Frequently Asked Questions | Aquatherm



  • What options are available for hot-tapping?
    aquatherm and McElroy partnered to introduce the industry’s first hot tap for polypropylene. For more information on hot tapping and training for the procedure, visit the Training page and take a look at the Hot Tap Tool Demo.
  • As this pipe is rated for indoor use with other products, can I use it for indoor natural gas?
    The codes do not allow for the use of plastic piping for the transport of flammable liquids/gases above ground. Some plastic piping is approved for use with flammable liquids and gases underground.
  • Can I use a band saw to cut aquatherm pipe?
    Band saws may be used to cut aquatherm pipe. As with circular or chop saws, the blade used should always be one that is intended for use with wood or plastic.
  • What paint(s) can I use to protect aquatherm pipe from UV exposure? How long will the product last?
    Due to the flexible nature of polypropylene, many paints will not be suitable as a UV protective coating. We recommend the use of a compatible primer and heavy-duty, water-based, elastomeric acrylic coating, which can adjust with the pipe without cracking. A list of compatible products for this purpose can be found on this page. The life cycle performance of any of these products will depend on many installation and use factors. The manufacturer of the coating should be consulted for this information.
  • What substance(s) can I use to clean the pipe prior to fusion?
    Remove standing dirt and oil using 91% or greater isopropyl alcohol, as denatured alcohol may contain impurities and other chemicals that could affect the integrity of the fusion joint.
  • If you increase the heating time (per aquatherm recommendations), do you also need to increase cooling time? By what metric?
    When installing at colder temperatures, the heating time must be increased as noted in the Installer Manual. Cooling time does not need to be increased.
  • How do I account for the pressure due to building height in a high-rise project?
    aquatherm piping is often used in high-rise construction. As with any piping material, the operating pressure, including the pressure due to the elevation above the lowest point in the zone, must be less than or equal to the pressure rating of the pipe. If the pipe is used as a riser for the full height of the building, then this height must be included in the operating pressure for the pipe at the lowest point. For further information, please refer to our technical bulletin regarding high rise construction.
  • Is the pipe sizing comparable to steel or copper pipe?

    The aquatherm piping systems are based on standard dimension ratio, or SDR. This means that for a given SDR, all pipe sizes will maintain the same ratio of OD to wall thickness. The benefit of this is that all pipe sizes of a given SDR have the same pressure rating. This is different than steel and copper which have different pressure ratings for different sizes of the same schedule, where the pressure rating decreases with larger sizes.

    For those more accustomed to metal pipe, the different SDR’s of aquatherm pipe can be thought of as different schedules or types. The wall thickness on SDR 7.4 will be more comparable to schedule 80, while SDR 11 is closer to schedule 40 and SDR 17.6 is similar to schedule 10. The nominal sizes of the aquatherm piping are intended to be comparable to the same nominal size metal pipe.

