ISO 21225-2:2018 specifies requirements and test methods for pipes and fittings which are part of plastics piping systems for the trenchless replacement of various underground pipeline networks, underground non-pressure and pressure drainage and sewerage networks and underground water and gas supply networks, by means of horizontal directional drilling and impact moling.
ISO 21225-2:2018 is applicable to polyethylene (PE) pipes and fittings, as manufactured, as well as to the installed replacement system.
ISO 21225-2:2018 is intended to be used in conjunction with standards applicable for the construction of PE pipeline systems where available.
Regarding manufactured pipes it is applicable to three different PE pipe types:
- PE solid wall single layered pipes (nominal outside diameter, dn), including any identification stripes;
- PE pipes with co-extruded layers on either or both the outside and inside of the pipe (total outside diameter, dn), as specified in Annex A, where all layers have the same MRS rating;
- PE pipes (outside diameter, dn) having a peelable, contiguous, thermoplastics additional layer on the outside of the pipe ("coated pipe"), see Annex A.
In addition, ISO 21225-2:2018 is applicable to:
- jointing of pipe lengths by means of butt fusion joint to form continuous strings prior to installation;
- fabricated and injection-moulded fittings made of PE.
Pipes made from other plastics, e.g. polypropylene (PP) are outside the scope of this document.
ISO 21225-2:2018 is not applicable to push-fit jointed discrete pipes assembled as part of the trenchless installation process.