and theory by which plastic materials are tested to determine their long term strength properties primarily for pressure piping applications. These long-term strength properties (up to 50 years or more) are published, by material, in PPI TR4, which lists this property as an HDB or hydrostatic design basis. These HDBs are then used by engineers in designing plastic piping products for excellent long term service.

PE products FAQ - part 1

What is PE (as in HDPE, MDPE, LDPE, LLDPE, etc.) and what are some of its uses?
Polyethylene (PE) is a plastic material belonging to a group of polymers called polyolefins. It is usually first categorized by its density as indicated in the abbreviations e.g. HDPE (high density PE), MDPE (medium density PE), LDPE (low density PE) , LLDPE (linear low density PE). Depending on its specific grade and properties, it is used in a wide range of plastic products from milk bottles and plastic bags (lower end of properties and cost) to high performance plastic pipes (high end of properties and cost).
What is used to make PE or HDPE?
All polyethylenes are made from petroleum feedstocks also known as hydrocarbons. Both the feedstocks (and raw materials) and polyethylene is composed of only hydrogen and carbon (hydrocarbon).
What is a polymer?
A polymer by definition is poly (many) mer (parts). It is generally a very simple molecule (mer) which is chemically combined (polymerized) many times until it attains the final desired properties as a polymer.
What is a stabilizer (thermal vs. ultraviolet stabilizer)?
Stabilizers are added to polymers to enhance their ability to resist natural, environmental, mechanisms which tend to shorten their useful lives. Antioxidants retard oxidation ultraviolet stabilizers retard sunlight degradation, and thermal stabilizers help buffer the degradation effects of high temperature exposure.
What is TiO2?
TiO2, titanium dioxide is essentially an inert white pigment which whitens and opacifies plastics.
What is carbon black?
Carbon black is a black pigment, which can also enhance mechanical properties as well as act as an excellent UV stabilizer when properly compounded into a plastic or rubber.

The introduction of PE tubing or pipes

GENERAL
Polyethylene (PE) is a thermoplastic material produced from the polymerization of ethylene. PE plastic pipe is manufactured by extrusion in sizes ranging from ? to 63". PE is available in rolled coils of various lengths or in straight lengths up to 40 feet. Generally small diameters are coiled and large diameters (>6" OD) are in straight lengths.Polyethylene can be used in low temperatures (0 F or colder) without risk of brittle failure. Thus, a major application for certain PE piping formulations is for low-temperature heat transfer applications such as radiant floor heating, snow melting, ice rinks, geothermal ground source heat pump piping, and compressed air distribution.
CODE STATUS
PE pipe is recognized as acceptable plumbing piping for water services, drainage, and sewer applications in most model plumbing codes. Verify acceptance and installation of PE piping systems with the local code enforcement authorities having jurisdiction.
AVAILABILITY
PE pipe and fittings are available from plumbing supply houses and various hardware retailers throughout the U.S.A. and Canada. PE pipe is generally less expensive than metallic piping materials.
MARKING
PE pipe must be labeled as follows:
1.The manufacturer's name or trademark
2.The standard to which it conforms
3.Pipe size
4.Material designation code (PE 2406 or PE 3408)
5.DWV if for drainage piping
6.Pressure rating if applicable
7.DR number or Schedule number
8.If the pipe is for potable water, a laboratory seal or mark attesting to suitability