  • Can polyurethane foam insulation be used around the pipe in wall and ceiling spaces?
    Yes, provided the foam is installed in accordance with the manufacturer’s instructions. These foam products will give off heat when curing, and can reach temperatures that may damage plastic pipe if not installed properly. This is normally achieved by ensuring the thickness of each pass is at or below the manufacturer’s recommendations.
  • Can I use a chamfer and cold-ring tool when doing socket fusion?
    Yes, provided they are designed for use with metric OD polypropylene pressure pipe. Tools intended for polyethylene (HDPE, MDPE) should not be used.
  • What temperature is the iron at for heating the material?
    The iron will normally operate at about 500°F (260°C) for socket fusion, and 410°F (210°C) for butt fusion.
  • How close together can fusion outlets be placed on the pipe?
    Fusion outlets can be placed very close together. This is usually limited by the size of the iron being used. On smaller size branch pipe it is possible to create manifolds with the outlets roughly 2” on center.
  • Can the fusion joints be taken apart if I need to modify the system?
    A heat-fused joint becomes one solid piece of material, and it cannot be undone. This is what creates a no-leak-path piping system, and what makes our leak-free joints the strongest part of the piping system.
  • Why can’t I dry fit the aquatherm fittings?
    The sockets of the fittings need to be slightly smaller than the outside of the pipe in order for the heat fusion process to work correctly. This helps to avoid leaving any joints unconnected.
  • What kinds of fusion techniques does aquatherm pipe use?
    aquatherm pipes are joined by four variations on basic heat fusion. Socket fusion uses socket fittings that go over the pipe. Outlet fusion is fusing a branch outlet to a piping system by using a drill to make a hole in the pipe, then heating the hole and the fusion outlet and then pressing the outlet into the heated hole. Butt fusion joins pipe together end-to-end. Butt fusion is done on piping 4” and larger. Electrofusion couplings are also available for joining pipe in very confined spaces where the pipe cannot be moved during the fusion process.
  • What kind of hanger does the pipe need?
    Hangers/supports should be intended for use with metric OD plastic pipe. Hangers/supports used with hot water piping must have a rubber or plastic coating where the hanger is in direct contact with the pipe. It is important to have hangers that will not gouge the outside of the pipe. Using hangers that gouge into the side of the pipe or that will not allow the pipe to expand will void the warranty. For more information, take a look at the Technical bulletins page.
  • What spacing/distance is needed for hangers/supports?

    Hanger spacing depends on the size of the pipe and on the intended temperature of the fluid in the pipe. The spacing will never be less than 32 inches, and will typically be at least 4 feet depending on local code requirements. On larger sizes and lower fluid temperatures, the spacing can be wider. The spacing can be found on page 4.04 of the Design & Planning Guide or on the website.

    Increased spacing (reduced hangers) can be achieved by use of the Walraven BIS pipe reinforcement. For more information, take a look at the Technical bulletins page.

  • How many tools will a contractor need?

    Each heating iron can only perform one connection at a time, but a skilled installer may be able to use several tools simultaneously. Therefore, it is important to have tools that reflect the number of installers who will be working on a project, as well as their skill and build strategy.

    For socket fusion, it best to have at least one iron per fusing installer, but it is a good practice to have extra irons on hand. Jigs and bench-style machines help speed the process on 2”-4” connections. For butt welded connections, 50-70% of a machine’s time is spent in cooldown phase, which would allow the fusion team to perform another connection if they have a second machine. However, the exact number and configuration of tools depends on many factors and should be carefully considered when planning an installation. Take a look at the Find a Rep and Training pages for more assistance.

  • How does aquatherm pipe transition to other systems?
    aquatherm has three main forms of transitions: threaded connections, flanges and PEX adapters. Flanges are available from 1” (32 mm) through 24” (630 mm). Threaded connections are available from ½” (20 mm) through 4” (125mm). There are also adapters for connecting to PEX (crimp and expansion) from ½” (20 mm) through 1” (32mm), and copper stub-outs.
  • How do the labor times using aquatherm piping compare to other products?
    The labor times on PP-R are comparable to the labor on other plastic systems (e.g. solvent cement) or copper press fittings in small sizes and butt-fused HDPE in large sizes. Installers typically see more savings as they become more familiar and comfortable with heat fusion. Labor savings can be 25-30% or higher, compared with metal piping such as welding steel.
  • How do I repair the pipe or a fitting if it leaks?
    Pipe and fittings properly fused, and that pass the pressure test should never leak unless they are exposed to excessive pressure, temperature or use conditions. Small puncture holes (such as those caused by drywall screws or nails) can be repaired using the repair pin. Larger holes can be repaired by drilling out the hole, fusing in an outlet, and capping off the outlet. Cracks in the pipe or badly leaking fittings will need to be cut out and replaced. Always inspect your pipe interior and exterior for cracks and your fittings for a proper seal (insertion depth mark and the double bead of material at the fusion joint) to avoid problems with leaks.
  • What training does an installer need to work with aquatherm pipe?
    Plumbers and pipe fitters who are installing aquatherm pipe need to be trained by an aquatherm Trained Professional (ATP). Installations done by untrained installers cannot qualify for the warranty. aquatherm Academy courses help supplement the skills plumbers or pipe fitters learned in their apprentice program and over the course of their career by focusing on heat fusion techniques and aquatherm-specific installation topics. There are courses available for each type of fusion, and successful completion will quickly save days of time on the jobsite.
    For more information, visit the aquatherm training page.
  • Can the pipe be buried without thrust blocking?
    The fusion joining process creates a continuous pipe section and does not need thrust blocking at the joints. Anchors may still be necessary where buried pipe enters a building foundation or other locations to minimize pipe movement.
  • Are dielectric unions required with aquatherm pipe?
    aquatherm pipes are non-metallic, as are most of the fittings, so no dielectric unions are required. However, if an aquatherm fitting with metal threads is being connected to a dissimilar metal (e.g. aquatherm brass to steel, or aquatherm stainless steel to copper), then a dielectric fitting should be used just as it would be for any other dissimilar metal joint connection.

