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FAQ (Water Pipe)

  • What is HDPE?
    • HDPE is the abbreviation for the material used to make Endot water pipe and tubing, High Density Polyethylene.

  • What is PE3408?
    • PE3408 is a specific grade of HDPE resin.  PE3408 is the most common grade of HDPE resin used for small diameter water pipe and tubing.  Other nomenclatures are PE2306 and PE3406.  PE2306 is Medium Density Polyethylene and PE3406 is an older resin that has been replaced for the most part by PE3408.

  • What is PE4710?
    • PE4710 is a newer high performance grade of HDPE resin developed in Europe over 2 decades ago.  PE4710 has a longer calculated service life, greater resistance to chemical attach and a 25% higher pressure rating than comparable PE3408 products.   PE4710 is rapidly becoming the resin of choice for water pipe and tubing. 

  • What is the SDR (SODR, SIDR)?
    • SDR is the Standard Dimension Ratio ( or Size to Diameter Ratio), that is, the ratio of the inside diameter (SIDR) or outside diameter (SODR) of the water pipe to the wall thickness of the water pipe.  The smaller the SDR number the thicker the wall of the pipe or tubing.  SODR refers to pipe or tubing that is OD controlled.  SIDR refers to pipe or tubing that is ID controlled.

  • What are ASTM’s?
    • ASTM’s are the standards produced by the American Society for Testing and Materials.  ASTM is a not for profit organization that writes standards for materials, products, systems and services.  Standards are developed through the consensus process by 33,000 technically qualified ASTM members worldwide.

      For water pipe and tubing ASTM standards for the HDPE material and the sizing of the pipe and tubing are commonly referred to in literature and bid specifications.  For materials ASTM D3350 is generally used.  (ASTM D1248 is an obsolete specification for materials).

      For Sizing of well pipe ASTM D2239 is used and for water service tubing ASTM D2737 is used.  For larger diameter pipe especially that used for Geothermal applications and for fusion welded water pipe ASTM D3035 is used.

      ASTM D2513 is used for the production of gas pipe and tubing.

  • What is the difference between pipe and tubing?
    • In small diameter polyethylene pipe and tubing (1/2” through 2”) pipe used in water well systems is generally made to ASTM D2239, Inside Diameter Controlled, specifications whereas tubing used in water service lines is generally made to ASTM D2737, Outside Diameter Controlled, specifications.

      Pipe made to ASTM D2239 is usually called IPS or Iron Pipe Size.  Tubing is usually called CTS or WST, Copper Tube Size or Water Service Tubing.

      Pipe made to ASTM D3035 is Outside Diameter Controlled and is also classified as IPS, Iron Pipe Size.

  • What is CTS?
    • CTS is the abbreviation for Copper Tube Sized water tubing. CTS products are most often used for municipal water service connections from the water main to the house or building. CTS is produced to ASTM D2737 and is Outside Diameter controlled allowing the use of external compression fittings for joining. CTS is usually only produced in a 200 PSI rating.

  • What is IPS?
    • IPS is the abbreviation for Iron Pipe Size. There are two ASTM Standards that are called IPS, ASTM D2239 and ASTM D3035. ASTM D2239 is ID controlled IPS pipe where the inside diameter remains constant and the wall thickness increases as the pressure rating increases with a larger and larger Outside Diameter. ASTM D3035 IPS pipe is Outside Diameter controlled and where the OD is constant the wall thickness increases and the ID decreases as the pressure ratings increase.

  • Why the different types of pipe?
    • Sizing standards for pipe and tubing were developed from older metal pipe standards and adjusted to provide suitable plastic pipe products that can withstand pressure.  This has resulted in a variety of standards that are all acceptable, but each user has to decide what works best for their system or application.

      ID Controlled IPS products are used for installations like hanging submersible pumps in a well and connecting water wells to the house.  ID controlled IPS is joined using barbed insert fittings sealed with gear clamps.

      CTS or WST is used for water service lines from water mains in the street into a house.  CTS or WST products are joined using Heavy duty bronze compression fittings.  These compression fittings are very reliable and durable and the choice of most water companies for service lines that will be buried indefinitely.

