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Frequently Asked Questions

ABS (Acrylonitrile Butadiene Styrene)

What is the flame spread rating for ABS pipe?

Flame spread tests, such as the ASTM E-84 tunnel test, are designed to test the flame spread characteristics of flat surface materials, such as draperies and finish materials. Since ABS DWV piping systems are installed behind walls, under floors and above ceilings, flame spread tests are not appropriate.

What product & performance standards apply to ABS pipe and fittings?

The ASTM Standards relating to ABS for plumbing and plumbing-related applications are:

  • D1527 - Pipe, Schedules 40 & 80.
  • D2235 - Solvent Cement.
  • D2321 - Underground Installation Procedures.
  • D2468 - Fittings, Schedule 40, Socket Type.
  • D2661 - Schedule 40 DWV Pipe & Fittings.
  • D2751 - Sewer Pipe & Fittings.
  • D3212 - Elastomeric Joints for Drain and Sewer Pipes.
  • D3965 - Rigid ABS Compounds for Pipe/Fittings.
  • F402 - Safe Handling of Solvent Cement.
  • F409 - Thermoplastic Accessible and Replaceable Tube & Fittings.
  • F477 - Elastomeric Seals for Joining Plastic Pipe.
  • F628 - Schedule 40 Cellular Core DWV Pipe.
  • F480 - Water Well Casings & Couplings Schedule 40 Cellular Core DWV, SDR for Schedule 40, 80.
  • F480 - Water Well Casings & Couplings Schedule 40 Cellular Core DWV, SDR for Schedule 40, 80.
  • F1488 - Standard Specification for Coextruded Composite Pipe

The CSA Standards relating to ABS are:

  • CSA B181.1-96 - ABS Drain, Waste, and Vent Pipe and Fittings.
  • CSA B182.1-96 - Plastic Drain and Sewer Pipe and Pipe Fittings.
The NSF International Standards relating to ABS are:
  • ANSI/NSF Standard 14

Can ABS piping be used for underground DWV applications?

Yes. ABS pipe when properly installed, can withstand loads of soil, under slab foundations and high surface loads without collapse, cracking or denting.

What kind of chemical resistance does ABS pipe provide?

ABS pipe offers excellent chemical resistance in many applications. It is resistant to any solution of ammonium chloride, calcium chloride or sodium hydroxide, all of which are corrosive to many metals. ABS pipe is also unaffected by water, aqueous salt solutions, mineral acids and alkalis.

How durable is ABS piping?

Super-tough ABS pipe withstands earth loads and shipping damage. It has excellent resistance to breaking, scratching, chipping and wear, even at low temperatures.

Will hot water damage ABS systems?

ABS pipe performs at an operational temperature up to 140°F (60°C). In addition, it absorbs heat slowly and is unaffected by the high temperatures of water discharged from dishwashers and washing machines.

Will ABS pipe rust or corrode?

ABS pipe does not rot, rust, corrode or collect waste. Its smooth interior finish ensures superior flow.

Are there cost advantages in using ABS pipe?

ABS pipe is not only less expensive than metal pipe, but also more economical to install, due to a one-step solvent cementing process. In addition, it takes less time to rough in a DWV system with ABS pipe than with any other DWV material.

Is ABS pipe easy to install?

Yes, even for the do-it-yourselfer. ABS pipe is so lightweight that one person can load and unload it. With a one-step solvent cementing process, ABS pipe is easy to join. It can also be cut with a variety of readily available tools.

Can ABS pipe and PVC pipe and fittings be used within the same system?

It's not recommended. However, ABS pipe and PVC pipe and fittings can be joined when connecting building drain to building sewer materials, if you use proper transition cement and adapters or other methods as approved by local plumbing codes.

Can insulated plastic piping meet the 25/50 requirement?

Plastic Piping in Return Air Plenums by R. C. Wilging - PE

Summary:Because plastic materials do not qualify as non-combustibles their use in air handling plenums has been an issue for years. The code provisions that cover this subject clearly refer to "exposed" materials. Questions about whether insulated plastic piping would meet the 25/50 limits have now been answered in the affirmative by modified ASTM E 84 tests of 4" and 6" PVC and ABS pipe with solid wall and with cellular core wall. To read the full response to this question, click here.

CPVC (Chlorinated Polyvinyl Chloride)

Where can I use CPVC?

Copper tube size (CTS) CPVC is designed for use in hot-and-cold-water distribution systems. CPVC systems are ideal for all potable water piping requirements in typical residential (single and multi-family), motel/hotel, mobile home, manufactured housing, light commercial, and institutional structures.

CPVC systems conforming to ASTM D2846 are rated for continuous service at 100 psi and 180 degrees F and are marked accordingly. The model codes recognize CPVC's capability to handle short-term pressure/temperature excursions beyond these levels. Therefore, CPVC is well suited for usage as T/P relief valve discharge lines, evidenced by its faultless service history over the past two decades in this application.

Iron pipe size (IPS) Schedule 40 and Schedule 80 are used for a wide variety of industrial applications.

What about CPVC's cost relative to other materials?

CPVC is a very cost-effective system. The basic molecular building blocks of the CPVC molecule are chlorine, derived from salt, and ethylene, which comes from oil or natural gas. Because 2/3 of the CPVC molecule is derived from common salt, less energy content goes into making one foot of CPVC pipe than any alternative material. The price of CPVC should remain more stable than other materials in the future.

What is the expected performance of a CPVC water distribution system?

CPVC piping systems have been installed and operated since 1959, and initial installations are still performing faultlessly. CPVC piping will not fail prematurely due to corrosion, electrolysis, or scale build-up in areas where water, soil, and/or atmospheric conditions are aggressive.

What about product availability?

CPVC pipe and fittings are available in 1/2 through 2 inch CTS (Copper Tube Size O.D.). A full range of fittings exists in all sizes. Specialty components including transition connections and chromed supply stops with CPVC solvent weld inserts have been introduced recently. Additional complementary components will naturally evolve (i.e. shower mixing valves and gate valve adapters). In applications calling for larger lines, CPVC is available in IPS sizes (sch. 40 and 80) up to 12" diameter. Transitions from CTS to IPS products can be accomplished in several easy ways.

Will CPVC save me money?

Yes. CPVC can be installed at least 25% more quickly than copper or iron systems. Financial savings are also realized with regard to lower tool costs and insurance advantages. Considering the frequent rise and fall of the copper price structure, CPVC offers a continuing material cost advantage, often as much as a full 30% savings.

Will a CPVC system offer a financial advantage to Owners in terms of utilities expense?

Yes. The thermal conductivity of a copper system is 2500 times that of a CPVC system. The improved insulating characteristics associated with CPVC can generate substantial long-term savings for an energy conscious home-owner or tenant. CPVC will keep hot water hot for a much longer period of time than copper tubing.

How should I size the lines in a CPVC system?

A CTS CPVC system will use the same size pipe that a copper system would, providing a full bore flow system. In general an IPS CPVC system will use the same size pipe as an iron system.

What is the thermal expansion rate for CPVC, and how can I best allow for expansion and contraction when installing?

CPVC piping will expand about 4 inches per 100 feet with a 100 degree F temperature change. The fact that CPVC has higher thermal expansion than metals has led to some concern. However, laboratory testing and installation experience have demonstrated that the problems are much smaller than the coefficient of thermal expansion would suggest. The stresses developed in CPVC pipe are generally much smaller than those developed in metal pipe for equal temperature changes because of the difference in elastic modulus.

Should special considerations be taken to connect CPVC to a hot water heater?

In some instances, yes. However, these considerations are based on concerns regarding external sources of heat. The hot water from the heater will not affect the CPVC.

When connecting to a gas water heater, CPVC should not be located within 6" of the heater's flue, if the flue has no insulation. A metal nipple or flexible appliance connector should be used. This measure eliminates the potential for damage to plastic piping that might result from excessive radiant heat from the flue. If the flue is insulated, the instructions of the flue manufacturer should be followed.

How can I use CPVC if I run under slab?

When using CPVC with joints under slab, YOU MUST PRESSURE TEST THE SYSTEM BEFORE POURING THE SLAB. Also, it is wise to use 1" foam insulation pipe sleeve at changes in direction, where the pipe comes out of the slab, and at construction joints. The pipe should be evenly supported in smooth bottom trenches. The backfill should be free of rocks and debris.

The purpose of the foam insulation is to:

  • Provide for a degree of movement at changes in direction due to thermal expansion.
  • Protect the tubing from shear forces due to minor shifts in the slab at construction joints.
  • Provide some protection from abuse during the construction phase for the pipe where it emerges from the slab. Longer lengths of pipe (rolled pipe) is also available for under slab installation. Follow the instructions of the manufacturer.

What method should I use to thaw a CPVC line?

If the frozen section of pipe is accessible, wrap it with a cloth saturated with hot water. Keep the cloth hot by re-dipping in hot water as necessary. Be careful not to burn your hands. A second technique that is quite successful is to blow heated air directly on the area where the freeze occurred using a low wattage heater/blower such as a hair dryer. Obviously, prevention is the best way to address frozen pipe problems.

Must I use plastic insulators wherever CPVC passes through a stud?

