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1.1 This practice describes procedures for making butt fusion joints with crosslinkable polyethylene (CX-PE) pipe and tubing2 which is less than 30 % crosslinked at the time of joining. This practice shall not be applied to crosslinked products, that is PEX pipe or tubing or to CX-PE after commissioning3 (commissioning transitions CX-PE pipe into crosslinked pipe).

1.2 The main difference between this practice and Practice F2620 is that the production date of pipe must be checked prior to butt fusion. Field experiments have indicated that it is best to make heat fused joints before the pipe has aged six months to ensure it has not crosslinked more than 30 % at ambient conditions. (See 7.2.)

1.3 Joints are made by means of butt-fusion joining in, but not limited to, a field environment. Other suitable butt-fusion joining procedures may be available from various sources including pipe and fitting manufacturers. This practice does not claim to address all possible butt-fusion joining procedures and does not prevent the use of qualified procedures developed by other parties that have been proven to produce reliable butt fusion joints.

1.4 The parameters and procedures set forth in this practice are applicable to the butt-fusion joining of CX-PE pipe and tubing. Consult with the manufacturers of CX-PE pipe or tubing to ensure that they approve of the use of this practice for butt-fusion joining of their products. This practice applies to butt fusion of both CX-PE pipe and tubing even when tubing is not explicitly referred to.

1.5 CX-PE pipe or tubing is required to produce sound joints when using the joining procedures described in this practice. Component ends joined in accordance with this practice shall be of the same nominal diameter and wall thickness.

1.6 The ability to join pipe using this practice does not imply that the pipe joined is suitable for any intended use.

1.7 This practice does not purport to address any issues related to the commissioning of a CX-PE system prior to its use. The intention of this standard practice is to set forth requirements for the butt fusion of CX-PE pipe and tubing which when followed are expected to yield durable joints in the said pipe and tubing.

1.8 Only procedures related to butt-fusion joining are covered in this practice. Saddle fusion and socket fusion are not included in this practice.

1.9 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.10 The text of this practice references notes, footnotes, and appendixes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the practice.

1.11 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.12 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

5.1 The procedures described in Section 8 are intended for butt-fusion joining of CX-PE pipe and tubing, using suitable equipment and appropriate environmental control procedures. Appropriate controls are established on the butt-fusion joining process to ensure that the pipe is suitable for joining, that the operator is properly trained, that adequate apparatus and procedures are used, and that the process is protected from environmental extremes. The controls are established by testing butt-fusion joints, operator skills, the apparatus and the procedures used. When this practice is properly implemented, strong pressure and leak-tight joints are produced. When joints made in accordance with this practice are destructively tested, failures are expected to occur outside the fusion-joined area.

5.2 Melt characteristics, average molecular weight and molecular weight distribution are influential factors in establishing suitable fusion parameters, therefore, consider the manufacturers instructions in the use or development of a specific fusion procedure.

5.3 The butt fusion procedures in this practice are suitable for joining CX-PE pipe and tubing that is used in pressure, low pressure, and non-pressure applications. For some applications, qualification of the procedure by testing joints made using the procedure in accordance with regulations from the authority having jurisdiction are required.

5.4 This butt-fusion joining practice shall only be used to join pipe or tubing made from compatible CX-PE compounds and meeting the same specification dimensions for outside diameter and wall.