Classification, general requirements and test methods

BS EN 17414-1:2020 pdf free.District cooling pipes一Factory made flexible pipe system Part 1: Classification, general requirements and test methods.
The flexibility of the pipe assembly is verified by testing at the minimum bending radius. The manufacturer of the pipe assembly shall declare the minimum installation bending radii for all dimensions produced, related to the central axis of the pipe assembly.
The minimum declared installation bending radius of the pipe assembly according to this document shall not exceed thirty times the outer diameter of the casing.
When bending to the minimum radius, the service pipe and the casing of the pipe assembly shall not break.
The ovality of the casing shall not exceed 30% when tested according to 7.2.2.
Cracks in the insulation layer shall not exceed a width of 5 mm when tested according 7.2.3.
NOTE 1 With a crack size below 5 mm, the number of cracks is not relevant for the integrity of the pipe system, because the temperature on the casing will not be influenced.
NOTE 2 The lower the SDR of the service pipe the higher the stress in the insulation.
Centre line deviation of service pipe
The deviation of the service pipe to the centre line shall not exceed 20 % when tested in accordance with 7.2.4.
Resistance to external load Ring stiffness The ring stiffness shall be tested according to EN ISO 9969 where the diameter of the test piece is the inner diameter of the casing determined at the cross section of the pipe assembly. The ring stiffness of the pipe assembly shall be at least 4 kN/m2 and the ring stiffness divided by the creep ratio according to EN ISO 9967 shall be at least 0,8.
Impact resistance The impact resistance shall be tested according to EN ISO 3127. The casing of pipe assemblies and joint casings shall show no cracks when exposed to an impact of 4 J.
NOTE The deformation of buried pipes with and without traffic load can be calculated according to EN 1295-1.
Thermal insulation Compressive creep The compressive creep shall be tested in accordance with 7.3. The thermal insulation shall not be
compressed by more than 10 %.
Water absorption at elevated temperatures
The water absorption shall not exceed the limit defined in Table 5 for the test option selected.
For test option A, the water absorption shall be tested in accordance with the test procedure in EN 17415-1.
The manufacturer shall declare a reference density in kg/rn3 for the pipe assemblies produced. The reference density may differ between different dimensions. The production shall follow this declared density with a tolerance of± 15 %.
The measurement of the density shall be done in accordance with EN 17415-1.
Non bonded system
The manufacturer shall declare a reference density in kg/rn3 for the pipe assemblies produced. The reference density could differ between different dimensions. The production shall follow this declared density with a tolerance of ± 15%.
The measurement of the density shall be done in accordance with EN ISO 845.
Casings shall be made of a material containing carbon black to the amount of (2,0 to 2,5) % by mass.
The carbon black content shall be determined in accordance with ISO 6964.
Alternatively, after an exposure of the pipe assembly to an energy of 3,5 GJ/m2 in accordance with EN ISO 16871, the requirements of Clauses 6.2 and 6.3 shall be met.
NOTE The IJV stability requirement is for storage purposes, only.
Thermal stability of the material
The oxidation induction time of the material to be used for the casing shall be at least 20 minutes at 210°C when tested in accordance with EN ISO 11357-6.
The time for the stress crack resistance of PE-HD materials used for the casing shall be at least 100 hours when tested at 4 MPa and 80°C in accordance to ISO 16770.
NOTE The test can be carried out on specimens prepared by compression moulding, injection moulding or extrusion from the same raw material as being used for the production of the casing.
PE-LD and PE-LLD materials used for the casing shall not exceed a failure rate F20 when tested for 1 000 hours in accordance with EN 60811-406:2012, procedure B.
Use of rework material
If rework material Is used, only clean, rework material generated from the manufacturer’s own production that does not include any PU insulation material, shall be used.
Surveillance systems
If measuring elements for surveillance systems are being installed in flexible pipe systems, all elements installed and the total installation in pipe systems shall comply with the requirements of EN 14419.
Test methods
Guidelines for testing frequencies and responsibilities are given in Annex D.
The test shall be performed on a straight length of pipe assembly, taken directly after the production. The pipe assembly shall be conditioned for 24 h at room temperature.
After conditioning, the pipe assembly shall be fixed onto a bending rig according to Figure 1. In addition, twin pipes shall be bent in a way that both service pipes will have the same bending radius, see Figure 2.
Whilst still fixed in the test rig according to Figure 1, detection windows shall be formed by removing the casing (e.g. milling, cutting) as shown in Figure 3. The machining of the windows shall not influence cracking in the thermal insulation. Depending on the pipe dimension and/or the casing design, two,three or four detection windows could be required. The windows shall have a size as shown in Figure 3.
The measurement of the cracks shall be carried out using a calliper.
Deviation of service pipe
One pipe assembly of the product range shall be taken.
In case of non-bonded pipe assembly the service pipe ends shall be fixed.
In case of spacers being present, the measuring point according to Figure 4 shall be in the middle of two adjacent spacers.
After bending according Figure 1 the deviation of the service pipe shall be measured.
This shall be carried out by drilling a hole in the casing In the middle of the bend at 45° (see Figure 4). The insulation shall be removed (e.g. by drilling cutter) without damaging the service pipe.
The test procedure for the compressive creep at maximum operating temperature of the insulation material shall be carried out in a similar way to EN 1606 (respectively EN 1605). In addition to these tests the following changes/additions in testing are standardized in order to reflect the special situation of insulation procedures for flexible pipe systems.
NOTE Table 6 and the test are based on the “Findley equation” (see EN 1606).
The traceability of the logarithmic coherence and the adequate verification of the test should be shown by calculation (with the squared factor for accuracy of determination larger than 0,9).
The compressive creep of specimens under pressure is tested by measuring the increase of deformation of a test specimen under a constant pressure load and defined conditions respectively temperature. humidity and time.
Plate for heating purposes (for heating up one side of the test specimens forming part of the pressure apparatus): The heated plate shall provide an equally distributed temperature at the surface of the heating plate and produce a heat flow vertical to the plate. The temperature shall be measured with an accuracy of ± 0,5 K.
Pressure apparatus: Consists of two horizontal plates with one being able to tilt in the plane in order to apply an even compressive load on the entire surface of the specimen in a vertical direction. It shall be ensured that the plates are able to withstand the test loads without deformation, so that the load during the test can vary by not more than ± S %.
Measuring equipment: Instrument for measuring the distance between both plates, i.e. the deformation of the specimen measured to within 0.01 mm.
The apparatus is shown in Figure 5.BS EN 17414-1 pdf download.Classification, general requirements and test methods