Technically, no such provision need be made when passing through wood studs. When passing through metal studs, some form of protection must be used to protect the pipe from abrasion and to prevent noise. This protection may come from plastic insulators, rubber grommets, pipe insulation, or similar devices.

Should I use metal nipples on a CPVC system when I come through the sheetrock?

In areas where there is a likelihood that stresses or impact abuse will occur, a metal nipple is recommended. Such applications as tub fillers, showerheads, and outside sillcocks are examples. However, CPVC stub-outs for closets, lavatories, and sinks are appropriate.

Should I use pipe dope, Teflon® tape, or Teflon® paste with CPVC threaded adapters?

Teflon® tape is always safe and effective with CPVC. If you wish to use a paste or pipe dope, always check with the manufacturer for a recommendation because some pastes or dopes contain solvents that may be incompatible with CPVC.

Should specific types of primers and solvent cements be used on a CPVC system? Are specific colors required?

CPVC solvent cement should always be for CPVC piping and manufactured to meet the requirements of ATM F 493. Purple primer manufactured for PVC pipe is acceptable. Faster flashing CPVC primer is available, and is recommended for cold weather installations. Orange CPVC solvent cement and purple primer are specifically required by certain code bodies to facilitate identification by plumbing inspectors. Unpigmented CPVC solvent cement and primers are available and are acceptable in various jurisdictions. Clear cement/primer provides neater finished appearance. One-step cements are now available and are fully satisfactory if the manufacturer's instructions are carefully followed. Your local plumbing inspector can provide a final answer to this question.

How long can CPVC systems be exposed to sunlight?

CPVC can easily withstand the ultraviolet exposure commonly experienced during the construction phase of a project, provided on-site inventories are turned regularly as would be anticipated. If CPVC is used in above-ground, outdoor applications, protection from ultraviolet attack can be achieved by shielding or by painting the system with an exterior-grade latex paint.

What are the preferred methods of cutting CPVC pipe?

A benefit of CPVC pipe is that numerous, inexpensive choices of cutting tools are available to the installer. CPVC piping has for years been cut by fine-tooth saws. The preferred method is the circular tubing cutter, modified with a plastic cutting blade. This cutter assures a square, clean cut each time and is extermely efficient in terms of labor.

An alternative method is the ratchet cutter. Although this option is quick and easy, the pressure created while cutting the pipe could cause cracking of the pipe wall. This problem is of prime concern during cooler weather (50 degrees F or lower). For this reason, ratchet cutters should be considered only during the summer months. Keep the cutting edges of the cutter sharpened.

Several power tools have been used on major job sites where larger diameter pipe is being installed. Circular saws and portable grinders with abrasive cutting discs are two of the numerous methods being employed by contractors.

I have been told that CPVC pipe can split during installation. Why would this occur? How can these cracks be prevented?

Most cracks are initiated by rough handling. This handling can occur during shipment, while being inventoried at the wholesaler, or while on the job site. Also, fine cracks can be caused by cutting the pipe with dull or damaged ratchet cutters, or by using ratchet cutters in lower temperatures.

The vast majority of cracks occur during colder weather months. When ambient temperatures are below 50 degrees F, CPVC should be handled more carefully.

To reduce problems resulting from cracked product, several measures can be initiated:

  • Educate your installers. Make them aware of the potential problem and instruct them to handle CPVC in an appropriate way.
  • Use a saw or a circular tubing cutter with a plastic cutting blade (Rigid #151P or similar) to cut pipe to length.
  • Inspect pipe ends thoroughly prior to making a joint. Should a crack be evident, cut off any split portion before proceeding.
  • During cold weather, gripping the tubing tightly around the area to be cut for about 10 seconds prior to making the cut will warm the tubing and reduce possible problems.

Are there insurance advantages associated with CPVC systems?

Yes, most definitely. Insurance cost reductions result from several factors:

  • Absence of the torch during construction.
  • Significant reduction in injuries, particularly burns, can translate to reduced workmen's compensation costs.
  • Reduced job site theft loss.

Is CPVC a factor in reducing noise associated with the movement of water?

Yes, CPVC is extremely quiet due to the polymeric structure of the product. CPVC systems are virtually silent. Also, noise associated with water hammer is all but eliminated.

Are there other benefits associated with the polymeric makeup of CPVC systems?

Yes. Due to the CPVC polymeric structure, costly condensation concerns are eliminated, further reducing the long-term problems that one expects with a metal installation. Also, CPVC offers a potable water distribution system that eliminates the metallic taste and potential health hazards associated with metal systems.

What about health, safety, and fire toxicity issues?

Metal piping interests have initiated many attacks on plastic systems, under the guise of health and safety issues. Tests performed at respected universities and independent laboratories confirm that CPVC is superior to copper/lead solder systems in terms of water quality effects and is "no more toxic than wood" in a fire.

All plastics used in potable water systems must be tested regularly and certified by a similar third party certifier as meeting the strict public health requirements of ANSI/NSF 61. This testing ensures that drinking water carried by plastic pipe meets all EPA standards.

PE (Polyethylene)

What is PE (as in HDPE, MDPE, LDPE, LLDPE, etc.) and what are some of its uses?

Polyethylene (PE) is a thermoplastic material belonging to a group of polymers called polyolefins. It is usually categorized by its density as indicated in the abbreviations; HDPE (high density PE), MDPE (medium density PE), LDPE (low density PE), and 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 to high performance plastic pipes.

What is used to make PE or HDPE?

All polyethylene is made from petroleum feedstocks also known as hydrocarbons. Both the feedstocks (and raw materials) and polyethylene are composed of only hydrogen and carbon (hydrocarbon). In North America, the feedstock is typically natural gas.

What is a polymer?

A polymer, by definition, is a long chain molecule composed of smaller parts called monomers. The derivation of the term is the combination of poly (meaning many) and mer (meaning parts). Monomers are generally very simple molecules which are chemically combined or polymerized many times until it attains the final desired properties as a polymer.

What is a stabilizer (thermal / ultraviolet)?

Stabilizers are added to polymer resins to enhance and extend their ability to resist natural, and environmental stresses. Antioxidants retard oxidation of the polymer, ultraviolet stabilizers reduce UV or sunlight degradation, and thermal stabilizers improve behavior in high temperature exposure.

What is TiO2?

TiO2, titanium dioxide is essentially an inert white pigment which whitens and opacifies plastics. Its additional benefit is it acts as a very effective UV “sunscreen”, protecting the pipe.

What is carbon black?

Carbon black is a black pigment, which can also enhance mechanical properties and act as an excellent UV blocker when properly compounded into a plastic or rubber. Sufficient quantities allow the use of some pipe above ground.

Are PE pipe and fittings safe for use in potable water systems?

Yes, PE is safe and commonly used in potable water systems 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. Polyethylene is also commonly used for food containers (milk bottles, plastic food bags, etc.)

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 US, especially those related to plastic materials and products testing. ASTM writes the standards that plastic piping and other products are manufactured to meet. ASTM does not conduct testing, listing, certifying, or enforcement of its standards. This is done by other organizations.

What is ASTM D 3350?

This is an ASTM Standard which provides a cell classification method for classifying plastics by their properties to help identify products. 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?

NSF (NSF International) is an independent, private, not-for-profit, 3rd party certification, testing, and standards writing organization. NSF International 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 International also writes consensus standards for product, material, and system assessment. NSF International provides an array of testing services to many different industries and provides the plumbing industry listing services and inspections for items such as pipes, fittings, valves, pumps, water heaters, sinks, showers, toilets, faucets, controllers, filters, materials, and ingredients.

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?

PPI (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. PPI typically deals with design stress, chemical resistance, and buried and municipal piping systems outside the building envelope.

What is PPI TR3?

Plastic Pipe Institute's Technical Report 3, or PPI TR3, is a standard published by PPI which describes 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 values are then used by engineers in designing plastic piping products for excellent long term service.

What does PE 4710 mean?

PE 4710 is a new designation for improved high performance PE materials. To understand the new PE 4710 designation and its commercialization, we must first explain the older PE 3408 designation and its use in the design of polyethylene piping. The term PE 3408 is based on the standard thermoplastics pipe material designation code defined in ASTM F 412 and it has been referenced extensively within the North American piping industry since the early 1980’s.

The standard thermoplastic pipe material “code” for polyethylene consists of an abbreviation for the type of plastic followed by 4 numbers that describe its key properties. The last two numbers refer to the hydrostatic design stress (HDS) for that material in units of 100 psi with any decimal figures dropped.

PE designation refers to polyethylene
Density cell class 3 per D3350, > 0.940 – 0.947 g/cc
SCG cell class 4 per D3350, ESCR,  condition C, F20 > 600 hours; or PENT value > 10 hours
800 psi hydrostatic design stress for water at 73° F1

In the chart above the term PE 3408 identifies the piping product as a polyethylene grade PE34 with a density cell class of 3, a “slow crack growth” cell class of 4 (both in accordance with ASTM D3350-04), and an 800 psi maximum hydrostatic design stress at 73°F as recommended by the Plastics Pipe Institute (PPI).

In the mid-1980’s, extensive research further improved on the recognized performance of polyethylene piping materials. The result of this research was the introduction of a new significantly improved polyethylene resin that was designated as PE 100 in accordance with the ISO standards used outside of North America.

