Pipe Stiffness and Burst Pressure Assessment Of Din 250
Report Pe Pipe
Introduction
This report details the determination of pipe stiffness
and burst pressure carried out on a DN 250 RPT Green Pipe
(recycled PE pipe) supplied by RECYCLED PLASTICS TECHNOLOGY
PTY LTD. Two 1 metre lengths and two 800 mm lengths flanged
on one end and sealed on the other end were supplied for the
assessment. The pipes were marked 45kg and 5Okg, and were
mottled green in colour with a coarse texture from the raw
material, which was chopped polyethylene bottle waste.
The following identifications were assigned for the pipe
samples:
- PDA 001019 1 45 kg pipe
- PDA 001019 2 50 kg pipe
Pipe Stiffness Assessment Experiments
300 mm in lengths were prepared from the samples and tested
in accordance with AS/NZS 1462.22:1997.
The pipe lengths supplied were marked on the outside with
a marking line drawn parallel to the pipe longitudinal axis
at 120 degrees apart around the circumference. Each mark was
identified as A, B and C respectively. Each specimen was then
cut to a length of 300 ± 10 mm and measurements taken
for internal diameter (ID) and specimen length at different
positions located around the circumference of the pipe specimen.
The specimens were then placed between two steel loading plates
and deflected at a rate of 20 ± 2 mm/min until the
deflection corresponding to 5 % of the ID was reached at each
of the three marked (fines. Load and displacement measurements
were continuously recorded through out the test.
Results:
The deflection of the pipe specimen in each case was taken
to be the movement of the crosshead on the compression testing
machine. Table 1 shows loads at 5% deflection and the calculated
pipe stiffness values for each of the pipe specimens tested.
The pipe stiffness values were calculated in accordance with
AS/NZS 1462.22: 1997, section 8.
Table 1. Deflection results and calculated stiffness values
| Specimen No. |
Pipe length
(mm) |
Average Inside
Diameter (mm) |
Force at 5%
Deflection
(NI300 mm) |
Stiffness at 5%
deflection
(N/m/m) |
| PDA00l019-1 |
298.8 |
247.47 |
1148 |
6162.9 |
| PDA00l019-2 |
298.95 |
242.76 |
1541 |
8427.6 |
Source: CSIRO Graham Road (PO Box 56), Hlghett, Victoria
3190, Australia, www.dbce.csiro.au.
Based on this relationship between stiffness and SDR, the
minimum wall thicknesses for pipes of different dimensions
and stiffness classes are presented in Table 2.
Table 2. Wall thickness projections for pipes of different
stiffness classes
| Stiffness |
SDR |
Wall thickness of pipe |
| N/m/m |
SN |
|
OD200 |
Od250 |
OD300 |
OD350 |
| 2000 |
|
40.4 |
4.49 |
6.18 |
7.42 |
8.65 |
| 3000 |
|
37.7 |
5.30 |
6.63 |
7.95 |
9.28 |
| 4000 |
4 |
35.0 |
5.71 |
7.14 |
8.57 |
10.00 |
| 5000 |
|
32.3 |
6.20 |
7.74 |
9.29 |
10.84 |
| 6000 |
6 |
2906 |
6.77 |
8.46 |
10.15 |
11.84 |
| 7000 |
|
26.8 |
7.45 |
9.32 |
11.18 |
13.04 |
| 8000 |
8 |
24.1 |
8.30 |
10.37 |
12.44 |
14.52 |
| 9000 |
|
21.4 |
9.35 |
11.69 |
14.03 |
16.37 |
| 10000 |
10 |
18.7 |
10.72 |
13.40 |
16.07 |
18.75 |
| 11000 |
|
15.9 |
12.55 |
15.68 |
18.82 |
21.96 |
| 12000 |
12 |
13.2 |
15.13 |
18.92 |
22.70 |
26.48 |
| 13000 |
|
10.5 |
19.06 |
23.83 |
28.59 |
33.36 |
| 14000 |
14 |
7.8 |
25.74 |
32.18 |
38.61 |
45.05 |
| 15000 |
|
5.0 |
39.63 |
49.54 |
59.45 |
69.36 |
| 16000 |
16 |
2.3 |
86.10 |
107.82 |
129.14 |
150.67 |
These projections are based on 4 determinations, two of two
of which were based on pipes of indifferent quality in terms
of wall thickness uniformity. Therefore the wail thicknesses
presented in Table 2 should be treated as a guide only, until
more stiffness determinations have been carried out, and accurate
stiffness values are available from production quality pipe
for a range of SDRs.
Conclusion
The 45kg (PDA 001019 1 ) meets the requirement of stiffness
class SN6 and the 5Okg pipe (PDA OOI019 2) meets the requirement
of stiffness class SN8. Based on these results and previous
test results, the wall thickness projections for different
SN classes and for several pipe sizes are presented.
|
Home
