The real meaning of part 5 in the system standards for drinking water and fuel gases distribution

16 May 2023

In the world of polyethylene (PE) piping systems we can found what, the experts, calls: “System Standard”. This term is used to individuate a series of different standards (or norms) under the same identification number (e.g. EN 12201, EN 1555, ISO 4427 or ISO 4437) that, taken all together, specifies the whole technical characteristics of all products concerned.  The concept is that any product (PE pipes or fittings or valves) which satisfy the dimensional and performance requirements, as requested by the specific product standards (eg. for fittings: EN 12201-3 or EN 1555-3 or ISO 4427-3 or ISO 4437-3) shall be able to be connected successfully to others, which bear the same technical characteristics and so, in parts 2, 3 and 4 (of the “system standards”), there is the specification (in the clause related to: “performance requirements”) that the joints “shall conform to the requirements given in part 5”. The Part 5 of the different “system standards” were developed with the clear intention to provide a means to the manufactures of PE pipes, fittings, or valves to demonstrate that their products are easy to connect to other piping system components, either in the case of normal and extreme ambient temperatures, and are able to create durable joints.

Practically, the system approach in these standard series means that any pipe, fitting, or other component is suitable for jointing to each other, providing they fulfil the requirements of the relevant part of the standard. It is not necessary or intended to test each pipe with each fitting brand in the market. The tests provided in parts 5 demonstrate joint performance for the piping system.

All designers involved in the design of a PE piping system should verify (or requiring) that the product: pipe, fitting or valve is able to origin joints conform to the part 5 of the system standard to which they refer to in their technical documentation.

Plastitalia S.p.A as manufacturer of PE fitting is the first company on the market that has invested and obtained a third part certification to the parts 5 of the system standards which witnesses the jointing ability of our electrofusion fittings. Another way to underpin that piping systems jointed by means of our fittings are “made for future generations”.


For the safety of your investments ask for products that come with a certificate of conformity to parts 5 and not only to parts 3.