In order to commercialize the high performance PE resins within the North American market, ASTM had to expand its coding system in ASTM D3350-06 to properly represent the improvements made and PPI’s Hydrostatic Stress Board (HSB) had to define the high performance criteria in utilizing a new design factor to establish the hydrostatic design stress for water at 73°F. Based upon the actions in ASTM and the PPI-HSB, a new standard thermoplastics pipe material designation code of PE 4710 resulted. The chart below illustrates how this pipe material designation code provides a basis for recognition and identification of the higher performance capability of these new piping products.

PE designation refers to polyethylene
Density cell class 4 per D3350-06, >0.947 – 0.955 g/cc
SCG cell class 7 per D3350-06, PENT value > 500 hours
1000 psi hydrostatic design stress for water at 73° F2

1 1600 psi hydrostatic design basis (HDB) X 0.5 design factor (DF) = 800 psi hydrostatic design stress (HDS) for water at 73°F 2 1600 psi hydrostatic design basis (HDB) X 0.63 design factor (DF) = 1000 psi hydrostatic design stress (HDS) for water at 73°F.

This short presentation will explain the changes in the nomenclature of the new PE4710 polyethylene resins in more detail. Click here to view the presentation.

Why are there two markings on the new PE4710 pipe?

ASTM expanded its coding system in ASTM D3350-06 to properly represent the improvements in PE resins to create PE 4710. Pipe producers responded in various ways although most chose to use both the old and new pipe material designation codes on the product where it applies. Some requirements, specifications and regulations reference the older versions of the standard. Pipe meeting these older versions may still carry the PE3408 designation. Most PE pipe will carry dual (PE3408/PE4710) or even triple markings (PE3408/PE4710 - PE100) as long as required by requirements, specifications and regulations.

What is PE3408/PE3608 marked pipe?

This dual marking is for the older resin materials. This pipe maintains the same characteristics of PE3408 pipe.

What is PE3408/PE3710 marked pipe?

This dual marking is for a resin material with an improvement over PE3408 in the hydrostatic design stress (HDS) category.

What is PE-100?

You may also find PE pipe product marked “PE3408/4710-PE100” or “PE4710- PE100”. The “PE100” is the ISO, or European, designation for higher performance PE pipe material.

Can old PE fittings be used with the new PE4710 pipe?

Yes, they are generally compatible. However, the system design must be based on the ratings of the lowest rated component of the system.

Can we fuse PE4710 pipe with the other types of PE pipes?

Yes, the new PE4710 pipe can be fused into other PE systems, and the resins are compatible, but the design pressure would have to remain within the ratings of the other PE system.

PEX (Cross-linked Polyethylene)

What is PEX?

PEX is cross-linked polyethylene. Through one of several processes, cross-linking creates bridges between the individual polyethylene molecules (thus the term "cross-linked"). This resulting material is more durable under temperature extremes and chemical attack and better resists creep deformation, making PEX an excellent material for hot water and other applications.

How long has PEX been used?

PEX was developed in the 1960s. PEX tubing has been in use in many European countries for plumbing, radiant heating and snow melt applications since that time. PEX was introduced in the United States in the 1980s, and has seen significant growth in market demand and production.

What are recommended uses for PEX?

PEX 's flexibility and strength at temperatures ranging from below freezing up to 200 degrees Fahrenheit makes it an ideal piping material for hot- and cold-water plumbing systems, service lines,  hydronic radiant heating and cooling systems, snow melting applications, outdoor turf conditioning, residential fire-sprinkler systems, ice rink systems and permafrost protection beneath refrigerated warehouses.

Why is PEX an excellent piping material for plumbing?

PEX is ideally suited for potable water plumbing applications. It is flexible, making it easy to install and service. PEX is able to withstand the high and low temperatures found in typical plumbing and heating applications, and is highly resistant to chemicals commonly found in the plumbing environment.
Flexible systems are quieter than rigid piping, subduing both flow noise and water hammer. The smooth interior of the tubing will not corrode, thus minimizing the effect that corrosion in other piping materials has on long term pipe flow characteristics. PEX is also freeze-break resistant. PEX systems have fewer joints and are easier to install providing a lower cost installation over traditional plumbing materials.

How can I be sure that PEX is a safe product for plumbing?

PEX is manufactured and tested according to stringent national consensus standards: ASTM F 876, F 877, AWWA C904 and CSA B137.5.  Both the product manufacturer and independent third party testing agencies conduct routine quality control and quality assurance evaluations to insure the product meets ASTM, ANSI/NSF International and CSA Standards. Compliance with the standards ensures the end user of safety and quality. Additionally, PEX is included in all of the major model plumbing codes used in the United States and Canada; NPC, UPC, IPC and NSPC, and approved by HUD for hot- and cold-potable water plumbing use.

Where is PEX approved for use?

PEX is an approved material in all the current model-plumbing codes; however, some local jurisdictions may have additional requirements. Contact the local authority with jurisdiction over plumbing to verify the acceptance of PEX tubing for plumbing applications in your area.

Can PEX be used under the slab?

Yes. The flexibility of PEX allows it to be supplied in coils meaning installations under the slab can be made in a single, continuous length without the need for fittings. PEX is not affected by concrete, (it is commonly encased in concrete for radiant floor heating). PEX, however, must be sleeved where it penetrates a slab. In addition, care should be taken to not overly saturate the "backfill" soil surrounding the PEX with liquid termiticides or insecticides.

Can PEX be used for underground cold-water service applications?

Yes. Although the enhanced temperature resistance of PEX makes it particularly suitable for hot- and cold-water interior plumbing applications, it also makes an excellent underground water service piping. The new AWWA C904 standard also applies to PEX used in this application. PEX can be installed using the same fittings recommended for copper tube sized SDR-9 polyethylene tubing.

Can PEX be used for aboveground outdoor applications?

No. PEX is currently designed for indoor and buried applications only and is not recommended for outdoor, aboveground use. Short exposures to sunlight or UV during construction are permissible, but should not exceed the manufacturer’s recommendations. PEX should be stored under cover, shielded from direct sunlight or other UV exposure.  

Can PEX save me money?

Yes. PEX saves money in many ways. For the installer, PEX tubing is competitively priced. Installation of flexible systems is fast because of the easy handling of the tubing and PEX installation requires fewer directional fittings. Since most plumbing problems occur at joints, fewer fittings also reduce the chances for leaks and callbacks, saving the installer even more time. The homeowner saves in the cost of the installed system, and can reduce utility costs in some layouts .

PEX tubing has thicker walls than rigid piping materials; hence, PEX tube contains less water in any given length, but with no sacrifice in flow characteristics or water delivery capability. Since PEX tube contains less water, there is a lesser amount of water to purge from a hot water line when a tap (faucet) is opened. By minimizing the amount of water that has to be purged while waiting for hot water to arrive, a considerable savings in water and energy can be realized. Also, since PEX tube can be “bent” around corners rather than utilizing 90-degree elbows, there is savings in the length of PEX tube needed to provide water to fixtures, and this shorter length also minimizes water and energy waste.

PEX plumbing systems can be installed in several configurations, and two, in particular, can help save water. Utilizing either homer run (also called manifold or parallel piping) or remote manifolds (also called multi-port tees), water and energy savings can be achieved by more efficiently delivering water to faucets.

Faster hot water delivery reduces water waste and the amount of times the water heater must cycleto supply hot water.

What is the expected performance of PEX water distribution systems?

PEX is designed and tested to perform as well or better than any other material approved for hot- and cold-water distribution systems. For indoor plumbing applications, PEX is expected to perform as long, or longer, than cpper, CPVC or any other approved plumbing distribution materials.

What joining systems are available?

There are several methods of connecting PEX, all of which involve mechanical fittings, such as insert fittings that use crimp rings or cold expansion systems that utilize over-sized fittings and external PEX rings. There are several approved standard specifications for PEX connections; ASTM F 1807, ASTM F2159, ASTM F2080, and ASTM F 1960. All of these standards reference permanent mechanical insert fittings of various configurations. Other fitting systems, including insert and outside diameter compression fittings, are also available. PEX cannot be joined by solvent cement or heat fusion methods. Depending on the connection method, PEX fittings can be made from engineered polymer (plastic), brass, or copper.

What manufacturing methods for PEX are available?

There are currently three methods for producing PEX tubing, the “Engle” or “Peroxide” (PEX-A) method, the “Silane” (PEX-B) method, and the “E-beam” (PEX-C) method. (The A,B,C nomenclature has no significance in indicating performance or characteristics; it is simply a designation system.) All three processes produce tubing that exceed the minimum requirements of ASTM F 876 and are acceptable for potable water distribution applications. All PEX that has been tested and certified for potable applications carries the mark(s) of nationally recognized third-party certification agencies such as NSF, IAPMO, ICBO-ES, Warnock Hersey, CSA or UL.

How long can PEX be exposed to sunlight?

PEX tubing is not intended for outdoor applications and must be stored in a covered environment not exposed to direct sunlight or UV. Refer to manufacturer’s instructions as to how long your pipe can have UV or sunlight exposure. The ASTM F876 standard includes an option that the UV resistance of PEX pipe may be listed in the Material Designation Code on the pipe. The second digit of the Material Designation Code has been reserved for the UV resistance of the pipe. The following digits have been assigned to show the UV resistance: 0= Not tested or rated 1= 1 Month UV resistance 2= 3 Months UV resistance 3= 6 Months UV resistance

What are temperature limitations for PEX?

