BS EN 253:2009 pdf download.District heatingpipes —Preinsulatedbonded pipe systemsfor directly buriedhot water networks—Pipe assembly ofsteel service pipe, polyurethane thermal insulation and outercasing of polyethylene.
The carbon black shall be finely dispersed in the material. When tested in accordance with 5.2.3, the following requirements shall be met:
Carbon black agglomerates, bubbles, voids or foreign matter shall not exceed 100 pm in diameter, No white or black stripes or smears may occur.
4.3.1.2 Melt mass-flow rat.
The melt mass-flow rate (MFR), en gil0 mm, of black PE matenals used for the manufacturing of casings shall lee within 02 MFR 1,4 gllO men determined In accordance with EN ISO 1133, conditIon T (5kg, 190 ‘C).
Black coloured PE mateflals conforming to 4.3,1.1. which do not differ more than 0.5 gIlO mm ii MFR shall be considered fusible to each other.
Casmgs made & PE materials outside this MFR range of 0.5 gllO mm may be fusion welded provided that the pipe manufacturer has demonstrated fusion compatibility by prepanng a but fusmn joint using the parameters as specified in Annex A of ISO 1 1414:1996.The requirement of fusion compatibility is a ductile failure mode of the joint when tested at 23 ‘C We accordance with ISO 13953.
4.3.1.3 Thermal stability
The thermal stability is determined by oxygen induction time (Or) of the black coloured PE material and shall be at
least 20 mm when tested at 210 C accordWig to EN 728.
4.3.1.4 Use ef rework material
Only clean, not degraded, rework material, generated from the manufacturer’s own production of pipes, shall be used.
4.3.2 Casing properties
4.3.2.1 NomInal outsIde diameter
The nominal outside diameter of the casing should be selected from Table 5.
The actual outside diameter shall be measured in accordance with EN ISO 3126.
4.3.2.2 WaIl thickness
The wall thickness of the casing shall be in accordance with Table 5.
The actual wall thickness shall be measured in accordance with EN ISO 3126.
Carbon black agglomerates, bubbles, voids or foreign matter shall not exceed 100 pm in diameter, No white or black stripes or smears may occur.
4.3.1.2 Melt mass-flow rat.
The melt mass-flow rate (MFR), en gil0 mm, of black PE matenals used for the manufacturing of casings shall lee within 02 MFR 1,4 gllO men determined In accordance with EN ISO 1133, conditIon T (5kg, 190 ‘C).
Black coloured PE mateflals conforming to 4.3,1.1. which do not differ more than 0.5 gIlO mm ii MFR shall be considered fusible to each other.
Casmgs made & PE materials outside this MFR range of 0.5 gllO mm may be fusion welded provided that the pipe manufacturer has demonstrated fusion compatibility by prepanng a but fusmn joint using the parameters as specified in Annex A of ISO 1 1414:1996.The requirement of fusion compatibility is a ductile failure mode of the joint when tested at 23 ‘C We accordance with ISO 13953.
4.3.1.3 Thermal stability
The thermal stability is determined by oxygen induction time (Or) of the black coloured PE material and shall be at
least 20 mm when tested at 210 C accordWig to EN 728.
4.3.1.4 Use ef rework material
Only clean, not degraded, rework material, generated from the manufacturer’s own production of pipes, shall be used.
4.3.2 Casing properties
4.3.2.1 NomInal outsIde diameter
The nominal outside diameter of the casing should be selected from Table 5.
The actual outside diameter shall be measured in accordance with EN ISO 3126.
4.3.2.2 WaIl thickness
The wall thickness of the casing shall be in accordance with Table 5.
The actual wall thickness shall be measured in accordance with EN ISO 3126.
