Pex FAQ   What is Pex? PEX is cross-linked polyethylene. Through one of several available processes, links between polyethylene macro-molecules are formed to create essentially one large molecule of polyethylene. This three-dimensional molecule is more resistant to temperature extremes, chemical attack and creep deformation which makes PEX ideal for use in hot water applications. Typical cross-linking levels in pipe are 65%- 89%. For more than three decades, PEX (or XLPE) has been used extensively in Europe for hot water heating and plumbing applications. How is Pex Made? The process starts with medium to high density polyethylene (MDPE or HDPE) resin. In some of the cross-linking methods, chemicals are added to the base resin which, either during extrusion or in a post-extrusion process, create the molecular cross-links through chemical reaction. These chemical methods can be compared to the vulcanization of rubber. Another method, radiation (nuclear or electron beam), uses high energy irradiation of the extruded pipe to form the molecular links. Finished properties of cross-linked material from these commercial methods are very similar. What cross-linking method is used to make Vanex PEX? Vanguard uses the silane method of chemical cross-linking. This process uses HDPE resin with additives that react when the extruded pipe is exposed to heat and moisture. The chemical reaction stops when cross-linking reaches 70-80%. Even with further exposure, no additional reaction will take place. Vanex PEX is tested to check the degree of cross-link before it leaves the factory. What about the chemicals used in cross-linking Vanex? Are they harmful? All of the chemical additives used in making Vanex are depleted during the cross-linking process. NSF International (formerly the National Sanitation Foundation) has tested Vanex tubing to Standard 61 (Health Effects) and found it safe for use in potable water systems. What sizes is Vanex available in? Vanguards Vanex PEX tubing is made in 3/8", 1/2", 5/8”, 3/4" and 1" sizes. The tubing is copper tube size, meaning that the actual outside diameter of the PEX is the same nominal size of copper tubing. Vanex has a wall thickness corresponding to SDR9 (Standard Dimension Ratio 9) meaning that the wall thickness is 1/9th of the outside diameter and is proportionate for each size maintaining the same pressure ratings for all sizes. What about freeze-break resistance? Vanex PEX will stretch slightly to accommodate the expansion of frozen water, then return to its original size when the water thaws. This memory is a feature of cross-linked material, giving it thermo-elastic behavior. Although freeze-break resistant, no pipe is freeze-break proof under all circumstances. Insulation of plumbing pipes as required by local codes is still recommended. What about flexibility and fewer fittings for changes in direction? Vanex is flexible and requires fewer fittings to install since most changes in direction can be accomplished without the need for elbows. Vanex is simply curved around obstructions unlike rigid piping materials. Compared to branch and main plumbing systems with rigid piping, a Vanex PEX system uses only about 1/2 of the fittings. What about the use temperatures and pressures ratings? Vanex PEX is rated for 100 psi @ 180° F and 160 psi @ 73° F. Vanex PEX tubing is manufactured, sampled, tested, marked and third-party-listed in accordance with ASTM standards F876 and F877, and CSA (Canadian Standards Association) standard B137.5. What approvals does Vanex PEX have? Vanex PEX was the first of a very limited number of PEX tubing manufacturers to acquire a third party certification listing with NSF, International for both chlorinated hot and cold potable water plumbing systems and chlorinated recirculating hot water plumbing loops. Vanex PEX is also third party listed for potable water plumbing use by: NSF International, IAPMO (International Association of Plumbing and Mechanical Officials), ICBO (International Conference of Building Officials) Evaluation Service and Warnock Hersey. Also, the PEX material used in the manufacture of Vanex is listed by the PPI (Plastics Pipe Institute). What about code approvals? Is PEX referenced in the plumbing codes? Yes. Currently, PEX manufactured to ASTM F876/F877 is listed in the BOCA National Plumbing Code, the BOCA National Mechanical Code, the Standard Plumbing Code (SBCCI), the CABO One and Two Family Dwelling Code and the International Plumbing Code (IPC) for use in plumbing systems as well as many state and local codes. Before installing Vanex PEX, check with your plumbing official for state or local variances from these national codes. Contact Vanguard for an up to date list of approvals. How can I be assured that Vanex PEX will hold up? Vanex PEX meets or exceeds all of the industry standards established to ensure quality and reliability. Through independent laboratory testing of tens-of-hundreds of pipe samples, test data is developed and analyzed to determine that Vanex PEX will perform. Continual monitoring by Vanguard and several third-party test agencies assures consistently high-quality. What do the letters A, B and C mean when used to describe PEX? The ABC letter designation system is used in Europe to identify the process by which a particular PEX tubing is cross-linked. It is NOT a grading system, but simply an identification system. PE-Xa is cross-linked with the peroxide method, PE-Xb is cross-linked with the silane method (Vanex is silane method) and PE-Xc is cross-linked by electron beam irradiation. What about the CRIMPSERT® fittings systems? The CRIMPSERT fitting system is extremely installation efficient and reliable. The system has a 25 year history of performance in flexible plumbing systems. The system is simple to assemble and requires no glues, solders, torches or lubricants. To make a CRIMPSERT connection, simply: 1) Position the crimp ring and insert the fitting into the tubing 2) Crimp the ring in place with the correct size crimp tool Each size takes its own, specially sized crimp tool to ensure consistent, properly made connections. CRIMPSERT is a gaugeable system allowing checking of the crimp connections for proper crimp size. All CRIMPSERT components and tools meet or exceed the requirements of ASTM standard specification F1807. This assures a consistent fit and compatibility with components from other manufacturers also making fittings to F1807. Can I use Vanex PEX with the MANABLOC® system? Yes, Vanex is ideal for MANABLOC installations. The flexibility of PEX allows one continuous length of tubing from the MANABLOC directly to each fixture. Can I use Vanex PEX in Hydronic Heating Systems? Yes, Vanex PEX is perfectly suited for hydronic heating loops. An oxygen-barrier version of the tubing and a complete line of heating system components are also available.