Material Properties

  • What is the thermal expansion compared to copper or steel?
    The thermal expansion for faser (MF) pipe is approximately double that of copper or steel, whereas other plastics, or PP without the faser layer, can be as much as 5 to 10 times that of copper or steel. So, while the faser layer does not reduce the expansion to be equal to metal pipe, it is much closer and as a result will require much less expansion compensation (e.g. loops, offsets, expansion joints, etc).
  • What is the friction factor or Hazen-Williams coefficient, and how does it compare to other materials?
    The Hazen-Williams coefficient for polypropylene pipe is 150. This coefficient is used with the Hazen-Williams equation for friction loss calculation in pipes. The higher the factor, the lower amount of friction loss there will be in the pipe system. In most cases aquatherm pipe has a higher Hazen-Williams coefficient than metal pipe when installed, and this factor won’t decrease over the lifetime of the system as it does with metal piping.
  • What is the vacuum rating for the pipe?
    The pipe is suitable for industrial vacuum lines (29.9 inches Hg or 760 mm Hg), but is not intended for ultra-high vacuum.
  • What is the chemical makeup of the pipe?
    aquatherm pipes and fittings are made entirely from the Fusiolen resin. Fusiolen is 97% pure polypropylene random, with the remaining 3% being a PP-R masterbatch which includes color pigments and stabilizers.
  • What chemicals are safe to use with aquatherm pipe?
    Polypropylene is non-reactive with many chemicals, but chemical compatibility also depends on concentration and temperature. There is a chemical resistance guide available on which includes many, but certainly not all chemicals. The easiest way to find out if aquatherm pipe is suitable for use with a certain chemical is to submit a chemical inquiry form either online or by email. aquatherm can confirm compatibility and return a written verification usually within 24-48 hours. The form can be found online, here.
  • What are the pressure and temperature ratings of the pipe?
    Working pressures and temperatures for aquatherm pipe can be found in the Design & Planning Guide and on the website.
  • Is aquatherm pipe affected by corrosion or scaling?
    Polypropylene will not corrode and is not affected by scaling, the way many other materials are. It also does not support microbiological growth. Information on pipe longevity can be found in the aquatherm Design and Planning Guide.
  • How much noise does the pipe generate?
    aquatherm pipes are much quieter than metal pipe and tend to dampen sounds rather than carry them. The wall thickness of the pipe and fittings are heavier than most other plastic piping, and the material modulus is substantially less than metal, thereby reducing the sound transmission when compared to other plastic and metal piping.
  • How is aquatherm pipe affected by thermal expansion?
    aquatherm pipe with multi-layer, faser-composite has its linear expansion reduced by at least 75% when compared to standard polypropylene and other plastic piping materials. Detailed charts can be found in the aquatherm Design & Planning Guide.
  • How does the pipe stand up to being frozen?

    aquatherm piping is considered to be freeze‐tolerant, meaning that it normally will not rupture if accidentally allowed to freeze provided the pipe can expand with the freezing water.