PEX tubing can be used up to 200° Fahrenheit for heating applications. For plumbing, PEX is limited to 180° F at 100 psi. Temperature limitations are always noted on the print line of the PEX tubing. PEX systems are tested to and can be used with standard T and P relief valves that operate at 210” F and 150 psi.

How are PEX systems tested for leaks?

PEX plumbing and radiant heating systems can be pressure tested using water to check for leaks. Follow manufacturer's instructions.

How soon after installation can you pressure test a PEX tubing installation?

Most PEX plumbing systems can be tested immediately after the installation is complete but follow manufacturer’s insturctions. There is no wait time for glue to dry or joint to cool off.

Where is PEX available?

PEX is available through most plumbing wholesale distributors throughout the United States and Canada. Many retail building supply outlets also supply PEX piping and fittings. Piping and fittings are commonly available in 1/4" through 2" CTS (Copper Tube Size) with some manufacturers also supplying larger sizes up to 4." Because the wall-thickness is proportionate for each size, the pressure ratings are the same for all sizes.

What sizes, lengths and packaging options of PEX are available?

PEX is available in 1/4" through 4" CTS (Copper Tube Size) and is packaged in coils or straight lengths. Some manufacturers’ tubing is color-coded for easy identification of hot- and cold-water lines. Coil lengths generally run to a maximum of 1000' and are available in a variety of shorter lengths as well.

Is flexible PEX plumbed differently than rigid material plumbing systems?

Yes, the flexibility of PEX allows many directional changes to be made without fittings. PEX systems are sized in the same manner as copper or CPVC CTS plumbing systems. PEX piping is also used in central or remote manifold plumbing systems that take advantage of the flexibility and potential cost savings.

What are manifold plumbing systems?

Manifold, parallel or home-run plumbing systems are much like a breaker box for the electrical system in the home. The manifold provides a common location from which all the plumbing fixtures are supplied. Some high-end manifolds also feature fixture shut-off valves allowing the user to shut off the water to individual fixtures from one location. However, even though shut-off valves may be located on the manifold, some codes require redundant shut-offs at the fixture locations. Others are semi-home run manifolds or termination manifolds, which may feed the plumbing requirements for a room or set of rooms and reduce the number of fittings required in the plumbing system.

How are PEX systems sized?

PEX systems are sized just like other CTS plumbing materials such as copper or CPVC when used in a trunk-and-branch installation. PEX can be sized in manifold systems to meet the specific demands of each fixture, reducing water and energy waste in the home.

Is the thermal expansion/contraction of PEX a problem?

No. While PEX expands more than other plumbing materials, directional changes made with the tubing and some slack in the tubing during installation accommodate the expansion and contraction of the system if properly installed. For systems that utilize large diameter PEX (i.e. 2 inches or greater), pre-engineered expansion loops may be available.

Is PEX freeze-break resistant?

PEX piping is freeze damage resistant and can expand and contract as water freezes and thaws within the tubing. No tubing material is freeze-break proof, however, and PEX should be installed using the same locally-prescribed insulation requirements to prevent freezing of any plumbing system.

How do I thaw PEX lines?

When water freezes inside PEX tubing, it can be thawed using a hair dryer, warm wet rags or self-limiting heat tape, taking care not to overheat the tubing beyond the maximum recommended temperature.

Can PEX be joined with solvent cement?

No. PEX cannot be joined with solvent cement, glues or heat fusion. PEX is installed using only mechanical fittings or compression fittings.

PVC (Polyvinyl Chloride)

What are the primary applications for PVC, and what are the standards?

1. Water Pipe:

  • ASTM D1785, Sch 40 and 80 pipe (1/8" to 24" sizes)
  • ASTM D2241, SDR pipe (SDR 13.5 to 64 - 1/8" to 36" sizes)
  • AWWA C900, Water mains 4" through 60"
  • AWWA C909, Molecularly Oriented Polyvinyl Chloride (PVCO) Pressure Pipe, 4" to 30" for Water Distribution 

2. Drain, Waste & Vent Pipe:

  • ASTM D2665, Sch 40 (Can be dual marked D1785)
  • ASTM F891, Cellular core Sch 40, 1 1/4" through 12"

3. Process Pipe:

  • ASTM D1785 & D2241, Iron Pipe Size OD pressure pipe

4. Sewer Pipe:

  • ASTM D3034, SDR pipe, 4" through 15"
  • ASTM F891, Cellular core sewer pipe ODs, 2" through 18"

5. Drain Pipe:

  • ASTM D2729 (2" through 6") or D3034

6. Folded PVC pipe:

  • ASTM F1504 - special product for relining of underground pipes, 4" through 15"
  • ASTM F1871 – special product for relining of underground Sewer pipes, 4” – 18”
*Note: Most of the early ASTM standards were written so that only a single product was included in each standard. Many recent standards include several different products. Therefore, be aware of this and fully identify the product needed, i.e., F891 Sch 40 DWV or F891 PS50 Sewer.

What joint systems are used for PVC?
PVC solvent cement joints are used for most above ground piping in buildings and for some underground piping, especially in smaller sizes. These systems are both pressure and non-pressure (gravity flow) and always utilize pipe in a bell or socket.

Gasketed joins are used extensively for underground systems, both pressure and non-pressure, but there are different standards for these joints.

Transition joints can be made with flanges, threads, grooved connectors, unions, gasket joints, plus various patented joints.

What colors are used for PVC pipe, and are they color coded?
Although PVC materials can be made in many colors and there is some pattern to what the industry has done, no established color coding exists. The earliest PVC piping was made in industrial gray, and that product line is still very active. Much of the PVC irrigation piping is white. Most PVC water piping is white, but there have been some manufacturers who use blue as a means to distinguish their product line. Many PVC sewer products are green. Much DWV piping is white, but certain manufacturers have opted for beige or buff colors.

What are the markings on PVC pipe?
The outside of PVC pipe must be labeled as follows:

  • The manufacturer's name or trademark
  • The standard to which it conforms
  • Pipe size
  • Material designation code
  • DWV if for drainage
  • Pressure rating if for pressure
  • SDR number or schedule number
  • If the pipe is for potable water, a laboratory seal or mark attesting to suitability for potable water

For those standards that cover several products, there must be additional markings to indicate the pipe stiffness number, the SDR, the EB or DB number. A certifier's mark may also be on the pipe.

What are the temperature limitations of PVC pipe?
The maximum use temperature for PVC pressure pipe is 140 degrees F. PVC DWV piping readily withstands the hot and cold water discharges that are normally associated with plumbing fixtures.

Can PVC pipe be exposed to the sun?
PVC does not readily degrade when exposed to sunlight (ultraviolet radiation) due to natural UV inhibitors present in the material. Short-term exposure to sunlight, such as during construction, is typically not a problem for PVC pipe. PVC piping may be used in outodoor applications when the piping system is painted with a light-colored water based acrylic or latex paint that is chemically compatible with PVC. When painted, the effects of UV exposure are significantly reduced.

Can insulated plastic piping meet the 25/50 requirement?

Plastic Piping in Return Air Plenums by R. C. Wilging - PE

Summary:Because plastic materials do not qualify as non-combustibles their use in air handling plenums has been an issue for years. The code provisions that cover this subject clearly refer to "exposed" materials. Questions about whether insulated plastic piping would meet the 25/50 limits have now been answered in the affirmative by ASTM E 84 tests of 4" and 6" PVC and ABS pipe with solid wall and with cellular core wall. To read the full response to this question, click here.

How does PVC pipe behave at different temperatures?
PVC pipe exhibits decreasing pressure rating and stiffness with increasing temperature.  As with dimensions, the pressure ratings and published pipe stiffness figures for PVC pipe are listed at an operating temperature of 73F.  To determine the pressure ratings and stiffness of PVC pipe at higher temperatures, multiply the pressure rating or pressure class and the stiffness / deflection by the pipes de-rating factors at that temperature.  An example of a table of PVC pipe de-rating factors is shown below. Consult with the manufacturer of your pipe for specific data. The typical upper limit for continuous use of PVC pipe is 140 F.

As an example, using the table above, a PVC pipe rated at 450 psi at 73 F, used at 100 F would have a pressure rating of:

450 psi x 0.62 = 279 psi

Does PVC pipe have a long life expectancy?
Yes, studies on PVC pipe made in Europe in the 1930’s and been in continuous use suggest a very long useful life for these products of a hundred years or more, which will generally exceed the lifespan of the structures they are installed in.

Can PVC piping products be recycled?
Yes they can. Since PVC pipe products have very long useful lives, not much pipe is currently available for recycling as it is still in use. While current standards do not generally allow for the practice of recycling used pipes into new certified pipes.  PVC pipe producers can recycle nearly all production scrap in-house. Since PVC is a thermoplastic PVC pipe can simply be reground, pulverized and returned to the extrusion process to make new pipe.

