BS EN 253:2009 pdf download

BS EN 253:2009 pdf download.District heating pipes— Preinsulated bonded pipe systems for directly buried hot water networks— Pipe assembly of steel service pipe,polyurethane thermalin sulation and out ercasing of polyethylene.
In the middle & the test samples a notch shall be produced perpendicular to the axis in all four sides in the same cross section,
Due to casing rounding the produced notch may have an uneven depth around the sample, but the notch depth and posAtlon shall be chosen such that no part of the sample cross section Is left unnotched.
The number of samples shall be four.
The test solution shall be water containing 2,0 % tenside.
The tenside shall be nonylphenol polyglycoIether with the same effect as the tenside with the trade name ‘Arkopal N 100”.
The temperature shall be 80 C.
The test load shall be 4.0 Nimm2.
5.3 Polyurethane rigId foam Insulation (PUR)
5.3.1 Composition
The MDI-lndex shall be calculated from the manufacturers production data and be recorded.
5.3.2 Voids and bubbles
Voids and bubbles shall be determined on cross sections of the insulation matenal.
Minimum 1,5 m from the foam end, 5 circumferential cuts through the casing and the insulation shall be made with a distance of 100 mm including a total of 400 mm casing
The four 100 mm flngs of casing and insulation shall be removed one by one and the five cross section surfaces inspected for voids and bubbles.
All voids larger than 6 mm in any direction shall be measured in 2 directions perpendicular to each other, and the product of the 2 measurements shall be defined as the area of the void.
Voids smaler than 6 mm shall be neglected.
The addition of the area of all the voids shall be expressed as a percentage of the total Inspected area,
5.3.3 Compressive strength
The compressive strength in a radial direction shall be tested in accordance with ISO 844.
The test specimen shall be In accordance with 5.1.2.4.
The test result shall be determined as an average value of 3 measurements.
5.4 Pipe assembly
5.4.1 AxIal shear strength
5.4.1.1 Test specimen
The test specimen shall be a length of pipe assembly equal to 2.5 tImes the thickness of the Insulation but not less than 200 mm. The test specimen shall be cut square to the axis of the pipe and be taken In accordance with 5.1.2.2 and in the middle of the pipe.
5.4.4 Thermal conductivity in unaged condition
The thermal conductivity (A) shall be determined in accordance with EN ISO 8497:1996 and Annex F.
The thermal conductivity shall be determined using a service pipe temperature of (80 ± 10) ‘C. For type test, the determination of thermal conductivity shall be performed on pope samples (5 1) weeks after production The density and cell size shall be measured in accordance with EN 489, The composition & the gas in the cells of the insulation shall be measured according to the Chalmers method21 for analysing the gas phase in polyurethane foam,
5.4.5 Thermal conductivity at artificially aged condition
Before the ageing of me pipe assembly the ends of the foam shall be adequately sealed to prevent gas diffusion. The ageing of the whole pipe assembly shall be performed at 90 ± 1 C dunng 150 days. The test shall be performed ii accordance with 5.4.4 on the steel pipe dimension DN 50 in 125 mm casing. The laboratory shall prove the sealings to prevent gas diffusion by analysing the composition of the gas In the cells of the insulation.
5.4.6 Impact resistance
A test specimen of the pope assembly with a length of at least 5 times the outside diameter of the casing shall be tested in accordance with ISO 3127 at a temperature of —20 ‘C. The falling weight shall have a mass of 3,0 kg, a hemispherical strikiog surface of 25 mm diameter and be dropped from a height of 2 000 mm.
Alter having drawn the equidistant hoes on the test specimen in accordance with Table 3 of ISO 3127:1994, the test specimen shall be conditioned at a temperature of (-20± 1) C for not less than 3 h before testing. The test shall commence within lOs of removal from the conditioning apparatus and shall be performed as fast as possible.
5.4.7 Long term creep resistance and modulus at 140 °C
The test specimen shall be taken from a length of a pipe assembly with the dimensions 60.31125 mm and be taken ii accordance with 5.1.2.2 and in the middle of the pipe.
One test specimen consists of one test part, A, and two insulation pans, B, one at each end. The test pan shall have a length of 100 mm. The insulation parts shaM be made of 50 mm of the original insulation and RE-casing and separated from the test part by two cuts through the RE-casing and the insulation to the steel pipe. The cuts shall be made perpendicular to the axis of the symmetry of the service pipe. See Figure 4
The test specimen shall be supported at both ends direct beside the insulation parts.
The thickness of the foam shall be measured at a temperature of (23 ± 2) ‘C and before heating of the pipe is started.
The test shall be carried out with the service pipe kept at a temperature of (140 ±2) C. This temperature shall be maintained for 500 h before applying the force.