    However, it is also not intended to be installed in a location where it would be subjected to repeated freeze/thaw cycles. Antifreeze measures should be taken if the pipe is expected to be subjected to freezing conditions repeatedly.

  • How does the pipe hold up to seismic activity?
    The heat fusion process gives the actual point of connection the same properties as the pipe and the joint, eliminating systematic weakness. After actual earthquake events, the pipe has been found to perform as well or better than metal piping in the same buildings.
  • Does aquatherm pipe have an oxygen barrier?
    Standard aquatherm pipe does not have an oxygen barrier, as oxygen permeation is very low and not found to cause any problems. In most applications, it will not affect the pipe if oxygen removal or treatment is added to protect the mechanical equipment. Submitting a chemical inquiry form can verify the suitability of the treatment. See this Technical Bulletin for more information.
  • Can the pipe be damaged by sunlight?
    Over an extended period of time, regular exposure to UV radiation will discolor the pipe and will weaken its physical integrity. The pipe can be stored outside unprotected for up to 6 months. The factory-issued bags that the pipe comes in will protect it from UV damage and should remain in place to cover the pipe until the pipe is ready to be installed.
    The pipe may be protected by either a permanent wrap or insulation, or by using UV protective paint. For more information on compatible products, see this page.

Fire Hazards

  • When the bare pipe burns, is the smoke toxic?
    The aquatherm piping is combustible and will burn in a fully developed fire. The combustion products are carbon dioxide and steam/water. Smoke toxicity testing has been done on the piping and has confirmed not only that the smoke meets the most stringent toxicity requirements, but also that it consists of carbon dioxide and water, with a few other constituents at trace levels well below indoor air quality guidelines and any smoke toxicity concerns.
  • Does the piping meet flame/smoke requirements for use in plenum spaces?
    aquatherm by itself will not meet the flame/smoke requirements for use in a plenum space. ASTM E84 in the US and CAN/ULC S-102.2 in Canada require a flame spread index lower than 25 and a smoke development index lower than 50. According to the IMC and UMC building codes, combustible materials that are completely enclosed in a fire rated material may be used. aquatherm piping with the appropriate insulation wrap is available as a listed system complying with the 25/50 plenum requirements of the mechanical codes.
  • What kinds of fire-stopping does aquatherm pipe require?
    As with any other piping material that penetrates a fire barrier, the aquatherm pipe must be installed with an approved firestop system. The required ratings and listings will depend on the specific type of fire barrier being penetrated. Firestopping systems are available for use with aquatherm piping in many common types of floor/ceiling and wall constructions. The listings are the responsibility of the firestop manufacturers, who should be consulted on any specific construction details and the acceptable use of their products with aquatherm piping. A listing of firestop manufacturers that have products compatible with aquatherm piping is found on the website.
  • Does aquatherm pipe still require insulation?

    PP-R has a natural insulation value, which can allow for a system to use less insulation than it would have with metal pipes or even other plastics. However, in some applications, insulation will still be required. It is up to the engineer on the project to determine how much insulation will be installed and where. Unless an area is exceptionally humid, aquatherm recommends not insulating domestic cold water piping.

    aquatherm pipe should be installed with insulation following the same ASHRAE standards as steel or copper. In hot water applications it is sometimes possible to leave the fittings uninsulated as the pipe has a natural R value of 1.4 per inch of material. The overall heat loss with the fittings uninsulated in some cases may be equal or less than insulated steel or copper.