Why do I need to use primer on a PVC solvent welded joints?
Primer is a mixture of solvents, similar to those found in the cement and is used to soften or “prime” the pipe and fitting prior to adding cement. Use of primer may be required by code in your area. Visit our cements page for more information on solvent cementing.

What is the best way to repair a leaking PVC solvent weld joint?
Whenever possible, cut out the leaking joint and start over.  A leaking solvent welded joint is an indication that the joint was not made correctly. It may not have been fully bottomed, a component may have been damaged or foreign materials may be trapped inside the joint. For a temporary repair, plastic fillet hot air welding can be used on the outside of the pipe and fitting to stop very minor leaks. This should only be used as a short term measure before the joint can be replaced.

Does long term exposure to sunlight degrade exposed PVC pipes?
PVC pipe contains stabilizers to protect the pipe against attack by UV present in sunlight. After several months of outdoor exposure a discoloration may appear on the surface of the pipe, however, the performance of the pipe is not affected.  After two years of exposure, there is only a slight reduction in the impact resistance of the material. PVC pipe used in permanent outdoor exposures should be protected by a light colored compatible water based paint. Do not use oil based paints.

Is PVC pipe easier to install than alternative materials?
PVC pipe is a light weight yet strong material when compared to many alternatives.  A length of PVC pipe will weigh 1/5 th of an equivalent size section of cast iron pipe making it easier to install. This product is easily assembled in solvent-welded or gasketed versions that are both intended to be leak free, once properly assembled. 

How does PVC pipe behave when exposed to fire?
PVC pipe, while combustible, does not continue to burn once a flame source is removed. A main cause of fire fatalities is exposure to carbon monoxide, which is produced from common materials and products like wood, furniture, carpet, and fabrics.  It is estimated that plastic pipe systems represent less than 1% of the mass of all combustible products in a building.  The majority of piping is also installed behind non-combustible materials such as gypsum wall board. More information can be found here: pdf/safety.pdf

Is PVC pipe permitted for use in high-rise buildings?
While local or state codes do vary in a few areas and have restrictions for plastic pipes, model codes allow for PVC DWV systems in high rise structures when firestopping methods are used to restore penetrations to original values. Firestopping in UPC chapter 15, for example, is required for both plastic and metal systems. To determine if there are any restrictions in your area, consult your codes.

My PVC fittings have a visible line in them, are they cracked?
No. The noticeable line you are seeing is a more than likely not a crack. If you are unable to open it up by pulling on the part, then what you are seeing is most likely a knit-line (other names include weld-line and flow-line). The formation of a knit-line is an intrinsic part of the injection-molding process and is created when hot melted plastic flows under pressure into a mold cavity, around cores and finally “knits” back together on the opposite side of the cavity fill point. Knit-lines will sometimes appear straight or as gently wavy curving lines running the length of the fitting (both inside and outside). A fitting that displays this type of line is not defective. A knit-line will not impact the integrity of the product or system.

Is the straight, slightly raised line on a PVC fitting a defect?
No. This slightly raised line is where the parting line of the mold is located and is not a defect of the fitting. The parting line is the location of where the two halves of the mold separate to allow part removal.

How PVC plastic is made.

About TIPS

What is TIPS?

TIPS is the acronym for Thermoplastic Industrial Piping Systems. TIPS is also a Product Line Committee of the PPFA consisting of several prestigious manufacturers of pipe, valves, fittings, and compounds with hundreds of years combined experience.

What piping materials are commonly included in TIPS?

CPVC (chlorinated polyvinyl chloride), PE (polyethylene), PP (polypropylene), PVC (polyvinyl chloride) and PVDF (polyvinylidene fluoride) are the most commonly used TIPS applications. Almost all of the piping systems are pressure rated with CPVC and PVC in most cases having a schedule 40 or 80 wall thickness or greater. Piping materials such as pressure-rated ABS (acrylonitrile-butadiene-styrene) and other fluorocarbons are also used in industrial installations.

What standards are TIPS piping products made to?

Examples of standards of TIPS products include; Sch 80 CPVC pipe made to ASTM F441, CPVC chemical drain waste pipe made to ASTM F2618, PP pipe made to ASTM F2389 for pressure applications, pressure PVC pipe made to ASTM D1785, and PVDF made to ASTM F1673 for drainage systems for corrosive applications.

Check with the product manufacturer for final determination of applicable standards.

What are the temperature and pressure limitations for TIPS?

When selecting a TIPS material, check the manufacturer’s published product information regarding the temperature and working pressure limitations, as these vary. There are multiple materials and products that can cover a wide range of operational conditions; from a maximum temperature of 275°F to a minimum of minus 40°F and a maximum working pressure of 230 psi to a minimum of full vacuum. Keep in mind that with most thermoplastic piping materials, an increase in temperature will reduce the allowable working pressure. Pressure derating tables to adjust the piping working pressure ratings at higher temperatures are available from the product manufacturer.

What joining methods are used to assemble TIPS products?

Two joining methods that can create joints as strong as, or stronger than the pipe or fitting, are solvent cementing and heat fusing. For ideal joint integrity CPVC and PVC are solvent welded and PE, PP and PVDF are heat fused. Other joining techniques such as flanging, threading, and other mechanical joining methods are also used.

Can TIPS be recycled?

All thermoplastic piping materials can be and are recyclable. In most cases there is 99% complete recycling within the manufacturing process. In many applications TIPS products have lasted for decades and are still in service, so that not much post-processed piping material is currently available for recycling. The plastics industry is, however, aggressively pursuing a program of recycling as many plastic materials as possible in the future.

What are the four advantages of using TIPS?

The four major advantages of TIPS are:

• Durability

• Safe and easy to use

• Environmentally sound

• Cost-effectiveness

What are the two most common manufacturing processes in producing TIPS?

Almost all TIPS pipe is extruded and most fittings, valves and pumps are injection molded. Both processes enable products to be made consistently to exacting industry standards. In unique and small volume items such as large diameter fittings or specialized valves the products are fabricated using machining and solvent and heat welding techniques.

How does one choose the best TIPS material for a particular application?

When selecting any piping material, one needs to have as much information on the conditions of service as possible---for example: description of the material being transported (chemical make-up, specific gravity, solids content, viscosity), maximum and minimum system pressure, internal and external temperature ranges, above or belowground, indoor or outdoor environment, codes required, joining method, and lastly, which material is most cost-effective.

How are TIPS tested after being installed?

TIPS piping systems are tested similarly to other piping materials with two major exceptions: (1) Unless a manufacturer states otherwise, never test TIPS with compressed air or other gases; and (2) When solvent cementing, make certain that joints are cured properly per manufacturer’s instructions before testing. (Compressed air or other gases contain large amount of stored energy, which present serious safety hazards should a system fail for any reason.)

What types of TIPS products are available?

Plastic piping systems are unmatched when it comes to breadth of product line and having one plastic piping system material to be in contact with all fluid-wetted parts. Readily available products for most TIPS include the following: pipe, fittings, valves, pumps, tanks, tubing, filters, fans and blowers, duct, scrubbers, scrubber packing, flow monitoring equipment, and heat exchangers. In addition, special engineered products can be easily fabricated to meet a particular engineering design.

TIPS have been and are being used on what applications?

A sample of just some of the applications TIPS has successfully been installed are:

Acid/Chemical Waste Drainage

Air Pollution Control

Amusement/Theme/Water Parks


Chemical Process


Compressed Air/Gases (special plastic compounds)



Environmental Protection

Fire Water Mains (industrial)

Fish Hatcheries/Farms


Geothermal Energy

Heating/Ventilating/Air Conditioning



Oil & Gas Gathering

Original Equipment Manufacturing


Power Plants

Pulp & Paper


Steel Processing

Surface Finishing (plating)

Swimming Pools (municipal & school)

Water & Waste Treatment


1. What is the minimum and maximum use temperature for PVDF Industrial Pressure Piping?

Under supported conditions and using a chemical compatibility chart, PVDF can be used continuously up to 300°F and most manufacturers rate it to 275°F in chemicals that have little attack on PVDF. As it relates to cold weather, PVDF is not brittle until minus 40°F, but most recommendations are to use minus 20°F as the lower limit in case there is some type of impact that occurs on the system. Flexible PVDF copolymers generally do better at very low temperatures compared to PVDF homopolymers, but they can all handle relatively cold weather.

2. What are the most common chemicals handled by PVDF that attack less expensive materials?

It is common to use PVDF piping to handle hot Chlorine, Methyl Chloroform, Hydrochloric Acid, Salt Water, Chlorobenzene, Sodium Hypochlorite (pH < 12), Sugars, Sulfuric Acid (97.5% and less), Chlorinated Salts, Phosphoric Acid, Hydrofluoric Acid, Metallic Chlorides, Acid Mixtures, Bromine, Hydrobromic Acid, Bromobenzene, Brominated Salts, Iodine, Salicylic Acid, Methane Sulfonic Acid, Acetic Acid (<50%), Methyl Alcohol, Chromic Acid, Nitric Acid, Deionized Water, Ozone, Biodiesel, Hydrocarbon and alcohol based fuels and mixtures.

3. Can PVDF piping be steam cleaned?

Studies have been published that confirm that after over 50 steam cycles at 260°F, PVDF piping had no change in properties versus a control sample. It is common to subject PVDF piping to low pressure steam in bio-pharma applications.