      OD controlled IPS products are used in water systems primarily for larger diameter applications as well as in geothermal systems.

  • ASTM F-714 & D-3035 Compared .
    • There are two ASTM’s (F 714 & D 3035) that provide the dimensions for IPS, OD Controlled, PE. They are titled the same. F 714 has two sets of dimensions, IPS (Iron Pipe Size) and DIPS (Ductile Iron Pipe Size). ASTM D3035 has IPS sizing only, not DIPS sizing. F714 starts at 3” and goes up to 54”. D3035 starts at ½” and goes through 24”. F714 has SDR 7.3 to 41 in IPS sizes. D3035 had SDR 7 to 32.5 in IPS sizes. F714 also contains ISO 161/1 .(European/metric) sizing in addition to ANSI B36.10 (USA/inch) sizing. D3035 does not contain ISO standards for metric sizing. D3035 and F714 IPS sizing is exactly the same where they overlap on sizes (3” to 24”).  

  • What is a insert or a stiffener?
    • When joining CTS tubing made to ASTM D2737 a plastic or stainless steel sleeve is inserted into the ID of the tubing to stiffen the tubing and prevent it from collapsing when joined with external compression fittings.

  • The stiffener I use is much longer than the fitting I use on CTS tubing, is this OK?
    • NO! It is important that the stiffener or insert be the one recommended by the compression fitting company. A stiffener that extend beyond the compression fitting can cause damage to the inside of the tubing and possible failure of the tubing.

  • Can plastic withstand city water pressure?
    • Yes!  Endot HDPE pipe and tubing is rated from 100 PSI to 200 PSI.  These rating are based on conformance to ASTM specifications and the use of NSF Certified resins.  All pressure ratings are far less than the actual pressure it takes to burst our pipe and tubing.

  • Can Endot pipe and tubing be used for hot water applications?
    • Generally speaking HDPE is not designed for hot water applications.  HDPE pipe and tubing is rated for its pressure at 73.4 o  F.   Any increase in temperature cause the plastic to become softer and therefore the pressure rating will drop.  The general rule is for every shift of 10 o  F the pressure rating will shift 12%.  See the chart on temperature vs. pressure.

  • Can Endot pipe and tubing be used inside of a house?
    • Generally No.  Endot PE3408 pipe and tubing is designed specifically for cold water applications, but not for hot water applications.  Most uses for Endot PE3408 pipe and tubing are outdoors.  If your local building codes allows HDPE pipe and tubing installation inside of a building you may use it.  Check with your local code official to determine what is acceptable usage in your community.

  • What is the Warranty on Endot pipe and tubing?
    • Endot provides a Lifetime Warranty on all NSF Certified Pipe and Tubing.  See our Warranty statements for details.

  • Can HDPE pipe and tubing rust or corrode?
    • No.  HDPE is almost chemically inert and does not rust or corrode.  Endot HDPE pipe and tubing carries a Lifetime Warranty against rust,  rot and corrosion.

  • How do I join IPS pipe?
    • It depends on the type of IPS pipe you are gong to use. ASTM D2239 IPS pipe is usually joined with barbed insert fittings and external gear clamps. A few companies also make external compression fittings for SDR 7, ASTM D2239 IPS pipe. If ASTM D3035 IPS pipe is to be used it is usually joined with heat fusion. There are compression fittings available for ASTM D3035 IPS pipe.  See Tech/Installation for more information on this subject.

  • Can Endot pipe and tubing be used to transport chemicals?
    • That depends on the chemicals.  HDPE is nearly chemically inert and is therefore resistant to most chemicals.  See the Chemical Resistance Chart for details of what chemicals HDPE is resistant to.

  • Why can’t I glue HDPE together rather than use mechanical fittings?
    • HDPE is nearly chemically inert and there is no glue known that can chemically bond HDPE together effectively.  There are products that produce a mechanical bond, but the strength of these joints is questionable.