Product Availability

  • What lengths does the pipe come in?
    All aquatherm pipe comes in 19 ft (5.8 meter) lengths. However, some pipe sizes, particularly those 4” and under, may come in 13 ft (4 meter) lengths as inventory is transitioned to 19 ft.
  • What dimensions does the pipe come in?
    aquatherm piping systems are manufactured based on metric OD. To make them easier to use, aquatherm has converted the pipes into imperial sizes based on nominal ID. green and lilac are available in sizes from 1/2″ to 18″ and blue is available from 1/2″ to 24″.
  • What is the availability of the pipe?
    aquatherm is available at local piping supply houses across North America. aquatherm works with several distributors in each major market to provide material, training, and support, including same-day pick-ups on inventoried items. These distributors are supplied through the aquatherm Logistics Center in Utah, which carries 6 months’ worth of inventory for North America. A map of the stocking distributor locations can be found on the aquatherm website.
  • What applications is green approved for?
    aquatherm green is approved for all potable water applications, food-grade applications, and NFPA 13D multi-purpose sprinkler systems.
  • What applications is blue approved for?
    aquatherm blue is approved for any non-steam mechanical applications, such as hydronic heating and cooling distribution and condenser water. It is also suitable for compressed air and many industrial/chemical applications.


  • Can I use aquatherm piping for food processing applications?
    aquatherm green has the NSF 51 certification which is the standard used to determine if a material is listed as “Food Grade”. Green pipe is acceptable for direct food contact, or for use as process water or plumbing piping in food processing areas.
  • Can the pipe be used in RO/DI systems?
    aquatherm pipe is a great option for use with RO/DI water systems. aquatherm pipe is used regularly with ASTM type II and III water systems which are the most common RO/DI water systems for labs and other uses. aquatherm pipe has also been tested with up to 18 mega-ohm (ultra-pure) ASTM type I water. At this purity level there may be extremely low level chemicals present. For ultra-pure applications, consult with the aquatherm Engineering Department.
  • If the pipe provides a thermal barrier, then how can it be used in the black panels or radiant and geothermal loops where heat conduction is necessary?
    When aquatherm tubing or smaller diameter pipe is used, the wall thickness is thin enough that the thermal barrier is insignificant. The aquatherm Black panels use rectangular tubes to increase the radiant surface area. These advantages allow PP-R to be used for radiant and geothermal applications more effectively.
  • Is the pipe approved for medical gases?
    At this time, aquatherm pipe is not approved for use with medical gases.
  • Is the pipe approved for compressed air?
    Yes, aquatherm pipe is suitable for use as compressed air piping. Please note that the air must be cooled to at or below the rated temperature before coming in contact with the aquatherm pipe.
  • How do the costs of aquatherm compare to other systems?
    aquatherm piping systems have a total installed cost that is competitive with traditional metal systems. The exact level of savings is dependent upon the market price of the metal pipe and the experience level of the installers. Contact your local rep or distributor for material pricing. You can also create an estimated material and labor cost using the aquatherm Quick Check Estimator.
  • Can the pipe be used for slurry applications?
    aquatherm pipe is extremely abrasion-resistant and is suitable for slurry applications. However, the exact suitability will depend on the type of slurry being conveyed and varies with each application. The engineer should submit a chemical compatibility form to the aquatherm Engineering Department. The form can be found in the aquatherm Design and Planning Guide or online at
  • Can the pipe be used for natural gas?
    Most codes do not allow any plastic pipe to be used inside a building for transporting flammable gases. The codes for underground transmission currently only allow polyethylene and polyamide.
  • Can the pipe be used for ground-source heating and cooling?
    aquatherm piping systems are excellent for ground-source energy systems. PP-R and PP-RCT can be direct-buried and are not affected by soil. The pipe can also go from outside the building to inside the building without any transitions. aquatherm blue pipe is listed in accordance with NSF 358-2 for geothermal piping systems.
  • Can the pipe be used for drainage applications?
    aquatherm does not currently manufacture gravity-flow fittings for drainage applications. However, the pipe may be used for drainage applications if gravity flow fittings are not required.
  • Can aquatherm piping be used with copper in a heating system?
    Yes, aquatherm blue pipe is a great choice for heating systems regardless of the other metallic (copper, steel) components present in the system. aquatherm has published some information about having copper with aquatherm green pipe in domestic hot water recirculating (DHWR) systems, but that does not apply to heating loops. DHWR systems are continuously replenished with fresh chlorinated water. Closed loop heating systems demand very little make-up water. The water must be continuously replenished with new chlorine for there to be a concern. Additionally, free copper ions must be replenished in the water from corrosion/erosion of the copper components, occurring due to excessive velocity or corrosive water chemistry (no corrosion inhibitor).