4. What joining methods are readily available for PVDF piping systems?

Generally PVDF pipe is joined either mechanically or by fusion welding. PVDF systems are offered by several pipe manufacturers in socket fusion, butt fusion, beadless butt-fusion (BCF/SIB), infrared fusion, electrofusion, sanitary mechanical, flanged mechanical, threaded mechanical, forced mechanical, plastic lined steel flanged, fiberglass reinforced flanged, and threaded.

5. What food and water regulatory listings are available for PVDF?

Certain grades of PVDF and PVDF copolymers are listed by NSF International forcompliance with NSF/ANSI 51 (hot food contact) and NSF/ANSI 61 (hot potable water). Certain grades comply with USP Class 6 testing. Certain grades comply with Sanitary 3A testing. Certain grades comply with FDA Title 21 CFR 177.2510 and CFR 177.2600 for repeated use with food contact. Certain grades comply with Kosher certification. There may be other listings and it is good to just contact the manufacturers of PVDF for advice.

6. What flame and smoke testing listings are available for PVDF?

Certain grades of PVDF have FM 4910 listing for Semiconductor Facilities. Certain grades of PVDF are listed to UL 2024 for plenum-rated raceway conduits. Certain grades of PVDF are listed to ASTM E84 with a 25/50 rating tested in sheet form (one listed product even has a 0/0 rating), and have achieved a 0/20, 5/40 rating tested as pipe geometry with the tunnel full in width and length as designed in the test with no addition of water or other potentially extinguishing media. Certain grades of PVDF comply with 25/50 rating for ULC S102.2. Certain grades of PVDF are used by companies that make listed wire and cable products for plenum areas in buildings. PVDF Foams with density as low as 0.03 specific gravity have passed ASTM E84 with a 25/50 rating and have achieved FM 4910 listing. There may be other listings, and it is good to just contact the manufacturer for written confirmation.

7. Can PVDF pipe be exposed to nuclear radiation?

PVDF has been used up to 1000 mega-rads of radiation exposure by government laboratories. There is much documentation about the use of PVDF in nuclear reclamation facilities.

8. What typical industries use PVDF piping to handle chemical processing?

The following industries use PVDF piping systems: Pulp & Paper, Chlor-Alkali, Metal Preparation, Petrochemical, Food & Beverage, Pharmaceutical/Biotech, Wastewater, Pesticides, Fertilizer, Semiconductor/Electronics, Institutional (Schools, Colleges and Universities), Brominated Chemicals, Marine, General Chemical Handling.

9. What is the abrasion resistance of PVDF?

Reported Tabor Abrasion Resistance shows PVDF to compare favorably with Nylon and UHMW-PE. This is over 2 times more resistant than many commodity polymers and 100 times more resistant than PTFE.

10. How resistant to sunlight is PVDF?

PVDF is very resistant to sunlight. It is commonly used in Solar Panels as a 40-year life protective film, long-life paint finishes for tall buildings and airports, and outdoor wiring and piping. Test panels showing little degradation after over 40 years of exposure in Florida are still intact.

11. What final products are readily available in PVDF to compliment piping systems?

Flexible tubing, fittings, films, coated ducting, pumps, nozzles, flowmeters, valves, tanks, membranes, fabrics, dump tower packing, filter housings, and nuts & bolts are readily available in stock for making a complete chemical handling system from PVDF.


My fittings have a visible line in them, are they cracked?
No. The noticeable line you are seeing is a more than likely not a crack. If you are unable to open it up by pulling on the part then what you are seeing is most likely a knit-line (other names include weld-line and flow-line). The formation of a knit-line is an intrinsic part of the injection-molding process and is created when hot melted plastic flows under pressure into a mold cavity, around cores and finally “knits” back together on the opposite side of the cavity fill point. Knit-lines will sometimes appear straight or as gently wavy curving lines running the length of the fitting (both inside and outside ). A fitting that displays this type of line is not defective. A knit-line will not impact the integrity of the product or system.

Is the straight, slightly raised line on a fitting a defect?
No. This slightly raised line is where the parting line of the mold is located and is not a defect of the fitting. The parting line is the location of where the two halves of the mold separate to allow part removal.

What is the outside diameter (OD) of a 1" fitting?
The outside diameter (OD) of a fitting will vary depending on manufacturer and minimum wall thickness requirements for a given size. Plastic fittings are generally specified by a nominal internal diameter (ID). Contact the manufacturer for detailed dimensional information.

What is a spigot end?
A spigot end, also known as a street end, is the male end of a fitting having a controlled OD dimension equal to that of the corresponding pipe size.

What is a socket or hub end?
A socket (or hub) is the female end of a fitting having a controlled ID dimension.

What is an interference fit?
An interference fit is the result of the sockets (or hubs) of plastic fittings being tapered. The socket entrance is slightly larger than the pipe OD to allow for easy pipe insertion. The socket bottom is slightly smaller than the pipe OD to ensure that a tight (interference) fit occurs when pipe is inserted. This interference fit is an integral part of producing a strong bond between pipe and fitting during the solvent cementing process.

Can a regular plastic female adapter fitting be used to transition from plastic to metal piping?
No. Plastic female adapters that are all-plastic should never be used as transitions from plastic to metal piping. In fact, you should never use any all-plastic female threaded fitting to transition to or from metal piping. The reason is because of large differences in tensile strengths and rates of thermal expansion/contraction between the two. The proper method to transition between plastic and metal is thru the use of special transition fittings. These special transition fittings are available in a variety of styles and configurations. Check with specific manufacturers on fittings that they recommend for use as transitions from metal to plastic.

Be sure to check local codes concerning acceptable transition practices.

Do I have to use a primer when joining solvent weld fittings?
The answer to this question depends upon the type of material being assembled or possible code requirements. For example, ABS piping material does not incorporate a primer in its assembly process but PVC piping material does. Some codes even require a purple primer be used to easily identify that it has been applied. Most codes allow CPVC CTS systems for domestic hot- and cold-water to be assembled without primer providing the proper type of one-step cement is utilized. Be sure to use primers if it is part of a system’s assembly requirement. For more information contact the specific manufacturer for details or visit the material's respective portion of this website.

Is it acceptable to alter the design of a plastic fitting?
No. Fittings are manufactured to stringent ASTM dimensional requirements. If you come across a need for a special fitting check with your plumbing wholesaler, they will provide you with many application configurations that will more than likely work for your situation. Modifications to a fitting will likely void any manufacturer’s warranty and could lead to part failure.

Can I use compressed air to pressure test a plastic system?
No, unless the procedure being used has been clearly and explicitly approved by the manufacturer(s) of the plastic products or system being tested. Compressed air contains a large amount of stored energy that presents a serious safety hazard should the piping system fail for any reason.

Can I use plastic fittings to build a compressed air piping system?
No. Plastic fittings should not be used to build a compressed air piping system unless they are specifically designed for such service. There are a few manufacturers that produce fittings from a special grade of ABS material that are designed for use in compressed air systems. Plastic pipe and fittings designed for compressed air systems are clearly marked and identified for this type of application. Do not attempt to use common black ABS DWV pipe and fittings for they are not designed for this type of application.

Can I store plastic fittings outside?
Yes, plastic fittings can be stored outside but only if they are covered properly and not exposed to sunlight or extreme weather conditions.

What type of thread sealant should I use on threaded plastic fittings?
You are always safe to use PTFE Teflon tape (3 mil thickness). If a specific fittings manufacturer recommends a specific brand of thread sealant then it is acceptable to use it on their fittings only. There are many different types of thread sealants on the market and even though some may say they are acceptable for use with plastic fittings they may not actually be chemically compatible. Even some Teflon paste sealants can cause premature fitting failure due to chemical attack.

Warning - Always follow the fitting manufacturer’s recommendations on the type and brand of thread sealant to use!

I've heard that too much solvent cement can be as bad as too little cement, is this true?
Yes. Excess solvent cement that is allowed to puddle inside the body of a fitting can be very detrimental and can shorten the life of the fitting. A puddle of solvent cement will “skin over” on its surface as the solvents evaporate. This “skinning over” is analogous to ice on a lake. Just like the ice prevents the water beneath from evaporating so does a “skin” of solvent cement. The difference being that the excess solvent cement beneath the “skin” will continue to soften and damage the wall of the fitting.

Are there ways to prevent excess solvent cement from puddling inside a fitting during the cementing process?
Yes, there are. First, be sure to tip the fitting socket at a downward angle. This will allow excess primer and cement to drip out during the application process. Second, (after applying primer and while the primer is still wet) apply a moderate to heavy coat of cement to the pipe then a lighter coat of cement to the socket and then a second moderate to heavy coat of cement to the pipe again. The two coats of cement on the pipe will ensure that all gaps will be properly filled when the pipe and fitting are assembled. Any excess solvent cement will be forced out of the fitting at the socket entrance instead of being pushed into the inside of the fitting body. Third, always bevel the leading edge of the pipe. This bevel on the pipe removes the sharp leading edge that would otherwise scrape cement from the socket wall producing a puddle of cement inside the fitting.

For additional information on solvent cementing see the respective materials section.

