BS 1555-1:2021 pdf download – Plastics piping systems for the supply of gaseous fuels — Polyethylene (PE) Part 1: General
5.1 Material of the components The pipes, fittings and valves shall be made of polyethylene compound conforming to this document.
This document includes materials classified PE 80 and PE 100. In addition another type of PE 100 designated PE 100-RC with enhanced resistance to slow crack growth is included in this document, see Annex A for additional information. The material described in this document is a compound which shall be supplied in the form of granules, suitable for the production of pipes complying with EN 1555-2, fittings complying with EN 1555-3, or valves complying with EN 1555-4.
5.2.1 Additives and pigments
The compound shall be made by the material producer by adding to the polyethylene base polymer only those additives, pigments (e.g. carbon black) necessary for the manufacture of pipes, fittings and valves conforming to EN 1555-2:2021, EN 1555-3:2021 or EN 1555-4:2021, as applicable, and for their fusibility, storage and use. The carbon black used in the production of black compound shall have an average (primary) particle size of 10 nm to 25 nm. All additives and pigments shall be uniformly dispersed.
5.2.2 Colour The colour of the compound shall be yellow (PE 80), orange (PE 100 and PE 100-RC), or black (PE 80, PE 100 and PE 100-RC).
188.8.131.52 Characteristics of the compound in the form of granules The compound in the form of granules used for the manufacture of pipes, fittings and valves shall have characteristics conforming to the requirements given in Table 1.
5.3 Fusion compatibility
5.3.1 The compounds conforming to Table 1 shall be fusible. The compound manufacturer shall check that the requirement for the failure mode in a tensile test given in Table 2 is fulfilled for a butt fusion joint. The test sample shall be prepared by using the parameters specified in Annex A of ISO 11414:2009, at an ambient temperature of (23 ± 2) °C from pipes both manufactured from that compound. This shall be demonstrated by the compound manufacturer for each compound of his own product range.
For 0,15 ≤ MFR < 0,20 compounds, fusion compatibility of pipes with diameter > 200 mm and wall thickness > 20 mm shall be investigated to confirm compatibility. If electrofusion is used, appropriate testing should be carried out to verify the fusion capability of such pipes.
5.3.2 Compounds conforming to Table 1 are considered fusible to each other. If requested, the compound manufacturer shall demonstrate this by checking that the requirement for the failure mode in a tensile test given in Table 2 is fulfilled for a butt fusion joint prepared by using the parameters as specified in ISO 11414:2009, Annex A at an ambient temperature of (23 ± 2) °C from two pipes manufactured from the compounds from his own range covered by this request.
5.4 Classification and designation Compounds shall be designated by the type of PE material. The minimum required strength (MRS) shall conform to Table 3 when tested in the form of pipe.
The compound shall be evaluated in accordance with EN ISO 9080 from pressure tests on pipe in accordance with EN ISO 1167-1:2006 and EN ISO 1167-2 performed on pipe at least at three temperatures, where the first temperature is 20 °C, and the second temperature is 80 °C, and a third temperature is free between 30 °C and 70 °C, to find the σ LPL . The MRS-value shall be derived from the σ LPL and the compound shall be classified by the compound producer in accordance with EN ISO 12162. At 80 °C, there shall be no knee detected in the regression curve at a time of < 5 000 h. The conformity of the designation of the compound to the classification given in Table 3 shall be demonstrated by the compound producer. Where fittings are manufactured from the same compound as pipes, then the material classification shall be the same as for pipes. For the classification of a compound intended only for the manufacture of fittings, test pieces in the form of extruded pipe made from the compound shall be used.
5.5 Design coefficient and design stress The design coefficient, C, for pipes, fittings and valves for the supply of gaseous fuels shall be greater or equal to 2. The maximum value for the design stress, σ s , shall be 4,0 MPa for PE 80, and 5,0 MPa for PE 100 and PE 100-RC materials.