  • What is fusion welding of pipe?
    • HDPE can be joined using a method called fusion welding (also called butt fusion and socket fusion).  The ends of the pipe are heated to very specific temperatures using specialized equipment.  When the pipe reaches the prescribed temperature the ends are pushed together and held in place until cooled.  This only takes a few minutes total, but in the process the HDPE pipe ends melt together to form a joint that is stronger than the pipe itself.  Fusion is preferred for larger diameter pipe and for geothermal systems where pressure drop and strong reliable joints are critical factors.

  • Will sunlight affect Endot pipe and tubing?
    • All black pipe and tubing has a natural resistance to sunlight due to the addition of a minimum of 2% carbon black to the HDPE.  Endot EndoPure, a blue water pipe, has Ultraviolet stabilizers added to provide years of sunlight resistance, but EndoPure is not recommended for any permanent above ground applications.

  • How deep a water well can Endot pipe be used in?
    • This depends on several factors.  What pressure rating is the pipe used, what is the pumping, or draw down, level of the well and what is the setting of the pressure switch on the storage tank.  See the Depth Setting Chart that describes well setting and how to calculate the depth each type of pipe can handle.

  • Does HDPE pipe and tubing get brittle when cold?
    • No.  HDPE does get harder and stiffer when cold, but HDPE does not get brittle like some plastics.  Even in sub-zero temperatures HDPE can be hit with a hammer and not crack.

  • When I uncoil a roll of HDPE pipe it wants to curl backup again. Why?
    • HDPE has memory.  That is HDPE remembers the position it has been stored in and wants to return to that position.  Warming the pipe will help overcome this minor problem.

  • An HDPE water line runs under our driveway. Will it be crushed by the weight?
    • Not if the pipe is buried according to recommended procedures.   HDPE is very durable and has a high crush strength.  ASTM D2774 provides details on correct installation of plastic pipe and tubing.

  • What’s the difference between Endot’s black water pipe and Endot’s blue EndoPure pipe?
    • Endot Blue Jet Water Pipe and Tubing is black HDPE and our standard product.  Endot EndoPure is a premium blue HDPE designed with more features and benefits for the user as well as a stronger warranty.

  • EndoPure pipe and Blue Jet pipe come with crimped ends. What is that?
    • Endot welds the ends of the pipe shut during the manufacturing process. .  A slight hiss of air will be heard when the end is cut off.  This assures the end user that the pipe is clean and without holes or breaks.

  • Can Endot pipe and tubing be purchased in lengths other than those listed on the data sheets?
    • Yes.  Endot can produce pipe and tubing in any length, but depending on the product and the amount ordered special lengths may take more time to deliver vs. standard coils which may be in stock for immediate shipment.

  • Can Endot pipe and tubing be supplied on wooden or steel reels?
    • Yes.  Endot can package water pipe or tubing on wooden or steel reels when extra long lengths are needed.  There is no additional charge for this, except for the cost of the reel.

  • This past summer my well ran dry and the pipe in it burst just above the pump. What happened?
    • If a submersible well pump is allowed to run without an adequate supply of water the pump will generate a great deal of heat. This heat will soften the HDPE pipe and the pressure from the water column in the pipe will eventually burst the wall. Pumps should have a low water cut off installed to shut the pump down when it runs out of water.

  • Where is Endot Pipe Made?
    • Endot has three production facilities, New Jersey, Oklahoma and Tennessee.  New Jersey and Oklahoma produce all products, water pipe, gas pipe, geothermal pipe and conduit.  Tennessee is primarily a water pipe, gas pipe and geothermal pipe production plant.

  • Is Endot Innerduct Made in America?
    • Not only are all Endot pipe and innerduct products Made in The USA, all of the materials used to produce Endot products are Made in The USA also.

  • Is plastic water pipe safe to drink from?
    • All Endot potable water pipe and tubing is National Sanitation Foundation  (NSF) Certified to be safe for use in potable water systems.  NSF is a third party certifying agency that regularly inspects Endot’s facilities and test our products in their own laboratories for conformance to rigid toxicity and material standards as well as conformance to the ASTM specifications.