Is it Okay to pre-apply primer the night before?
No. Primer should not be pre-applied the night before you are going to make solvent welds. Once primer dries (evaporates) it is no longer effective. Solvent cement must be applied directly over the surface of wet primer.

Can primer be reapplied on top of dried primer if the process gets interrupted?
Yes. Primer can be reapplied on top of dried primer.

Can solvent cement be reapplied on top of dried cement if the process gets interrupted?
No. Once the solvent cement has dried (evaporated) the surface of the pipe will be slightly larger in diameter and the fitting socket will be slightly smaller in diameter. This will make it difficult if not impossible to insert the pipe and fitting together. This increased interference fit will also place greater tensile stress on the female fitting socket causing possible premature fitting failure (from splitting).

Is there an easy method I can use to tell if I am solvent cementing correctly?
Yes, there is. The best method for checking your solvent cementing skill is to cut open a cemented sample. Use a coupling of the largest diameter you will encounter. After reviewing the “solvent cementing procedures”. Cement a piece of pipe approximately 1” longer than the socket depth into each end of a coupling. Next, using a hand saw, cut the coupling in half (in the same direction as flow). Now, with a screwdriver, carefully pry the pieces of pipe from the pieces of fitting socket. The surfaces should be uniform and dull in appearance indicating that the cement was in full contact with both pipe and fitting wall. If shiny patches are found this indicates an improper bond was made. The most likely cause of which is a lack of cement or the outer edge of the pipe was not beveled.

Fire Sprinklers

Plastic Pipe Fire Sprinkler Systems:

But won’t plastic pipes melt in a fire? No. The heads are designed to rapidly activate when ceiling temperatures indicate a fire is occurring in the room long before excessive temperatures are reached. Water in the pipe is dispersed immediately when the head is activated. Also, any piping systems are typically installed behind the drywall of the ceiling or wall – an effective fire barrier. Based on extensive fire exposure tests performed at third party agencies, some PEX and CPVC systems are listed for use exposed or without protection. Installations must be done in strict accordance with the limitations defined by the agency. Refer to the manufacturer's installation instructions for details.

Don’t all the heads activate at once? No. That only happens in the movies! Heads must reach a predetermined high temperature to activate, and typically only one or two heads are used to control or extinguish a fire in a residential building.

Aren’t they ugly or distracting? Residential heads are smaller than commercial units. There are even fully recessed models that are concealed by a cover plate that can be matched to the ceiling. The cover is held in place by a heat-activated metallic fuse, and the head drops down when activated.

Can I install them myself? This is not recommended. Life safety systems must be installed in compliance with codes and standards so that the design is correct and an adequate water supply to the heads is available. Properly trained and qualified contractors should install fire sprinklers.

Can any plastic pipe be used to install a fire sprinkler system? No. Only specially listed products that have been tested by an independent laboratory and listed as approved for fire protection appications can be used.

Why should I consider installing home fire sprinklers? Every 90 seconds a home fire is reported in the United States. According to the National Fire Protection Association (NFPA), eight out of 10 fire fatalities occur where Americans feel safest — in their own homes.

Don’t smoke alarms already protect homes? Smoke detectors certainly do reduce home fire deaths…but only if they’re properly maintained and operational. And smoke detectors only warn of a fire, they can’t control a fire like a sprinkler system. Adding a sprinkler system increases the likelihood of surviving a fire. Without fire sprinklers, a home can be engulfed in flames rapidly, whereas a single sprinkler can control, or in many cases, extinguish, a fire in seconds.

Is demand for residential fire sprinklers increasing? More and more homebuyers are demanding fire sprinklers in their homes. According to a Harris Interactive poll, many homeowners would prefer to install a fire sprinkler system over cabinet upgrades (35%) or hardwood floors (36%). And 38% said they would be more likely to purchase a new home with sprinklers than one without.

Will residential fire sprinkler systems become mandatory? As cities and fire departments realize the life-saving benefits of residential fire sprinklers, more and more localities are mandating sprinklers. More than 400 jurisdictions in the United States currently require fire sprinklers in single family homes. It is expected that these ordinances will continue to expand rapidly, as more cities, counties and states discover that residential sprinklers affordably protect lives and homes. The International Residential Code (IRC) has required fire sprinklers in all new home construction since 2011.

Why would a builder offer sprinklers before they’re mandated? Progressive and forward-thinking builders have an opportunity to differentiate themselves from their competition by providing homebuyers with a desirable safety feature. And by adding fire sprinklers to a housing development, site development costs can often be reduced due to allowances for narrower streets, increased hydrant spacing, additional units, smaller turnarounds, etc.

How do fire sprinklers look in a home? Barely noticeable, each sprinkler can be recessed or tastefully concealed behind a cover plate that falls away when activated.

How do fire sprinklers work? Sprinklers are activated by heat, not smoke. So a sprinkler will activate only where the fire is, and many house fires can be controlled by just one sprinkler.

Do fire sprinkler systems require maintenance? Multipurpose systems are integrated into a home's cold-water plumbing, so they don’t require back flow preventers or check valves and the maintenance associated with a commercial system. Stand-alone systems may require simple inspection of a back flow preventer and antifreeze protection.

How are sprinkler system layouts designed? Fire sprinkler systems have to be designed to ensure that, if there is an activation, the sprinklers will operate as expected. To be certain that adequate water pressure and flow is available to each sprinkler, the system needs to be hydraulically designed by a qualified design technician. Sprinkler design qualifications may vary among jurisdictions, so check with your sprinkler system manufacturer or contractor for design assistance.

What information is needed to create a sprinkler layout design? In addition to a detailed house plan, the designer will also need information on the available water supply, including water pressure, distance from the street to the meter, water supply pipe size, water meter size, etc.

What if the house is not on city water? Many residential fire sprinkler systems are installed in homes with well-water supplies. Your sprinkler layout designer will ensure that the home’s well and pump is able to supply the necessary water flow.

Does installing a fire sprinkler system require an additional contractor? Both stand-alone and multipurpose systems can be installed by any contractor that meets the requirements of that particular jurisdiction. Multipurpose systems combine fire sprinklers with a home’s cold water plumbing, which means that in many cases, the sprinklers can be installed by the qualified plumber that’s already on the job site.

How can the operation of a fire sprinkler system be verified? Sprinkler layouts are created by performing hydraulic calculations which ensure that the system is properly designed. Another way is that an installed system can be “flow tested” by unscrewing the sprinkler from the most hydraulically remote fitting (identified in the sprinkler layout plan) and running water through the system into a container. This test demonstrates that the system is flowing the necessary water, as designed. And with a multipurpose system, since it’s connected to the cold-water plumbing, every time you use a cold-water plumbing fixture, you know that water is also flowing through the sprinkler system. An alarm can be installed that will provide an alert should there be a sprinkler activation,

Will installing a sprinkler system affect a home building schedule? No. It’s just a matter of the builder and the fire sprinkler installer coordinating their schedules. Since a multipurpose sprinkler system is connected to a home’s plumbing, this combined system can be installed by the qualified, licensed plumber who is already on the jobsite. In some cases, the fire sprinkler contractor can install and test the fire sprinkler side of the multipurpose system and the plumbing contractor can run the plumbing pipe to the cold water fixtures from stub outs left on the fire sprinkler system, minimizing any coordination or scheduling issues.

Are there any concerns about installing sprinklers in cold-climate homes? When properly installed with appropriate insulation, there is virtually no danger of sprinkler tubing freezing. In cold-weather regions, stand-alone sprinkler systems can be filled with a suitable non-freezing liquid. Since multipurpose systems are connected to the plumbing system, water moves through the system every time a cold-water plumbing fixture is used, reducing the likelihood of unexpected freezing. It is important to remember that all plumbing systems and fire sprinkler systems need to be and can be designed so they are not at risk of freezing.

Have home fire sprinklers been established and proven in the market? Sprinklers have been trusted in the market for over 100 years and trained professionals have installed thousands of UL approved sprinkler systems in homes all over the U.S. In addition, residential fire sprinkler systems use the same trusted, high-quality plastic tubing that is used in home plumbing systems. So you can count on its affordability and durability.

What industry regulations, codes and standards apply to sprinkler systems? The industry standard for the installation of residential fire sprinklers is NFPA 13D, published by the National Fire Protection Association. Other applicable listings are UL1821 and NSF (National Sanitation Foundation, for multipurpose systems).

Can a sprinkler go off accidentally? Fire sprinklers respond to heat, not smoke. The odds of a malfunction are remote.

Can fire sprinklers be accidentally damaged? Since residential sprinklers can be recessed into the ceiling and protected by an attractive cover plate, the potential for accidental damage is minimized.

What about potential water damage? When activated, a residential fire sprinkler system will utilize only 10 to 15 gallons of water per minute, whereas a fire department response will pour up to 250 gallons of water per minute into a burning home.

How much does a fire sprinkler system cost? A fire sprinkler system typically adds as little as 1 to 1.5% to the cost of constructing a new home…about the same as carpet or cabinetry upgrade. A small price to pay to protect lives, property and possessions.

How does a residential fire sprinkler system affect insurance rates? Insurance companies recognize the life and property saving benefits of residential fire sprinklers, and many offer homeowners fire insurance premium discounts up to 30%.