    In a heating system loop, neither chlorine nor copper ion replenishment would be occurring. The fresh water make-up is a small percentage of the system volume over long periods of time. The small amount of chlorine introduced is dissipated very quickly so there is not any long-term continuous exposure to high chlorine levels.
    Most heating systems will also incorporate corrosion inhibitors when necessary to protect the steel and copper components from aggressive water chemistry. Systems and equipment design and operation will normally ensure the water velocity in the piping and boiler will not result in erosion/corrosion of the copper components.

    For information regarding the use of copper in chlorinated domestic hot water systems, please refer to aquatherm Technical Bulletin 201207C – AQTTB and the TechTV video which can be found at
    As noted in the bulletin and video, the potential for this type of oxidative degradation of the polypropylene piping as well as other plastic and elastomeric products requires the continuous combination of chlorine, copper and heat over an extended period of time. While a heating system does provide the temperature aspect, it does not provide the continuous copper + chlorine necessary to degrade the plastics and elastomers in the system.


  • Can the scrap material be recycled, and is anyone actually doing this?
    Scrap material can be recycled, and this has been done with scrap material at aquatherm. The scrap material is not used to make new pipe, but instead it is recycled to make new products out of polypropylene.


  • Does aquatherm piping comply with the various Red List materials?
    aquatherm piping does comply with the various Red List materials. It does not contain any harmful chemicals such as bis-phenol A (BPA), phthalates, or chlorine, and it emits no VOCs. aquatherm pipe has been used on LEED buildings as well as Living Building Challenge construction.
  • Where is aquatherm pipe approved for use?
    aquatherm piping systems are now listed by NSF, IAPMO and ICC in accordance with U.S. and CSA standards, effectively making them available all across the United States and Canada.
  • Does the pipe have a warranty?
    When aquatherm pipe is installed by an aquatherm trained installer, the installed system is protected under a warranty that covers up to ten years against product defects. The warranty covers replacement aquatherm product, personal injury, or property damage caused by material failure due to manufacturer defect. For more information, visit the warranty page.
  • Does aquatherm pipe qualify for LEED points?
    aquatherm was the first piping system in North America to directly contribute to LEED v4 credits. For more information, take a look at our sustainability page.
  • Does aquatherm qualify for North American Free Trade Agreement (NAFTA) exemptions?
    aquatherm does not qualify for North American Free Trade Agreement (NAFTA), exemptions. However, our products are exempt from the “Buy American Act.” This act is designed to help encourage American purchasing agents to support domestic manufacturers when given the choice of comparable domestic and foreign products. It is not intended to stop consumers from acquiring new products and technology simply because such materials are not manufactured in the United States. aquatherm’s products are unique in their technology and performance and no comparable products are produced in the United States, thus placing them outside the restrictions of this act.


  • Is there concern with tamping, or driving over buried pipe, in regards to its ability to remain undamaged?
    Compaction of sand around the pipe will not harm the pipe and is often necessary to ensure the proper soil conditions for embedment. The burial depth required for safe driving over the pipe is a function of the soil properties and pipe SDR. See the following technical bulletin.
  • Do the stripes on the pipe serve any purpose beyond aesthetics, especially since they aren’t true guides for manifold holes, etc?
    The stripes on the pipe can be used to identify the intended use for the pipe, cold vs hot, and also whether or not the pipe contains the faser (MF) layer.
  • Are the beads of plastic on the inside going to be a problem?
    PP-R is smooth and causes less friction than other, more commonly used materials, so the incidental beads that form during the heat fusion process are not consequential. Larger beads, caused by excessive heating and pressure, may cause restrictions and block the pipe. Blocked connections should be removed and replaced. The installer is responsible for making sure that the connections are clear and unobstructed. This is best achieved by using the proper equipment and following the aquatherm fusion instructions.