Can alternative (non-potable) water be used with residential fire sprinkler systems? PPFA recommends that potable water be used as the default source to charge and supply residential fire sprinkler systems. Alternative sources may be used where approved by the authority having jurisdiction with proper consideration for continuous supply, purity, and compatibility with the system components; however, residential fire sprinkler systems are life-safety systems and this consideration should take priority.

What else is important to know? Always check the chemical compatibility of antifreezes, thread sealants, firestops, and any other construction products used with the systems with the manufacturer. Incompatible materials may damage the systems and void any warranty.

Who manufactures these systems? Contact the following PPFA member companies for more information on these systems.

Georg Fischer Harvel
(BlazeMaster Marketing Partner)
IPEX (BlazeMaster Marketing Partner)

(BlazeMaster Marketing Partner)


What other sources of outside information on fire sprinklers can you recommend?

Solvent Cements & Primers

What is the difference between pipe cleaner, primer/cleaner and primer?

All pipe surfaces should be thoroughly cleaned with pipe cleaner. Pipe cleaner is formulated to remove surface dirt and any oils or grease that remain on the pipe from the manufacturing process or from the work environment. Primer/cleaner and primer contain more aggressive solvents and will soften the pipe surface to allow the solvent cement to penetrate more effectively. Primer is often required by plumbing codes and sometimes a purple colored primer is specified. Colorless primers, visible under UV or black lights can be used in place of purple primers as permitted in ASTM F656. (see below)

What are “UV” primers, “black light” primers and “Unpurple” primers?

These are all terms used to describe colorless primers that are visible only under UV/black lights which are used as a substitute for purple primers. These primers function identically to standard purple primers except they are colorless and invisible to the naked eye when applied. The installer/inspector may use a “black light” or “black light” flashlight to inspect for the presence of correctly applied primer as required by the plumbing codes. These “black light” flashlights are available from the primer manufacturers and are also available at a nominal cost on the web. These “Unpurple” primers offer the benefits of a colored primer with none of the aesthetic and cleanup disadvantages of purple primers.

What temperature should solvent cements be applied?

While it is recommended that the cement be applied between 40-100 degrees F, weather conditions may not make this feasible. A strong solvent welded joint can be made at temperatures below freezing, as long as the cement is fluid, cure times are extended and other handling precautions are followed. Cements are available which are designed for temperatures outside of this temperature range – consult manufacturer’s web sites for more use and proper storage information.

What is the difference between PVC, CPVC and ABS?

These are three different types of plastic pipe used in plumbing applications that are joined by solvent cementing: PVC (Polyvinyl Chloride); CPVC (Chlorinated Polyvinyl Chloride); and ABS (Acrylonitrile-Butadiene- Styrene). PVC and ABS pipe are normally used for Drain, Waste and Vent (DWV) systems, while CPVC is used for water distribution systems. PVC pipe can be used in pressure applications - such as water mains, service lines and irrigation. It is important to choose the correct solvent cement based on the type of plastic pipe being used.

What type of applicator should be used to apply the solvent cement?

Most solvent cements come with a dauber included in the can. This dauber is typically one inch in size and be used to apply cement to pipe sizes up to 2". Installer should check the dauber size as different size cans can have large and small daubers. The dauber size should be as close as possible to ½ the diameter of the pipe. (Using a dauber which is too large in size can cause the cement to puddle in the fitting causing potential solvent stress cracking.) Above 2" diameter, a brush ½ the pipe diameter can be used, rollers should be avoided for the smaller sizes (¼” thru 3”). For above 3” diameter, it is recommended that the installer consult the manufacturer’s installation guide for possible applicators and sizes.

Should a gelled or lumpy cement be used?

Do not use gelled or thickened cements on plastic pipe. The solvents in the can will evaporate if left open for extended periods of time, causing the product to thicken or gel. It is not recommended that you attempt to thin solvent cements.

What cement should be used for PVC, CPVC and ABS pipe?

It is important to carefully select the proper solvent cement for your application. PVC cements should be used for PVC pipe and fittings, CPVC cements should be used for CPVC pipe and fittings and ABS cement should be used for ABS pipe and fittings.

Should primer or primer/cleaner be allowed to dry before applying solvent cement?

Because the primers will soften the pipe surface, it is important to apply cement to the pipe and fittings while the primer is still wet for maximum bond strength.

What are Low VOC solvent cements? 

In areas of the country where population and geography combine to produce ozone and smog air quality issues, low volatile organic compound (VOC) products, like paints and adhesives, are either recommended, or required by law. These products have special formulations that have lower solvent content and/or use alternative solvents, like acetone, that are less reactive in the atmosphere. Solvent cements and primers are produced that meet the requirements in California’s South Coast Air Quality Management District (SCAQMD) and other regions which have similar VOC regulations. These products still meet required levels of performance required by standards and third party certifiers.

Can I use solvent cements in “green” and “sustainable” building systems, like LEED?

Yes. While solvent cements contain VOC’s, the total quantity used during home construction is very small compared with other products commonly used by the gallon, like paints and other adhesives. Solvent cemented plumbing systems are essentially permanent once installed and do not need repair or reapplication. LEED V 2.2 does require the use of low VOC solvent cements in Environmental Quality credit 4.1. In order to obtain the credit point, all adhesives and sealants used on the interior of the building are to meet SCAQMD rule #1168. Low-VOC solvent cements manufactured to comply with SCAQMD and are commercially available. Solvent cemented piping systems, like ABS, PVC and CPVC each find uses in sustainable piping systems such as gray water, subsurface irrigation, radon venting, rain water catchment, and higher efficiency hot water distribution.

Where can shippers of solvent cement products learn about placarding and other DOT transportation regulations? 

Under certain conditions, and because of their flammability, larger containers of solvent cements, cleaners and primers "offered for shipment" require special placarding of vehicles. To properly follow U.S. Department of Transportation (DOT) shipping regulations, training of employees is required.     Containers with volumes under one liter are considered ORM-D (consumer commodity) by DOT and are generally exempt.    DOT does not certify hazmat employees, or endorse any private sector training program or certification. Rather, the hazmat employer must choose what training is appropriate for its employees under the Hazardous Material Regulations, and certify that employees are appropriately trained. Training must be done initially with a new employee and at least every three years. Any employee whose work directly affects hazardous materials transportation safety is required to have this training.

The following link:  contains links to pre-made DOT training materials your company may find useful.

Does PPFA have a position on spray or aerosol solvent cement products?

The Plastic Pipe and Fittings Association and its members fully support the development of new technologies and their adoption in the marketplace. At the same time PPFA strongly encourages careful consideration of several factors. To view PPFA's position on Alternate Methods and Materials for Joining Plastic Pipe Systems Using Plastic Pipe Cements click here.

FAQs for Applicability of Plastic Piping Systems to Green Rating Systems

Do your products have to meet LEED requirements, and are they certified to meet LEED requirements?

LEED does not specifically require certification of products. LEED does not rate plumbing products. Therefore, piping and similar products are not eligible to be certified to LEED compliance. If anyone tells you a piping system is “LEED-certified”, the statement is not accurate.

Do USGBC LEED rating systems give credits to buildings for use of certain types of piping material?

No. LEED rating systems do not prefer one piping material over another. LEED NC 2009 contains this language, similar to LEED NC 2.2, in the materials resource (MR) section;

“Mechanical, electrical and plumbing components and specialty items such as elevators and equipment cannot be included in this calculation.”

The calculations in these sections do provide credits for such factors as a product’s recycled content, reused materials, or regional materials.

Since, LEED rating systems exclude piping from the materials credit section which includes Materials Reuse, Recycled Content, and Regional Materials, you should choose the most appropriate piping material for the application.

However, points for your building can be obtained by installing one or more of the sustainable systems listed below that substantially rely on plastic pipe.

How can plastic pipe help achieve credits in LEED or other sustainable building standards or rating systems?

The following sustainable systems provide credits in LEED New Construction (NC) and in LEED for Homes. Most of these systems are empowered by the use of plastic piping;

Gray water reuse and irrigation systems, Water Efficiency 1, 2 (New Construction (NC) / Homes)
Geothermal ground loops for heating and cooling, Energy Efficiency 1 (NC) Energy Efficiency 6 (Homes)
Efficient hot water distribution systems, Energy & Atmosphere 7.1 (Homes)
Rainwater harvesting, Water Efficiency 1, 2 (NC)
Radon venting, Indoor Environmental Quality 9 (Homes)
Central vacuum systems, Indoor Environmental Quality 8.2 (Homes)
Waste water treatment, Water Efficiency 1, 2 (NC)
Efficient irrigation, Water Efficiency 1 (NC)
Foundation drainage, Water Efficiency 1 (NC)
Radiant floor heating, Indoor Environmental Quality 7 (Homes)

Can I use solvent cements in “green” and “sustainable” building rating systems, like LEED?

Yes. LEED V 2.2 and LEED 2009 both require the use of low VOC solvent cements in Environmental Quality credit 4.1 in order to obtain the credit point. Low-VOC solvent cements complying with SCAQMD Rule 1168 are commercially available. Solvent cemented piping systems, like ABS, PVC and CPVC each find uses in sustainable piping systems such as gray water, subsurface irrigation, radon venting, rain water catchment, and higher efficiency hot water distribution.